Morphometry and variations of the human suprascapular notch.

Aim: The present study proposes a simple method to study variations in shape and dimensions of suprascapular notch, to classify different types and subtypes of notch and to measure the thickness of superior transverse scapular bar (ossified superior transverse ligament of scapula).

Material And Methods: Seven hundred and twenty-eight dried scapulae were observed, examined and studied in detail. Scapulae with suprascapular notch, with suprascapular foramen having varying degree of ossification in the form of transverse scapular bar were included in the present study. Measurements of suprascapular notch and superior transverse scapular bar were taken with the help of digital vernier calliper and recorded in millimetres. The superior transverse diameter, inferior transverse diameter, depth, maximum thickness of suprascapular notch and thickness at lateral and medial end of transverse scapular bar, mean thickness of superior transverse scapular bar were recorded. The data was analyzed statistically.

Observations And Results: We observed five types of notch in scapulae, type I: without a discrete notch (ill defined), 25 (3.43%); type II: a "V" shaped notch, 192 (26.37%); type III: "U" shaped notch, 383 (52.60%); type IV: inverted "V" shaped notch, 28 (3.84%); type V with absent suprascapular notch: 6 (0.82%). Type II and type III were again subclassified into subtypes (a, b, c and d) on the basis of depth of notch. Scapulae with superior transverse scapular bar (n=94, 12.91%) were classified according to variation in mean thickness of transverse scapular bar (MTSB).

Conclusion: This study will help clinicians to correlate suprascapular nerve entrapment with a specific type of suprascapular notch and notch with ossified transverse scapular ligament.