Study of variations in the branching pattern of lower subscapular nerve.

Background: Variations in the origin of lower subscapular nerve of the posterior cord of brachial plexus are important during surgical approaches to the axilla and upper arm, administration of anesthetic blocks, interpreting effects of nervous compressions and in repair of plexus injuries. The patterns of origin show population differences. Data from the South Indian population is scarce.

Objective: To describe the variations in the origin of the lower subscapular nerve of the posterior cord of brachial plexus in the South Indian population.

Materials And Methods: Forty brachial plexuses from 20 formalin fixed cadavers were explored by gross dissection. Origin and order of branching of lower subscapular nerve was recorded. Representative photographs were then taken using a digital camera (Sony Cyber shot R, W200, 7.2 Megapixels).

Results: Lower subscapular nerves had origin from axillary nerve in 57.5% of specimens, in 37.5% specimens, it was originating from the posterior cord and in 5% of specimens it arose from common trunk.

Conclusion: Lower subscapular nerves in studied population display a wide range of variations. Anesthesiologists administering local anesthetic blocks, clinicians interpreting effects of nerve injuries of the upper limb and surgeons operating in the axilla should be aware of these patterns to avoid in advertent injury.