Limbs overview Flashcards
Skeleton components
-made of axial skeleton (skull, vertebral column and thoracic cage) and appendicular skeleton (limbs)
Limb development
NERVE SUPPLY:
- upper limbs supplied by C5-T1
- lower limbs supplied by L2-S3
FLEXORS AND EXTENSORS:
- in the upper limb, the flexors are anterior and the extensors are posterior
- the lower limbs rotate internally so the extensors are anterior and the flexors are posterior
Internal rotation of the developing lower limb
- lower limb undergoes permanent pronation (internally rotates) during development
- results in twisting of the dermatome fields=twisted oblique fields as opposed to straighter fields in the upper limb
- in the thigh and leg, the extensors are anterior and the flexors are posterior
Limb compartments
- tend to have distinct function
- tend to have same nerve supply
- tend to have same blood supply
Compartments of the upper limb
- pectoral girdle muscles (anterior and posterior)
- intrinsic shoulder muscles
- anterior arm muscles
- posterior arm muscles
- anterior forearm muscles
- posterior forearm muscles
- intrinsic hand muscles (palmar and dorsal surface)
Pectoral girdle
- shoulder movement involves both arm movements relative to the scapula at the shoulder joint and scapula movements relative to the chest wall
- muscles acting on shoulder joint have attachments in neck, anterior chest, back and arm
Compartments of the lower limb
- hip abductors (gluteal)
- hip extensors (gluteal)
- hip flexors
- anterior thigh muscles (extensors)
- medial thigh muscles (adductors)
- posterior thigh muscles (flexors)
- anterior leg muscles (extensors)
- lateral leg muscles (foot evertors)
- posterior leg muscles (flexors)
- intrinsic foot muscles
Muscles and nerves of the lower limb
- arise in abdominal and pelvic cavities
- muscles with attachments in abdomen and pelvis are flexors of hip (iliacus and psoas)
- nerves supplying lower limb arise from lumbosacral plexus (L2-S3)=femoral nerve, sciatic nerve
Upper limb arterial supply
FROM HEART TO HAND
- Aorta
- Subclavian artery
- Axillary artery
- Brachial artery (pulse point) including deep brachial artery
- Ulnar and radial arteries (pulse points)
- Hand palmar arches (deep and superficial)
- Metacarpal and digital arteries
Upper limb venous drainage (superficial and deep systems)
FROM HAND TO HEART
- Dorsal venous arch (superficial)
- Cephalic and basilic veins (superficial)
- Venae comitantes (deep)
- Axillary vein (deep)
- Subclavian vein
- Superior vena cava
Superficial veins in cubital fossa
- superficial veins in cubital fossa region commonly used for phlebotomy or venous line insertion
- median cubital vein (links cephalic and basilic veins) not always present
Lower limb arterial supply////////
FROM PELVIS TO FOOT
- Aorta
- Common iliac arteries (internal and external)
- External iliac artery
- Femoral artery (pulse point) to deep femoral
- Popliteal artery (pulse points) to posterior tibial artery, anterior tibial artery, peroneal artery and dorsalis pedis artery
Lower limb venous drainage
DEEP SYSTEM -anterior and posterior tibial venae comitantes -popliteal vein -femoral vein -external iliac vein SUPERFICIAL SYSTEM -venous arches -long (great) saphenous vein -short (small) saphenous vein
Superficial veins of lower limb
- great and small saphenous veins arise from venous network of dorsum of foot
- great saphenous vein drains into femoral vein at groin
- small saphenous vein drains into popliteal vein at popliteal fossa
-saphenous veins are consistent but other superficial veins are more variable
Femoral triangle
- region of the grain where femoral artery can be accessed (cardiac vessel access to carry out angiograms and angioplasty)
- pulse point of femoral artery
Varicose veins
- perforating veins connect superficial and deep veins
- perforating veins contain a valve that will allow flow only from superficial to deep
- compromised valve means blood is pushed from deep to superficial veins, resulting in varicose veins
Surgical socks
- valves in veins allow flow only up towards heart
- deep vessels in legs are sandwiched between calf muscle layers
- during exercise (walking and running ), contraction of calf muscles squeezes thin-walled veins and pushes blood up the veins (CALF PUMP)
- immobility (post-surgery) means less efficient venous return from foot and leg
- sluggish deep venous return results in DVT
- elastic surgical socks compress superficial veins to promote more vigorous deep venous return
Spinal nerve anatomy
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 or 2 coccygeal
Spinal nerve organisation
C1-4=neck C5-T1=upper limb T2-L1=trunk L2-S3=lower limb S2-C2=perineum
Brachial plexus
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Lumbosacral plexus
Nerves supplying lower limb emerge from lumbosacral plexus
- femoral nerve supplies anterior compartment of thigh
- obturator nerve supplies medial compartment of thigh
- sciatic nerve (or tibial and common peroneal nerves) supplies the remaining compartments
Segmental motor supply
-groups of motor nerve cell bodies in the spinal cord
Segmental supply principles
- muscles supplied by 2 adjacent segments
- same action on a joint means same nerve supply
- opposing muscles have nerves 1-2 segments above or below each other
- more distal muscles in limb=nerves originate more caudal in the spine (near tail)
Upper limb segmental motor supply
SHOULDER -abduction=C5 -adduction-C6,C7,C8 -external rotation=C5 -internal rotation=C6,C7,C8 ELBOW -flexion=C5,C6 -extension=C7,C8 FOREARM -supination=C6 -pronation=C7,C8 WRIST -flexion=C6,C7 -extension=C6,C7 LONG TENDONS TO HAND -flexion=C7,C8 -extension=C7,C8 INTRINSIC HAND -T1
Lower limb segmental motor supply
HIP -flexion=L2,L3 -extension=L4,L5 KNEE -extension=L3,L4 -flexion=L5,S1 ANKLE -dorsiflexion=L4,L5 -plantarflexion=S1,S2
Upper limb sensory segmental supply
C4=infraclavicular region C5=lateral arm C6=lateral forearm and thumb C7=middle finger C8=medial side of hand, forearm and little finger T1=medial arm T2=axilla and trunk T4=nipple T10=umbilicus T12=lower abdomen
Lower limb sensory segmental supply
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Nerve function assessment
1) motor function
2) sensory function
3) reflex function
4) autonomic function
Root injury (prolapsed intervertebral disc at L5/S1)
1) motor=loss of eversion
2) sensory=loss of sensation on outer border of foot
3) reflex=loss of ankle jerk (S1)
4) autonomic=minimal
Lesion of common peroneal nerve at fibular neck
1) motor=foot drop
2) sensory=dorsum of foot at least
3) reflex=non
4) autonomic=minimal
Compartment syndrome
- muscle groups in confined compartments separated by fibrous septa
- syndrome is ischaemia caused by trauma-induced increased pressure in a confined limb compartment
- commonly affects anterior, posterior and lateral compartments of leg
- normal pressure (25 mmHg), and only need 50-60 mmHg to collapse vessels and cause ischaemia=but pulse still present
- acute compartment syndrome is trauma associated
- chronic compartment syndrome is exercise-induced
- emergency fasciotomy required to prevent muscle and tissue death in affected compartment
Gluteal safe area
- for intramuscular injections into gluteus medius
- in the buttock, the muscles have a greater blood supply so drug uptake is often faster than subcutaneous and sub-dermal injections
- intramuscular injections into buttock often contraindicated due to proximity to major vessels and nerves and the variation in adipose tissue over the muscles
Venae comitantes
-pair of veins (or more) that closely accompany an artery in such manner that the artery pulsations aid venous return
