ABSTRACT
Background: Brachial plexus is the plexus of nerves that supplies the upper limb. Variations in the branches of brachial plexus are common but variations in the roots and trunks are very rare. Methods: Here, we report one of such rare variations in the formations of the upper trunk, middle trunk, and lower trunk of the brachial plexus in the right and left upper limb of a male and female cadaver. Results: In the present study1 limb (1.6%), there was absence of the upper trunk on the left side of a male cadaver with approximate age of 20 years. And In 1 limb (1.6%), upper trunk of the brachial plexus was found unilaterally on the right side of a male cadaver aged approximately 55 years. the upper trunk was present in 2 limbs (3.3%), both on the right side of male cadavers with approximate age of 55 and 50 years In both cases, C5 and C6 roots were split in anterior and posterior divisions (Figure No. 5). Both anterior divisions joined to give origin to an “anterior superior trunk” and both posterior divisions joined to give origin to a “posterior superior trunk”. These trunks joined to give origin to the superior (upper) trunk. In 2 limbs (3.3%) The middle trunk was absent. in the right upper limb (1.6%) of a male cadaver with approximate age of 35 years the lower trunk was formed by the union of ventral rami of C7, C8 and T1 nerve roots. Conclusions: The knowledge of variations in the formation of brachial plexus is very useful for the anatomists, radiologists, anesthesiologists, neurosurgeons and orthopedic surgeons.
ABSTRACT
Background: Anatomical variations in the formation, branching pattern and relations of the brachial plexus have been described in humans by many authors; however these have not been extensively catalogued. The aim of the study was to describe variations in brachial plexus formation, branching pattern and relation with major vessels. Methods: This study included thorough dissection of 60 brachial plexuses which belonged to 30 cadavers (male: female ratio = 28:02 ) with age range of 20-60 years, obtained from the Department of Anatomy, College of Medical Sciences (CMS-TH), following standard guidelines. Results: Out of 60 limbs dissected in present study, the variation in formation was found in 20 limbs (33.3%), out of which 12 limbs (20%) had variations in the trunk and 8 limbs (13.3%) had variations in the cord, remaining 40 limbs (66.6%) were normal in the formation of brachial plexus. Normal branching pattern of the posterior cord was encountered in 52 (86.67%) limbs, the remaining 8 (13.33%) being variants in one form or the other. The upper subscapular nerve, the thoracodorsal nerve, the lower subscapular nerve and the axillary nerve were found to arise normally in 91.66%, 96.66%, 96.66% and 98.33% of the limbs respectively. Conclusion: The present study carried out on adult human cadavers revealed some rare variations in the formation, branching pattern and relations of the brachial plexus. These variations are of clinical significance for the surgeons, radiologists and the anesthesiologists.