LO for brachial plexus not covered in main lecture

Question 1

describe the origin course and distribution of main arteries and their branches that supply the shoulder, arm, forearm and hand *

Answer 1

subclavian arises from aorta (L) or R brachiocephalic trunk - runs towards axilla going under clavical and rib 1

becomes axillary artery giving off branches in the axilla and to scapular

when axillary crosses border of teres minor becomes brachial artery

brachial artery gives off profunda brachii artery to seep muscles of arm - this is the biggest branch

profunda brachii divides at forearm into ulnar and radial arteries

there are extensive anastomoses at the elbow

radial artery travels down laterl aspect of forearm under brachioradialis muscle - crosses floor of anatomical snuff box

ulnar travels in medial anterior compartment of teh arm lateral to FCU

ulnar artery branches into common interosseous branch which immediately branches into anterior and posterior interosseous branch

posterior interosseous pierces the interosseous membrane and runs posteriorly, anterior stays anterior

both contribute to the vessels of the hand

ulnar passes on ulnar side of palmar surface of wrist, lateral to the ulnar nerve which is lateral to flexor carpi ulnaris - passes into wrist over the flexor retinaculum through guyon’s canal

ulnar then divides into superficial palmar arch (which gives of 3 common palmar digital arteries) and teh deep palmar arch

–

radial artery passes down lateral aspect of the forearmunder brachioradialis and beside FCR at wrist - enters palm of hand between 2 heads of 1st dorsal interosseous muscle then passes between the 2 heads of the adductor pollicis muscle - anastomoses with deep palmar branch of ulnar artery to form the deep palmar arch

deep palmar arch gives rise to palmar metacarpal arteries

the arteries also form dorsal carpal arch

Question 2

explain where the arteries of the upper limb are suseptible to injury *

Answer 2

fracture of rib 1- subclavian artery is fixed to rib 1, a fracture here can damage the distal part of the subclavian, or the start of the axillary artery

anterior dislocation of the humorak head - may compress teh axillary artery causing vessel occlusion

can transect the radial or ulnar artery eg when put hand through glass, because the vessels are subcutaneous

Question 3

describe the importance of arterial anastomoses *

Answer 3

at the vulnerable areas for the arteries there are anastomoses

at rib 1 there are anastomotic connections between branhces of the subclavian artery and the axillary artery which form a network around the scapula and prox end of humerus - therefore even with complete vessel rupture the arm is rarely rendered ischemic

Question 4

explain the importance of the axillary lymph nodes *

Answer 4

all lymphatics of the upper limb drain into the axillary lymph nodes

also drain an extensive area of the trunk and 75% of the mammary gland

Question 5

describe the significance of the axillary lymph nodes for cancer *

Answer 5

lymph drainage from the lateral part of the breast drains into the axilla

some patients have radiotherapy to prevent the spread of disease

if you remove the lymph nodes it also stops drainage and spread

if he drainage is damaged the upper limb is damaged and the arm may swell adn pitting oedema might develop

Question 6

describe teh anatomoy of teh axillary nodes *

Answer 6

there are 20-30 nodes divided inot 5 groups on the basis of location

humeral - posteromedial to the axillary vein

pectoral - along inferior mrgin of pec minor

subscapular - posterior axillary wall

central nodes - embedded in axillary fat

apical - most superior group, drain all the other nodes

efferent vessels from apical group converge to form the apical trunk which joins the venous system

Question 7

how do you test the function of the axillary nerve *

Answer 7

abduction between 15-90 degrees

sargeant’s patch - loss of sensation

Question 8

how do you test function of the radial nerve *

Answer 8

extend against resistance

Question 9

how do test the function of the musculocutaneous nerve *

Answer 9

flex against resistance

Question 10

how would you test the median nerve *

Answer 10

pinch the lateral part of the hand to test sensation

Question 11

how would you test the ulnar nerve *

Answer 11

pinch the medial side of the hand to test sensation

Question 12

how do you assess the power of the upper limb *

Answer 12

you ask pt to move muscle and apply pressure against the muscle and feel the power of the movement compared to normal power

Question 13

describe teh course of the main veins of the upper limb *

Answer 13

dorsal digital veins drain into the dorsal venous arch

the dorsal venous network in hands form the cephalic vein which runs up lateral arm and the basiclic vein up medial

cephalic passes deep into delto-pectoral groove - joins the axillary and becomes the subclavian

basilic stays superficial, the goes deep in arm by passing into the depp fascia, joins the venae comitantes of brachial artery to form the axillary in arm

basilic and cephalic join at cubita; fossa as median cubital vein

lateral thoracic joins the axillary

thoroepigastric vein connects superficial epigastric vein to lateral thoracic vein as a shunt for blood if the portal system develops hypertension or a blockage

axillary vein becomes subclavian at 1st rib

deep and superficial veins are connected with valves allowing one way flow from superficial to deep system

Question 14

what is at risk form venepuncture in the cubital fossa *

Answer 14

biceps tendon

median nerve

radial nerve

Question 15

difference between deep and superficial veins *

Answer 15

deep veins run along muscles so blood is pushed along by the contraction of muscle

superficial are in in fatty layer so are not affected by contraction of muscle so blood moves slower

Question 16

common sites of venous access *

Answer 16

subclavicular vein

median cubital vein

Question 17

structures close to the subclavicular vein for venous access *

Answer 17

subclavicular artery

subclavius muscle