Hello everyone,hope you all are doing well and i am too and i request you all to went through all my previous posts so that you can get some knowledge about human body.coming to the post now i am going to tell about ulnar nerve the major nerve which is left to study.
ULNAR NERVE
Origin - Medial cord of brachial plexus
Supplies - 1.Arm - no supply
2.Forearm - *medial 1½ muscles of anterior compartment*
a)*flexor carpi ulnaris*
b)*flexor digitorum profoundus(medial half)*
3.Hand - *a)hypothenar muscles*, b)*all interossei(4 palmar+4 dorsal)*, c)*lumbricals -L3,L4 4)*adductor pollicis(graveyard of the ulnar nerve as it goes and ends there)*
Ulnar supplies 15 muscles of hand so it is called dominant hand of nerve of hand.
It is also called musician's nerve
Ulnar nerve passes behind medial epicondlye and it enters forarm by passing between the heads of flexor carpi ulnaris through the cubital tunnel. When cubital tuneel compresses ulnar nerve then it leads to cubital tunnel syndrome.
Ulnar nerve passes superficial to flexor retinaculum and it gives to two branches superficial branch deep branch
To make you understand i made a schematic diagram
CLINICAL ASPECTS
| Site of injury | Higher lesion | lower lesion |
|---|---|---|
| Causes | fracture of medial epicondyle,cubital tunnel syndrome | wrist laceration or slashing,guyon's canal syndrome |
| Motor loss | claw hand deformity,hypothenar&interosseous wasting | claw hand deformity(more pronounced),hypothenar&interosseous wasting |
| Sensory loss | over palmar&dorsal aspect of the medial third of the hand,sensory loss over palmar&dorsal aspect of the medial 1½ fingers | No sensory loss over palmar&dorsal aspect of the medial third of the hand,sensory loss over palmar&dorsal aspect of the medial 1½ fingers |
| Tests | card test- positive, froment sign- positive | card test- positive,froment sign- positive |
ClAW HAND
TESTS-
These tests are done to find ulnar nerve is injured or not.
I will demonstate the tests and its interpretations.
1.card test
To test - palmar interrosei muscles
In this test a card is placed in between fingers(mainly between little finger and ring finger)of patient and asked to hold the card between fingers.then doctor will try to pull the card.
- Interpretation - if he cannot hold the card then we cane to know that adduction is impaired i.e., palmer interrosei muscles are paralysed due to injury to ulnar nerve.so patient cannot hold card in between fingers.
2.Froment test/sign
To test - adductor pollicis muscle
Patient is asked to hold the card between thumb and index finger like in the 1st image.so 1st image shows the patient is holding in a correct way byusing his adductor pollicis muscle. So froment sign is negative.
In the second image the patient is hold the card but he is not holding the card by using adductor pollicis.instead he used flexor pollicis longus muscle which is supplies by median nerve.so here adductor pollicis is not working due to injury to ulnar nerve.so patient cannot adduct his thumb to hold the card instead he flexes thumb by using flexor pollicis muscles to hold the card.then froment sign is said to be positive.
Froment sign - negative
Froment sign - positive
3.Egawa test
To test - dorsal interossei for abduction of fingers
In this test the middle finger is abducted on both sides.
I will share my youtube short video here that i demonstated by using my hand to make you understand
Thank you for reading my post,
With regards