Learn / Level 3
Brachial plexus
Randy Travis Drinks Cold Beer — Roots, Trunks, Divisions, Cords, Branches — plus all eleven side branches drawn where they come off. Click around in Reference, then drill: name it, find it, say where it comes from, and pick its root levels.
How to read it
Five roots (C5–T1) merge into three trunks: C5+C6 → upper, C7 → middle, C8+T1 → lower. Each trunk splits into an anterior and a posterior division (anterior = flexor compartments, posterior = extensor). The three posterior divisions form the posterior cord; the anterior divisions of the upper and middle trunks form the lateral cord; the anterior division of the lower trunk continues as the medial cord. Cords are named for their position around the axillary artery.
Side branches come off the roots (dorsal scapular, long thoracic), the upper trunk (suprascapular, nerve to subclavius) and the cords — Lateral: lateral pectoral; Posterior: upper subscapular, thoracodorsal, lower subscapular; Medial: medial pectoral and the two medial cutaneous nerves. Terminal branches: Musculocutaneous, Axillary, Radial, Median, Ulnar.
Click any node to trace its fibres back to the roots and see what it supplies.
All sixteen nerves
| Nerve | From | Roots | Supplies |
|---|---|---|---|
| Musculocutaneous nerve | Lateral cord | C5, C6, C7 | Coracobrachialis, biceps brachii, brachialis; skin of the lateral forearm |
| Axillary nerve | Posterior cord | C5, C6, C7, C8, T1 | Deltoid, teres minor; skin over the 'regimental badge' area |
| Median nerve | Lateral cord + Medial cord | C5, C6, C7, C8, T1 | Anterior forearm (all but FCU and medial FDP), LOAF hand muscles; skin of the lateral 3½ digits |
| Radial nerve | Posterior cord | C5, C6, C7, C8, T1 | Every extensor of the arm and forearm (triceps, brachioradialis, wrist and finger extensors, supinator); skin of the posterior arm/forearm and dorsal 1st web space |
| Ulnar nerve | Medial cord | C8, T1 | FCU, medial half of FDP, most intrinsic hand muscles (interossei, hypothenar, medial 2 lumbricals, adductor pollicis); skin of the medial 1½ digits |
| Dorsal scapular nerve | C5 | C5 | Rhomboid major and minor, levator scapulae |
| Long thoracic nerve | C5 + C6 + C7 | C5, C6, C7 | Serratus anterior |
| Suprascapular nerve | Upper trunk | C5, C6 | Supraspinatus, infraspinatus |
| Nerve to subclavius | Upper trunk | C5, C6 | Subclavius |
| Lateral pectoral nerve | Lateral cord | C5, C6, C7 | Pectoralis major (clavicular head) |
| Upper subscapular nerve | Posterior cord | C5, C6 | Subscapularis (upper part) |
| Thoracodorsal nerve | Posterior cord | C6, C7, C8 | Latissimus dorsi |
| Lower subscapular nerve | Posterior cord | C5, C6 | Subscapularis (lower part), teres major |
| Medial pectoral nerve | Medial cord | C8, T1 | Pectoralis minor, pectoralis major (sternocostal head) |
| Medial brachial cutaneous nerve | Medial cord | C8, T1 | Skin of the medial arm |
| Medial antebrachial cutaneous nerve | Medial cord | C8, T1 | Skin of the medial forearm |