Upper limb anatomy

Question 1

musculocutaenous nerve

C5/C6/C7

Answer 1

arises from lateral cord of the brachial plexus

sensory- skin of lateral forearm

motor- anterior compartment of the arm

BBC
biceps brachi: flex elbow, supinate forearm
brachialis: flex elbow
coracobrachialis: flex and adduct

Question 2

axillary nerve
C5/C6
(wraps around head of the humerus)

Answer 2

originates from the posterior cord

ensory- sargents patch (lower part of the deltoid)

motor- shoulder muscles
deltoid: abduct of shoulder, lateral rotation of shoulder. flex, extend shoulder
teres minor: exterally rotate shoulder

Question 3

radial nerve
C5/C6/C7/C8/T1

spiral groove of the humerus
suprficial branch and a deep branch

Answer 3

sensory: posterior foraerm, lateral 2/3 of dorsum of hand

motor: triceps (extend, adduct)
posterior forearm extension- extension of the digits, wrist and elbow. supination of the forearm

wrist drop (unopposed flexion)

the nerve lies in the spiral groove of the humeral shaft so is prone to injury or damage in a mid-shaft humeral fracture.

test with extension (cannot extend)

Question 4

median nerve

Answer 4

sensory: none in the uppper arm
thenar eminence
lateral 2/3 of palm
palmar aspect of 3 1/2 fingers

motor: pronation and flexion of the anterior compartment
* Sign of benediction

Question 5

hand of benediction

Answer 5

this is a sign in a median nerve injury. the median nerve is responsible for flexion of fingers 1-3 1/2.

when a patient is asked to make a fist, they will be unable to flex they’re thumb, index and middle finger. the ring finger and little finger will be flexed. (sign of benediction) (ulnar innervates those)

Question 6

ulnar nerve

C8/T1

Answer 6

sensory: the hypothenar eminence, medial 1/3 palm of hand 1/2 fingers
motor: flexion but EXTENSION of 4th and 5th
* Ulnar claw

Question 7

claw hand

Answer 7

The ulnar nerve is responsible for extension of the 4th and 5th fingers. if there is damage the patient will be unable to extend their fourth and fifth finger so they will remain flexed.

Question 8

Erb’s palsy

Answer 8

damage to C5 and C6 (upper trunk of the brachial plexus)

adducted and internally rotated shoulder with elbow extension, pronation and wrist felxion (waiter’s tip)

babies suffering from dystocia in delivery

c5 and c6 provides innervation to:

• diaphragm
• levator scapulae
• rhomboid major and minor
• supraspinatous
• infraspinatous
• teres major
• serratous anteiror
• deltoid
• bicerms brachii, brachialis, brachioradialis,
• spinator
• abduction of the shoulder
• external rotation of the shoulder
• flexion of the ebow
• supinatn of the forearm

C5 also provides sensory function oth e lateral aspect of the upper arm
C6 supllies sensory function to the lateral asect of the foraerm

Question 9

humeral supracondylar fracture

Answer 9

weakness to the right index finger due to an anterior interossesous nerve injury

Question 10

suprascapular nerve

Answer 10

upper trunk of the brachial plexus
carries fibres from the C5-C6 nerve roots

motor innervation to the supraspinatous and intraspinatous muslce
shoulder abduction, external rotation

sensory innervation to ehs kin over the posterior aspect of the sohulder.

Question 11

lower trunk of the brachial plexus

Answer 11

contains C8 and T1 fibres
median and ulnar nerve

median (C5-C8, T1) supplies thumb, index and middle finger, lateral half of the ring finger. unable to hold piece of paper between fingers

ulnar (c8,t1) littel finger and medial half of ring finger.

Question 12

long thoracic nerve

Answer 12

serratus anterior muscle
draws the scapula forward and rotates upwards.
all reaching and pushing mvoements

(damage in mastectomy- winging of the scapula)

Question 13

Saturday night palsy

Answer 13

history of sleeping over a chair
damage the radial nerve

feeling of numbness and tingling on the back of his hands around thumb, index and middle finger. weakness in elbow and wrist.
reduced elbow and wrist extension

Question 14

carpal tunnel syndrome

Answer 14

median nerve
passes through the carpal tunnel
tingling, numbness, pain at the palmar side fo the thumb, index, middle and ring finger

conditions like hypothyroidism, RA, pregnancy increase risk

Question 15

cubital tunnel syndrome

Answer 15

ulnar nerve
impingement of the ulnar nerve at the cubital tunnel in the elbow

numbness and tingling at the uulnar side of the ring finger and small finger

claw deformity.

Question 16

klumpke’s palsy

Answer 16

injury of brachial plexus C5-T1 usually lower roots (C8 and T1)

claw hand (intrinsic muscle of hand affected)
can be acompanied with Horner (miosis, anhidorisis, ptosis)

breech deliver of baby

Question 17

fracture of surgical neck of humerus

Answer 17

axillary nerve injury (C5, C6)
nerve is closely approximated to the bone as it passes through the surgical neck of hte humerus

lack of innervation of the deltoid an teres minor
loss of abduction at the shoulder
loss of sensation at regimental badge area.