Unusual morphology of scapulae: incidence and dimensions of ossified ligaments and supraspinous bony tunnels for clinical consideration

Abstract

INTRODUCTIONKnowledge of anatomical variations and anomalies along the course of the suprascapular nerve (SSN) is important in the treatment of SSN entrapment syndrome, and bony and brachial plexus injuries. This knowledge is also important for surgeons carrying out surgical interventions at the shoulder region.The SSN provides sensory innervation to the posterosuperior aspect of the shoulder and motor innervation to the supraspinatus and infraspinatus muscles. The SSN passes beneath the superior transverse scapular ligament (STSL) and inferior transverse scapular ligament (ITSL) at the fibro-osseous canals of the suprascapular notch and spinoglenoid notch, respectively. Therefore, the STSL and ITSL are potential sites of SSN compression. Complete ossification of the STSL with formation of bony foramina is the most recognised predisposing factor for compression at the suprascapular notch;(1) it is also a risk factor in surgical exploration for SSN decompression. In a recent histological and immunohistochemical study, it was found that all five cadaveric shoulders that had STSL ossification showed signs of neural degeneration in the nerve specimens.(3) However, a high incidence of ossified STSL does not proportionally correlate with the occurrence of SSN entrapment; (4,5) this could be due to the lack of focus on the influence that the body ridge shape (created by the ossified STSL) has on SSN entrapment. With this in mind, the present study was designed to analyse the variable morphological aspects of the ossified STSL, along with other ossified ligaments found in the scapula. We also document any rare findings of ossified ITSL and bony tunnels (i.e. the bony canal found between the suprascapular notch and spinoglenoid notch), as well as their dimensions, as these structures could potentially compress vascular and neural elements by reducing available space in the spinoglenoid notch. (6,7) In short, the present study explored the incidence of ossified ligaments and bony tunnels along the course of the SSN in dry human scapulae from a North Indian population. We also measured and recorded the dimensions of osseous ligaments and any rare bony tunnel and foramina at the suprascapular notch and spinoglenoid notch. As the existing data on ossified ligaments of dry human scapulae is limited, the data obtained in the present study would augment the current anatomical and morphological reference values. This would also aid in defining the anatomical risk factors for SSN entrapment and identifying the surgical hazards present during open and arthroscopic interventions in the suprascapular and spinoglenoid notch regions. METHODSThe present study was conducted on 268 dry human adult scapulae of unknown gender from a North Indian population. Among the 268 scapulae, 126 were right-sided and 142 were

Morphometric study of suprascapular notch and scapular dimensions in Ugandan dry scapulae with specific reference to the incidence of completely ossified superior transverse scapular ligament

“…In general, the correlation analyses of our study have shown that the scapular dimensions (scapular length and width; glenoid length and width) might be of value in the diagnosis, assessment, and prevention of SN entrapment syndrome associated with scapulae of type III, IV and VI SSN emphasizing the clinical significance of scapular dimensions in helping clinicians, radiologists, and orthopedic surgeons perform better with minimal complications in agreement with previous findings [ 1 – 3 ].…”

“…The knowledge of the anatomy and variations of SSN is important for clinicians and surgeons that carry out diagnoses, assessment, management, surgical interventions at the shoulder region. This knowledge is vital in the diagnosis, management, assessment, and prevention of suprascapular nerve entrapment disorder around the shoulder joint [ 1 – 3 ]. The suprascapular notch (SSN) forms a depression on the lateral aspect of the superior border of the scapula, medial to the coracoid process [ 4 ], is bridged by the superior transverse scapular ligament (STSL), which may sometimes be completely ossified with a resultant conversion of the notch into a foramen [ 4 ].…”

Correlations of Scapular Dimensions: A Tool to Identify Scapulae with Completely Ossified Superior Transverse Scapular Ligaments and Suprascapular Neuropathy

“…In general, the correlation analyses of our study have shown that the scapular dimensions (scapular length and width; glenoid length and width) might be of value in the diagnosis, assessment, and prevention of SN entrapment syndrome associated with scapulae of type III, IV and VI SSN emphasizing the clinical signi cance of scapula, glenoid and other related scapular dimensions in helping clinicians, radiologists, and orthopaedic surgeons. perform better with minimal complications [1][2][3]. However, the equation that can be used to predict the relationship of different scapular dimensions and the SSN types could not be determined.…”

“…of suprascapular notch variations are important in the management and prevention of the SSN entrapment syndrome, and bony and brachial plexus injuries, furthermore, this knowledge is important for clinicians and surgeons that carry out diagnoses, assessment, management and surgical interventions at the shoulder region and in the prevention of this disorder. [1][2][3]. The suprascapular notch (SSN) forms a depression on the lateral aspect of the superior border of the scapula and located medial to the coracoid process [4], is bridged by the superior transverse scapular ligament (STSL), which may sometime be ossi ed with a resultant conversion of the notch into a foramen [4].…”

Morphometric study of suprascapular notch and scapular dimensions in Ugandan dry scapulae with specific reference to the incidence of completely ossified superior transverse scapular ligament

“…The knowledge of the anatomy and variations of SSN is important for clinicians and surgeons that carry out diagnoses, assessment, management, surgical interventions at the shoulder region. This knowledge is vital in the diagnosis, management, assessment, and prevention of suprascapular nerve entrapment disorder around the shoulder joint [1][2][3]. The suprascapular notch (SSN) forms a depression on the lateral aspect of the superior border of the scapula, medial to the coracoid process [4], is bridged by the superior transverse scapular ligament (STSL), which may sometimes be completely ossi ed with a resultant conversion of the notch into a foramen [4].…”