MSK

Question 1

• Provide examples of synarthroses, diarthroses and amphiarthroses

Answer 1

Synarthroses or fibrous joints
are joints where adjacent bones are directly connected by fibrous connective tissue. There is no synovial cavity.
Examples include:
- an interlocking suture line between adjacent bones (e.g. skull). Sutures consists of strong fibrous tissue between skull bones e.g. sagittal suture
- Syndesmoses which consist of a fibrous ligament or membrane connecting bones e.g. interosseous membrane between the radius and ulna (technically amphiarthroses as some degree of motion is permitted)
- Gomphoses which consists of periodontal ligaments tethering teeth onto sockets e.g. roots of teeth in sockets of mandible

Amphiarthroses or cartilaginous joints
can be defined by the presence of cartilage, either hyaline or fibro-, between articulating bones. There is no synovial joint cavity.
- synchrondrosis or primary cartilaginous joints are connected by hyaline cartilage. Some are temporary e.g. epiphyseal plate, first sternocostal joint, or permanent e.g. costochrondral joints. Immovable.
- symphysis or secondary cartilaginous joints are joined by fibrocartilage e.g. pubic symphysis, interbody joints between vertebral bodies and intervertebral discs. Movable.

Synovial or Diarthrodial Joints
are freely movable, but limited by surrounding joint capsule, ligaments and muscles.
Many examples: knee/hinge, shoulder/ball and socket etc

• Types: Hinge, Ball and socket, Saddle (as well as ellipsoid/condyloid, pivot, plane)

Question 2

• Provide an example of a ball-and-socket, hinge, pivot, condyloid, saddle, and plane joint

Answer 2

Question 3

• Describe the function of menisci/labrum/bursae and provide an example of each

Answer 3

Menisci:
pads of fibrocartilage ^[[[Histology Lecture 4]]]. Discs allow bones of different shapes to fit better, thus increasing the joint’s stability

e.g. of knee

Labrum:
a fibrocartilaginous ring which deepens the articular surface of a bone, increasing the surface area available for articulation and thus improving joint stability

e.g. in GH joint

Bursa:
sac-like structures, found between bones and adjacent structures (skin, tendons, muscle ligaments, or fibrous capsules). Bursae work to reduce friction between moving parts

e.g. supra and prepatellar bursae

Question 4

• Distinguish between types of cartilage

Answer 4

• Articular or hyaline cartilage – e.g. found in synovial joints, cartilaginous. Appears blue or glue microscopically
• Fibrocartilage – attaches tendons and ligaments to bone. Appears white microscopically
• Elastic cartilage – auricles ^[think ear and elastic], nose, epiglottis, trachea. Appears yellow.
• Fibroelastic cartilage – intervertebral discs and intraarticular menisci (load bearing and shock absorption). Appears yellow microscopically

Question 5

• Discuss the components of ground substance (PGs and collagen)

Answer 5

Proteoglycans
- Components of the ground substance.
- Secreted by chondrocytes
- Among collagen fibrils
- 15-40% of dry weight
- Hydrophilic - this means it attracts the water within the synovial fluid, giving the cartilage its resilient properties, permitting shock absorption (note in osteoarthritis the cartilage becomes ‘dried out’)
- Core protein plus side chains of glycosaminoglycans
- Chondroitin and keratin sulphate
- Attach to hyaluronic acid filaments (aggregation)

Collagen
- Collagen is produced by fibroblasts, as well as chondroblasts and osteoblasts
- 28 types, 90% is type 1.
- All collagen types are composed of three alpha polypeptide chains arranged like a three stranded rope

• Type 1 - skin, fascia, tendon, ligament, bone. (It is this, within the ground substance of the bone ECM (osteoid) that becomes mineralised)
• Type 2 – all forms of cartilage.
• Type 3 - in association with type 1, found in skin, artery, uterus
• Type 4 - basement membrane
• Type 5- placenta, blood vessels
• Determines the tensile strength of tissues
• Provides a framework
• Limits movement of other tissue components
• Induces platelet aggregation and clot formation
• Regulates hydroxyapatite deposition in bone (Hydroxyapatite deposition on collagen fibres confers hardness. Recall that deposition occurs in the first few days but can take months to complete calcification)

Question 6

• Distinguish ligaments and tendons

Answer 6

Ligament
- Dense collagenous structure linking bone to bone.
- Similar to a tendon (more collagen)
- Rows of fibroblasts within extracellular matrix of mainly type 1 collagen fibres.
- Elastin allows stretch, allowing an extra degree of movement e.g. rotation at knee joint, otherwise known to be a hinge joint (uniaxial motion)
- Deformation curve gives it a crimped appearance
- Function: Prevent excessive movement.
- Injury to the ligament is termed a sprain.

Tendon

• Dense collagenous structure linking muscle to bone.
• Collagen fibrils embedded in ground substance
• A matrix of PGs, GAGs, structural glycoproteins…
• More collagen (65-75% of dry mass) and less ground substance than ligaments.
• 86% type I collagen, some elastin (2% dry mass) ^[less stretchy than ligaments]
• Very linear collagen fibre arrangement - thus no stress strain relationship as with ligaments
• Fibroblasts (tenocytes) in parallel rows between collagen bundles, synthesise collagen, elastin, PGs, and GAGs
• Carries tensile forces. ^[Think Tendon, Think Tension]
• Main injuries: tear or degeneration.
• Tendonopathy not tendonitis.

Question 7

• Describe paratenon, epitenon, enthesis

Answer 7

Paratenon and Epitenon
- Paratenon – loose, areolar connective tissue around tendons.
- Type 1 and 3 collagen fibres, elastic fibrils and synovial cells
- Permits free movement of the tendon against surrounding structures
- Epitenon – fine connective tissue sheath covering the tendon.
- Injury – peritendonitis.

Enthesis
- Attachment of tendon to bone.
- Four zones
1. Tendon or ligament, whose collagen bundles continue into…
2. Fibrocartilage, which separates from…
3. Mineralised fibrocartilage
4. Bone
- Common site of disease in spondyloarthropathies (cause of lower back pain, j.o.interest = sacroiliac)

Question 8

HII

• Discuss the main upper limb muscles (Action, attachments, innervation)

Answer 8

Key upper limb muscles
There are three main muscles that are of high clinical importance.
- deltoid
- attachments: the deltoid has a wide origin (lateral third anterior clavicle, acromion process, spine of scapula posterior border) inserted into deltoid tuberosity of humerus
- movements: abduction of the humerus – although it needs rotator cuff to function correctly (otherwise would simply elevate, rotator cuff holds humeral head down)
- innervation: axillary nerve, supplying it from posterior to anterior ^[susceptible to palsy with dislocation of humeral head as it wraps around it to supply deltoid]
- vascularisation: posterior circumflex humeral artery
- triceps
- features
- three heads: long, lateral, medial
- long: infraglenoid tubercle of the scapula (or inferior glenoid lip)
- lateral: posterior aspect of the humerus, superior to the radial groove (or superior lip)
- medial: posterior aspect of humerus, inferior to the radial groove on the shaft. Medial head is deep.
- attachments: inserts into posterior surface of olecranon process of ulna
- movements: elbow extension
- innervation: radial nerve
- vascularisation: deep brachial artery
- biceps
- features: long head (from glenoid labrum, arises intra-articularly), short head (from coracoid process)
- attachments: inserts into the radial tuberosity
- movements: elbow flexor and supinator
- innervation: musculocutaneous nerve
- vascularisation: muscular branches of brachial artery
- note: long head is highly susceptible to injury as it sits in bicipital groove
- pectoralis major
- attachments: from the chest wall (clavicle and sternocostal) to the lateral lip of the bicipital groove
- movements: adduction and flexion of humerus (also medially rotates the glenohumeral joint). The clavicular head flexes the glenohumeral joint and the sternocostal head extends the glenohumeral joint from the flexed position
- innervation: lateral and medial pectoral nerves supplying the two heads
- vascularisation: several (thoraco-acromial - pectoral branch, internal thoracic artery — perforating branches…)

Question 9

HII

• Discuss the muscles of the forearm, and intrinsic muscles of the hand (as above)

action attachments innervation

Answer 9

go to forearm and hand deck

Question 10

HII

• List and describe the joints of the shoulder

Answer 10

Question 11

HII

• Describe the key ligaments of the shoulder

Answer 11

Two key ligaments is the coracoclavicular ligament, which has a conoid and trapezoid component; and the glenohumeral ligament, whose inferior component is the prime stabiliser of the shoulder joint. A full list is included below:
- glenohumeral ligament: divided into superior middle and inferior. Middle and inferior prevent shoulder dislocation as most dislocations are anterio-inferior. tighten with extremes of movement preventing further translation. inferior glenohumeral ligament is the prime stabiliser of the shoulder
- coracohumeral ligament:
- coracoacromial ligament:
- coracoclavicular ligament:
- acromioclavicular ligament:
- long head of biceps tendon:

Question 12

HII

• Describe the key ligaments of the elbow, and key ligament/s of the wrist and fingers

Answer 12

There are three main ligaments that support the elbow joint: the ulnar collateral ligament, radial collateral ligament and annular ligament.

The medial collateral ligament has three bands:
- anterior (strong)
- posterior (weaker)
- oblique
The MCL is crucial for combatting valgus stress. The anterior band of MCL is especially crucial for this.

The annular ligament runs around the radial head from the anterior and the posterior margin of the radial notch, to approximate the radial head to the radial notch and enclose the radial circumference. It encircles 80% of the radial head and functions to maintain the relationship between the head of the radius and the humerus and ulna.

Function:
- Holding the proximal radius against the ulna as it fits strongly around the radial head,
- It permits for free rotation of radial head as it’s internal surface is lined with cartilage.

Note that the radial is synonymous with the lateral collateral ligament. Similarly the ulnar is synonymous with the medial collateral ligament.

Question 13

• Describe the innervation and vascular supply of the upper and lower limb

Answer 13

Upper limb

Nerves of the upper limb
The major peripheral nerves that innervate the upper limb are the:

• Axillary
• Radial
• Musculocutaneous
• Median
• Ulnar

Innervation of upper limb muscles

• Musculocutaneous nerve: all anterior arm compartment muscles
• Median nerve: anterior forerarm compartment muscles exceptflexor carpi ulnaris muscle andmedial half of flexor digitorum profundus
• Ulnar nerve: intrinsic muscles of the hand, except for the thenar muscles and two lateral lumbrical muscles,
• Radial nerve: posterior arem and forearm compartment muscles
• Axillary nerve: deltoid and teres minor muscles

Sensory innervation of the upper limb

• Musculocutaneous nerve: skin on anterolateral forearm
• Median nerve: skin on palmar surface of the lateral three and one-half digits
• Ulnar nerve: skin on medial one and one-half digits
• Radial nerve: skin on posterior surface of forearm and dorsolateral surface of hand
• Axillary nerve: skin on lateral arm

Blood supply of the upper limb
## Arteries

The major arteries include the:

• Subclavian
• Axillary
• Brachial, continuing axillary
  
  • Radial
  • Ulnar
• Palmar arches

The deep veins accompany the arteries of the same name.

The superficial veins empty into the dorsal venous network on the posterior hand over the metacarpal bones.

The cephalic vein originates from the lateral side of the dorsal venous network and travels through the lateral forearm and arm before emptying into the axillary vein.

The basilic vein originates from the medial side of the dorsal venous network and passes into the dorsomedial aspect of the forearm. It pierces the deep fascia in the middle of the arm to become the axillary vein.

Lower limb
## Blood supply
As the external iliac artery passes under the inguinal ligament, it becomes the femoral artery.

The femoral artery passes through the femoral triangle between the femoral vein and femoral nerve. At the apex of the femoral triangle it enters the adductor canal (deep to the sartorius muscle) and then passes through the adductor hiatus of the adductor magnus muscle where it enters the popliteal fossa and becomes the popliteal artery. The popliteal artery lies deep to the tibial nerve and popliteal vein in the popliteal fossa.

• From the popliteal artery
• Five geniculate branches – middle, and medial and lateral superior and inferior geniculate arteries
• Superiors curve around the femoral condyles proximal to the epicondyles
• Inferiors course around the margins of the tibial plateau, passing under the collateral ligaments
• Anastomoses around the knee joint
• Middle and inferior arteries supply the menisci, the outer ¼ of which are vascular.

Nerve Supply

• Three sources
  
  • Sciatic nerve – branches from tibial and common peroneal nerves
  • Femoral nerves – branches travelling via the vastus muscles
  • Obturator nerve – small nerve from posterior division, accompanies femoral artery to popliteal fossa ^[relevant in paeds: knee looks fine]
    
    • May explain referral of hip pain to the knee
• Popliteal artery is a continuation of the femoral artery
• Below the knee it divides into the anterior and posterior tibial arteries
• The posterior tibial artery follows the course of the tibial nerve and
  supplies the posterior muscles of the leg.
• It passes behind the medial malleolus and passes to the plantar
  aspect of the foot
• Forms the medial and lateral plantar arteries which supply the
  plantar structures
• Below the bifurcation of the popliteal artery the peroneal artery
  arises
• This passes across the back of the interossesos membrane and
  descends on the lateral aspect of the leg to supply the lateral
  muscles
• The bifurcation of the popliteal artery gives rise to the anterior tibial
  artery
• This passes anteriorly between the tibia and fibula across the upper
  margin of the interosseous membrane and courses down the
  anterior surface of this structure.
• It supplies the muscles of the anterior compartment of the leg (TA,
  EHL, EDL)
• Reaches the dorsum of the foot as the dorsalis pedis artery
• Terminal branches are the dorsal metatarsal and dorsal digital
  arteries

Nerve supply
* The main nerve to the lower leg and foot, the tibial nerve is a
continuation of the sciatic nerve.
* It enters the lower leg between the two heads of the gastrocnemius and passes deep to the soleus to enter the posterior compartment of the leg.
* The tibial nerve supplies the gastrocnemius, soleus, and the three muscles whose tendons pass behind the medial malleolus (tibialis posterior, FHL, FDL) – plantar flexors.
* Posterior tibial nerve divides into the medial and lateral plantar
nerve and sends a branch to the calcaneus

• The other division of the sciatic nerve, the common peroneal nerve arises above the knee joint.
• After passing behind the head of the fibula it wraps around the neck of the fibula and divides near here into the superficial and deep peroneal nerves.
• The superficial peroneal nerve descends adjacent to the fibula to supply peroneus longus and brevis (everters of the foot)
• The deep peroneal nerve supplies the dorsiflexors of the ankle
  (anterior compartment – tibialis anterior, extensor digitorum longus, extensor hallucis longus)
• It ends supplying extensor digitorum brevis
• It supplies a small area of sensation between the first two toes on the dorsum of the foot

Question 14

• Identify the key features of the scapula, clavicle, humerus, radius and ulna/pelvis, tibia, fibula (Alternatively label an Xray)

Answer 14

Key features:

Tthe key features of the clavicle are:
- sternal end or the medial end- viewable both superiorly and inferiorly. Note that the sternal end is more flat.
- acromial end or the lateral end- viewable both superiorly and inferiorly. The acromial end is more likely to be dislocated.
- body or shaft
- conoid tubercle
- trapezoid line
- impression for costoclavicular ligament

Scapula
The scapula is a large flat bone.
Key features include:
- Body
- Spine, which terminates in the acromion laterally
- Coracoid process (coracobrachialis, pectoralis minor and short head of biceps originate here)
- Acromion, which is important because deltoid muscle attaches here, and rotator cuff muscles pass underneath. The narrowed subacromial space or downward sloping acromion pinches the cuff during elevation (see below for [[#Rotator cuff (mightily important)]])
- Glenoid cavity, articular surface with humerus
- Subscapular fossa
- Supraspinous fossa
- Infraspinous fossa
- Superior angle
- Inferior angle
- Medial border
- Lateral border

Humerus
is a long bone, and the only bone of the upper arm.
It has several key features, including:
- head
- anatomical neck, and surgical neck: note that these two terms are NOT synonymous. Anatomical neck rings around the articular surface, and separates rough humerus from smooth articular surface. Surgical neck is common site of fracture
- greater and lesser tuberosity. Note that the greater tuberosity is more lateral to the lesser tuberosity when viewed anteriorly. The lesser tuberosity is not visible at all posteriorly.
- supraspinous, infraspinous and teres minor (off rotator cuff) insert onto greater tuberosity
- subscapularis inserts onto lesser tuberosity
- bicipital groove: the long head of the biceps runs through here. Other muscles attach to the lateral lip, medial lip and floor
- lateral lip: pectoralis major
- medial lip: teres major
- floor: latissimus dorsi
- shaft
- deltoid tuberosity
- olecranon fossa
- coronoid fossa
- capitulum
- trochlea
- medial epicondyle
- lateral epicondyle

Radius
Key features of the radius include:
- head: The discoid head of the radius articulates superiorly with the capitulum of the humerus, contributing to the formation of the elbow joint. At the same time, the head of the radius also articulates with the ulna forming the proximal radioulnar joint. In this joint, the circumference of the head of the radius is situated on the radial notch of ulna.
- neck
- radial tuberosity/biceps tuberosity: where biceps inserts
- styloid process: The lateral aspect of the distal radius forms a ridge and terminates distally as the radial styloid process.
- ulnar notch: The distal end of the radius widens to form three smooth, concave surfaces. The medial aspect of the distal radius forms a concavity known as the ulnar notch, which articulates with the distal ulna.

Ulna
Key features of the ulna include:
- olecranon
- trochlear notch
- coronoid process: Projecting anteriorly from the proximal portion of the ulna is the coronoid process. The coronoid process aids in stabilizing the elbow joint and preventing hyperflexion of the forearm.
- head: The distal end of the ulna tapers to form the disc-like head of the ulna. The head of the ulna does not articulate with the carpal bones and is therefore not a component of the wrist joint
- radial notch
- ulnar tuberosity: Inferior to the coronoid process is the tuberosity of ulna, which functions as an attachment point for the brachialis muscle.
- styloid process: Projecting from the head of the ulna is a small bony protrusion known as the styloid process of ulna.

ILIUM
- superior portion of hip
- Large wing like, or fan shaped Ala
- Key features include: Iliac crest ,tubercle, four spines ASIS AIIS, PSIS, PIIS
- Like the scapula, it has flat surfaces for muscle origin
- Main weight bearer along with ischium
- Another key feature is the iliopubic eminence is junction with pubic bone

• the gluteal Surface has three lines separating gluteus max, med and min
• Tensor Fascia sits between ASIS and tubercle
• Reflected head of Rectus femoris sits above acetabulum
• ASIS is a point of attachment for Inguinal lig , Sartorius
• AIIS is a point of attachment for Straight head RF and iliofemoral lig

Pubis
- Smallest Section of the Hip
- Forms anterior inferior section of the acetabulum.
- Upper surface of body is the pubic crest which terminates laterally at the pubic tubercle
- Key features include: Superior and inferior pubic rami, pubic tubercle, obturator foramen
- Pubis and ischium border the obturator foramen
- obturator foramen is covered in a membrane, is a site of muscle attachment
- Body is quadrilateral
- Projected Laterally as Superior Ramus, joining Ilium and Ischium at Acetabulum and Inferiorly as Inferior Ramus, fuses with Ischial Ramus
- Symphysis medially located, coated with fibrocartilage, secondary cartilaginous joint ^[enables expansion during delivery for infant head]
- Upper border Body is convex
- Laterally is pubic tubercle
- 2 ridges go out laterally, upper sharp, pectineal line continues into Arcuate line
- Below this is Obturator crest, Nerve ( on Bone ) and Vessels below, over the obturator foramen

Ischium
- L shaped bone, upper portion “Body”, joins with Ilium and Pubis at acetabulum, extends down to ischial tuberosity, for sitting and Hamstrings, and lower medial, thinner bar , ischial ramus, joins the pubic ramus to enclose the Obturator foramen
- Key features: ischial tuberosity and ramus, spine
- Tuberosity has oval upper and crest below
- Hamstrings attached oval area Semimembranosus laterally and Semitendinosis and Biceps medially
- Spine of Ischium , extends medially to separate the Greater and Lesser sciatic notches

Femur
- articulates with hip at aceatbulum
- Key features include: head, neck, greater and lesser trochanter, intertrochanteric crest, shaft, linea aspera, gluteal tuberosity, patellar surface, lateral and medial epicondyles, lateral and medial condyles,

Tibia
- Major weight transmission
- Forms most of the ankle (talo-crural) joint
- Medial malleolus extends one third the way down the talus
- Medial malleolus is anterior to the lateral
- Inferior articular surface is rectangular
- Tibial tuberosity
- Medial and lateral condyles
- Shaft
- Articulates with talus and fibula
- Origin of deltoid ligament, on medial aspect, very strong

Fibula
- Lateral side of the leg, parallel with the tibia
- No or very little weight transmission
- Forms part of the ankle (talo-crural) joint
- Lateral malleolus extends more inferiorly by 1cm
- Lateral malleolus is posterior to the medial
- Head and shaft
- Articulates with the lateral surface of the talus and tibia
- Origin of important ligaments – anterior and posterior talo-fibular, calcaneo-fibular, anterior inferior tibio-fibular

See notes for X-ray

NOTE: ignores knee

Question 15

• Name carpal and tarsal bones

Answer 15

self explanatory

Question 16

Label this Xray of the lower leg

Answer 16

Question 17

Label this Xray of the shoulder

Answer 17

Question 18

Discuss micro and macro features of osteosarcoma

Answer 18

Compared to normal bone, osteosarcoma shows:
- Architecture: crowded/more cellular
- Cytology: Tumour cells often ‘spindle’ shaped, hyperchromatic, variable
- Pathognomonic feature = production of neoplastic osteoid/ matrix (appears pink due to lack of mineralisation)
- Often scanty, irregular/’lace-like’ & does not mineralize normally
- Tumor cells may also show predominantly fibrosarcomatous or chondrosarcomatous differentiation

Question 19

HII

• Identify common pathologies associated with carpal bones

Answer 19

Scaphoid fractures
- Scaphoid within the wrist minimal soft tissue attachment
- Limited blood supply
- Retrograde supply to proximal pole
- Difficult to diagnose
- Easily missed: not very painful
- Develops avascular necrosis and arthritis untreated
- May require internal fixation

Lunate avascular necrosis
also known as Keinboch’s disease. Occurs spontaneously in 30-40 year old males.

Other issues include the trapezium developing arthritis, , arthritis developing in the junction between the pisiform and triquetral bones, hook of hamate issue causing tendon rupture.

Scapholunate ligament can tear:
- Fall or twisting Injury
- Sprained or weak wrist
- Clunk or pop with activity, weak wrist
- Predictable arthritic pattern
- Needs repair

Question 20

HII

• Identify NoF fracture; describe blood supply to femoral neck and how different fractures that interfere with blood supply

Answer 20

• note: intracapsular fractures e.g. subcapital and transcervical will jeopardise the vascular supply of the head as it is retrograde ^[similar to scaphoid bone]
  
  • blood supply is two-fold
    
    • interosseous, travelling up to the head (retrograde intramedullary vessels): not affected by intracapsular fractures
    • travels through capsule around neck to the head (medial and lateral circumflex femoral arteries )

n.b. intra-capsular and extra-capsular fx will both cut off the intramedullary retrograde supply.
BUT, only intra-capsular fx will cut off the medial femoral circumflex artery.

Question 21

HII

• What is Trendelenburg gait and what causes it?

Answer 21

• occurs if medius and minimus fail to fire, as they work to stabilise and keep pelvis level when opposite leg is raised
• result is opposite end drops
• causes include: loss of hip abductors, L5 radiculopathy, polio, detachment of abductors, fracture or operation on greater trochanter

Question 22

• Describe the innervation (SENSORY AND MOTOR) and vascular supply of the upper limb

Answer 22

Innervation of upper limb muscles
Musculocutaneous nerve: all anterior arm compartment muscles
Median nerve: anterior forerarm compartment muscles except flexor carpi ulnaris muscle and medial half of flexor digitorum profundus
Ulnar nerve: intrinsic muscles of the hand, except for the thenar muscles and two lateral lumbrical muscles,
Radial nerve: posterior arem and forearm compartment muscles
Axillary nerve: deltoid and teres minor muscles

Sensory innervation of the upper limb

Musculocutaneous nerve: skin on anterolateral forearm
Median nerve: skin on palmar surface of the lateral three and one-half digits
Ulnar nerve: skin on medial one and one-half digits
Radial nerve: skin on posterior surface of forearm and dorsolateral surface of hand
Axillary nerve: skin on lateral arm

Vascular:

Question 23

HII

• Label hip muscles and briefly describe their attachements, action and innervation

Answer 23

SEE Hip deck (gluteal muscles)

Question 24

HII

• Label thigh muscles (Anterior and posterior) and briefly describe their function/Lis t and describe their function and innervation

Answer 24

See thigh deck

Question 25

# HII - List muscles of lower leg: anterior, posterior, lateral compartments. Their attachments, innervation and action

Answer 25

See lower limb deck

Question 26

- Describe how nerve of the lower limb arise from the sciatic nerve | links to popliteal

Answer 26

The sciatic nerve arises in the lumbosacral region. It descends through the posterior aspect of the thigh. Before entering the popliteal fossa, the nerve terminates by splitting into two large terminal branches: the tibial nerve and common fibular (peroneal nerve). Note that peroneal splits again into superficial and depp peroneal nerves.

Question 27

# LAbel Knee HII - Label knee structures. What does ACL do? What does meniscus do?

Answer 27

Role of ACL: - **Prevents anterior translation of the tibia on a fixed femur** - **FFAATT** - **Controls rotation** - **From the area between the posterior ends of the menisci** - **Passes forwards, medially, and upwards** - **To antero-lateral surface of medial condyle of the femur** Note mechanism of ACL injury: non-contact injuries e.g. landings. Recurrent collapses of the knee increase the risk of osteoarthritis. Role of meniscus: - semilunar Cartilages - **Medial and lateral** - **Crescentic pieces of fibrocartilage** - **Lateral meniscus is a fuller crescent** - **Attached to the periphery of the articular surfaces of the lateral and medial tibial condyles by the adjacent deep parts of the capsule – the coronary ligaments.** - **Thick at the periphery, thin inner edges (wedge in cross-section)** - **Upper femoral surface is concave** - **Lower tibial surface is flat** - **Improve congruence of joint surfaces** - **Guide movement** - **Shock absorption** Mechanism of injury to menisci: semi-flexed, weight-bearing, and twist

Question 28

- List the typical vertebrae features, and specific features of cervical, thoracic and lumbar vertebrae/**distinguish between cervical thoracic and lumbar vertebrae

Answer 28

Common features to all vertebrae include (from anterior to posterior): - vertebral body and foramen - pedicle - transverse process - articular processes - lamina - spinous process Cervical vertebrae There are seven cervical vertebrae. They are the smallest of the vertebrae. They are characterised by: - an uncus on either side of the vertebral body (anterior side) - a **bifid spinous process** (with exceptions...C7 may not bifurcate) - **transverse foramina**, in each transverse process. Through here, vertebral arteries travel to the brain - **a *triangular* vertebral foramen - **articular processes are 'open' ( ..allows x movement. See physiopedia) There are several features that distinguish thoracic vertebrae: - **spinous processes are oriented obliquely, inferiorly and posteriorly - **articular processes are 'reading the book' ( ..allows x movement. See physiopedia) - **circular vertebral foramen - **demi facets**, one superior and one inferior, on either end of the vertebral body - the demi facets articulate with the heads of two different ribs to form the costovertebral joints- -- e.g. at T2, the head of rib 2 articulates with the superior demi facet of T2, and the head of rib 3 articulates with the inferior demi facet of T2 - **costal facet** on the transverse process which articulates with the shaft of the rib of the same number e.g. costal facet of T2 articulates with shaft of rib 2 Special characteristics include: - **kidney shaped vertebral bodies** - **triangle shaped vertebral foramen - shorter spinous processes c.v. thoracic vertebrae and do not extend inferiorly - **articular processes 'close the book' ( ..allows x movement. See physiopedia) ## Footnote Atlas or C1. It articulates with the occiput and C2. It has **NO**: - vertebral body - spinous process It **has**: - lateral masses, with oval-shaped superior articular facets (articulating with occipital condyles) and inferior articular facets (articulating with C2) connected by... - **anterior arch**, which has a facet for articulating with the dens of the axis, which is secured by the transverse ligament of the atlas (see below) - **posterior arch**, which has a groove for the vertebral artery and C1 spinal nerve Axis or C2, which articulates with C1 and C3. Its most characteristic feature is the **dens**, in addition to the general features of the typical cervical vertebrae.

Question 29

- How do the vertebrae facilitate or disallow movement?

Answer 29

Intervertebral joints Vertebrae will articulate with each other via two types of joints #### Facet (zygapophysial) joints Facet joints are **synovial plane joints**, between the superior articular facets of the inferior vertebra and the inferior articular facets of the superior vertebra. It works to **guide and limit** movements between vertebrae. As synovial plane joints, the facet joints are composed of: - hyaline articular cartilage which lines the facet surfaces of the superior and inferior articular processes - synovial joint cavity between the articular surfaces which contains synovial fluid - fibrous capsule, surrounding the joint, and lined by synovial membrane - except for the anterior fibrous capsule, which is formed by the ligamentum flavum The articular surfaces glide in a multitude of directions, which collectively produce movement in the spine of all planes: - flexion and extension - right and left lateral flexion - right and left rotation Interbody joints Interbody joints sit between the vertebral bodies and intervertebral discs. It is a cartilaginous symphysis. Interbody joints connect the vertebrae anteriorly, to enable movement. The disc is also involved in: - weight-bearing - shock absorption - load distribution

Question 30

- **Describe the surface anatomy of the shoulder/elbow/hand/KNEE/foot**

Answer 30

Shoulder: At the acromion, one can palpate the acromion itself, the acromioclavicular joint, and scapular spine. Humeral head and GT, bicipital groove can also be palpated. Elbow: - lateral epicondyle - medial epicondyle - olecranon - radial head - wrist: - radial styloid - lister's tubercle: EPL runs around it to thumb - ulnar styloid Hand: - DIPS, PIPS, MCPs - extensor tendons - snuffbox - pisiform - radial and ulnar tubercles Knee: - patella - tibial tuberosity - quadriceps tendon - patellar tendon - medial and lateral joint lines Foot: - lateral malleolus - medial malleolus - edl tendons - ehl tendon - tibialis anterior tendon - 5th MT base - calcaneal tendon

Question 31

- **Identify the different parts of the brachial plexus, and some significant branches of the plexus

Answer 31

The brachial plexus can be divided into roots, trunks, divisions and cords. It provides motor and sensory innervation to the upper limb structures. It is formed by the ventral rami of C5-T1 spinal nerves . The plexus originates in the neck and then passes laterally and inferiorly over the first rib to enter the axilla. As it crosses the first rib, the brachial plexus is located with the axillary artery between the anterior and middle scalene muscles. This is where the roots can be found. Trunks emerge in the posterior triangle of the neck. C5 and C6 merge to form one trunk, C7 is its own trunk, and C8 and T1 merge to form a trunk. Divisions emerge behind the clavicle. Each trunk forms an anterior and posterior divisions. Cords emerge in the axilla. Three cords emerge: - lateral: which is formed from the merging of the anterior divisions from upper and middle trunks - posterior: which is formed from the merging of the three posterior divisions - medial: which is formed from the merging of anterior division from lower trunk - Axillary and radial nerves from the posterior cord - innervate posterior muscles and skin - Musculocutaneous, median and ulnar nerves from the medial and lateral cords - innervation anterior muscles and skin

Question 32

# HII - What forms the ulnar nerve (from brachial plexus)? What forms the medial nerve? The radial nerve?

Answer 32

- Axillary and radial nerves from the posterior cord - innervate posterior muscles and skin - Musculocutaneous, median and ulnar nerves from the medial and lateral cords - innervation anterior muscles and skin

Question 33

- List and describe the ligaments of the spinal cord

Answer 33

There are five main ligaments of the spine: - the anterior longitudinal ligament which connects the anterior vertebral bodies and intervertebral discs up to the anterior tubercle of C1. The **anterior atlanto-occipital membrane** then connects the anterior tubercle of C1 to the occiput. - the posterior longitudinal ligament which connects the posterior aspects of the vertebral bodies and intervertebral discs up to the C2 vertebral body. The **tectorial membrane** then connects C2 to the occiput - the ligamentum flavum which is composed of elastic tissue and connects the laminae of adjacent vertebrae up to the posterior arch of C1. The **posterior atlanto-occipital membrane** connects the posterior arch of C1 and the occiput - the interspinous ligament which connects adjacent spinous processes - the supraspinous ligament which connects the tips of the spinous processes up to the C7 spinous process. It forms a strong broad ligament extending between the C7 spinous process and external occipital protuberance known as the **ligamentum nuchae** and is an important site of muscle attachment -- - transverse ligament, which is a strong thick horizontal band that passes behind the dens of C2 as it attaches between the lateral masses of C1. - It is essential to maintaining the stability of the median atlanto-axial joint by preventing posterior displacement of the dens and anterior displacement of C1. - Alar ligaments, which extend between the sides of the dens and the lateral margins of the foramen magnum. - The alar ligaments prevent excessive rotation of the atlanto-axial joints. -- - anterior longitudinal ligament = limits hyperextension of spine - posterior longitudinal ligament = limits hyperflexion of spine; prevents posterior herniation of IVD - ligamentum flavum = limits separation of laminae to prevent hyperflexion of spine - interspinous ligament = prevents separation of spinous processes during flexion; resisting hyperflexion - supraspinous = prevents separation of spinous processes during flexion; resisting hyperflexion - transverse = resists separation of vertebral bodies?, in order to resist or limit flexion

Question 34

- Describe the (relevant) layers of anterior and posterior spinal cord muscles

Answer 34

Posterior muscles Layer 1 - latissimus dorsi - function - glenohumeral joint: extension, adduction, and medial rotation - innervation: thoracodorsal nerve (C6 - C8 ventral rami) - trapezius - function - scapula: elevation, depression, rotation and retraction - head and neck: extension and lateral flexion - innervation: CN XI, and C3-4 ventral rami #### Layer 2 - levator scapulae - function - scapula: elevation and rotation - neck: extension and lateral flexion - innervation - dorsal scapular nerve (C4,5); C3-C4 ventral rami - rhomboids - function - scapula: retraction - innervation - dorsal scapular nerve (C4,5) Layer 4 - splenius capitis and cervicis - function - head and neck: extension, lateral flexion and ipsilateral rotation - innervation - dorsal rami (capitis: C3 and C4?, cervicis: 'lower cervical nerves'; c5-8?) #### Layer 5 - erector spinae (iliocostalis, longissimus, spinalis) - function - spine: extension and lateral flexion - innervation - dorsal rami (C1-L5) -- ### Anterior muscles Layer 1 - sternocleidomastoid - function - head and neck: flexion, lateral flexion and contralateral rotation - atlanto-occipital joints: extension - innervation - CN XI; C2-3/4 ventral rami ##### Layer 2 - scalenes (anterior, middle and posterior) - function - neck: flexion, lateral flexion and rotation - innervation - ventral rami (C3-8?) Deep head and neck (aka Layer 3) - Longus capitis and colli Superficial lumbar - rectus abdominis, external oblique, internal oblique and transversus abdominis - function: flexion, lateral flexion and rotation - innervation: ventral rami Deep lumbar - psoas major - function - lumbar spine: flexion and lateral flexion - hip joint: flexion - innervation: ventral rami (L1-4, plus femoral nerve branches?) - quadratus lumborum - function - lumbar spine: lateral flexion - innervation: ventral rami (L12, S1-5?)

Question 35

# HII - List the muscles in the six extensor compartments, and pathology associated with the extensor compartment

Answer 35

**Extensor Tendons** - Wrist has 6 extensor compartments - Extensor Retinaculum covers the tendons - Prevents Bowstringing of the tendons - Improved mechanical advantage - Tendons are susceptible to compression friction or attrition rupture within the compartments **Extensor tendons: compartments** 1. Abductor Pollicis Longus and Extensor Pollicus Brevus 2. Extensor Carpi Radialis Longus and Brevus 3. Extensor Pollicis Longus 4. Extensor Digitorum Longus and Extensor indicis Proprius 5. Extensor Digiti Minimi 6. Extensor Carpi Ulnaris De Quervain’s Tendonitis - Common Cause of radial wrist pain - Over use or narrow compartment - Treatment : Rest, Physio, stretching NSAID gel, Injection with Steroid - Surgery if resistant

Question 36

- What is wrist drop? What nerves are involved?

Answer 36

Wrist drop is caused by damage to the radial nerve, which travels down the arm and controls the movement of the triceps muscle at the back of the upper arm, because of several conditions. This nerve controls the backward bend of wrists and helps with the movement and sensation of the wrist and fingers. The wrist and the fingers cannot extend at the metacarpophalangeal joints. The wrist remains partially flexed due to an opposing action of flexor muscles of the forearm. As a result, the extensor muscles in the posterior compartment remain paralyzed.

Question 37

**- List the contents of the carpal tunnel**

Answer 37

The contents of the carpal tunnel are as follows: - 4 Profundus tendons - 4 superficialis tendons - flexor pollicis longus - median nerve Carpal bones make up the walls and the floor. The tunnel was roofed by the flexor retinaculum.

Question 38

**- What pathology is associated with CT? How does it occur? List risk factors, presentation and treatment

Answer 38

- Median nerve compression due to either reduced volume or increase in the size of structures passing through the carpal tunnel - Intermittent paraesthesia median nerve distribution - Wasting of thenar muscle when severe and longstanding - Many causes including over use, pregnancy, gigantism, SLE, other inflammatory conditions - rest ice strtch - CS and NSAIDs - Splint - CT surgery

Question 39

**- What are the common extensor and flexor origin? List ligaments/muscles/nerves (as they apply) that attach to the common extensor origin and common flexor origin**

Answer 39

Tendons attach around the elbow at two sites: - common extensor origin: CEO - a blend of muscles whose tendons attach to the lateral epicondyle - ECRB - EDC - ECU - EDM - common flexor origin: CFO - a blend of muscles whose tendons attach to the medial epicondyle - Pronator Teres - Flexor Carpi Radialis - Flexor Digitorum Superficialis - Palmaris Longus - Flexor Carpi Ulnaris

Question 40

**- Describe pathology associated with CFO and CEO?**

Answer 40

- #clinicallyrelevant : tennis elbow, or lateral epicondylitis - Damage to the tendinous insertion common wrist and finger extensors - Pain and tenderness at common extensor origin and Lateral epicondyle - Pain with wrist and finger extension - Treated with rest and stretching, physiotherapy and cortisone injection - Rarely requires surgery to cut tendon - common flexor origin: CFO - a blend of muscles whose tendons attach to the medial epicondyle - Pronator Teres - Flexor Carpi Radialis - Flexor Digitorum Superficialis - Palmaris Longus - Flexor Carpi Ulnaris - #clinicallyrelevant : golfer's elbow or medial epicondylitis - damage to the tendinous insertion common wrist and finger flexors - pain and tenderness at common flexor origin and medial epicondyle - pain with wrist and finger flexion - treated with rest and stretching, physiotherapy and cortisone injection - rarely requires surgery

Question 41

**- What are the rotator cuff muscles, their attachments and actions, and innervation?**

Answer 41

There are four muscles that comprise the rotator cuff: - subscapularis: which originates from the whole anterior surface of the scapula and inserts on the lesser tuberosity. **Subscapularis***  medially rotates the glenohumeral joint. It is supplied by the _upper & lower subscapular nerves._ - supraspinatus: originates from the supraspinatus fossa and inserts on the greater tuberosity. **Supraspinatus*** intitiates and assists deltoid with abduction of the glenohumeral joint. Innervated by the _suprascapular nerve_ - infraspinatus: originate from the infraspinatus fossa and inserts on the greater tuberosity. **Infraspinatus*** laterally rotates the glenohumeral joint. It is innervated by the _suprascapular nerve._ - teres minor: originates from the inferior angle of the scapula and inserts on the greater tuberosity. **Teres minor***  laterally rotates the glenohumeral joint. It is innervated by the _axillary nerve._ The tendons of supraspinatus, infraspinatus and teres minor blend together at the greater tuberosity. _All of the rotator cuff muscles function to **stabilise the glenohumeral joint.**_ The rotator cuff muscles hold down the humeral head while the deltoid abducts the arm. Without the rotator cuff muscles the deltoid would pull the head upwards. They are actually head depressors --- holds down the head while the deltoid abducts the humerus. The rotator cuff also has a role in internal and external rotation.

Question 42

- List some examples of rotator cuff disease, and broad examples of management

Answer 42

The rotator cuff is commonly compressed. This leads to bursitis, and partial and full thickness tears, with pain and limited movement. Treatment involves rest and restriction of overhead activity. It also involves: - anti-inflammatory medications - physio - cortisone injection Sometimes surgery is required: - arthroscopic decompression, open acromioplasty - repair of the rotator cuff

Question 43

**- Patient presents with loss of sensation to dorsum of foot and foot is inverted and plantarflexed at rest. Loss of eversion and dorsiflexion. Which nerve is likely to be involved?**

Answer 43

Deep peroneal is responsible for dorsiflexion and eversion Foot eversion is coordinated by superficial peroneal. Superficial nerve innervates most of dorsal surface. Deep peroneal only innervates region betweebig and index toe.

Question 44

**- List the key nerves supplying the lower limb and list one or two muscles innervated by these nerves**

Answer 44

Nerves of lower limb The major peripheral nerves that innervate the lower limb are the: 1. Femoral 2. Obturator 3. Sciatic. The sciatic nerve is composed of the: - Common Peroneal (Fibular) - Superficial Peroneal (Fibular) and Deep Peroneal (Fibular) nerves - Tibial nerve **Innervation of lower limb muscles** Femoral nerve: anterior thigh compartment muscles Obturator nerve: medial thigh compartment muscles Sciatic nerve: posterior thigh compartment muscles - Superficial Peroneal (Fibular) nerve: lateral leg compartment muscles - Deep Peroneal (Fibular) nerve: anterior leg compartment muscles - Tibial nerve: posterior leg compartment muscles

Question 45

**- What structures form the sciatic foramen? What structures travel through? How can we avoid injecting the sciatic nerve?**

Answer 45

Sciatic Foramen - Greater and lesser sciatic notches - Converted to Foramen by ligaments - Sacrospinous converts Greater - Sacrotuberous ligament converts Lesser Ligaments and Greater Sciatic Foramen - Sciatic Nerve, with nerve to Quadratus Femorus deep to it, lies on the ischium, one third of the way up from the ischial tuberosity to PSIS - **Sciatic Nerve can be located at the top of thigh, just medial to midpoint of GT and Ischial tuberosity** ^[important NOT to inject here, instead **superior lateral quadrant**] - Pudendal nerve lies on the ligament, medial to spine - Internal Pudendal vessels, cross the tip - Nerve to obturator internus lies on the base of the spine - **Piriformis exits through greater foramen, sciatic nerve can be located inferior to Piriformis** - Lesser Sciatic Notch - Obturator Internus muscle and Pudendal Vessels **List of nerves at greater sciatic notch** * 7 nerves: * **Sciatic Nerve** * Superior Gluteal Nerve * Inferior Gluteal Nerve * Pudendal Nerve * Posterior Femoral Cutaneous Nerve * Nerve to Quadratus Femoris * Nerve to Obturator Internus * 3 Vessel Sets: * **Superior Gluteal Artery & Vein** * Inferior Gluteal Artery & vein * **Internal Pudendal Artery & vein** * 1 Muscle: * **Piriformis **List of nerves at lesser sciatic notch** * 2 nerves: * Pudendal Nerve * Nerve to Obturator Internus * 1 Vessel Set: * Internal Pudendal Artery & vein * 1 Muscle: * Obturator Internus Upper right quadrant is site of injection

Question 46

**- Identify the content and borders of the femoral triangle**

Answer 46

Femoral Triangle - **Borders** - Inguinal Ligament is base, lateral border Sartorius and medial border adductor Longus ^[this means sartorius is NOT part of the triangle, but adductor longus is] - **Floor** - **Iliacus, Psoas (or iliopsoas)**, **Pectineus**, and Adductor Longus - **Contents** - Lateral to medial: Femoral nerve, artery and vein

Question 47

**- Identify the contents and borders of the popliteal fossa**

Answer 47

The popliteal fossa is the space behind the knee Above – medial – semitendonosis and semimembranosus Above – lateral – biceps femoris Below – medial and lateral heads of gastrocnemius Roof – fascia lata Floor – popliteal surface of femur, capsule of the knee joint (oblique popliteal ligament), popliteus muscle Contents of the popliteal fossa Common peroneal nerve – branch of sciatic nerve- lateral, medial to biceps tendon, runs behind head of fibula. - Tibial nerve – branch of sciatic nerve – more central, passes deep to gastrocnemius, sensory branch is the sural nerve - Popliteal artery – from the hiatus in adductor magnus to the fibrous arch in soleus, deepest of the neurovascular structures, superiorly medial to the sciatic nerve. This will branch into peroneal; anterior and posterior tibial arteries - popliteal vein - sciatic nerve- which branches briefly before hand to give rise to tibial and common peroneal

Question 48

**- Describe acetabular dysplasia, and the spectrum of instability**

Answer 48

Acetabular Dysplasia - USUALLY The normal hip has good cover of the femoral head by the acetabulum - This helps bear the weight and distribute it evenly - \**Acetabular dysplasia** is characterised by an **acetabulum** wherein the **load bearing** surface is **less horizontal** and the head of the **femur** is **less well covered** - Acetabular angle can be measured - Changes in angle can indicate dysplasia to subluxation and full dislocation - dysplasia in adults, subluxation more of a paediatric issue

Question 49

- List the joints that make up the knee and ankle joints

Answer 49

Knee - **Two distal joint surfaces – anterior patello-femoral, inferior tibio-femoral** ^[note that there is no direct contact between fibia and femur] - **Patello-femoral – femur** - **Patellar groove or trochlea** - **Distally the groove becomes the intercondylar notch** - **Saddle shaped, asymmetrical** - **Lateral face larger and more convex than the medial face** - **Lined with articular cartilage** - **Tibio-femoral – femur** - **Flattened anteriorly, curved posteriorly** - **Two condyles separated by a deep U-shaped notch, the intercondylar fossa** - **Two articular surfaces- medial and lateral** - **Two surfaces arch up towards each other and are separated by two bony spines – intercondylar eminence.** - **Covered by articular cartilage 3-4cm thick.** - **Vaguely triangular with a rounded base and sharper but still rounded inferior point.** - **The “extensor mechanism” – quadriceps - quadriceps tendon – patella –patella tendon – tibial tuberosity.** ^[i.e. patella sites within quadriceps tendon] ^[note also that patella tendon may be interchanged with patellar ligament] - **Posterior surface is wedge shaped with three facets.** - **Lateral facet is longer** - **Median ridge orientated in the long axis separates the medial and lateral facets** - **“Odd” facet – along the medial border of patella** - **Thick articular cartilage**: 6-7x the weight of the body is applied on patella during 90 degrees squat, so it protects against stress on patella - **Glides in the trochlea of the femur** Ankle - **Talo-crural** - a synovial joint that connects the bones of the leg, the fibula and tibia, with the talus of the foot - main action of the ankle joint is to allow dorsiflexion and plantar flexion of the foot, as well as some degree of pronation and supination with subtalar and midtarsal joints. - The joint also acts as a shock absorber as the heel strikes the ground during the first phases of gait. - **Subtalar joint** - the talus and calcaneus - the joint is classed structurally as a synovial joint, and functionally as a plane synovial joint - chief site within the foot for generation of eversion and inversion movements

Question 50

# HII - Describe pathology associated with structures surrounding the knee joint

Answer 50

Baker's cyst: POPLITEAL BURSA – BAKER’S CYST A synovial cyst in the popliteal fossa. Occurs when bursa distends. Can be confused with an aneurysm ACL tear: mechanism of ACL injury: non-contact injuries e.g. landings. Recurrent collapses of the knee increase the risk of osteoarthritis. Signs include popping, severe pain and inabiliy to continue activity, rapid swelling, loss of ROM. PCL tear: rarer than ACL. a posteriorly directed force on the anterior aspect of the proximal tibia with the knee flexed Meniscal tear: catching / locking - think of the meniscus as a horizontal, circular, twisting circle. MCL/LCL tear: valgus / varus stress test - think of how a lateral/medial blow can easily rip something that is vertically situated.

Question 51

- List the key ligaments of the knee joint and describe their roles | also provide examples of what could go wrong

Answer 51

see pathology question

Question 52

# HII - List the key ligaments of the ankle and describe their function and associated common pathology

Answer 52

**Syndesmosis** - Holds the tibia and fibula together - Anterior and posterior inferior tibio-fibular ligaments and interosseous membrane **Lateral Ankle (sprained ankle)** - Anterior talo-fibular ligament (neck of talus to fibula): first to damage in sprain (mechanism of damage is inversion with plantarflexion) ^[there is a posterior equivalent but it is rarely damaged] - Calcaneofibular ligament (calcaneus to fibula) - next in line of damage - Posterior talo-fibular ligament (body of talus to fibula) ^[also anterior inferior tibio-fibular important] **Medial ankle** - Deltoid ligament - Shaped like a delta - Medial malleolus to navicular, sustentaculum tali and posterior aspect of talus - Four bands - Complete tears are rare Inversion injury: ATaloFL Eversion: deltoid and A/PTibioFL | note also bifurcate ## Footnote Bifurcate ligament * Origin - the upper part of the calcaneus * Insertion – both the cuboid and navicular * May lead to avulsion fracture in inversion injuries of the ankle Traction can produce a fracture that is easily missed.

Question 53

- Taking a history e.g. for joint pain

Answer 53

Consider red flags Acute or acute on chronic situations - Swelling, erythema (flushing of skin, may be hot to touch), marked reduction in range of motion – infection or inflammation (e.g. sepsis, gout) - Systemic features in the absence of trauma – infection or inflammation - Rapid swelling of a joint following trauma – haemarthrosis - Pain and/or abnormal sensation with loss of power or altered reflexes - radiculopathy ^[usually at the exit foramen or lateral recess] (compression of nerve by spinal process) Chronic or persistent alterations - Unusually severe pain, swelling, temperature change, cyanosis/pallor and immobility in a limb or part thereof, **often following a minor injury** – complex regional pain syndrome. - Diffuse limb pain in the absence of other signs – somatic referred pain - Pain and/or abnormal sensation with loss of power or altered reflexes - radiculopathy - Persistent localized pain uninfluenced by posture or movement – bone disease ^[n.b. soft tissue would be influenced by posture or movement] If Traumatic - Mechanism of injury? - Direct – extrinsic force - Indirect – intrinsic force - Lever - Also: describe what happened to you If Spontaneous - Onset - Duration - Intensity - Fluctuations - Timing: Nocturnal? Morning stiffness? - Varying factors/movement – at rest, with movement, weight bearing. Site - Joint - Non-joint - bone - soft tissue - referred - diffuse - radiation - Multiple sites? - Distribution?

Question 54

- Dx for joint pain e.g. of hands

Answer 54

- gout: e.g. 1st MTP, knee, MCP - 'initially' asymmetrical monoarthritis - RA: symmetrical polyarthritis - wrists, MCP, PIP NO DIP NO CMC - PsA: asymmetrical poly/oligoarthritis - DIP, spinal, large joints (Shoulder, knee) - AS: stiffening spine: mainly lumbosacral and neck; less heel knee, shoulder; virtually all SI - OA:weightbearing, PIP, DIP, 1st CMC; spares wrist and MCP; asymmetrical polyarthritis

Question 55

- Steps of physical exam: shoulder, hand and elbow, knee, foot, spine, hip

Answer 55

Rapid recall and check KSG

Question 56

**- Label bones of wrist and hand XR frontal**

Answer 56

Question 57

**- Label bones of wrist and hand XR oblique/lateral**

Answer 57

Question 58

- Label bones of foot XR

Answer 58

Lateral: - tibia - fibula - lateral/medial malleolus - talus - calcaneum - cuboid - navicular - 5th MT base Frontal: - phalanges - metatarsals - cuneiforms: lateral, intermediate, middle - cuboid - navicular - talus - calcaneus - tibia - fibula Medial view: - phalanges - metatarsals - cuneiforms - navicular - cuboid - talus - calcaneus

Question 59

- Identify wrist fracture XR

Answer 59

Scaphoid wrist fracture Risk of avascular necrosis due to retrograde blood supply

Question 60

# HII - Label XR pelvis

Answer 60

see question below

Question 61

- Label knee XR

Answer 61

see question below

Question 62

**- Label spine MRI and identify exiting/transiting nerves**

Answer 62

Question 63

**- Label spine MRI, identify types of disc bulge** | degrees etc

Answer 63

>90 is disc bulge <90 is protrusion

Question 64

**- Identify NoF fracture; comment on effect on vascular supply**

Answer 64

- note: intracapsular fractures e.g. subcapital and transcervical will jeopardise the vascular supply of the head as it is retrograde ^[similar to scaphoid bone] - blood supply is two-fold - interosseous, travelling up to the head (retrograde intramedullary vessels): not affected by intracapsular fractures - travels through capsule around neck to the head (medial and lateral circumflex femoral arteries ) ## Footnote n.b. intra-capsular and extra-capsular (inter or sub trochanteric) fx will both cut off the intramedullary retrograde supply. BUT, only intra-capsular fx will cut off the medial femoral circumflex artery.

Question 65

**- Describe the role of inflammation in SLE**

Answer 65

PATHOPHYSIOLOGY An interplay of genetic factors and environmental factors can trigger the inflammatory process. Inflammatory process engages the innate and adaptive immune systems. These interacting roles of innate and adaptive immunity allow the production of autoantibodies, acute tissue inflammation, and damage. Dendritic cells, macrophages, and B cells are involved in innate immunity, whilst subsets of T and B lymphocytes are involved with adaptive immunity. B cells are certainly central players in the pathogenesis. Loss of self-tolerance in B cell development contributes to the development of autoimmunity. B cells also play a key role in T cell activation and contribute to the production of inflammatory cytokines. These autoantibodies are pathogenic and cause organ damage by immune complex deposition, complement, and neutrophil activation, altering cell function leading to apoptosis and cytokine production.

Question 66

**- List and describe some examples of autoimmune MSK conditions associated with HLA polymorphisms**

Answer 66

- **Rheumatoid arthritis** - MHC class II - HLA DRB1 *0401*/*0404* (HLA DR4) - **Spondylarthritis** - MHC class I - Strong association with HLA B27 - **Systemic lupus erythematosus** - MHC class II - **Polymyositis** - MHC class II

Question 67

- Distinguish between central and peripheral tolerance

Answer 67

- Central tolerance. - Developing lymphocytes encounter antigen in the primary/central lymphoid organs. - Deletion - Editing - **Site of Action** - Thymus - Bone marrow - Peripheral tolerance. - Mature lymphocytes encounter antigen in secondary lymphoid organs. - anergy, Treg, deletion

Question 68

**- Describe lab findings in RA/SLE**

Answer 68

RA: - elevated erythrocyte sedimentation rate (ESR, also known as sed rate) or C-reactive protein (CRP) level - Rheumatoid factor (RF): Not all people with RA test positive for RF; some people test positive for RF but never develop the disease; and some people test positive but have another disease. - Anti-cyclic citrullinated peptide antibody (anti-CCP) SLE: - ANA - anti-dsDNA - anti-Sm - anti-Ro/La

Question 69

**- Define osteoarthritis**

Answer 69

OA is now considered as **a partly inflammatory whole-joint disease** that affects various anatomical structures in and around the joint capsule. These include muscle, ligaments, entheses, synovial tissue, and the sub-chondral bone.

Question 70

**- Define osteoporosis, list some risk factors, distinguish between osteoporosis and osteomalacia

Answer 70

Osteoporosis: - Fragility of bone causing increased risk of fracture - WHO Classification: BMD T score < -2.5 defined as osteoporosis Risk factors: inadequate amounts of dietary calcium. low vitamin D levels. cigarette smoking or alcohol intake of more than two standard drinks per day. lack of physical activity. early menopause (before the age of 45) loss of menstrual period if it is associated with reduced production of oestrogen Osteoporosis vs osteomalacia: Osteopenia/Osteoporosis - Bone matrix normally mineralised but there is less bone (osteopenia not < 2.5) Osteomalacia - When there is insufficient Calcium and Phosphate to mineralise newly formed osteoid. Bone is softer and liable to bend, deform or fracture

Question 71

**- Describe the pathogenesis of osteoporosis

Answer 71

background: - OC resorption over 3 weeks - OB activation and bone formation over 3 months Key point - underpinning osteoporosis pathogenesis - - **Remodelling imbalance** - Resorption cavities deeper and more frequent, resulting in perforations - Cavities incompletely filled, resulting in... - Progressive loss of trabecular bone due to increased osteoclastogenesis Osteoblast and osteoclast communication - Receptor activator of nuclear factor kappa B (NFkB) RANK, RANK ligand system and OPG (Osteoprotegrin) involved in OB-OC communication - OC maturation dependent on RANK and RANKL interaction (RANKL on OB, stromal cells) - OPG and RANKL compete. OPG is the decoy, keeps OC stimulation in check - Estrogen may exert antiresorptive effect on bone by stimulating OPG expression in OB - Antibodies to RANKL (Denosumab) now available for osteoporosis Osteoblast regulation - LDL receptor – related protein 5 (LRP5) is modulator of OB function. - Co receptor of series of OB stimulating proteins operating through Wnt signalling pathway. - Frizzled and LRP5 bind to Wnt, activating bone formation Sclerostin - Sclerostin antagonizes Wnt signaling by occupying Wnt coreceptors LRP5/6 and preventing their binding to Wnt ligands, which inhibits downstream canonical Wnt signaling.--- inhibiting bone formation?

Question 72

**- Describe how osteoporosis is investigated and diagnosed

Answer 72

Diagnosis of Osteoporosis - Early diagnosis now possible before fracture occurs - Osteoporosis is defined in relation to degree to which bone mineral density is reduced - T score (number of standard deviations from the young normal mean) -- used to make diagnosis - Z score (number of standard deviation from age matched mean) -- gives a clue as to whether secondary cause is indicated - Osteoporosis is defined as T score below –2.5 BMD - Spine (L1-4 or L2-4) - Predicts spine fracture - Useful for monitoring – treatment changes are largest - **Trabecular bone** - Note: Osteophytes can cause falsely high bone density results - Hip (Femoral neck, intertrochanteric, trochanteric) - Femoral neck or total hip - Predictive of fracture risk hip and spine - **Cortical bone** T scores and Z scores - T score – measured BMD compared with mean value for young healthy population. T score is number of standard deviation below or above this average. Used for diagnosis of osteoporosis - Z score – the measured BMD (g/cm2) compared with mean value for age and sex and race matched population. Useful to determine if a secondary cause exists for OP BMD - 1994 benchmark for diagnosis of Osteoporosis - Good predictor of fracture - As good as, if not better, than ability to predict heart disease from blood cholesterol and to predict stroke from blood pressure - Note: severe osteoporosis= -2.5 or less, plus fracture Bone Mineral Density Advantages - Quick and easy - Minimal radiation exposure - Widely used in clinical trials - WHO classification based on DEXA - Good correlation with risk of fracture Limitations - Mineral content across a specific area not taking depth into consideration - Does not provide full assessment of bone strength (microarchitecture, bone turnover) - Vary between instruments (therefore do follow-up densities in the same clinic if possible) FRAX Tool –WHO Fracture Risk Assessment Tool - Clinical risk factors as well as bone mineral density (BMD) at the femoral neck. - FRAX® tool is computer-driven - FRAX® algorithms give the 10-year probability of fracture. The output is a 10-year probability of hip fracture and the 10-year probability of a major osteoporotic fracture (clinical spine, forearm, hip or shoulder fracture). - 10 yr probability >20% in MOP and >3% for Hip # - consideration for treatment - Avoids possibility of overtreating someone with bone density low alone, with low probability of fracture

Question 73

**- Describe prevention for osteoporosis

Answer 73

Prevention strategies - Attain Best Peak Bone Density - Good Calcium Intake - Exercise - Avoid smoking, excessive alcohol - Minimise drugs that can influence BMD adversely

Question 74

- Distinguish between primary and secondary osteoporosis

Answer 74

- Osteoporosis unassociated with other diseases – Primary Osteoporosis - Osteoporosis associated with other diseases – Secondary Osteoporosis

Question 75

**- Detail some treatments and lifestyle changes for osteoporosis (aka management)

Answer 75

Pharmacological management - **Antiresorptives – 1st line agents** - Bisphosphonates - SERMS - RANK Ligand inhibitor - Calcitriol - **Anabolic Agents – 2nd line** - Parathyroid Hormone - Antisclerostin Ab - **Dual Agents** - Strontium Ralenate Non-Pharmacological treatment - Weight Bearing Exercises - Adequate Calcium 800mg – 1200mg/day - Vitamin D intake - Avoid Risk Factors –smoking, alcohol

Question 76

**- Compare and contrast RA and OA: clinical features, joint distribution, extra-articular manifestations and systemic features

Answer 76

OA: Frequency: - most common - commonly affect older people - over 55 has greater prevalence in women Pathogenesis: 1. Mechanical damage to joint + metainflammatory systemic state 2. Degeneration of cartilage → inflammatory response 3. Chondrocytes release matrix metalloproteinases → kill chondrocytes & destroy cartilage ECM 4. Progressive loss of cartilage * Release of cartilage and bone breakdown products into the joint cavity triggers synovitis (can also precede cartilage destruction w/ hypercholesterolaemia, metainflammatory state) Associated with: * Major risk factors: obesity, joint overuse, untreated ligament injury Presentation: * Slow, progressive disorder w/ pain in weight-bearing joints after use (eg, at the end of the day), improving with rest; morning stiffness <30mins) * Asymmetric joint involvement o Hands: 1st CMC, DIPs (Heberden’s nodes) o Other: 1st MTP, hip, knees, spine (cervical & lumbar) o Bony swelling (no inflammation) * No systemic symptoms Investigations (+ findings): * X-ray: osteophytes, joint space narrowing, subchondral sclerosis (+/- cysts) * Arthrocentesis: non-inflammatory * Bloods: rheumatoid factor (-ve), anti-CCP antibodies (-ve), ESR & CRP (normal) Management: * Lifestyle: education, physical therapy (strengthen quads for knee OA), weight loss, orthotics, walking aids, heat * Pharm: oral NSAIDs, intra-articular corticosteroids (for flare-ups) * Surgical: joint replacement RA: Frequency: second most common, occurs in young people with family history, greater prevalence in womenn Pathogenesis: 1. Autoimmune response against synovium o Synovium expresses peptidyl-arginine deaminase (arginine residues → citrulline) o Citrulline recognised as foreign antigen, activating CD4+ T-cells → activation of B cells (autoantibodies) & macrophages (TNF-α → inflammation) 2. Inflammation → formation of pannus (granulation tissue) 3. Pannus invades of cartilage and bone → progressive destruction 4. Autoantibodies (anti-CCP, & RF) are produced → inflammation * RF is an IgM antibody against Fc portion of IgG (can aid in removing autoantibodies) Associated with: * Genetics: HLA-DR4; smoking Presentation: * Pain, swelling, & morning stiffness (>1hr), improving with use * Symmetric joint involvement o Hands: MCP, PIP (not DIP) o Arthritis in 3 or more areas o Synovial +/- bony swelling (inflammation, hot/red) * Systemic symptoms (fever, fatigue, weight loss) * Extraarticular manifestations: rheumatoid nodules (subcutaneous & lungs), interstitial lung disease, pericarditis, pleuritis, anaemia, neutropenia, scleritis, vasculitis Investigations (+ findings): * X-ray: joint space narrowing, erosions, osteopenia (+ soft tissue swelling) * Arthrocentesis: inflammatory (↑WBC) * Bloods: rheumatoid factor (+ve), anti-CCP antibodies (+ve), ESR & CRP (elevated), anaemia of chronic disease (normocytic), thrombocytosis Management: * Lifestyle: education, physical therapy * Pharm: NSAIDs (pain) & corticosteroids (inflammation, often used in combination), DMARDs (csDMARD/methotrexate → bDMARDs → tsDMARDs/JAK inhibitors)

Question 77

**- Differences in radiological findings for SLE, RA, OA, gout

Answer 77

OA: Characterized by osteophyte formation, non-uniform narrowing within joints, and progressive worsening. - distribution: Hips, Knees, 1 st MTP, L4/5, C5/6, DIPs, PIPs, 1 st CMC - non-uniform narrowing within joints, and progressive worsening - juxta-articular sclerosis - symmetric: although one side can be worse than the other RA:Affects the synovium, leading to uniform narrowing within joints, bone resorption, juxta-articular osteopenia, and erosions. - disease of synovium - exhibits erosions (visible as dark holes or dots) - will show erosions at **lateral edge of joint** (juxta-articular osteopaenia): ends look chewed - **joint space still preserved** (uniform narrowing within joint) - resorbs bone - degeneration (laxity of joints) with progression of disease SLE: soft tissue swelling, normal joint spaces, swan neck/boutonniere, subluxation, hallux valgus, Gout: which can be distinguished from RA by **overhanging edge**, soft tissue swelling, and involvement of DIPs. - Dense soft tissue swelling - **Erosions with sclerotic margins** distant to the joint space - Incidental calcific arteriopathy - **Bone density** preserved on either side of the joint - indicated by demographics (ethnicity), hx (genetics, alcohol consumption, systemic disease)

Question 78

**- Distinguish between gout and non-gout, including clinical features and lab findings

Answer 78

Gout: common in men over 40, women over 55 Frequency: Associated with: * Renal impairment * Diabetes, hypertension, obesity, dyslipidaemia, hyperuricaemia Frequency: Associated with: * Hyperparathyroidism * Hemochromatosis (↑Fe) Pathogenesis: 1. Gout: hyperuricaemia (serum >0.4mmol/L) → monosodium urate (MSU) deposition/formation in joint space o 90% due to underexcretion (purine metabolism → uric acid) & 10% overproduction 3. Macrophages (via Pattern Recognition Receptors) detect & phagocytose crystalline deposits in joints → NLRP3 inflammasome forms → inflammatory cascade mediated by IL-1 * Neutrophils invade joint and bind crystals via neutrophil extracellular traps (NETs) Presentation: * Asymmetric mono-, oligo- or polyarthritis * Inflamed: swollen, red, painful & loss of movement (esp. 1st MTPJ/podagra) * Precipitants for acute attack: large meal in purines (red meat, seafood), trauma, surgery, infection, dehydration, diuresis, or alcohol consumption * Chronic/interval: tophus formation (external ear, olecranon bursa or calcaneal tendon) Investigations (+ findings): * X-ray: erosions w/ overhanging sclerotic margins, normal joint space, soft tissue tophi * Arthrocentesis: inflammatory (↑WBC, cloudy & yellow), MSU crystals (brightly birefringent, needle-shaped & yellow) Management: * Lifestyle: diet changes, weight loss * Acute Pharm: NSAIDs, glucocorticoids & colchicine * Chronic pharm (>2 acute attacks): xanthine oxidase inhibitors (allopurinol, febuxostat) Pseudo-gout: Frequency: over 50 years and equal between genders Associated with: * Hyperparathyroidism * Hemochromatosis (↑Fe) Pathogenesis: 2. CPPD: deposition of calcium pyrophosphate crystals within joint space. 3. Macrophages (via Pattern Recognition Receptors) detect & phagocytose crystalline deposits in joints → NLRP3 inflammasome forms → inflammatory cascade mediated by IL-1 * Neutrophils invade joint and bind crystals via neutrophil extracellular traps (NETs) Presentation: * Mono- or oligoarthritis * Inflamed: pain, swelling (esp. knee) Investigations (+ findings): * X-ray: cartilage calcification * Arthrocentesis: inflammatory (↑WBC, cloudy & yellow), CPPD crystals (positive birefringent, rhomboidal/rectangular shape & blue) Management: * Acute episode mostly self-limiting (5-7days) * Pharm: NSAIDs, glucocorticoids, colchicine * Joint aspiration * Treat any underlying metabolic condition

Question 79

- Provide some examples and features of seronegative arthritis

Answer 79

seronegative spondyloarthropathies: psoriatic, ankylosing spondylitis Spondylarthritis Types and Characteristics - Reactive arthritis e.g. after STI - Psoriatic arthritis - Arthritis related to inflammatory bowel disease - Ankylosing spondylitis - M:F ratio 2-3:1 for AS - Onset usually in 3rd decade of life - Strong association with HLA B27 Association between Spondylarthritis and HLA-B27 Disease and HLA-B27 Frequency Note that there is variation in frequency across ethnic populations, e.g. over-represented in European populations. - Ankylosing spondylitis: > 90% - Undifferentiated spondyloarthropathy: 70% - Reactive arthritis: 30-70% - Psoriatic arthritis: 40-50% - Iritis: 50% - Cardiac manifestations: >80% Clinical features (some) - peripheral enthesitis - dactylitis - skin psoriasis - peripheral ulceration - peripheral inflammatory arthritis - extra-articular manifestations: skin psoriasis, anterior uveitis and conjunctivitis

Question 80

- What is the serum uric acid level above which it will precipitate into tissue? What are some causes of this?

Answer 80

- Uric acid - end product of purine metabolism and is present in the serum and tissues in the form of monosodium urate. - Serum uric acid levels higher than 0.40 mmol/L monosodium urate supersaturates the serum and precipitates into tissues. - Elevated levels of uric acid do not necessarily translate into clinical disease. - An acute gouty attack occurs when monosodium urate crystals are released or form de novo in the joint space. - Trauma, surgery, infections, or initiation of medications such as allopurinol or diuretic agents can abruptly alter uric acid levels and incite an attack of gout. ## Footnote Gout Risk Factors - Hyperuricemia - Male sex if younger than 60 years - Obesity - High-purine diet (e.g., red meat, shellfish) - Alcohol (esp. beer and spirits) and high-fructose drinks - Medications (esp. thiazide diuretics or cyclosporine) - Renal insufficiency - Lead exposure - Organ transplantation - Specific diseases (e.g., hypertension, diabetes, hyperlipidemia, hematologic malignant conditions) - Genetic risk factors

Question 81

- Briefly describe reactive and septic arthritis

Answer 81

Reactive arthritis: Frequency: * Commonly affects 20-40yr olds * More common in men & Caucasians Pathogenesis: Arthritis developing soon after or during an infection elsewhere in the body, but in which microorganisms cannot not be recovered from the joint Associated with: * Recent infections: chlamydia, salmonella, campylobacter * Genetics: HLA-B27 (along with other seronegative spondyloarthropathies: psoriatic, ankylosing spondylitis & inflammatory bowel disease) Presentation * Acute, asymmetric oligoarthritiis * Affects large joints * Triad: conjunctivitis, urethritis (non-gonococcal, e.g.,), arthritis Investigations (+ findings): * X-ray: ill-defined erosions, bone proliferation, enthesopathy * Bloods: ESR & CRP (usually elevated), HLA-B27 (+ve) * Arthrocentesis: inflammatory (elevated WBCs, yellow colour) Management: * Pharm: NSAIDs, antibiotics for infection Septic arthritis: Frequency: * Uncommon but more likely in elderly Pathogenesis: Acute arthritis due to an active infection in a joint, commonly bacterial from hematogenous seeding. Associated with: * Most common causes: S. Aureus, Streptococcus, and Neisseria gonorrhoeae Presentation: * Abrupt monoarticular pain w/ swelling (+redness, heat) * Knee involved in 50% of cases Investigations (+ findings): * X-ray: usually normal joints, joint effusion & swelling, destruction of articular cartilage * Arthrocentesis: bacteria (S. Aureus, gonorrhoea, strep), very high WBC & PMNs, purulent/yellow, ↑viscosity Management: * Pharm: antibiotics * Aspiration, drainage (+/- debridement) to prevent irreversible joint damage Complications: osteomyelitis, chronic pain, irreversible joint damage, sepsis

Question 82

- What are some conditions associated with gout?

Answer 82

hypertension, diabetes, hyperlipidemia, hematologic malignant conditions

Question 83

**- What is SLE? What is thought to be the cause?**

Answer 83

DEFINITION A chronic autoimmune disease, characterized by multisystem clinical manifestations, as the complex pathogenesis can cause inflammation of any organ. The key pathogenesis relates to a dysfunctional immune system that results in overproduction of autoantibodies usually against cell nuclei, deposition of antibodies into tissues and complement activation and induction of chronic inflammation, ultimately culminating in end-organ damage and dysfunction. PATHOPHYSIOLOGY An interplay of genetic factors and environmental factors can trigger the inflammatory process. Inflammatory process engages the innate and adaptive immune systems. These interacting roles of innate and adaptive immunity allow the production of autoantibodies, acute tissue inflammation, and damage. Dendritic cells, macrophages, and B cells are involved in innate immunity, whilst subsets of T and B lymphocytes are involved with adaptive immunity. B cells are certainly central players in the pathogenesis. Loss of self-tolerance in B cell development contributes to the development of autoimmunity. B cells also play a key role in T cell activation and contribute to the production of inflammatory cytokines.

Question 84

**- Outline the non-pharmacological and pharmacological management of SLE**

Answer 84

The general principles include monitoring disease activity e.g. via autoantibodies and clinical signs (Aim remission (SLEDAI REM<2, LDA 2-4)), preventing flares of disease but not treating serology alone, preventing damage (15-20% irreversible organ dysfunction 1st 2 years, 40-50% in 5 years), limiting steroid use and tapering off ASAP, and using antimalarial drugs (hydroxychloroquine) at all stages. Additional needs include monitoring for adverse therapy side effects & treating infection, osteoporosis, monitoring for & treating co-existent vascular risk factors (BP, lipids, smoking), if associated hypocomplementemia – pneumococcal immunization, if thromboembolism-anticoagulation with aspirin, warfarin, heparins, NOACs; photo-protective measures (Sunscreen creams, hat, long-sleeve clothing, Vit D), care with contraception and timing of family issues, and education on disease, diet, exercise. Antimalarial Drugs - Emphasis on Hydroxychloroquine (Plaquenil) - Direct immunomodulatory effects have resulted in its use in Rheumatoid Arthritis, Primary Sjogren’s Syndrome, SLE, and Antiphospholipid Syndrome. - In SLE, should be used in most patients during the entire course of the disease, particularly useful for skin and joint manifestations. Immunomodulatory capacity also prevents disease flares, promotes long-term survival in SLE, controls autoimmune disease activity during pregnancies without evidence of fetotoxic or embryonic effects, can delay or prevent organ damage, and has antithrombotic effects in SLE. Helps successful tapering corticosteroids. - For this and other inflammatory rheumatic diseases, can also reduce rates of atherosclerosis, improve hyperglycemia, and protect against infections Skin & Musculoskeletal Treatment Other Immunosuppressive Drugs

Question 85

**- Describe the diagnostic criteria for SLE**

Answer 85

- Expansion on neuropsych manifestations - Haematology and immunological criteria are expanded - Need 4 or more criteria with at least **1 clinical +1 **immunological laboratory criteria EXCEPT WHEN Biopsy-proven lupus nephritis - Criteria are cumulative and need not be present concurrently

Question 86

**- Distinguish between the presentation of gout and RA**

Answer 86

- Symmetrical polyarthritis in small joints of hands and feet - whereas gout involves monoarticular and rarely oligo arthritis. Not likely symmetrical - Hand involvement more likely than in gout- 1st MTP classic finding - Subcutaneous nodules - similar to tophi in gout-- lower extremities and ear helix - X-ray: soft-tissue swelling, diffuse joint space-narrowing (in a joint), marginal erosions of small joints, symmetrical multiple joint involvement - Usually osteopenic without signs of repair - gout subsides in 3 to 14 days post treatment, RA does not | clarify with lecturer

Question 87

**- Discuss the synovial fluid findings of gout**

Answer 87

Crystal Analysis - MSU crystals are more easily detected than CPPD crystals. - CPPD crystals have a rhomboidal or rectangular shape and have positive birefringence. - Compared to MSU crystals birefringence is weaker, and some CPPD crystals may not appear birefringent. - A birefringent CPPD crystal appears blue. - MSU crystals are brightly birefringent and needle-shaped; MSU crystals appear yellow.

Question 88

**- Discuss the benefits of exercise, discuss some papers to this effect (signposted in Kieran’s lecture)**

Question 89

**- Discuss OA risk factors, pathogenesis**

Answer 89

see combined

Question 90

**- Discuss OA management**

Answer 90

see combined

Question 91

**- Describe the ladder of treatment for RA (DMARDs lecture)**

Answer 91

Phase I treatment - MTX, and if not, leflunomide or sulfasalazine ^[used more than HCQ due to efficacy in reducing radiological damage] - may be used in conjunction with short-term steroids Phase II Move to biologics or alternative csDMARD depending on prognostic factors.

Question 92

**- Describe the pathology of fracture healing and detail the timeline, and list factors that complicate fracture healing**

Answer 92

1. Reactive phase: * Haematoma formation (hrs - 3 days): haemorrhaging and clot forms in medullary cavity and surrounding soft tissue * Inflammation (<48hrs-10 days): vasodilation, increased permeability & inflammatory cell infiltration, releasing cytokine and recruiting mesenchymal stem cells; clot is reabsorbed * Granulation tissue formation (2-12 days): neovascularisation and fibrovascular primitive connective tissue forms (composed of fibroblasts, mesenchymal cells, and inflammatory cells/macrophages) around the ends of the fracture 2. Reparative phase: soft callus begins as fibrocartilaginous tissue (new connective tissue, microscopic blood vessels, cartilage) and woven bone that then becomes spongy bone. * Soft callus formation (1 week-months): fibroblasts and osteoblasts influx, producing fibrocartilaginous tissue (soft callus) that bridges the fracture site * Hard callus formation (1 week– months): endochondral ossification converts soft callus to hard callus of woven bone. With adequate immobilisation, gradual connection of bone filaments to woven bones supports strengthening of bone * Ossification (2 weeks – months): Mineralisation of bone matrix converts hard callus to lamella bone, uniting fracture and forming new haversian system 3. Remodelling phase: * Bone remodelling (months to years): hard callus/new lamella bone is progressively remodelled to restore normal bone contour Factors: Conditions that interfere with fracture healing - Poor blood supply to fractured area; could lead to avascular or aseptic necrosis - Poor immobilization of the fracture site may cause misalignment or deformity - Infection – more common with open fractures Local Anatomic Factors That Influence Fracture Healing - Soft tissue injury - Interruption of local blood supply - Interposition of soft tissue at fracture site - Bone death caused by radiation, thermal or chemical burns or infection Systemic Factors That Decrease Fracture Healing - Malnutrition - Reduces activity and proliferation of osteochondral cells - Decreased callus formation - Smoking - Cigarette smoke inhibits osteoblasts - Nicotine causes vasoconstriction diminishing blood flow at the fracture site - Diabetes Mellitus - Associated with collagen defects including decreased collagen content, defective cross-linking and alterations in collagen subtype ratios - Anti-Inflammatory Medications - Cause (at least a temporary) reduction in bone healing

Question 93

**- List systemic and local factors that can impact fracture healing**

Answer 93

Conditions that interfere with fracture healing - Poor blood supply to fractured area; could lead to avascular or aseptic necrosis - Poor immobilization of the fracture site may cause misalignment or deformity - Infection – more common with open fractures Local Anatomic Factors That Influence Fracture Healing - Soft tissue injury - Interruption of local blood supply - Interposition of soft tissue at fracture site - Bone death caused by radiation, thermal or chemical burns or infection Systemic Factors That Decrease Fracture Healing - Malnutrition - Reduces activity and proliferation of osteochondral cells - Decreased callus formation - Smoking - Cigarette smoke inhibits osteoblasts - Nicotine causes vasoconstriction diminishing blood flow at the fracture site - Diabetes Mellitus - Associated with collagen defects including decreased collagen content, defective cross-linking and alterations in collagen subtype ratios - Anti-Inflammatory Medications - Cause (at least a temporary) reduction in bone healing

Question 94

**- Distinguish between woven and lamellar bone**

Answer 94

- Bone exists in 2 main forms - Lamellar bone: Regular parallel bands of collagen arranged in sheets. Replaces woven bone in development by undergoing remodelling to have collagen fibres in parallel. Lamellar bone is mature bone, and is found in two types: compact and cancellous - Woven Bone: Immature form with randomly arranged collagen fibres in osteoid. Remodelled to form lamellar bone. Found in - Foetal bone development. If not foetal, then produced when osteoid is rapidly produced e.g. ... - Healing fracture - or a developmental disease e.g. Paget's disease of bone

Question 95

- What are the cells found in bone?

Answer 95

Cells - Osteoblasts: which synthesise matrix components e.g. osteoid, as well as mediating mineralisation. - Osteocytes: which are resting or inactive osteoblasts trapped within formed or mature bone - Osteoclasts: which are responsible for the resorption of bone, which itself comprises two steps: erosion and remodelling

Question 96

- What types of collagen are found in bone? Hyaline cartilage?

Answer 96

Collagen in bone is 1 Collagen in hyaline cartilage is 2 - Type 1 - skin, fascia, tendon, ligament, bone. (It is this, within the ground substance of the bone ECM (osteoid) that becomes mineralised) - Type 2 – all forms of cartilage. - Type 3 - in association with type 1, found in skin, artery, uterus - Type 4 - basement membrane - Type 5- placenta, blood vessels

Question 97

- What are the differences between intramembranous ossification and endochondral ossification?

Answer 97

In intramembranous ossification, bone develops directly from sheets of mesenchymal connective tissue. In endochondral ossification, bone develops by replacing hyaline cartilage. Activity in the epiphyseal plate enables bones to grow in length (this is interstitial growth).

Question 98

- Distinguish between the two main types of sarcoma

Answer 98

Osteosarcoma Definition - Malignant tumour differentiating towards osteoblasts, with production of osteoid/bone Epidemiology - Most common bone sarcoma (35%) - M:F = 2:1 - Usually in children/adolescents (during maximal bone growth); also in older adults Etiology - Most cases = Unknown - Patients with retinoblastoma (Rb) gene mutations = several hundred-fold greater incidence - Associated with conditions of high bone turnover, such as Paget’s disease and fibrous dysplasia of bone, also if prior radiotherapy or bone necrosis - Older adults with osteosarcoma often have one of these predisposing conditions (= ‘secondary’ osteosarcoma) Clinical Features - Metaphysis (most often distal femur, proximal tibia) - Localized pain and swelling **or pathological fracture** - ~10-20% of patients have pulmonary metastases at diagnosis Investigations for Diagnosis and Staging - **Imaging:** - XR - CT: cortical irregularities/fracture sites/mineralisation - MRI: extension into soft tissue/marrow/joint space - PET scan: assess primary lesion; detect metastases elsewhere - Radionuclide bone scan. - **Biochemistry:** Elevated ALP ^[indicates osteoblast activity] + LDH ^[indicates high cell turnover]. - **Biopsy:** Core or open (incisional) biopsy preferred - core limits risk of recurrence; FNA is inappropriate due to loss of architectural information. Osteosarcoma features Compared to normal bone, osteosarcoma shows: - Architecture: crowded/more cellular - Cytology: Tumour cells often ‘spindle’ shaped, hyperchromatic, variable - Pathognomonic feature = production of neoplastic osteoid/ matrix (appears pink due to lack of mineralisation) - Often scanty, irregular/’lace-like’ & does not mineralize normally - Tumor cells may also show predominantly fibrosarcomatous or chondrosarcomatous differentiation Treatment - Combination of neoadjuvant (ie pre-surgical) chemotherapy, surgery and adjuvant (ie post-surgery) chemotherapy - Complete excision with negative margins (within a specialist sarcoma unit) - Adjuvant treatment may include radiotherapy Prognosis - Depends on stage and response to neoadjuvant treatment: - Tumour necrosis of ≥ 90% has a > 90% disease free survival - < 90% necrosis has < 50% survival - Overall 5-year survival with current treatment, 60-70% ---- Well-differentiated Liposarcoma (WDLPS) **Definition:** Locally aggressive mesenchymal neoplasm with mature adipocytes and stromal cells showing focal nuclear atypia. **Epidemiology:** Most common form of liposarcoma, affecting middle-aged to elderly adults. - extremely rare in childhood - Sex: M = F **Etiology**: Unknown. Molecularly characterized by ring or giant marker / rod chromosomes, with amplification of several genes including MDM2. **Clinical Features:** - Location: - Deep thigh or other proximal limbs, retroperitoneum, trunk, spermatic cord, mediastinum - May also arise in subcutaneous tissue; rarely in skin (‘atypical lipomatous tumour’) - Less frequent in head/neck area - Slow-growing, painless, deep-seated mass - Retroperitoneal tumours may only be discovered after attaining significant growth (> 20 cm) **Investigations for Diagnosis and Staging:** - MRI preferred for imaging. - Biopsy: Core, incisional, or excisional; FNA inappropriate. **Treatment:** - Complete excision with negative margins often curative - Surgical debulking for large, multifocal retroperitoneal/intra-abdominal tumours - May require partial or complete resection of intraabdominal organs **Prognosis:** Behaviour depends on location. - Superficial locations more surgically amenable – can resect with negative margins - In skin it’s called an ‘atypical lipomatous tumour’ (ALT) - Deep locations (eg retroperitoneum) more difficult to resect – often recur locally – and can undergo ‘de-differentiation’ and subsequently metastasise - No metastatic potential unless dedifferentiation is present

Question 99

- Explain how sarcomas are graded

Answer 99

Based on Combination of Three Features: 1. **Tumour Differentiation:** (1, 2, or 3 points based on how closely it resembles normal tissue) 2. **Mitotic Count:** (1, 2, or 3 points based on how many mitoses per 10 high power fields) 3. **Tumour Necrosis:** (0, 1, or 2 points if no necrosis, <50% or >50% necrosis) - **Grade = Sum total of scores for differentiation, mitotic count, and necrosis** - 2-3 points = Grade 1 (low grade) - 4-5 points = Grade 2 (intermediate grade) - 6-8 points = Grade 3 (high grade)

Question 100

Compare and contrast sarcoma and carcinoma

Answer 100

- **Sarcoma** - Arises from connective tissues (e.g., bone, cartilage, muscle, fat, nerve) - Rare - Usually haematogenous spread - Mostly affects children/young adults - **Carcinoma** - Arises from epithelial tissues (e.g., lung, breast, prostate, colon, skin) - Common - Usually lymphatic spread - Mostly affects people >50

Question 101

Discuss macro and micro features of WDLPS

Answer 101

Image of liposarcoma ![[Pasted image 20240216190134.png]] - Well-circumscribed, lobular - Cream/tan/grey, homogeneous cut surface - Appears to arise from fat and bulge into muscle - Thickened fibrous bands may be evident - Fat necrosis may be seen in larger tumours (not pictured. Looks very pale yellow) Lipomyosarcoma: microscopy Compared to normal fat, liposarcoma shows: - Significant variation in size and shape of adipocytes - Focal nuclear hyperchromasia and mild atypia - Thickened, irregular fibrous bands/septa - Often contain atypical spindle shaped cells - Lipoblasts may be seen * Multivacuolated * Nucleus indented by the vacuoles - Significant nuclear pleomorphism/atypia absent

Question 102

- Discuss Neoplasms of UMP

Answer 102

- Some bone tumours are difficult to classify as benign or malignant (e.g., Giant Cell Tumour is locally aggressive and sometimes metastasizes) i.e. intermediate

Question 103

- Discuss osteosarcoma

Answer 103

Definition - Malignant tumour differentiating towards osteoblasts, with production of osteoid/bone Epidemiology - Most common bone sarcoma (35%) - M:F = 2:1 - Usually in children/adolescents (during maximal bone growth); also in older adults Etiology - Most cases = Unknown - Patients with retinoblastoma (Rb) gene mutations = several hundred-fold greater incidence - Associated with conditions of high bone turnover, such as Paget’s disease and fibrous dysplasia of bone, also if prior radiotherapy or bone necrosis - Older adults with osteosarcoma often have one of these predisposing conditions (= ‘secondary’ osteosarcoma) Clinical Features - Metaphysis (most often distal femur, proximal tibia) - Localized pain and swelling **or pathological fracture** - ~10-20% of patients have pulmonary metastases at diagnosis Investigations for Diagnosis and Staging - **Imaging:** - XR - CT: cortical irregularities/fracture sites/mineralisation - MRI: extension into soft tissue/marrow/joint space - PET scan: assess primary lesion; detect metastases elsewhere - Radionuclide bone scan. - **Biochemistry:** Elevated ALP ^[indicates osteoblast activity] + LDH ^[indicates high cell turnover]. - **Biopsy:** Core or open (incisional) biopsy preferred - core limits risk of recurrence; FNA is inappropriate due to loss of architectural information.

Question 104

- Discuss liposarcoma

Answer 104

Well-differentiated Liposarcoma (WDLPS) **Definition:** Locally aggressive mesenchymal neoplasm with mature adipocytes and stromal cells showing focal nuclear atypia. **Epidemiology:** Most common form of liposarcoma, affecting middle-aged to elderly adults. - extremely rare in childhood - Sex: M = F **Etiology**: Unknown. Molecularly characterized by ring or giant marker / rod chromosomes, with amplification of several genes including MDM2. **Clinical Features:** - Location: - Deep thigh or other proximal limbs, retroperitoneum, trunk, spermatic cord, mediastinum - May also arise in subcutaneous tissue; rarely in skin (‘atypical lipomatous tumour’) - Less frequent in head/neck area - Slow-growing, painless, deep-seated mass - Retroperitoneal tumours may only be discovered after attaining significant growth (> 20 cm) **Investigations for Diagnosis and Staging:** - MRI preferred for imaging. - Biopsy: Core, incisional, or excisional; FNA inappropriate. **Treatment:** - Complete excision with negative margins often curative - Surgical debulking for large, multifocal retroperitoneal/intra-abdominal tumours - May require partial or complete resection of intraabdominal organs **Prognosis:** Behaviour depends on location. - Superficial locations more surgically amenable – can resect with negative margins - In skin it’s called an ‘atypical lipomatous tumour’ (ALT) - Deep locations (eg retroperitoneum) more difficult to resect – often recur locally – and can undergo ‘de-differentiation’ and subsequently metastasise - No metastatic potential unless dedifferentiation is present

Question 105

**- Provide two examples of NSAIDs, detail their MoA, SEs, role in therapy, precuations and/or contraindications**

Answer 105

- ibuprofen - naproxen - diclofenac - *indomethacin* - *piroxicam* - NSAIDs work by inhibiting COX-1 and COX-2 enzymes - COX-1 are expressed in most tissues and platelets, primarily involved in tissue homeostasis, and responsible for producing prostaglandins involved in renal blood flow autoregulation, and platelet aggregation (1) - COX-2 is induced in many inflammatory cells, and is responsible for prostinoid mediators of inflammation; activated by IL-1, TNHa, and other inflammatory cytokines - They appear on the second step of the WHO ladder, and are considered simple analgesia Antipyretic effects: Temperature balance is regulated by hypothalamus, NSAIDs rest this control returning it to normal point when fever is present Do not alter normal temperature Achieved by inhibition of prostaglandin production in the hypothalamus Analgesic effects: Used for mild to moderate pain caused my inflammation or tissue damage Peripherally ↓ prostaglandin production that sensitise receptors to inflammatory mediators SEs: - related to inhibition of COX-1 and COX-2 - CV: **Rise in blood pressure, fluid retention, myocardial infarct, stroke (caution advised for patients with cardiovascular disease)** - GI: Upper abdominal pain, gastric erosions, peptic ulcers, oesophageal ulcers, GI bleeding, perforation. (Relative risk varies between different NSAIDs and is dose related). Selective COX-2 have less (but not none) GI complications. If a NSAID must be used and there is concern about GI bleed a proton pump inhibitor (PPI) may be co-prescribed to prevent (or atleast reduce the risk) of GI complications. Of the NSAIDs, Diclofenac and Ibuprofen appear to have the lowest risk of GI complications (and are commonly used in practice) - Renal: Renal impairment (risk is increased in elderly, perioperatively, pre-existing renal disease and coadministration with ACEI and diuretics (triple whammy) or co-administration with other nephrotoxic medications should be considered before prescribing. - Skin: Erythematous reactions Urticaria Photosensitivity Stevens-Johnson Syndrome (rare) - Lungs Aspirin-sensitive asthma (5% of asthmatics) Bronchospasm (does not occur with coxibs) - Liver: NSAIDs should NOT be prescribed to patients with severe hepatic impairment!! Precautions: - if given with paracetamol should use a lower dose of NSAID - triple whammy - Low dose aspirin is not used for pain (high doses can be used in some conditions such as Migraine) Unsafe in children due to risk of Reye Syndrome Most commonly used as an antiplatelet for cardiovascular and neurological indications. - Do not stop low dose aspirin when using a NSAID (as the antiplatelet effect of NSAIDs is less reliable than low dose aspirin)

Question 106

**- Discuss bDMARDs, their MoA, indications, side effects, provide some examples, and explain why they are not first line drugs**

Answer 106

- Abatacept=Interruption 2nd T cell costimulation signal - Tocilizimab=IL-6 cytokine receptor inhibitor - Rituximab=B cell blocker(CD 20 monoclonal antibody) - JAK inhibitors tofacitinib, baracitinib, upadacitinib Abatacept, Tocilizimab, Rituximab, JAKs Cautions - Same as TNF-inhibitors for prescreening and exclusions - Discontinue Rx if a patient develops serious infection (more likely if on steroids, over 65 years –perhaps etanercept, abatacept, rituximab less infection risk) - Monitor immunoglobulin levels for those on rituximab - Monitor full blood count(especially neutrophils), liver function and lipids for those on tocilizimab - Vaccination against influenza and pneumococcus all RA patients. Ideally also herpes zoster vaccine pre starting boDMARDs and tsDMARDs - Avoid JAK inhibitors if significant clot and vascular history All in RA All seronegative except tocilizumab, rituximab, anakinra, abatacept. Contraindications: Current infections (TB, hepatitis, HIV) Exposure to serious infections (hepatitis, HIV) Malignancy (breast cancer) Multiple Sclerosis HF SEs: Infections Rash, itch Headache Auto-Ab Psoriasis, eczema Blood dyscrasia Malignancies Demyelination Interstitial lung disease Vasculitis HF Note: rituximab requires Ig monotrong, certolizumab-pegol is safe for pregnancy, and tocilizumab needs monitoring of LFT, FBC, WCC

Question 107

- What is the role of corticosteroids in rheumatic disease? What are some side effects?

Answer 107

Part of conservative management Indicated for multiple: - short term relief OA - first line acute gout attack along with NSAIDs or colchicine - optional part of phase I for RA - De Q tendonitis - Not first line and not ongoing due to side effects: - avascular necrosis of bone - osteoporosis - tendonopathies

Question 108

**- Discuss azathioprine/cyclophosphamide/cyclosporin/tacrolimus/mycophenolate mofetil/rituximab: administration/MoA and indications, side effects, contraindications and monitoring/toxicity**

Answer 108

Go straight to Immsupp deck

Question 109

**- Provide examples of csDMARDs, their MoA, indications, side effects, any contraindications**

Answer 109

Names: Methotrexate Sulfasalazin Hydroxychloroquine Leflunomide, Cyclosporine MTX: Antimetabolite Folic acid analogue which binds to dihydrofolate reductase enzyme & antagonises folic acid. As folic acid is essential to DNA synthesis, MTX impairs cell division , reduces monocytic cell growth & induces apoptosis Has cytotoxic and immunosuppressant activity Common first choice drug for RA ADVEs: heptox, myelotox, pulmo tox; synergistic BM, liver and pulmo tox with leflunomide; contrad in pregnancy Monitring: FBC and LFTs, renal function Once a week therapy. Consideration for implications for compliance Co-administration of folic acid (not on the same day as methotrexate) reduces GI adverse effects and hepatotxicity -- Leflu Anti metabolite Inhibits pyrimidine synthesis by competitively blocking dihydro-orotate dehydrogenase and thus inhibiting activated lymphocytes. It has immunosuppressive, immunomodulating and antiproliferative properties. Also has uricosuric effects. - hep, myelo, pulmo tox and BP - synergistic BM, liver, lung with MTX - monitoring: FBC, LFT, BP (Renal function) CONTRAINDICATED IN PREGNANCY Washout procedure - Due to long half-life of active metabolite, if cessation of leflunomide is required (particularly due to adverse effects or unexpected pregnancy etc) a washout may be required --- Sulf May act by scavenging the toxic oxygen metabolites produced by neutrophils Anti-inflammatory and immunosuppressant - usually used if methotrexate is not required first line eg if the patient has low-grade inflammation, few affected joints and no indicators of poor prognosis. hep, myelotox; hypersensitivity Monitor: FBC, LFT (renal function) Reversible decrease in sperm count has been reported (but safe in female pregnancies) --- HCQ Inhibits the release of lysosomal enzymes, PML chemotaxis, IL-1 release and the action of phospholipase A2 -> ↓ formation of inflammatory mediators Monotherapy with hydroxychloroquine may be used if the patient has low-grade inflammation, few affected joints and no indicators of poor prognosis (and therefore doesn't require methotrexate). - advEs: retinopathy and GIT - monitor: eye exam, renal and LFTs, FBC - ONTRAINDICATED IN PREGNANCY Monitoring : check complete blood count, renal and hepatic function at baseline - may take approximately 2–6 months of treatment before benefit is seen Ocular toxicity: - Blurred vision is common. - Corneal changes (eg oedema, opacities) occur infrequently, are transient or reversible and may cause effects such as blurred vision and halos. - Retinopathy is related to daily dose and duration of treatment. Retinal toxicity can lead to vision loss. Damage is irreversible and may progress after stopping hydroxychloroquine. - Baseline and regular ophthalmological examination required.

Question 110

**- Provide examples of anti-resorptive agents, their MoA, indications, side effects, any contraindications**

Answer 110

SERM and calcitriol S: Antiresorptive Acts on estrogen receptors andindicated in post-menopausal osteoporosis - Acts on estrogen receptors in bone and not in the breast tissue Improves boen density and reduces vertebral bone fractures - Evidence of improved bone density - Evidence for reduced fracture at vertebral site Calcitriol: - antiresorptive indication: osteoporosis - improves bone density but does not reduce bone fractures Bisphosphonates: Bisphosphonate molecules attach to osteoclasts where they disrupt bone resorption Post-menopausal osteoporosis Male osteoporosis Corticosteroid induced osteoporosis Osteoporosis – primary prevention Side effects: GI upset and osteonecrosis of jaw; atypical fractures EXTRA: - poor compliance: Weekly medications, Risendronate now monthly, IV Zolendronic Acid – annual infusion - 50% compliance for orals - improves bone density reduced compact and trabecular bone fractures e.g.s alendronate risendronate

Question 111

**- Provide examples of anabolic agnets, their MoA, indications, side effects, any contraindications**

Answer 111

Anabolic MoA:PTH homolog. Intermittent exposure activates osteoblasts. - Chronically elevated PTH will deplete bone stores. - Intermittent exposure to PTH - activate osteoblasts more than osteoclasts. - - Once-daily injections of teriparatide have a net effect of stimulating new bone formation leading to increased bone mineral density. Indications:Post-menopausal osteoporosis Side effects/name: Sarcoma if used for longer then 18 months Teriparatide

Question 112

**- Provide an example of a dual agent, its MoA, indications, side effects and any other relevant information**

Answer 112

Strontium Ralenate Dissociates bone remodelling – increases bone formation. Induces preosteoblasts. Inhibits osteoclast formation. SEs: Hypertension, PH and CVA, Thrombosis Extra: Reduces compact and trabecular bone fractures.

Question 113

Describe hip fractures and their relative severity

Answer 113

Pelvic Fractures ^[imp] - fractures of superior and inferior rami are stable, can be treated conservatively - similarly, fractures of the iliac wing, although high energy, can also be managed conservatively - by contrast, disruption of sacroiliac joint (and pubic symphysis is more serious) - The most serious of these is a pelvic diastasis, with risk of rupture of retroperitoneal veins, bleeding, and haemodynamic instability. MUST BE CLOSED ^[Open book fracture _(anterior + posterior pelvic ring fracture)_ ]: "**superior lateral quadrant**" -

Question 114

Describe psoas abscess

Answer 114

Infection within psoas major can cause irritability and infection can be transmitted to hip joint Psoas major abscess can lead to septic arthritis of the hip joint

Question 115

Label this Xray of the elbow

Answer 115

Question 116

Label this Xray of the pelvis

Answer 116

Question 117

Label this Xray of the knee

Answer 117

Question 118

Describe the sensory innervation of the lower limb

Answer 118

- obturator nerve: L2-4 -- medial thigh - lateral femoral cutaneous nerve -- anterolateral thigh - femoral nerve -- anteromedial thigh - sural -- posterolateral leg (from sciatic -> tibial) - saphenous -- branch of femoral: medial leg and foot - deep peroneal -- first web space - superficial peroneal -- dorsum of foot and anterolateral leg (from sciatic) - tibial -- plantar foot (via sciatic) - common peroneal -- lateral knee