Atlas of Human Anatomy by Netter

FACTS & HINTS

HIGH-YIELD FACTS

Clinical Points
page 240
page 241

Brachial Plexus Injury

Disease, trauma or excessive stretching (because of birth trauma) of the posterior triangle of the neck or axilla may damage brachial plexus

Results in paralysis and anaesthesia in the distribution of the affected nerves

Various terms used to describe the different lesions

Erb's palsy affects areas supplied by nerves from superior part of the plexus

Klumpke's palsy affects areas supplied by nerves from the inferior part

Carpal Tunnel Syndrome

A result of compression of the median nerve as it passes under flexor retinaculum

Compression caused by any process that significantly reduces the size of the carpal tunnel: inflammation of the synovial sheaths, fluid

retention, and infection

Pain or paraesthesia felt in the lateral 3½ digits, may radiate toward the elbow and is often worse at night

Also loss of sensation and diminished control of the median nerve-innervated muscles

Surgical division of the flexor retinaculum may be necessary to relieve symptoms

Ulnar Nerve Injury

Ulnar nerve may be compressed as it passes behind medial epicondyle of the humerus or through the Guyon canal at the wrist

Pain and/or paraesthesia felt at medial aspect of the elbow radiating to the medial forearm and medial 1½ digits

Also may be weakness of the intrinsic muscles of the hand

Radial Nerve Injury

Palsy of the radial nerve common after prolonged pressure on the back of the arm by resting it against a hard surface (such as back of

movie theater seat-the "Saturday night palsy")

Nerve may also be injured in fractures of humerus as it winds along spiral groove

Extensors of the wrist are paralyzed, resulting in a wrist drop

Triceps not affected unless the nerve is injured proximally in the axilla

MNEMONICS

Memory Aids

Parts of the brachial plexus: Really Thirsty? Drink Cold Beer

Roots, Trunks, Divisions, Cords, Branches

Terminal nerves of plexus: MARMU

Musculocutaneous, Axillary, Radial, Median, Ulnar

Muscles supplied by median nerve supply in

hand:

LOAF

Lumbricals (lateral), Opponens pollicis, Abductor pollicis brevis, Flexor pollicis

brevis

Memory Aids

Branches of brachial plexus medial cord: Money Makes Many Men Unhappy

Medial pectoral nerve

Medial branch of median nerve

Medial cutaneous nerve of arm

Medial cutaneous nerve of forearm

Ulnar nerve