Left Infant Brachial Plexus Anatomy and Injuries
This exhibit depicts the normal anatomy and function of the infant brachial plexus, injuries to the brachial plexus, and subsequent repair with nerve grafts. The brachial plexus is classified into five different segments: roots, trunks, divisions, cords, and terminal branches. The lateral cord (with contributions from nerve roots C5,C6, and C7) supplies the pectoralis via the lateral pectoral nerve, and the biceps brachii. The medial cord (with contributions from nerve roots C8 and T1) supplies the pectoralis via the medial pectoral nerve, and the intrinsic muscles of the hand. Divisions from the lateral and medial cord join together to form the median nerve. The median nerve (with contributions from nerve roots C7, C8, and T1) supplies the pronator teres, flexor muscles of the fingers, flexor muscles of the wrist, and provides sensation to the arm/hand. The posterior cord (with contributions from nerve roots C5, C6, C7, and C8) supplies the deltoid, posterior shoulder muscles, triceps brachii, latissimus dorsi, brachioradialis, extensor muscles of the fingers, extensor muscles of the wrist, extensor and abductor muscles of the thumb, and provides sensation to the shoulder. Injuries include a neuroma at the junction of C5-6 (superior trunk), C7 root avulsion, C8 root rupture, and T1 neuropraxia. These injuries to the brachial plexus cause interruptions in nerve supply to the upper limb, resulting in loss of sensory-motor function. Surgical repair is accomplished by excising the neuroma and injured nerve roots. Nerve grafts are then utilized to repair plexus continuity.