The variable morphology of suprascapular nerve and vessels at suprascapular notch: a proposal for classification and its potential clinical implications

Abstract

PurposeThe most common place for suprascapular nerve entrapment is the suprascapular notch. The aim of the study was to determine the morphological variation of the location of the suprascapular nerve, artery and vein, and measure the reduction in size of the suprascapular opening in each type of the passage. MethodsA total of 106 human formalin-fixed cadaveric shoulders were included in the study. After dissection of the suprascapular region, the topography of the suprascapular nerve, artery and vein was evaluated. Additionally, the area of the suprascapular opening was measured using professional image analysis software.ResultsFour arrangements of the suprascapular vein, artery and nerve were distinguished with regard to the superior transverse scapular ligament: type I (61.3 %) (suprascapular artery was running above ligament, while suprascapular vein and nerve below it), type II (17 %) (both vessels pass above ligament, while nerve passes under it), type III (12.3 %) (suprascapular vessels and nerve lie under ligament) and type IV (9.4 %), which comprises the other variants of these structures. Statistically significant differences regarding the suprascapular opening were observed between the specimens with types II and III. Anterior coracoscapular ligaments were present in 55 from 106 shoulders.ConclusionThe morphological variations described in this study are necessary to better understand the possible anatomical conditions which may promote suprascapular nerve entrapment (especially type III). They may be useful during open and endoscopic procedures at the suprascapular notch to prevent such complications as unexpected bleeding.

Suprascapular foramen: a rare variation caused by ossified suprascapular ligaments

“…In aetiology of the SN entrapment, less attention has been paid to the topography of the complete suprascapular triad: the nerve, artery and vein [39]. The SSA which supplies the supraspinatus muscle enters the supraspinous fossa on the dorsal aspect of the scapula superior to the STSL [26].…”

“…When the route of the SSA passes under the STSL, it may cause SN entrapment [6,44,49]. Polguj et al [39] found that specimens including type III suprascapular triad (the suprascapular vessels and nerve lie beneath the STSL) had smallest mean area of the suprascapular opening, when compared with the others.…”

“…The ossified suprascapular ligament narrows the suprascapular foramen [39]; therefore, it causes compression of SN and complaints of SN entrapment. It is essential to define precisely the anatomical variations of scapular notch, scapular ligament, SN and vessels for surgeons performing SN decompression surgery, especially with arthroscopic techniques.…”

A quantitative study of the arrangement of the suprascapular nerve and vessels in the suprascapular notch region: new findings based on parametric analysis

“…However, the locations of the associated suprascapular vein and artery are highly variable [16,20,22].…”

“…Nevertheless, this is a very important subject, because the position of the suprascapular artery under the STSL could be one of the possible causes of SN entrapment [2,16,19,20].…”