Branches of the Brachial Plexus
The branches of the brachial plexus are divided into supraclavicular branches (from roots and trunks) and infraclavicular branches (from cords).
Total supraclavicular branches: 4 named + contributions to scaleni and phrenic nerve Total infraclavicular branches: 5 terminal nerves + 10 collateral nerves from cords
A. Branches from Roots (Supraclavicular)
| Branch | Root Value | Supplies |
|---|---|---|
| Long thoracic nerve (nerve to serratus anterior / Bell’s nerve) | C5, C6, C7 | Serratus anterior |
| Dorsal scapular nerve (nerve to rhomboids) | C5 | Rhomboideus major, rhomboideus minor, levator scapulae (partly) |
| Branches to scalene muscles and longus colli | C5, C6, C7, C8 | Scaleni, longus colli |
| Contribution to phrenic nerve | C5 | Diaphragm (minor contribution) |
B. Branches from Trunks (Supraclavicular)
Both branches arise from the upper trunk only:
| Branch | Root Value | Supplies |
|---|---|---|
| Suprascapular nerve | C5, C6 | Supraspinatus, infraspinatus |
| Nerve to subclavius | C5, C6 | Subclavius |
N.B. No branches arise from the middle or lower trunks. All root and trunk branches = supraclavicular branches of the brachial plexus.
Erb’s Point
The upper trunk is called Erb’s point — the region where six nerves meet:
- Ventral ramus of C5 root
- Ventral ramus of C6 root
- Suprascapular nerve (from upper trunk)
- Nerve to subclavius (from upper trunk)
- Anterior division of upper trunk
- Posterior division of upper trunk
Injury at Erb’s point → Erb’s paralysis (upper plexus injury)
C. Branches from Cords (Infraclavicular)
From Lateral Cord
| Branch | Root Value | Key Supply |
|---|---|---|
| Lateral pectoral nerve | C5, C6, C7 | Pectoralis major (clavicular head) |
| Musculocutaneous nerve | C5, C6, C7 | Coracobrachialis, biceps brachii, brachialis; skin of lateral forearm |
| Lateral root of median nerve | C5, C6, C7 | (Joins medial root → median nerve) |
Memory: “Lateral cord → L-M-M” = Lateral pectoral, Musculocutaneous, lateral root of Median
From Medial Cord
| Branch | Root Value | Key Supply |
|---|---|---|
| Medial pectoral nerve | C8, T1 | Pectoralis major (sternocostal head) + pectoralis minor |
| Medial cutaneous nerve of arm | T1 | Skin of medial side of arm |
| Medial cutaneous nerve of forearm | C8, T1 | Skin of medial side of forearm |
| Medial root of median nerve | C8, T1 | (Joins lateral root → median nerve) |
| Ulnar nerve | C7, C8, T1 | See Terminal Nerves |
Memory: “Medial cord → M-M-M-M-U” = Medial pectoral, cutaneous of arm, cutaneous of forearm, Medial root of median, Ulnar
From Posterior Cord
| Branch | Root Value | Key Supply |
|---|---|---|
| Upper subscapular nerve | C5, C6 | Subscapularis (upper part) |
| Thoracodorsal nerve (nerve to latissimus dorsi) | C6, C7, C8 | Latissimus dorsi |
| Lower subscapular nerve | C5, C6 | Subscapularis (lower part) + teres major |
| Axillary nerve | C5, C6 | Deltoid, teres minor; skin of lower deltoid |
| Radial nerve | C5, C6, C7, C8, T1 | See Terminal Nerves |
Memory: “Posterior cord → U-T-L-A-R” = Upper subscapular, Thoracodorsal, Lower subscapular, Axillary, Radial Or: “ULTRA” from posterior cord
Terminal Nerves (5 Major)
The five terminal nerves of the brachial plexus arise from the cords:
| Nerve | Origin | Root Value |
|---|---|---|
| Musculocutaneous | Lateral cord | C5, C6, C7 |
| Median | Lateral + medial cords (two roots) | C5, C6, C7, C8, T1 |
| Ulnar | Medial cord | C7, C8, T1 |
| Radial | Posterior cord | C5, C6, C7, C8, T1 |
| Axillary | Posterior cord | C5, C6 |
Memory: “My Aunt Ragged My Uncle” (from lateral to medial in axilla): Musculocutaneous, Axillary, Radial, Median, Ulnar
Summary — Complete Branch List
Supraclavicular Branches (4 named)
- Long thoracic nerve (C5, C6, C7)
- Dorsal scapular nerve (C5)
- Suprascapular nerve (C5, C6) ← from upper trunk
- Nerve to subclavius (C5, C6) ← from upper trunk
Infraclavicular Branches from Lateral Cord (3)
- Lateral pectoral nerve
- Musculocutaneous nerve
- Lateral root of median nerve
Infraclavicular Branches from Medial Cord (5)
- Medial pectoral nerve
- Medial cutaneous nerve of arm
- Medial cutaneous nerve of forearm
- Medial root of median nerve
- Ulnar nerve
Infraclavicular Branches from Posterior Cord (5)
- Upper subscapular nerve
- Thoracodorsal nerve
- Lower subscapular nerve
- Axillary nerve
- Radial nerve
Segmental Control of Upper Limb Movements
| Movement | Spinal Segments |
|---|---|
| Adduction of shoulder | C5 |
| Abduction of shoulder | C5, C6 |
| Flexion of elbow | C5, C6 |
| Extension of elbow | C6, C7 |
| Flexion of wrist and fingers | C8, T1 |
| Small muscles of hand | T1 |
Viva Pearls
- Only upper trunk gives branches (suprascapular + nerve to subclavius)
- Middle and lower trunks give no named branches
- Erb’s point = 6 nerves meet at upper trunk
- Long thoracic nerve (C5,6,7) supplies serratus anterior; injury → winging of scapula
- Dorsal scapular nerve (C5) supplies rhomboids
- Lateral cord → 3 branches (lateral pectoral, musculocutaneous, lateral root of median)
- Medial cord → 5 branches (medial pectoral, MC arm, MC forearm, medial root of median, ulnar)
- Posterior cord → 5 branches (ULTRA: upper subscapular, thoracodorsal, lower subscapular, axillary, radial)
- Median nerve = both lateral AND medial cord (only nerve with 2 cord origins)
- Suprascapular nerve is NOT a cord branch — it is a trunk branch