Brachial Plexus PDF

Brachial Plexus A major nerve network begins in the neck and extends into the axilla, supplying the upper limb with motor, sensory and autonomic innervation.  Formation: Brachial plexus is formed by the union of the anterior rami of the last four cervical and the...

Brachial Plexus A major nerve network begins in the neck and extends into the axilla, supplying the upper limb with motor, sensory and autonomic innervation.  Formation: Brachial plexus is formed by the union of the anterior rami of the last four cervical and the first thoracic spinal nerves that constitute the roots. The roots usually pass through the gap between the anterior and the middle scalene (scalenus anterior and medius) muscles with the subclavian artery.  Formation: In the inferior part of the neck, the roots of the brachial plexus 1 unite to form three trunks: 2 1. A superior trunk, from the union of the C5 and C6 roots. 2. A middle trunk, which is a continuation of the C7 root. 3. An inferior trunk, from the union of the C8 and T1 roots. 3  Formation: Each trunk of the brachial plexus divides into anterior and posterior divisions as the plexus passes 1 through the cervicoaxillary canal posterior to the clavicle. The 3 divisions of the trunks form three cords of the brachial plexus: 1. Anterior divisions of the superior and middle trunks unite to form the lateral cord. 2. Anterior division of the inferior trunk continues as the medial 2 cord. 3. Posterior divisions of all three trunks unite to form the posterior cord. Schematic drawing of Brachial Plexus  Branches of Brachial Plexus  Branches from the roots: Muscle connecting scapula to vertebrae 1. Dorsal Scapular N. (C5):  Rhomboids & Levator Scapulae 2. Long Thoracic N. (C5,6,7):  Serratus anterior  Branches from the trunks (Superior only): 1. Suprascapular N. (C5,6):  Supra & Infraspinatus 2. N. to Subclavius (C5,6) Division has none  Branches from Lateral Cord: 1. Lateral Pectoral N. (C5,6,7)  Pectoralis major 2. Musculocutaneous N. (C5,6,7)  B.B.C. coracobrachialis, biceps brachii, and brachialis muscles. 3. Lateral root of Median N. (C5,6,7)  Branches of Brachial Plexus  Branches from Medial Cord: 1. Medial Pectoral N. (C8-T1)  Pectoralis minor & major 2. Medial Cutaneous N. of arm (C8-T1) 3. Medial Cutaneous N. of forearm (C8-T1) 4. Medial root of Median N. (C8-T1) 5. Ulnar N (C8-T1)  Flexor carpi ulnaris and ulnar half of flexor digitorum profundus (forearm); most intrinsic muscles of hand  Branches of Brachial Plexus  Branches from Posterior Cord: 1. Upper Subscapular N. (C5,6)  Subscapularis 2. Lower Subscapular N. (C5,6)  Subscapularis & Teres major 3. Thoracodorsal N. (C6,7,8)  Latissimus dorsi 4. Axillary N. (C5,6)  Deltoid & Teres minor 5. Radial N. (C5-T1)  All muscles of posterior compartment of arm & forearm Roots, trunks, divisions, cords, and terminal branches of the brachial plexus. Roots, trunks, divisions, cords, and terminal branches of the brachial plexus.