Variable morphology of the suprascapular notch: An investigation and quantitative measurements in Chinese population

Abstract

Although several morphological variations and classification of the suprascapular notch (SSN) were reported in western populations, little attention has been paid to this anatomic issue in the Chinese population. In this research of SSN morphology in Chinese people, 295 specimens of intact dry Chinese adult scapulas were investigated and measured thoroughly and systematically. Morphological features of SSN variations were observed by visual inspection, and correlation parameters of variability and classification were measured in digital images with image processing software and bones with a vernier caliper, respectively. The incidence of different subtypes of SSN classification and comparative analysis of correlation parameters were calculated. It was interesting that a new variable morphology of SSN with a double suprascapular foramen had been found. We found the most prevalent groups were Type II (an incisura that was longer in its transverse diameter) and Type III (an incisura that was longer in its vertical diameter) which accounted for 58.16 and 28.23%, respectively. The circumference and area of Type II and Type III was larger than those of Type IV. The thickness of 1 mm below the lowest point of the SSN ranges from 0.55 to 3.00 mm. Eight cases with a narrow groove on the lowest point of SSN and four cases with bony canals formed by the ossified superior transverse scapular ligament were found. Further, the distance between the SSN and bony landmarks were varied. For AD (the distance between the lowest point of the SSN and the supraglenoid tubercle), Type I was largest, followed by the Type II, Type III, and Type IV. For AE (the distance between the lowest point of the SSN and the base of the spinoglenoid notch), Type IV was the shortest and there was no statistical difference between other types. This study reveals that SSN variations are common in Chinese population. This anatomic information is important in the management of entrapment neuropathy or interventional procedure of the SSN.

Morphology and Morphometric Analysis of Suprascapular Notch

“…This corresponds with the results of Wang et al (Chinese population) where also the most common type of SSN reported is Type II (58.6%) , where the notch is longest in transverse diameter and the least common is Type V where both notch and foramen are present (none). 8 Natsis et al in their study reported an equal incidence of types II and III SSN. 5 On gross examination without involving any measurements, the results of the present study correspond with that of Sinkeet et al who also reported the U shaped notch as most common (29%) and the complete ossification of STSL as least common (4%) in Kenyan population.…”

“…3 SSN has been classified by various workers in different populations on the basis of parameters such as vertical length of the notch, transverse diameter of the notch and shape of the notch. 4,5,6,7,8 Knowing the anatomical variations in detail is better for understanding of location and source of the entrapment syndrome.However, the literature focusing on SSN and SN IJBAR (2013) 04 (01) www.ssjournals.com…”

A Morphometric Study of Suprascapular Notch and Its Safe Zone

“…Therefore various studies have been done on suprascapular notch variations in different populations. Rengachary et al, [6] Ticker et al, [11], Bayramoglu et al, [12] Natsis et al, [13] Sinkeet [14] Wang [15] and Polguj [16]. Depending on the shape of suprascapular notch and the degree of ossification, Rengachary et al, [6] classified SSN into six types .…”

Morphology of suprascapular notch in medieval skeletons from Bulgaria

“…Iqbal et al [13] separated the notches into 3 types -"U", "V" and "J" types, without involving any measurements. Wang et al [37] have found a new variable morphology of the SSN with a double suprascapular foramen. The classification of SSN that was used in our study is simple and does not require complicated measurements, and it makes possible to very easily distinguish the three types of the notch -its absence (type 1) and the partial and complete ossification of the superior transverse suprascapular ligament (types 4 and 5), which are supposed to be risk factors for suprascapular entrapment neuropathy.…”

“…According to Wang et al [37] and Soni et al [33], the most common type in their samples is the type, where the notch has longer transversal diameter than the vertical length. The results of Natsis et al [19] show an equal inci- dence of the types, where the notch is longest in its transverse diameter or it is longest in its vertical length.…”