Flashcards in Clinical Considerations for the Upper Limb Deck (26)
The axillary nerve is a terminal branch of the brachial plexus off the ____1____ cord. It passes through the ___2___ space
1) posterior cord
What are the boundaries of the quadrangular space?
the teres minor superiorly, the long head of the triceps medially, the teres major inferiorly, and the surgical neck of the humerus laterally
When may damage or impingement of the axillary nerve occur?
Overworking the shoulder muscles (uncommon)
Damage in an anterior shoulder dislocation
When trying to diagnose damage to the axillary nerve how can you rule out C5 nerve root dysfunction?
Test of supra scapular nerve- test the supra and infraspinatus muscles
What movements and sensation would be reduced or absent in axillary nerve damage or impingement?
External rotation (teres minor), reduced abduction (deltoid), reduced sensation over the badge patch
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____
2) around the radial groove
3) triceps brachii
4) anterior to lateral epicondyle
6) posterior interosseous nerve
7) posterior forearm muscles
What does the superficial radial nerve innervate?
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.
What does the posterior cutaneous nerve of the arm innervate?
most of the skin on the back of the arm
Describe how you can get impingement or damage to the radial nerve?
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.
What nerve is damaged if there is a wrist drop?
What may you look for in someone you suspect has radial nerve damage?
A wrist drop
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.
4) anterior interosseous nerve
What does the median nerve innervate?
Flexor digitorum Superficialis
Flexor Digitorum Profundus (index and middle finger)
Lumbricals (index and middle finger)
Flexor Pollicis Longus
Sensation of thumb, index, middle and half of ring finger
How can you test the function of the lumbricals?
Lumbricals flex the MCPs so get them to post one hand through other.
Flexor Digitorum Superficialis flexes the ___1___
Flexor Digitorum Profundus flexes the ___2____
The lumbricals flex the ___3____
Actions of the thenar eminence?
Abductor pollicis brevis
Flexor pollicis brevis
Explain when you may get Ape hand deformity and why?
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.
Signs of carpal tunnel syndrome?
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.
Compression of what nerve causes the hand of benediction? Where is the compression?
Compression of the median nerve high up.
Explain the hand of benediction deformity?
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.
Hand of benediction and claw hand look similar- what is a key difference?
Claw hand is at rest, hand of benediction deformity occurs only when person goes to make a fist.
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______
1) medial cord
6) ulnar artery and vein
What does the ulnar nerve supply?
Flexor carpi ulnaris
Flexor Digitorum profundus- 4th and 5th digits
Medial 2 lumbricals
Palmar and Dorsal Interossei
Sensation to the skin of the pinky, medial 1/2 of ring finger, medial palm.
Explain what is meant by the ulnar paradox?
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.
Explain how problem with ulnar nerve from the wrist could cause a deformity?
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