Arnab Bhar1, Ananya Biswas2
BACKGROUND
Supernumerary heads of the biceps brachii are a common anatomical variation,
with an incidence of 3.7 % to 20.5 % in various studies carried out around the
world. They can occur in various forms, and produce a range of clinical symptoms,
such as impingement syndromes at the shoulder joint, and nerve-compression
syndromes in the arm. An awareness of these variations is helpful when assessing
patients with pain symptoms in the region of the shoulder and arm. The purpose
of this study was to examine the morphology, nerve supply, and variations in
morphology, of the biceps brachii in a population in Eastern India.
METHODS
This observational study was carried out on 20 (17 males, 3 females) formalinembalmed
cadavers during routine gross anatomy dissection of the upper limb,
using standard dissection methods. We examined the morphology, nerve supply,
and variations in morphology, of the biceps brachii in a population in Eastern India.
RESULTS
Three upper limbs (7.5 % out of 40 limbs) showed supernumerary heads. In one
male, a third humeral head of origin, from the anteromedial surface of the shaft
of the humerus was observed in the left upper limb. In another male cadaver, we
found a unique case with bilateral third heads with an aponeurotic origin from the
capsule of the shoulder joint, with the third head comparable in size and bulk to
the long and short heads. The remaining upper limbs showed the usual
morphology, with the long head originating intracapsularly from the supraglenoid
tubercle of the humerus and the glenoid labrum, and the short head from the tip
of the coracoid process of the scapula. Insertions were usual.
CONCLUSIONS
Our study found an incidence of 7.5 % in a population sample from Eastern India,
North Bengal. Supernumerary heads can occur in various forms, and can result in
varied clinical symptoms.
