Anatomy Flashcards
What parts make up the appendicular skeleton?
Hip bones (of pelvic girdle)
Pectoral girdle
Limbs (upper & lower)
Describe the basic layout of the upper and lower limb bones
Girdle
Single long bone
Paired long bones
Short and long bones
What functions is the upper limb specialised for?
Range of movement in preference to strength Carriage Fine manipulative tasks Feeding Minimal locomotion
What functions is the lower limb specialised for?
Strength in preference to range of movement Support body weight Maintain upright posture Locomotion (gait) Accommodate shock loading
What is the pectoral girdle?
Mobile structure, clavicle and scapula
Only one joint with axial skeleton - clavicle at sternum
Compressive forces transmitted via the clavicle
Tension transmitted via muscles
What is the pelvic girdle?
Rigid ring of bone that is partly formed by the axial skeleton
Distributes weight of axial body to lower limbs
Enables locomotion & standing
Force transmission mostly via compression
What are the major joint types?
Fibrous - skull sutures, gomphosis (teeth), syndesmosis
Primary cartilaginous - growth plate
Secondary cartilaginous - between vertebrae
Synovial
Describe the structure of synovial joints
Hyaline cartilage at the end of bones
Surrounded by synovial cavity with fluid
Surrounded by synovium (serous membrane secretes fluid)
Surrounded by fibrous joint capsule
What are bursae? And how can they be treated?
Pockets of synovium & synovial fluid found in regions of friction/wear
Some are isolated & some communicate with joint spaces
Bursa inflammation = bursitis
Bursitis causes localised pain & tenderness to palpation
Can be aspirated/injected with steroid
What are tendons surrounded by at points of wear, friction or direction change?
Synovial sheath
What is Tenosynovitis?
Inflammmation of both sheath & tendon
Describe the anatomy of a long bone
Epiphysis - ends
Metaphysis
Diaphysis - shaft
What are sesamoid bones?
Found within tendons eg patella
Reduce wear
Improve muscle efficiency
What are flat bones?
Large surface areas for muscle attachment
Weight / force transfer region
Protection (pelvic girdle & skull)
What is Wolff’s Law?
Bone is deposited and reabsorbed in accordance with the stresses placed upon it (it is able to remodel)
When do limb buds grow out of embryo during development?
From week 4/5
Upper limbs buds appear 36h before the lower
Digits and limb shape present by week 8
What is Amelia/Meromelia/phocomelia?
No limb formation
Abnormal limb formation
Seal like limb
What is Polydactyly?
Extra digits
What can be causes of limb defects?
Thalidomide (anti-nauseant, sleeping pill)
Retinoids (vitamin A derivatives)
Mechanical – amniotic bands ‘strangle’ tissue
How does embryology help to explain dermatomes of the upper limb?
Limbs appear with ventral & dorsal surfaces - Initially look like flippers that later rotate
Upper limb rotates laterally, Lower limb rotates medially
Dermatomes wind around the limbs
Eg C5 outside of arm, T1 inside of arm
What are nerve plexi?
Regions where the ventral rami of spinal nerves join and exchange neurons
Brachial plexus = upper limb, Lumbar and sacral plexi = lower limbs
Most named nerves of the limbs consequently contain neurons from multiple spinal nerves
What advantage does having nerve plexi have?
Means damage to a spinal nerve won’t leave the entire limb paralysed
What is a dermatome?
Area of skin innervated by a single spinal nerve
What is a Cutaneous nerve area?
Area of skin innervated by a named cutaneous nerve eg sciatic nerve
What separates the limbs into compartments?
Thick deep fascia
What function does the anterior compartment of the upper limb have?
Flexor
What function does the posterior compartment of the upper limb have?
Mostly extensor function
How many compartments does the upper limb have?
2
Anterior and posterior
How many compartments does the thigh have? And what do they do?
3
Anterior - Knee extensor
Posterior - Hip extensor, knee flexor
Medial - Hip adductor
How many compartments does the leg have? And what do they do?
3
Anterior - Foot dorsiflexor
Posterior - Foot plantarflexor
Lateral - Foot evertor
Which nerve and artery supply the anterior thigh compartment?
Femoral nerve (L2,L3 & L4) Femoral artery
What are retinacula?
Thick bands of fascia
Prevent tendon bowstringing
Keep tendons in proximity of a joint enabling functioning through range of joint motion
Describe the artery supply to the upper limb
Subclavian Artery
Axillary Artery, gives off profunda branch
Brachial Artery (pulse)
Radial and ulnar artery (pulses at wrist)
Palmar arches
Describe the blood supply to the lower limb
Femoral Artery, gives off profunda branch
Popliteal artery (pulse)
Anterior and posterior tibial, gives off fibular
Dorsalis pedis (pulse anterior)
Posterior tibial (pulse)
Deep plantar arch and arcuate artery
What run close to superficial veins?
Cutaneous nerves
What are Venae comitantes? And why are they where they are?
Run with arteries & between muscles
Usually paired at sides of arteries
Muscle pump mechanisms help venous return
Valves direct blood flow
What is the cubital fossa?
Axillary nodes in the armpit
Humeral, subscapular, pectoral drain to Central
This drains to apical which in turn drains to supraclavicular
What is the popliteal fossa?
Inguinal nodes, superficial and deep
What are the root values of the sciatic nerve?
L4-S3
What root values supply the hamstrings?
L5-S2
What root values supply gastrocnemius and soleus?
S1-S2
What root values supply tibialis posterior and popliteus?
L4-L5
Which area of the skin is supplied by the obturator nerve?
Medial thigh
What type of joint is the pubic symphysis?
Secondary cartilaginous
What are the 3 bones of the hip?
Ilium
Ischium
Pubic
Why is the ischial tuberosity so large?
Hamstring muscles pull on it so it is remodelled and strengthened
What is the acetabulum?
Socket part of hip joint
Union of the 3 bones of the pelvis
Describe the hip joint
Ball & socket joint (synovial)
Shares features with the shoulder joint
Combines mobility & transmission of weight
Wide range of movement sacrificed for stability
Supported by muscles, ligaments, bone shape & acetabular labrum
What is the acetabular labrum?
Fibrocartilage rim surrounding the acetabulum
Attaches to bony margin of acetabulum, Makes socket deeper
Aids joint stability
Can get impinged within joint causing pain on movement
What is special about the ligaments of the hip? And what are they?
Thickened joint capsule
Iliofemoral, ischiofemoral (posterior), pubofemoral
Hip joint less stable when flexed as ligaments are lax and not providing as much support
Why is blood supply to the hip joint vulnerable to interruption from injury?
Arteries to the femoral head pass through retinacular fibres of the joint capsule, Circumflex arteries surround femoral neck, Branches travel to femoral neck & head
Intra-capsular femoral neck fractures can disrupt blood supply
Avascular necrosis of femoral head can result from intra-capsular fracture
What is an intertrochanteric fracture?
Extracapsular hip fracture between greater and lesser trochanter
What is coxa valga? (Valgus)
Distal part of bone directed away from the midline
What is coxa vara? (Varus)
Distal part of bone directed toward the midline
What is the iliotibial tract?
Lateral thickening of fascia lata
Acts as a muscle attachment point
Assists in knee extension & stability as it crosses the knee joint so allows gluteous maximus to aid in control of the knee
What surrounds the compartments of the thigh and forms structural features?
Fascia lata
Where does the saphenous vein run?
Superficial to the fascia lata, medial thigh
What are the root values of the femoral nerve?
L2-L4
What are the root values of the the tibial part of the sciatic nerve?
L5 S1
What are the gluteal muscles and what is their job?
Gluteus maximus, medius and minimus
Powerful hip/trunk extension (stair climbing, arising from chair) and pelvic stabilisation during walking
What nerve supplies gluteus maximus?
Inferior gluteal nerve (L5-S1)
Which nerve supplies gluteus minimus and medius?
Superior gluteal nerve (L4-L5)
What covers the ischial tuberosity?
Ischial bursa – bursitis causes pain on sitting & deep palpation
Where do gluteus minimus and medius attach?
Greater trochanter of the femur
What does damage or paralysis of gluteus medius and minimus lead to?
Trendelenburg sign & lurch when walking
What function do the gluteal muscles perform during walking?
Medius & minimus: prevents pelvis tilting toward unsupported side
Maximus: prevents trunk from tipping forwards
What does damage or paralysis of gluteus maximus lead to?
Lurching backward when the weaker limb is on the floor during walking; makes getting out of a chair difficult
What is the greater sciatic foramen?
Connects to pelvic cavity & gluteal region
Above sacrospinous ligament
What is the lesser sciatic foramen?
Connects to perineal & gluteal regions
Below sacrospinous ligament, posterior border sacrotuberous ligament
What are the lateral rotator muscles?
Support and laterally rotate the hip
Located deep to gluteus medius
Pass between the pelvic bones & ligaments & proximal femur
Innervated by L4-S2
Piriformis, Gemelli, Quadratus femoris, obturator internus
What does the piriformis muscle divide the greater sciatic foramen into?
Supra and infra piriform parts
Superior gluteal artery & nerve emerge above piriformis
Inferior gluteal artery & nerve and sciatic nerve emerge below piriformis
Where does the sciatic nerve run in relation to the hip joint?
Posterior
What are the 2 methods for finding the safe zone for intramuscular injection into the gluteal region?
Method 1: Vertical line through highest point of iliac crest, Horizontal line midway between ischial tuberosity and highest point of iliac crest
Method 2: Vertical line through highest point of crest, Line from PSIS to the greater trochanter
What is iliopsoas?
Powerful hip flexor L1-L2
Psoas major - attachment to lumbar vertebrae Hip flexion can exacerbate back pain
Iliacus - Inner surface of iliac bone
Attach to lesser trochanter which can be subject to avulsion fracture
What can mimic a femoral hernia?
Abscesses can track down the fibrous sheath covering psoas producing a femoral triangle swelling that can mimic a femoral hernia
What are the hip adductor muscles?
Occupy medial thigh (obturator n. L2,3) – Adduct the hip joint
Pectineus, Adductor Longus (superficial)
Adductor Brevis, Adductor Magnus (deep)
What passes through the adductor hiatus?
Femoral artery passes through adductor hiatus to go behind knee and continue as the popliteal artery
What are the quadriceps?
Quadriceps muscle group (Femoral n. L3,4) = knee extension & hip flexor
Rectus femoris
Vastus intermedius (deep to rectus femoris)
Vastus lateralis
Vastus medialis
What muscles other than the quads occupy the anterior compartment?
Sartorius
Tensor fascia lata
What does loss of function of the quads lead to?
Weak or absent knee extension
Difficulty getting out of a chair
What are the hamstrings?
Hamstring muscle group (tibial part of sciatic nerve L5, S1)– hip extension & knee flexion
Semimembranosus
Semitendinosus
Biceps femoris
Which muscles cross the knee joint and attach to the tibia and fibula?
Biceps femoris
Semitendinosus
What muscle does the lumbar plexus sit around?
Psoas major
What does the lumbar plexus innervate?
Anterior and medial thigh muscles
What nerve branches come off the lumbar plexus?
Lumbosacral trunk (L4,5) Obturator n. (L2, L3, L4) Genitofemoral n. (L1,L2) Femoral n. (L2, L3, L4) Subcostal n. (T12) Iliohypogastric n. (L1) Ilioinguinal n. (L1) Lateral cutaneous nerve of thigh (L2,L3)
What forms the borders of the femoral triangle?
Inguinal ligament (between ASIS and PT) Adductor longus Sartorius
Where does the femoral artery enter the femoral triangle?
Midinguinal point +/- 1.5cm
What do Inguinal lymph nodes drain?
Lower limb Perineal region Penis Lower anal canal Lower vagina Anterior labia majora / scrotal skin
What is a saphena varix?
Great saphenous vein running in superficial location to meet femoral vein, Can dilate here forming a saphena varix
What supplies the main arterial supply to the lower limb?
Common iliac artery
What are the 4 phases of walking?
Heel strike - stance
Support - stance
Toe-off - swing
Swing / Carry through - swing
What is the fibrous joint between tibia and fibula & muscle attachment point?
Interosseous membrane
Where does long saphenous vein pass in ankle?
Anterior to medial malleolus
Where does short saphenous vein run in the ankle?
Posterior to lateral malleolus
What parts of the ankle can be avulsed following excess inversion?
Lateral malleolus and tuberosity of the 5th metatarsal
What is the axis of abduction adduction in the foot?
2nd digit
How many phalanges are there in the toes?
Big toe has 2: proximal and distal
Other digits have 3: proximal, middle and distal
What is the bony mass of the heel?
Calcaneous
What are the tarsals of the foot?
Cuneiform bones nearest to metatarsals
Cuboid near tuberosity of 5th metatarsal
Navicular between cuneiform and talus
Talus part of ankle joint and calcaneus is heel
Describe the anterior compartment of the leg including neurovascular supply
Foot & digit dorsiflexion & inversion
Deep fibular nerve L4, L5
Anterior tibial artery
Describe the lateral compartment of the leg including neurovascular supply
Foot eversion
Superficial fibular nerve L5,S1
Fibular artery
Which nerve runs in close proximity to the short saphenous vein?
Sural nerve
Which nerve runs in close proximity to the great saphenous vein?
Saphenous nerve
Describe the posterior compartment of the leg including neurovascular supply
Foot & digit plantarflexion & inversion
Tibial nerve S1, S2
Posterior tibial artery
What movements are available at the knee joint?
Flexion-extension
Rotation (medial & lateral)
Translocation (Sliding)
Where is the knee joint line?
Palpable anteriorly, sits ~2cm distal to the skin crease behind the joint
What type of joint is the knee?
Modified synovial hinge joint
What are the articulations at the knee joint?
3 Articulations: 2 femero-tibial, 1 femero-patellar
What is the piece of bone between the tibial condyles called?
Intercondylar eminence
What supports the knee joint?
Muscles
Ligaments
Menisci
What are menisci?
Crescent shaped pieces of fibrocartilage sat on the tibial condyles
What are the functions of the menisci?
Increase contact area
Weight-bearing
Act as shock absorbers
Participate in locking mechanism
What can damage menisci?
Compression and medial collateral ligament tears
What is the patella?
Sesamoid bone that articulates with the femoral condyles
What is the function of the patella?
Reduces ligament & tendon wear Spreads forces passing to femoral condyles Increases moment (mechanical bending force) of quadriceps muscles
Where does the patella ligament insert into?
Tibial tuberosity
What do the cruciate ligaments do?
Resist anterior-posterior translocation & rotation of the knee
What does the anterior cruciate do?
Prevents anterior tibial movement on femur
What does the posterior cruciate ligament do?
Prevents posterior tibial movement on femur
When is the ACL at risk of injury?
Force/kick to back of flexed knee
When is the PCL at risk of injury?
Force/kick to front of load-bearing knee
What test can be used to examine cruciate ligament integrity or laxity?
Drawer or Lachman test
What do the collateral ligaments in the knee do?
Medial & lateral collateral ligaments resist valgus and varus forces at the knee
What does the medial collateral ligament do?
Prevents tibial abduction (valgus)
What does the lateral collateral ligament do?
Prevents tibial adduction (varus)
How can medial collateral ligaments be damaged?
Injured by lateral blow
Attached to medial meniscus so both can be damaged together
How can the lateral collateral ligament be damaged?
By a medial blow
What does valgus and varus deformity describe?
Appearance of the part of the bone distal to the joint in question
Describe the blood supply to the knee
Extensive and anastomotic genicular vessels
Tibial or femoral fractures do not normally result in avascular bone necrosis
What is Housemaids knee?
Prepatella bursitis
What is clergymans knee?
Infrapatella bursitis
Where can knee joint inflammation/effusion extend to? And how can this be tested?
Suprapatellar bursa
Patella tap: Milk suprapatellar bursa inferiorly then press patella posteriorly
What is close-packing of the knee joint? And which muscle can release it?
Femur rotates medially on tibia & locks
Passive movement
Ligaments under tension
Position of stability
Popliteus laterally rotates knee to unlock it
Where is the common fibular nerve at risk of compression?
Subcutaneous at head of fibula
Loss of which nerve and muscle can result in foot drop?
Tibialis anterior muscle, L4
What do the anterior leg muscles do? And what might cause pain here?
Guides foot placement during gait
Supports arches of foot
Regional pain from compartment syndrome, tibial stress # or chronic exertional stress on fascia
What are the anterior compartment leg muscles?
Tibialis anterior - L4
Extensor digitorum longus - L5
Extensor hallucis longus - L5
Which nerve supplies the anterior compartment of the leg?
Deep fibular nerve
What are the superior and inferior extensor retinaculum and what do they do?
Fibrous thickening of fascia
Prevent bowstringing of the anterior leg compartment muscle tendons
Which tendon does the dorsalis pedis pulse sit laterally to?
Extensor hallucis longus tendon
What are the lateral leg compartment muscles?
Fibularis longus
Fibularis brevis
What do the lateral leg muscles do?
Primary foot eversion & weak plantarflexion
Help prevent excess foot inversion
Protect lateral collateral ligament from excess inversion stress
Help balance body on foot & foot placement
Which nerve supplies the lateral leg muscles?
Superficial fibular nerve L5, S1
What are the posterior compartment muscles?
Gastrocnemius and soleus - superficial
Tibialis posterior, flexor digitorum, flexor hallucis - deep
What nerve roots does the calcaneal reflex test?
S1-S2
What do the posterior leg compartment muscles do?
Foot & digit plantarflexion & foot inversion
Support arches of foot
Loss of function = weak/absent push-off
What nerve supplies the posterior leg muscles?
Tibial nerve
What muscles are responsible for ankle dorsiflexion?
Tibialis anterior, extensor hallucis longus & extensor digitorum longus
Which muscles are responsible for ankle plantarflexion?
Gastrocnemius, Soleus
FLexor digitorum & flexor hallucis
FIbularis longus & fibularis brevis
Which muscles cause ankle inversion?
Tibialis anterior
Tibialis posterior
Which muscles cause ankle eversion?
Fibularis longus
Fibularis brevis
What is the popliteal fossa? And what are its borders?
Diamond-shaped fat-filled region sat behind the knee Semimembranosus/Semitendinosus Biceps femoris Gastrocnemius medial head Gastrocnemius lateral head