Morphological study of the inferior transverse scapular ligament
Entrapment of the suprascapular nerves (SSN) commonly occurs at either the suprascapular or the spinoglenoid notch. Typical isolated atrophy of the infraspinatus muscle and weakness towards external rotation are often present in case of an entrapped SSN at the spinoglenoid notch. One of the presumed causes of this phenomenon is a hypertrophic inferior transverse scapular ligament (ITSL, also known as spinoglenoid ligament).
Findings in previous studies are inconsistent regarding the incidence, and if present components and shape of the ITSL. In this study, 110 shoulders from 72 cadavers were dissected – overlying muscles (i.e. deltoid, trapezius, supra- and infraspinatus) were revealed and subsequently (partially) removed in order to expose the ITSL, and its length and width were measured.
In 73 (66.4%) of the 110 shoulders an ITSL was present. In the majority of specimens, it attached at the posterior glenoid margin. A membranous structure was observed in 40 (36.4%) cases, a ligament was seen in 25 (22.7%) cases and in eight (7.3%) cases both a membranous as well as a ligamentous structure were present. Based on the shape of the ITSL in the observed specimens, three types of ITSL could be distinguished: 1) band-like (n=37, 33.6%); 2) triangular (n=17, 15.5%), or; 3) irregular (n=19, 17.3%). > From: Won et al., Clin Anat (2013) (Epub ahead of print). All rights reserved to Wiley Periodicals, Inc.
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