A four trunked brachial plexus and a post fixed brachial plexus: A conjunction or a co‐incidence?: Report of three cases

Abstract

The anatomical variations of the brachial plexus in humans have clinical significance for surgeons, radiologists, and anatomists. In a study of 60 brachial plexuses, four trunked brachial plexuses were encountered in three limbs (two female and one male), all of them being post fixed and on left side of cadavers. The third trunk in all these limbs gave rise to two anterior divisions (upper and lower) and one posterior division. In two limbs belonging to the female sex, the upper anterior division joined with the anterior division of the second trunk to form the lateral cord while its lower anterior division joined with the anterior division of the fourth trunk to form the medial cord. In the sole male limb, along with the third trunk, the fourth trunk also divided into upper and lower anterior divisions. Upper anterior divisions of the third and fourth trunks joined to form the medial root of the median nerve while lower anterior divisions joined to form the ulnar nerve. No medial cord was formed as such. Further, it is inferred that in postfixed brachial plexus, there is a tendency to failure on part of T1 and T2 to join C8 which continues as the third trunk while T1 and T2 continue as the fourth trunk. Since it was seen in all postfixed brachial plexuses of the present study, it is emphasized to be given a place in the textbooks of anatomy or to conduct a study on a larger database.

Variations in the formation of the trunks of brachial plexus

“…The first trunk was formed by the union of C5 and C6 (Trunk I) and the second, third and fourth trunks were a continuation of C7, C8 and T1 roots respectively. A similar finding was also described by Chaudhary, Singla, Kalsey et al (2012), although differing with regard to the divisions for the formation of lateral, medial and posterior cords.…”

A prefix brachial plexus with two trunks and one anterior cord

“…Almost 50% of the BP showed variability in their branching pattern [2]. Anomalies of the cords and terminal branches of BP have been well documented [8,10,25]; however, anomalies of the roots and trunks are comparatively rare and have been report- ed in only a few cases [4,11,25]. BP variants are of immense importance during surgery of the axilla and arm region and during nerve blockade.…”

Bilateral Anatomical Variation in the Formation of Trunks of the Brachial Plexus - A Case Report

“…There are very few reports in the scientific literature addressing cases of BP with four trunks. Investigating 60 BPs which belonged to 30 cadavers, Chaudhary et al 10 found four trunked brachial plexuses on the left side in three cases. Of the three cases, one BP (prefixed and postfixed) was composed of roots C4-T2 which formed four trunks: first trunk (C4-C6), second trunk (C7), third trunk (C8), and fourth trunk (T1 and T2).…”