19 Nerves (Radial & Ulnar) Flashcards
What is the source of the radial nerve?
Posterior cord of brachial plexus (C5-T1)
What is the path of the radial nerve in the arm?
Exits axilla
Enters posterior compartment of the arm
In the lateral triangular space of the posterior shoulder (with profunda brachii artery)
Travels in the radial groove between the medial and lateral head of the triceps (with profunda brachii artery)
At the lateral border of the humerus, crosses from the posterior compartment into the anterior compartment of the arm
Pierces lateral intermuscular septum of the arm (at lateral border of humerus)
Descends between brachialis and brachioradialis
Located in lateral aspect of cubital fossa
What is the path of the radial nerve in the forearm?
Located in lateral aspect of cubital fossa
At the level of the lateral epicondyle, splits into deep and superficial branches
What is the path of the deep branch of the radial nerve?
Stems from radial nerve at the level of the lateral epicondyle ( in cubital fossa)
enters forearm between two heads of the supinator muscle
runs around lateral aspect of radial neck into the posterior compartment of the forearm
becomes the posterior interosseous nerve
What is the path of the superficial branch of the radial nerve?
Stems from the radial nerve at the level of the lateral epicondyle (in the cubital fossa)
Descends the forearm under the brachioradialis muscle
Emerges in the distal forearm
Crosses the wrist on the lateral side, superficial to the anatomical snuffbox
What does the radial nerve innervate?
All posterior muscles of the arm
All posterior muscles of the forearm (as deep branch / posterior interosseous nerve)
Skin and joints of the hand (as the superficial branch)
What is the source of the ulnar nerve?
Medial cord of brachial plexus (C8-T1)
What is the path of the ulnar nerve in the arm?
Passes through anterior arm near brachial artery
Midway down arm, pierces medial intermuscular septum
Passes posterior to medial epicondyle (funny bone)
What is the path of the ulnar nerve in the forearm?
Enters forearm medially between the two heads of the Flexor Carpi Ulnaris
Descends medially between the Flexor Carpi Ulnaris and Flexor Digitorum Profundus muscles
Passes into the wrist superficially to the flexor retinaculum
Passes through the Tunnel of Guyon into the hand
What are the branches of the ulnar nerve?
No branches in the axilla or arm
Cutaneous branches arise in forearm (palmar and dorsal)
Deep branches supply the muscles in the hand
What does the ulnar nerve innervate?
Flexor Carpi Ulnaris
Medial half of Flexor Digitorum Profundus
Deep branch:
Hypothenar eminance
Interossei muscles
Adductor Pollicis
Flexor Pollicis Brevis
Lumbricals 3-4
