Eur J Anat, 14 (2): 59-65 (2010)

Why are medial cord variations seen infrequently?

Ajay R. Nene

Department of Anatomy, GSL Medical College, Rajahmundry, Andhra Pradesh 533296, India.

ABSTRACT The brachial plexus is formed by a series of stages- roots, trunks, divisions, cords and branches. The lateral and medial cords are derived from ventral divisions of the trunks, while the dorsal divisions together form the posterior cord. The lateral and medial cords are destined to supply the pectoral region and front of the entire upper limb. Often, during their formation and course, the cords and their branches show a plethora of variations, especially the lateral cord and its branches. Compared to the lateral cord, the medial cord shows variations much more infrequently. In the present work, a comparative study was performed in a set of one hundred upper limbs to note the variations in these two cords and their branches. It was observed that the lateral cord variations outnumbered those of the medial cord. The reason for this probably lies in the development and histogenesis of the brachial plexus during embryonic life. The stepwise journey of the path-finding axons and their interactions with guidance cues probably explains why medial cord variations are seen more infrequently than those of the lateral cord.

Keywords: Brachial plexus, Medial cord, Lateral cord, Variations