Brachial plexus - branches and innervations

#1 DSN C5

Dorsal Scapular Nerve

- levator scapula
- rhomboids minor
- rhomboids major

#2 LTN C5+C6+C7

Long thoracic nerve

- serratus anterior

#3 SN Superior trunk

Suprascapular nerve

- supraspinatous
- infraspinatous
- shoulder joint

#4 NtS Superior trunk

Nerve to subclavius

- subclavius

#5 LP Lateral cord

Lateral Pectoral Nerve

- pectoralis major

#6 US Posterior cord

Upper Subscapular Nerve

- Subscapularis

#7 TN Posterior cord

Thoracodorsal Nerve

- latissimus dorsi

#8 LSN Posterior cord

Lower Subscapular Nerve

- subscapularis
- teres major

#9 MP Medial cord

Medial Pectoral

- pectoralis major
- pectoralis minor

#10 MBC Medial cord

Medial Brachial cord

Sensory for medial arm

#11 MAC Medial cord

Medial antebrachial cord

Sensory for medial forearm and elbow

2 branches of lateral cord

musculocutaneous nerve
median nerve (lateral root)

2 branches of posterior cord

axillary nerve
radial nerve

2 branches of medial cord

median nerve
ulnar nerve

What cord is damaged from a trauma where ulnar-innervated muscles are paralysed?

Medial cord

While the median nerve is supplied by the medial cord, it will only be partially affected, not completely paralyzed, because it is also supplied by the lateral cord

What nerves are affected from a posterior cord injury? Which muscle groups are affected and what function is lost?

Axillary and radial branches

Affects posterior arm muscles/ extensors (eg. tricep), leads to loss of extension in forearm