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anatomy of the limbs > brachial plexus and vessels > Flashcards

brachial plexus and vessels Flashcards

1
Q

what is a plexus

A

a structure where spinal nerves merge and mix to produce peripheral nerves - usuallyu with fibres from more than 1 spinal root

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2
Q

illustrate the organisation of the brachial plexus - whar are the differnet levels, and name nerves that come off them *

A

roots (supraclavicular in posterior triangle between middle and anteriro scalene muscles)

trunks (supraclavicular)

divisions (supraclavicular)

cords (infraclavicular, axilla)

terminal branches/peripheral nerves (axilla)

(real teenages drink cold beer)

brachial plexus is made of spinal nerves of c5-t1

dorsal scapula nerve comes from C5

long thoracic nerve comes from C5 6 7 - supples the serratus anterior

branches from roots, trunks and divisions are suprascapular, branches from cords and terminal branches are infrascapular

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3
Q

describe the path of the branches in the brachial plexus *

A

from C5-T1

C5 and 6 form the upper trunk

7 is middle trunk

8 and 1 form lower trunk

the trunks split into anterior and posterior divisions

upper and medial anterior divisions form lateral cord

all posterior divisions form posterior cord

lower anterior division becomes median cord

peripheral nerves emerge from these cords - from lateral cord have the lateral pectoral nerve, from the posterior cord have the upper and lower subscapular nerves supplying subscapularis and teres major, thoracodorsal nerve supplying latissimus dorsi

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4
Q

what cords do the main nerves branch from *

A

musculocutaneous - lateral

axillary - posterior

radial - posterior

median - lateral and median

ulnar - median

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5
Q

what are the names of the cords based around *

A

their position around the axillary artery ie posterior cord is posterior to artery

nerves of posterior cord generally supply posterior muscles

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6
Q

what spinal nerve of the brachial plexus (and above this) supply which body region *

A

c3-7 shoulder girdle muscles

5 6 shoulder joint muscles and elbow flexors

7-8 elbow joint extensors

6-8 wrist and course hand muscles

8-t1 small muscles of hand for fine movements

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7
Q

illustrate the segmental supply of the upper limb for movement

A

opposing movements are supplied by adjacent spinal nerve segments

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8
Q

illustrate the dermatomes of the upper limb *

A

they go as a continuum around

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9
Q

why is the sensory nerve distribution different to teh dermatomes *

A

fibres supplying the dermatome come from more tahn 1 peripheral nerve

eg superior lateral cutaneous nerve and inferior lateral cutaneous nerve both come from c5 6 but are distinct peripheral nerves

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10
Q

describe the path of the axillary nerve *

A

smaller of 2 branches from the posterior cord - c5 and 6

winds round neck of the humerus

passes posteriorly then laterally

pass under shoulder

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11
Q

where is the axillary nerve commonly damaged *

A

through shoulder dislocations and fracture of surgical neck of the humerus

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12
Q

what does the axillary nerve supply *

A

deltoid

teres minor - this is a rotator cuff muscle

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13
Q

effect of damage to the axillary nerve *

A

wasting of deltoid muscle - smoothness of shoulder lost because you can see underlying structures

loss of abduction

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14
Q

how do you assess axillary nerve injury *

A

the axillary nerve branches into superior lateral cutaneous nerve of arm - supplies skin over this area - called the regiment’s patch

loss of sensation here shows lost axillary nerve function

important because you dont want to ask pt to move shoulder to test axillary nerve when they have a shoulder disslocation

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15
Q

describe the path of the radial nerve *

A

larger of the 2 branches from the posterior cord c7-t1

travels out from the axillary region into posterior arm and forearm

runs posterior to the humerus on the radial/spiral groove of the humerus, artery travels with it

1/3 above the elbow it enters the lateral compartment of the arm

divides at elbow into deep branch and cutaneus branch

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16
Q

where can the radial nerve be damaged *

A

humeral fractures because it runs closely opposed to the shaft of the humerus

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17
Q

effect of radial nerve damage *

A

wrist drop - damage supply to the posterior muscles which would normally extend the wrist

anaesthesia of the lateral dorsal of hand - effects a variable area on posterior surface of the thumb because of substantial overlap of other nerves

loss of muscle mass in arm and forearm - wastage of muscle if happens further up - lose functioning of arm

lose the power grip - need the extensor muscles to get the most efficient power grip - when hand extended flexor muscles are already stretched so when they start working to make the grip they are already half way there

elbow extended because cant innervate triceps

supinator effected

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18
Q

describe the path of the musculocutaneous nerve *

A

come from the lateral cord = c5-7

extend in the axilla into arm and pierce coracobrachialis muscle

give off lateral branch to reach forearm - lateral cutaneous nerve of forearm - supplies the skin of the lateral part of forearm

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19
Q

what does the musculocutaneous nerve supply *

A

supply anterior arm, biceps and brachialis

lateral cutaneous skin of forearm

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20
Q

how is musculocutaenous nerve damaged *

A

not in trauma really because protected by muscles

may be damaged by surgery for breast cancer in removal of the axial lymph nodes

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21
Q

describe the path of the ulnar nerve *

A

biggest branch from the middle cord - c8-T1

emerges in teh axilla and continues down the arm

runs medial to the brachial artery

pierces the medial intermuscular septum to enter the posterior compartment of the arm - lies in groove for the ulnar nerve between medial epicondyle and olecranon

goes behind the medial epicondyle of humerus

passes between 2 heads of flexor carpi ulnaris - enters flexor compartment fo teh forearm, descends on FDP to wrist

goes to ulnar canal at the wrist and passes into hand on flexor retinaculum along the pisiform

divides into superior and deep branches

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22
Q

in vague terms what does the ulnar nerve supply *

A

doesnt supply anything in arm

some forearm

lots in hand

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23
Q

what muscles does the ulnar nerve supply *

A

flexor carpi ulnaris

palmaris brevis

hypothenar muscles

medial lumbricles - 4 5

dorsal and palmer interossei

adductor pollicus

flexor digitorum profundus

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24
Q

what causes damage to the ulnar nerve *

A

self harm at wrist

injuries to the medial epicondyle of humerus at elbow

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25
Q

effect of damage to the ulnar nerve *

A

claw deformity - hand at rest automatically claws

lumbricles are affected - lumbricles normally extend the digits by pulling on the extension expansion on the surface of the digit (they flex the MPJ and extend the IPJ)

after ulnar nerve injury - loss of lumbricles means loss of flexion in MPJ and weakened extension of IPJs

also lose abduction and adduction from dorsnal and palmar interosseis respectively (DAB and PAD)

many small muscles of the hand are effected but the thumb and index finger are spared because tehse lumbricles not affected

sensory problems along medial part of hand and medial 1.5 fingers are inconvenient - less serious than loss of the median nerve

weakness and wasting of small muscles of the hand

muscles affected - FCU FDP (Medial) medial lumbricles and all interossei and hypothenar

difficulty making a fist - flexion of distal IPJs is not complete so unopposed action of extensor digitorum so MPJs are hyperextended

loss of sensation of medial hand

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26
Q

describe teh ulnar paradox *

A

‘the closer to the paw the worse the claw’

ulnar inhury at the wrist = more damage than injury at the elbow

if damage is at elbow - also lose innervation to the medial side of FDP so there fwould be less flexion of the IPJs.

at the wrist the FDP is spared causing more unopposed flexion at the IPJs = more claw like appearance

27
Q

describe the path of teh median nerve *

A

lateral and median cords c6-t1

leave axilla

pass with the brachial artery to enter teh cubital fossa - medial to brachial artery here

go medially down forearm between 2 heads of pronator teres ansd passes beneath FDS - branches to superficial and deep forearm muscles

go medially down the forearm

at wrist it emerges between the tendons of the FDS and palmaris longus

into the carpal tunnel

28
Q

in vague terms what does the median nerve supply *

A

nothing in arm

most of forearm

some in hand

sensory fibres supply lateral part of hand

29
Q

ulnar relation to the carpel tunnel *

A

not in tunnel

pass medially to it

30
Q

does all of the median nerve pass through the carpal tunnel *

A

no - gives branch that stays superficial and supplies the palm

31
Q

describe the ulnar and medial supply to the hand

A

when median nerve exits carpal tunnel it gives off a recurrent branch to thenar muscles

median gives sensory branches to the thumb, index, middle and half of ring finger

ulnar branch gives sensation to little finger and half of the ring finger

there is a communicating branch between ulnar and median nerves for sensory - but notrmally clear cut off between sensation

32
Q

what is the effect of carpal tunnel syndrome *

A

wasting of the thenar eminance

abductor pollicus is evident - supplied by the unlnar nerve

loss of sensation and movement in lateral digits causes severe disability - because lateral lumbricals are effected and loss of thenar muscles = loss of fine movement

loss of sensation in thumb, index middle and hald of ring finger

33
Q

describe teh path of the long thoracic nerve *

A

comes from c5 6 7

emerges from the root of the neck over the serratus anterior

is relatively superficial - therefore easily damaged

34
Q

describe attachments of the serratus anterior muscle *

A

attaches to the medial ege of the scapula and fibres come around surface of the thoracic wall and insert into ribs 1 to 9

it attaches the trunk to the medial side of the scapular

func: hold scapula down and protration

35
Q

how would you damage the long thoracic nerve *

A

car accident

stabbed in this region

36
Q

effect of damage to the long thoracic nerve *

A

pressing against a wall will lead to winging of the scapula resulting from the loss of activity from the serratus anterior

37
Q

what is injury to the upper roots called *

A

Erb-Duchenne palsy

38
Q

what type of injury would damage upper roots *

A

falling on head

injuries during birth - pulled out by head, motorcycle injury

stretch the neck relative to the shoulder

damage c 5 6

39
Q

what is damaged in the upper root injuries *

A

anything to the upper trunks - ie c5 6

40
Q

effect of damage to the upper roots *

A

waiter’s tip position

many muscles affected - shoulder and anterior arm

forearm pronated because of lack of biceps supination (loss of function of musculocutaneos nerve)

anterior arm affected - flexion of elbow is difficult

wrist has unopposed flexion - radial nerve affected

arm adducted, medially rotated

get wasting of the limb

41
Q

example of injury that would cause lower root injury *

A

during birth - pull out by arm

over abduction due to gripping overhead to break fall

42
Q

what are lower root injuries *

A

damage to T1 and sometimes T8

called Klumpke’s palsy

‘klumpe’s monkey falls from a tree’

posterior and middle cords are affected

43
Q

what will the outcomes be of a lower root injury *

A

T1 mainly supples small muscles of hand via ulnar and median nerves - loss of their activity results in a clawed hand

loss of ulnar and median = loss of lumbricles so loss of extension of ICJs and loss of flexion MPJs = claw

44
Q

what is the function of the brachial plexus

A

rearrange the nerve fibres from c5 - T1 into bundles travelling to appropriate parts of the limbs

all nerves supplying extensor muscles pass through posterior cord

all nerves supplying flexor muscles pass through lateral and medial cord

45
Q

function of the lateral pectoral nerve

A

supplies pec major

comes of lateral cord of brachial plexus

46
Q

function of the medial pectoral cord

A

from medial cord to supply pec minor

47
Q

what is the artery supply to the scapular region *

A

it is form the suprascapular and transverse cervical arteries - branches of the thyrocervical trunk from the 1st part of the subclavian artery

48
Q

describe the arterial supply of the upper limb*

A

enters the axilla as a continuation of the subclavian artery

thoracoacromial and superior thoracidc arteries arise in the most prox part

at the level of the neck of humerus - there are the anterior and posterior circumflex humoral branches and the subscapular artery

becomes the brachial artery in the arm, distal to inferior border of teres major muscle

at the cubital fossa the brachial artery bifurcates into ulnar and radial arteries

the ulnar gives off a short common interosseous branch that divides to give anterior, posterior and recurrent interossous arteries

the ulnar artery crosses the wrist to form the superficial palmar arch and contribute to the deep palmar arch

teh radial artery passes distally in forearm and crosses wrist entering the thenar eminence forming the deep palmar arch and contributing to the superficial palmar arch

at wrist a branch of the radial artery passes dorsally to anastomose with the distal end of the anterior and posterior interosseous arteries to form the dorsal carpal arch

49
Q

describe the venous drainage of the upper limb*

A

digital veins run into teh dorsal venous network of the hand

they form the cephalic and basilic veins - superficial

they run subcutaneously into forearm and arm with a communicating branch just distal to elbow region - median cubital vein

cephalic vein passes between the deltoid and pec major muscles (the delto-pectoral groove) to pierce the clavipectoral fascia to drain into the prox axillary vein

the basilic vein passes deeply, approx mid arm, runs with the brachial artery and joins its venae comitantes to form the axillary vein

the deep veins are the venae comitantes of teh arteries - they form a plexus around teh arteries - the venae comitantes increase in calibre as they pass proximally

there are perforating branches connecting the deep and superficial veins

50
Q

where can you palpate the nerves

A

trunks - supraclavicular fossa

median nerve - cubital fossa, medial to brdachial artery

radial nerve - cubital fossa lateral to biceps tendon

ulnar - medial epicondyle

median - wrist

ulnar - wrist - medial to ulnar pulse

51
Q

identify the nerves in the body *

A

pic from living anatomy

52
Q

effect of damage to the median nerve *

A

muscles involved - FDP (lateral half), lumbricles of lateral side

when makuing a fist 2nd and 3rd fingers fail to flex completely - thumb unable to oppose

MPJs are hyperextended because of unopposed action of the extensor digitorum

thumb unable to oppose because of paralysis of opponens pollicis and FPB

wrist flexors are affected - wrist adducted

pronators affected - wrist in supine position

thenar muscles paralysed

loss of sensation to lateral half of palm and lateral digits

53
Q

what causes a true claw *

A

ulnar and median nerve damage c5-T1 roots

clawing in all 4 fingers with thumb abducted

54
Q

effect of damage to the musculocutaneous nerve *

A

elbow flexors are effected

loss of sensation on lateral side of forearm up to wrist

55
Q

describe frozen shoulder

A

pain and stiffness of the shoulder especially during external rotation

have shoulder pain for 2 to 9 months - severe followed by increasing stiffness

localised autoimmune response is a possible cause

56
Q

describe shoulder impingement syndrome

A

pain and weakness when you raise your arm because of tendon ‘catching’ in shoulder

it involves the supraspinatous tendon in the subacromial space

cause

  • bone spurs under acromion at top of subacromial space - can narrow the space and catch on the tendon
  • swelling or thickening of the rotator cuff tendon - from injury or general overuse of the shoulder
  • inflammation of the fluid filled sac that lies between the rotator cuff tendons and the acromion - bursitis
  • a build up of ca deposits within the rotator cuff tendon

treatment

  • avoid provokative activities
  • hydrocortisone injections
  • LA
  • exision or aspiration of calcified materaial
  • decompression of impingement
57
Q

describe tennis elbow

A

injury to extensor tendons on lateral epicondyle

because of sharp flexion of the wrist while extensors are contracted

58
Q

golfer’s elbow

A

similar to tennis but common flexor attachment on medial epicondyole is strained

cause - sharp flexion of elbow

59
Q

cause of mallet finger

A

avulsion of extensor igitorum longus tendon at base of distal phalanx

60
Q

game keepers thumb

A

damage to medial collateral ligament of 1st MPJs by violent abduction

thumb becomes unstable

61
Q

trigger finger

A

flexor profundus longus tendon causes friction to tendinous sheath and results in swelling of tendon which irritates sheath causing it to narrow

when finger is flexed it gets stuck in the sheath in a flexed position becasue the extensors are not string enough to straighten finger

62
Q

colle’s fracture

A

fracture of the distal radius within 1inch of wrist joint and ulnar styloid

dorsal displacement and dorsal angulation

prox impaction and radial deviation

in severe cases the distal radio-ulnar joint may be dislocated

63
Q

osteoarthritis

A

irreversible degenerative changes in cartilage

loss of articular cartilage and periarticular bone

narrowing of joint spaces in the interphalangeal joints

causes pain, stiffness and discomfort

64
Q

rheumatoid arthritis

A

chronic inflammatory synovitis of peripheral joints

immunological casue

swelling of joints

joint deformity

loss of function

anatomy of the limbs (14 decks)

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