Study of variations in the origin and distance of origin of upper sub scapular nerve in central Karnataka

Background: Upper subscapular nerve is one of the most varied nerves of Brachial plexus. Variations in the origin of upper subscapular nerve of the posterior cord of brachial plexus are essential in surgical approaches to the axilla and upper arm, administration of anesthetic blocks, interpreting effects of nervous compressions and in repair of plexus injuries. The plethora of variations in the origin shows population differences. Data from central Karnataka population is scanty and needs detailed documentation. Objective: To describe the variations in the origin of upper subscapular nerve of the posterior cord of brachial plexus and its distance of origin from mid-clavicular point in the Central Karnataka population. Material and Methods: Forty brachial plexuses from 20 formalin fixed cadavers were explored by gross dissection. Origin and number of upper subscapular nerve was recorded. The distance of origin from mid-clavicular point was measured. Representative photographs were then taken using a digital camera. Results: Upper subscapular nerve had origin from the posterior cord in100 % specimens and 17.5% of specimens showed two upper subscapular nerves. Upper subscapular nerve in 63.8% specimens had origin at a distance of 3.6 – 4.0 cm, 19.1% of specimens at a distance of 3.1 – 3.5 cm and 17% of specimens at a distance of 4.1 – 4.5 cm.