Ulnar nerve Flashcards
What nerve roots is the ulnar nerve derived from?
C8/T1
What is the origin of the ulnar nerve?
Medial cord
What is the course of this nerve?
he ulnar nerve runs down the arm on the medial side of the brachial artery
it passes behind the medial epicondyle of the humerus and enters the forearm between the two heads of flexor carpi ulnaris
it travels through the anterior compartment of the forearm beneath flexor carpi ulnaris
it then enters the palm of the hand through Guyon’s canal
What is the sensory supply of this nerve?
skin over hypothenar eminence medial ⅓ palm of hand palmar aspect of lateral 1½ fingers medial ⅓ dorsum of hand dorsal aspect of medial 1½ fingers (little finger and half of ring finger)
What is the motor supply of this nerve?
two muscles of anterior compartment of forearm
flexor carpi ulnaris – flexes and adducts wrist
medial two parts of flexor digitorum profundus – flex ring and little fingers at DIPJs
most of the intrinsic muscles of the hand – HILA muscles
a) hypothenar eminence: opponens digiti minimi, flexor digiti minimi brevis and abductor digiti minimi – oppose, flex and abduct little finger
b) interossei – palmar interossei adduct, dorsal interossei abduct
c) medial two lumbricals – flex MCPJs and extend IPJs of ring and little finger
d) adductor pollicis – adducts thumb
How could you injure this nerve?
Compression either at the cubital tunnel in the elbow or at Guyon’s canal in the wrist
Supracondylar fracture of humerus
Fractures or soft tissue injuries to medial epicondyle of humerus
What are the features of injuring this nerve?
Claw hand- can’t extend little or ring fingers
Numbness of hypothenar eminence and ulnar distribution
Weak wrist flexion and adduction
Weak MCPJ flexion and IPJ extension of ring and little fingers, loss of finger abduction and adduction, loss of opposition of little finger
Weak flexion of ring and little finger DIPJs
