The brachial plexus prone for injury because of following reasons.
- The upper limb is connected to the axial skeleton mainly by the soft tissues, with the only bone connection of upper limb to axial skeleton being the clavicle.
- Supraclavicular portion of brachial plexus is relatively superficial.
- The shoulder girdle has a wide arc of movement.
These factors increases the risk injury especially to the brachial plexus.
Homer described brachial plexus injury in the duel between Hector and Teucrus in Iliad.
1947- Seddon described nerve grafting.
1961- Yeoman and Seddon described intercostal nerve transfer.
1966- SICOT congress in Paris reached a consensus to discourage surgery for BPI due to discouraging results.
1970s- Work by Millesi in Vienna and Narakas in Lausanne demonstrated the utility of brachial plexus reconstruction
- Dorsal roots (sensory) and ventral roots (motor) unite to form the spinal nerve.
- The spinal nerve divides into dorsal and ventral rami. Dorsal rami supply the muscles and skin of paravertebral region.
- The ventral rami of C5-C8 and T1 merge and decussate to form the brachial plexus with variable contribution from C4 and T2 between the anterior and middle scalene muscles. The brachial plexus can be divided to roots, trunks, divisions, cords and individual nerves.
- Trunks are formed in the interscalene triangle. Cords are formed distal to the outer margin of first rib. Cords are named according to their relationship to the second part of axillary artery situated posterior to the pectorals minor.
- C5 and C6 ventral rami unite to form the upper trunk (C5-6). C7 continues as middle trunk (C7). C8 and T1 unite to form the lower trunk (C8-T1).
- Each trunk divides into anterior and posterior divisions. The anterior divisions of upper and middle trunk unite to form the lateral cord (C5,6,7). The anterior division of lower trunk continue as medial cord (C8-T1). Posterior divisions of upper, middle and lower trunks unite to form the posterior cord.
- Individual nerves may arise from the roots, trunks or cords of brachial plexus.
- No nerves arise from the divisions of brachial plexus.
- The phrenic nerve, long thoracic nerve and dorsal scapular nerve arises from the roots.
- Long thoracic nerve arises from C5, C6 and C7 roots and supplies the serratus anterior.
- Dorsal scapular nerve arises from C5 root and supplies the levator scapulae and the rhomboids major and minor.
- The nerve to subclavius (C5) and suprascapular nerve (C5,6) arise from the upper trunk.
- Suprascapular nerve (C5,6) supplies the supraspinatus, infraspinatus and teres minor.
- Lateral cord (C5,6,7) gives rise to lateral pectoral nerve, musculocutaneous nerve and lateral root of medial nerve (Mnemonic- LML).
- Medial cord (C8,T1) gives rise to medial cutaneous nerve of arm, medial cutaneous nerve of forearm, medial root of median nerve, medial pectoral nerve and ulnar nerve (Mnemonic- MMUMM).
- Posterior cord gives rise to subscapular nerve, thoracodorsal nerve, axillary nerve and radial nerve (Mnemonic- STAR).