MSK Flashcards
What are the contents of the popliteal fossa, medial to lateral?
Popliteal artery
Popliteal vein
Tibial nerve
Common fibulae nerve
What are the borders of the cubical fossa?
Lateral: medial side of the brachioradialis
Medial: lateral border of pronator teres
Superior: imaginary line between the epicondyles of the humerous
What are the contents of the cubical fossa, lateral to medial?
Radial nerve
Biceps tendon
Brachial artery
Median nerve
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What are the borders of the anatomical snuffbox?
Medial: tendon of extensor pollicis longus
Lateral: tendons of the abductor pollicis longus and extensor pollicis brevis
Proximal border: styloid process of the radius
Floor: carpal bones, scaphoid and trapezium
Roof: skin
What are the contents of the carpal tunnel?
Median nerve
Tendon of flexor pollicis longus
4 tendons of flexor digitorum profundus
4 tendons of flexor digitorum superficialis
What are the borders of the femoral triangle?
Superior: inguinal ligament
Lateral: medial border of the sartorius
Medial: medial border of the adductor longus
Floor: pectineus, iliopsoas and adductor longus
Roof: fascia lata
What are the contents of the femoral triangle, lateral to medial?
Femoral nerve Femoral artery Femoral vein Femoral canal (NAVEL)
What are the borders of the femoral canal?
Medial: lacunar ligament
Lateral: femoral vein
Anterior: inguinal ligament
Posterior: pectineal ligament, superior rami of the pubi and the pectineus muscle
What are the contents of the femoral canal?
Lymphatic vessels (draining the deep inguinal lymph nodes)
Deep lymph node (lacunar node)
Empty space (allows distension of adjacent femoral vein)
Loose connective tissue
What are the borders of the adductor canal?
Anterior: sartorius
Lateral: vastus medialis
Posterior: adductor longus and adductor magnus
Apex: adductor hiatus
What are the borders of the popliteal fossa?
Superiomedial border: semimembranosus
Superiolateral border: biceps femoris
Inferiomedial border: medial head of gastrocnemius
Inferiolateral border: lateral head of gastrocnemius and plantaris
Floor: posterior surface of the knee joint/femur
Roof: popliteal fascia/skin
List some functions of the skeleton
Support Protection Movement Mineral and growth factor storage Haematopoeisis
Explain the 5 classifications of bones
Flat - curved, protect organs
Short - equal in length and width
Irregular e.g. Vertebra
Long - longer than they are wide, muscles act upon them as levers
Sesamoid (embedded within a tendon or muscle) and sutural (within cranial suture)
What is avascular necrosis?
Death of bone due to interruption of blood supply
What are some synonyms for avascular necrosis?
Osteonecrosis
Aseptic necrosis
Ischaemic necrosis
What might cause avascular necrosis?
Fracture Dislocation Steroid use Radiation Decompression sickness
How are joints classified structurally?
Fibrous
Cartilaginous
Synovial
How are joints classified functionally?
Synarthrosis (immobile)
Amphiarthrosis (slightly mobile)
Diarthrosis (freely mobile)
What is gomphosis?
Connective tissue connecting teeth to bone
Name 3 types of fibrous joints
Suture
Syndesmosis
Gomphosis
Describe suture joints
Restricted to cranium
Synostosis on completion of growth
Describe syndesmosis fibrous joints and give an example
Permits a small amount of movement (amphiarthrosis)
E.g. Inferior tibiofibular joint, radio ulnar interosseous membrane, posterior sacroiliac joint
Describe a primary cartilaginous joint (synchondrosis)
United by hyaline cartilage
Functional lassitude as a synarthrosis (immovable joint)
E.g. 1st sternocostal joint
What is a synarthrosis joint?
Immovable
What is a amphiarthrosis joint?
Slightly movable
What is a diarthrosis joint?
Freely mobile
Describe a secondary cartilaginous joint (symphysis)
Articulating bones covered with hyaline cartilage, with a pad of fibrocartilage between them
Amphiarthrosis (slightly movable)
E.g. Pubic symphysis, intervertebral disc, manubiosternal joint
What is a synovial joint?
A joint cavity containing synovial fluid. These are freely movable (diarthrosis).
List the characteristics of a synovial joint
Articular cartilage (usually hyaline) Fibrous capsule Synovial membrane Synovial fluid Bursa/Tendon sheaths
What does articular cartilage in a synovial joint do?
Usually hyaline, provides low friction surface, resists compression.
What does the fibrous capsule in a synovial joint do?
Comprised of collagen. Completely encloses joint (apart from synovial protrusions e.g. Bursa). Resists dislocation, stabilises joint but permits movement
What does the synovial membrane of a synovial joint do?
Thin, highly vascularised membrane which lines capsule, covers exposed osseous surfaces, tendon sheaths, bursa (but does NOT cover articular cartilage or discs/menisci). Produces synovial fluid
What does synovial fluid do in a synovial joint?
Reduces frictions shock absorption, nutrient and waste transportation. Clear/pale yellow fluid, viscous, slightly alkaline. Small volume, consisting of hyaluronic acid, lubricant, proteinase, collegians.
What is a bursa?
Sac lined with synovial membrane, filled with synovial fluid
What is a tendon sheath?
Elongated bursa, wrapped around a tendon
Describe the blood supply of a synovial joint
Periarticular arterial plexus (circulus arteriolus vascuolus)
Articular cartilage is avascular
Fibrous capsule and ligaments have poor blood supply
Synovial membrane has rich blood supply
Describe Hiltons law with regards to joints
The nerves supplying the joint capsule also supply the muscles moving the joint and the skin overlying the insertions of these muscles
How are synovial joints classified?
Dependent upon the shape of articulating surface
Describe a planar joint
Flat or slightly curved articulating surface
Gliding or sliding movements
Give an example of a planar joint
Sternoclavicular joint
Acromioclavicular joint
Intercarpal joints
Vertebral facet joints
Describe a hinge joint
Uniaxial/monaxial
Convex surface of one bone fits into concave surface of another
Give an example of a hinge joint
Knee
Ankle
Humeroulnar joint of elbow
Describe a pivot joint
Rounded or pointed surface of one bone articulates within ring formed by the concavity of another bone and a fibrous ligament
Give an example of a pivot joint
Proximal radioulnar joint
Atlantoaxial joint
Describe a condyloid/ellipsoidal joint
Biaxial joint
Oval shaped condolences of one bone rests on elliptical cavity of another
Enables flexion, extension, abduction, adduction (and therefore circumduction)
Give an example of a condyloid/ellipsoidal joint
Metacarpophalangeal joints
Radiocarpal (wrist) joint
Atlanto-occipital joint
Describe a saddle joint
Biaxial joint
One bone is ‘saddle shaped’ (concavoconvex), the other bone resembles the legs of the rider
Enables flexion, extension, adduction, abduction (therefore circumduction)
Give an example of a saddle joint
1st carpometacarpal joint
Trapezium to 1st metacarpal
Describe a ball and socket joint
Multiaxial/polyaxial
Ball-like surface of one bone fits into cup-like surface of another
Enables flexion, extension, abduction, adduction, (therefore circumduction) AND rotation
Give and example of a ball and socket joint
Hip
Shoulder
Incudostapedial joint (middle ear)
Name the 2 bursa of the elbow joint which are likely to give rise to problems
Subcutaneous olecranon bursa
Subtendinous olecranon bursa
List 7 factors affecting stability and range of motion of joints
- Structure/shape of articulating bones
- Strength and tension of joint ligaments
- Arrangement and tone of muscles
- Apposition of neighbouring soft tissues
- Hormones e.g. Relaxin in pregnancy
- Use/disuse
- Age (decreased production of synovial fluid, thinning of articular cartilage, shortening of ligaments - decreased flexibility, degenerative changes)
How does ageing effect joints?
Decreased production of synovial fluid
Thinning of articular cartilage
Shortening of ligaments - decreased flexibility
Degenerative changes
What are osteophytes?
Protrusions of bone present in osteoarthritis
What is Paget’s disease of the bone?
The normal cycle of bone renewal and recycling is interrupted, causing bones to become weak and deformed, enlarged and misshapen. Typically localised to only a few bones, as opposed to osteoporosis which effects them all.
Describe circular muscles
Act as spinsters to adjust opening
Concentric fibres
Attach to skin, ligaments and fascia, rather than to bone
Give an example of a circular muscle
Orbicularis occuli
Orbicularis oris
Name the 3 main categories for parallel muscles
Strap
Fusiform
Fan shaped (‘convergent’)
Describe strap parallel muscles and give an example
Fibres run longitudinally to contraction direction
E.g. Sartorius
Describe fusiform parallel muscles and give an example
Wider and cylindrically shaped in the centre, tapers off at ends
E.g. Biceps Brachii
Describe fan shaped ‘convergent’ muscles and give an example
Fibres converge at one end and spread over broad area at the other
E.g. Pectoralis major
What are the 3 types of pennants muscles?
Unipennate (all fascicles on same side of tendon)
Bipennate (fascicles on both sides of central tendon)
Multipennate (central tendon branches)
What is compartment syndrome?
Trauma in one compartment of limb (delineated by fascia), can cause internal bleeding which exerts pressure on blood vessels and nerves
What are the symptoms of compartment syndrome?
Deep constant, poorly localised pain, aggravated by passive stretch of muscle group.
Paresthesia (‘pins and needles’)
Compartment may feel firm and tense. Swollen, shiny skin, sometimes with obvious bruising
Prolonged capillary refill time
How is compartment syndrome treated?
Fasciotomy
Subsequently covered by skin graft
What is agonists role in muscle movement?
Prime movers, cause flexion
What is antagonists role in muscle movement?
Oppose prime movers
What is synergists role in muscle movement?
Assist prime movers (but acting alone they cannot perform the movement. Angle of pull assists)
What is neutralisers role in muscle movement?
Prevent unwanted actions that an agonist can perform
What is fixators role in muscle movement?
Act to hold a body part immobile whilst another body part is moving
What is contraction?
The generation of force, not just the shortening of muscle
What are the types of contraction?
Isotonic contraction (constant tension, variable muscle length - muscle changes length to move load). Can be
- concentric (muscle shortens)
- eccentric (muscle exerts a force while being extended. Can lead to delayed-onset muscle soreness in excess)
Isometric contraction (constant length, variable tension e.g. hand grip)
What are the 3 types of biomechanical levers?
First class lever - 'see saw', effort at one end, load at other. E.g. Semispinalis capitas in neck extension. Second class lever - 'wheelbarrow', effort at one end, fulcrum at other. E.g. Plantar flexion of foot. Third class lever - 'fishing rod', effort between load and fulcrum. E.g. Biceps brachii in flexion of the elbow.
Name the 3 main muscle fibre types
Slow type I
Fast type IIA
Fast type IIX
Also several intermediate ‘hybrid’ types
What is the size principle with regards to controlling muscle force?
Small motor neurones recruited before large
Slow type I –> Fase IIA –> Fast IIX
What is baseline muscle tone due to?
Motor neuron activity
Muscle elasticity
What is hypotonia?
A lack of skeletal muscle. A symptom not a condition.
What type of ACh receptor is present at the neuromuscular junction?
Nicotinic ACh channels. Enable influx of Na+.
What is myotonia congenita?
Symptoms include muscle stiffness, particularly in leg muscles. I handed by cold and inactivity.
Caused by mutations in chloride channel (CLCN1).
Can be recessive (Becker type) or dominant (Thomsen type).
Why are Cl- ions so important in skeletal muscle?
About 70% of the conductance in resting fibres is due to Cl- flow.
When membrane potential deviates from rest, large Cl- currents flow, returning membrane voltage to resting value.
Although no treatment is usually required, how can symptoms of myotonia congenita be relieved?
Anticonvulsant drugs
What is dislocation?
Complete loss of contact of the joint surface
What is subluxation?
Partial dislocation of a joint, so that the bone ends are misaligned but still in contact.
What is the name of where most spinal cord segments end?
Cornus medullaris
At what level is the Cronus medullaris?
L2
Where does the spinal cord begin?
Inferior margin of the medulla oblongata
What does the meningeal branch of the spinal rami supply?
Re-enters spinal canal through intervertebral foramen. Supplies vertebrae, ligaments, blood vessels and meninges
What are the functions of bone?
Biomechanics Growth Repair Protection Mineral homeostasis Haemopoiesis
What are the signs and symptoms of a fracture?
Pain Loss of function Swelling Deformity 'Bony' tenderness Crepitus Abnormal movement
How would you describe a fracture?
Location Configuration Parts Articular Displacement (angulation, displacement, axial, rotation)
What are the 3 phases of fracture healing?
Inflammatory 1-5 days
Reparative 4-40 days
Remodelling 25-200 days
List some factors that influence bone healing
Local:
Injury itself (fracture configuration, soft tissue injury?)
Type of bone (cancellous or cortical?)
Treatment (reduction, stability, infection)
Regional: (blood supply, muscle cover)
Systemic: (age, co-morbidity, bone pathology, head injury)
How may bone heal incorrectly?
Malunion (deformity, late arthrosis)
Non-Union (hypertrophic - not immobilised) (atrophic - not good enough blood supply/poor quality bone)
Infection
List some early, local, fracture complications
Nerve injury Vascular injury Compartment syndrome Avascular necrosis Infection Surgical
List some early, systemic, fracture complications
Hypovolaemia/shock Fat embolism Thromboembolism Acute respiratory distress syndrome Disseminated intravascular coagulation
List some late, local, fracture complications
Delayed Union (slow healing) Non-Union (doesn't heal) Malunion (heals wrong) Myositis ossificans Re-fracture
What is myositis ossificans?
Bleeding into muscle (e.g. From fracture), muscle becomes calcified, bone forms in muscle.
Difficult to treat, occurs particularly around the elbow
List some late, regional, fracture complications
Osteoporosis Joint stiffness Chronic regional pain syndrome (sympathetic nervous system overreacts to injury) Abnormal biomechanics Osteoarthrosis
What is compartment syndrome?
Raised pressure within an enclosed fascial space leading to localised tissue ischaemia
Passive stretch pain
Neuromuscular changes are late
Changes in blood pressure can occur, difficult to cure - must divide fascia
What must you be watch out for with open fractures?
Bone may have come out, then gone back in again bringing foreign material with it.
Why are growth plate (epiphyseal) fractures in children particularly bad?
Growth may then occur wrong (twisted/not at all)
What are stress fractures caused by?
Repetitive, non-violent stresses
Frequently seen in spine/tibia/femur/pelvis/foot
Predispositions: osteoporosis, sports, eating disorders
Initial assessment of a fracture should always be what?
Airway
Breathing
Circulation
What is a dorsal, distal radius fracture called?
Colles fracture
What is a palmar, distal radius fracture called?
Smiths fracture
When is the stance phase of walking?
Foot is in contact with the ground
Begins with heel strike, flat foot, then mid stance ends with push-off
When is the swing phase of walking?
Foot is off the ground
Begins after push off, lift leg and swing phase
What are the lateral rotators of the hip?
Obturator externus Obturator internus Gemeli Piriformis Quadratus femoris
What are the medial rotators of the hip?
Gluteus medius
Gluteus minimus
Tensor fascia lata
Describe a trendelenburg gait
‘Waddling’
Weakness of hip abductors
Describe what causes a high stepping/foot drop gait
Damage to common perineal nerve
What is an ‘antalgic’ gait?
A limp
Shortened stance phase, gentle heel strike
Describe a neurapraxia nerve injury?
Conduction block
Axons are intact, nerve sheath intact. No wallerian degeneration. Complete recovery
Describe an axonotmesis nerve injury
Nerve damage and axon loss
Compression and/or traction. Axons damaged/nerve sheath disruption. Wallerian degeneration. Partial-full recovery
Describe a neurotmesis nerve injury
Severed nerve
Rupture or avulsion. Axon disruption, nerve sheath disruption. Wallerian degeneration. No recovery without surgery
What is synovial fluid comprised of?
Hyaluronic acid, lubricant, proteinase, collegians. Clear/pale yellow fluid
What are the nerve roots of the superior gluteal nerve?
L4, L5, S1
What are the nerve roots of the inferior gluteal nerve?
L5, S1, S2
What are the nerve roots of the nerve to piriformis?
S1, S2
What are the nerve roots of the nerve to obturator internus?
L5, S1
What are the nerve roots of the nerve to quadratus femoris?
L4, L5, S1
What are the nerve roots of the accessory nerve?
C1-C6
Spinal nerve CNXI
What are the nerve roots of the thoracodorsal nerve?
C6, C7, C8
What are the nerve roots of the dorsal scapular nerve?
C5
What are the nerve roots of the musculocutaneous nerve?
C5, C6, C7
What are the nerve roots of the axillary nerve?
C5, C6
What are the nerve roots of the median nerve?
C5, C6, C7, C8, T1
What are the nerve roots of the ulnar nerve?
C8, T1
What are the nerve roots of the radial nerve?
C5, C6, C7, C8, T1
What are the nerve roots of the medial pectoral nerve?
C7, C8, T1
What are the nerve roots of the lateral pectoral nerve?
C5, C6
What are the nerve roots of the long thoracic nerve?
C5, C6, C7
What are the nerve roots of the femoral nerve?
L2, L3, L4
What are the nerve roots of the obturator nerve?
L2, L3, L4
What are the nerve roots of the sciatic nerve?
L4, L5, S1, S2, S3
What are the nerve roots of the tibial nerve?
L4, L5, S1, S2, S3
What are the nerve roots of the common peroneal nerve?
L4, L5, S1, S2, S3
What are the nerve roots of the superficial peroneal nerve?
L4, L5, S1
What are the nerve roots of the deep peroneal nerve?
L4, L5
