Clinical Considerations for the Upper Limb

Question 1

The axillary nerve is a terminal branch of the brachial plexus off the ____1____ cord. It passes through the ___2___ space

Answer 1

1) posterior cord

2) quadrangular

Question 2

What are the boundaries of the quadrangular space?

Answer 2

the teres minor superiorly, the long head of the triceps medially, the teres major inferiorly, and the surgical neck of the humerus laterally

Question 3

When may damage or impingement of the axillary nerve occur?

Answer 3

Overworking the shoulder muscles (uncommon)

Damage in an anterior shoulder dislocation

Question 4

When trying to diagnose damage to the axillary nerve how can you rule out C5 nerve root dysfunction?

Answer 4

Test of supra scapular nerve- test the supra and infraspinatus muscles

Question 5

What movements and sensation would be reduced or absent in axillary nerve damage or impingement?

Answer 5

External rotation (teres minor), reduced abduction (deltoid), reduced sensation over the badge patch

Question 6

Radial nerve is a terminal branch of the brachial plexus off the __1_____ cord. It passes to the posterior compartment of the arm and courses ___2_____ of humerus and innervates ___3_____ It then divides into superficial and deep branch just _________4_______ The deep branch passes into the posterior compartment of the forearm by winding around the neck of the radius and passing through the ___5__ muscle which it supplies. After passing through it is renamed the ____6_____ and supplies ___7____

Answer 6

1) posterior
2) around the radial groove
3) triceps brachii
4) anterior to lateral epicondyle
5) supinator
6) posterior interosseous nerve
7) posterior forearm muscles

Question 7

What does the superficial radial nerve innervate?

Answer 7

Thumb, index, middle and some of the ring finger on the DORSAL surface of the hand- it doesn’t go down to the tips of these fingers.

Question 8

What does the posterior cutaneous nerve of the arm innervate?

Answer 8

most of the skin on the back of the arm

Question 9

Describe how you can get impingement or damage to the radial nerve?

Answer 9

People who supinate a lot e.g. workers with tools and screws can get hypertrophy of the supinator which would impinge the posterior interosseous nerve. Damage to radial nerve can also occur in a mid humerus fracture.

Question 10

What nerve is damaged if there is a wrist drop?

Answer 10

Radial

Question 11

What may you look for in someone you suspect has radial nerve damage?

Answer 11

A wrist drop

Question 12

The median nerve is a terminal branch of the brachial plexus formed from branch of the __1___ and __2__ cord.
Median nerve runs __3_____ in the cubital fossa and then into the anterior compartment of the forearm. The deep muscles are supplied by the ____4___ which is a branch of the median nerve.

Answer 12

1) medial
2) lateral
3) anterior
4) anterior interosseous nerve

Question 13

What does the median nerve innervate?

Answer 13

Flexor digitorum Superficialis
Flexor Digitorum Profundus (index and middle finger)
Thenar eminence
Lumbricals (index and middle finger)
Flexor Pollicis Longus
Sensation of thumb, index, middle and half of ring finger

Question 14

How can you test the function of the lumbricals?

Answer 14

Lumbricals flex the MCPs so get them to post one hand through other.

Question 15

Flexor Digitorum Superficialis flexes the ___1___
Flexor Digitorum Profundus flexes the ___2____
The lumbricals flex the ___3____

Answer 15

1) PIPs
2) DIPs
3) MCPs

Question 16

Actions of the thenar eminence?

Answer 16

THenar= THumb
Thumb opposition
Thumb abduction
Thumb flexor

Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis

Question 17

Explain when you may get Ape hand deformity and why?

Answer 17

CARPAL TUNNEL SYNDROME: The median nerve is compressed at the carpal tunnel so this impacts the intrinsic muscles of the hand supplied by the median nerve. This results in paralysis of the thenar muscles, with nothing to oppose adductor policis (abductor pollicis lies in the thenar eminence) the thumb which usually in rest would sit slightly away is pulled into the plane of the other digits resulting in the appearance of an ape hand.

Question 18

Signs of carpal tunnel syndrome?

Answer 18

Wasting of the thenar muscles and lateral two lumbricals. Sensation is potentially lost on thumb, index, middle and half of ring finger. Small lateral area of skin is not affected as the palmar cutaneous branch of the median nerve does not pass through the carpal tunnel.

Question 19

Compression of what nerve causes the hand of benediction? Where is the compression?

Answer 19

Compression of the median nerve high up.

Question 20

Explain the hand of benediction deformity?

Answer 20

This is not like ape hand which is at rest- this is a deformity encountered when the patient goes to make a fist!

COMPRESSION OF THE MEDIAN NERVE: Lost function of flexor digitorum superficial, flexor policis longus and braves, 2nd and 3rd of flexor digitorum profundus. The only remaining flexor is the ulnar nerve 1/2 of flexor digitorum profundus. So get flexion partially of digits 4 and 5 but the rest stay extended.

Question 21

Hand of benediction and claw hand look similar- what is a key difference?

Answer 21

Claw hand is at rest, hand of benediction deformity occurs only when person goes to make a fist.

Question 22

The ulnar nerve is a terminal branch of the brachial plexus off the __1____ cord It runs medial in the arm with the median nerve before coursing __2___. It crosses the posterior surface of the _____3___ epicondyle of the humerus where it can be palpated and readily injured. It passes through flexor carpi radials in the ___4___ tunnel to reach the ___5____ forearm. It passes into the hand with the ____6______

Answer 22

1) medial cord
2) posteriorly
3) medial
4) cubital
5) anterior
6) ulnar artery and vein

Question 23

What does the ulnar nerve supply?

Answer 23

Flexor carpi ulnaris
Flexor Digitorum profundus- 4th and 5th digits
Medial 2 lumbricals
Palmar and Dorsal Interossei
Hypothenar eminence
Sensation to the skin of the pinky, medial 1/2 of ring finger, medial palm.

Question 24

Explain what is meant by the ulnar paradox?

Answer 24

If the ulnar lesion occurs more proximally the FDP may also be denervated. This means there is less flexion of the fingers so despite the lesions paralysing more muscles the deformity/ the claw hand actually doesn’t look as extreme.

Question 25

Explain how problem with ulnar nerve from the wrist could cause a deformity?

Answer 25

Function of FDP is maintained.
Digits 2 and 3 are largely unaffected (can’t abduct or adduct but not greatly relevant)
Digits 4 and 5 are greatly unaffected as loss of opposition from the lumbricals for extensor digitorum so there is hyperextension of the MCP joints. Extensor digitorum also can’t counteract the flexion of FDS and FDP due to loss of lumbricals and interossei so get hyeprflexion of the DIP and PIP joints.

Lumbrical action = opposition of extensor digitorum at the MCPS and opposition of FDP and FDS at the IPs

Question 26

Explain how problem with the ulnar nerve high up could cause a deformity?

Answer 26

This would cause less of a deformity as patient loses function of FDP too so can only achieve very slight flexion of the 4th and 5th digits, hence less of a claw than a lower down lesion ——> ulnar paradox