A morphometric study of spinoglenoid notch, subcoracoacromial arch, and spinous process of the scapula on shoulder impingement :Senthil Ganesh P Kannappan, Ishwar B Bagoji, Senthil Kumar, MGM Journal of Medical Sciences

ORIGINAL ARTICLE
Year : 2022 | Volume : 9 | Issue : 4 | Page : 459--464

A morphometric study of spinoglenoid notch, subcoracoacromial arch, and spinous process of the scapula on shoulder impingement

Senthil Ganesh P Kannappan¹, Ishwar B Bagoji², Senthil Kumar³,
¹ Department of Anatomy, Sri Venkateshwaraa Medical College Hospital & Research Centre, Chennai, Tamil Nadu, India
² Department of Anatomy, Shri B M Patil Medical College Hospital and Research Centre, BLDE – Deemed to be University, Vijayapura, Karnataka, India
³ Department of Anatomy, Sri Venkateswaraa Medical College Hospital and Research Centre, Ariyur, Puducherry, India

Correspondence Address:
Dr. Senthil Ganesh P Kannappan
Department of Anatomy, Sri Venkateshwaraa Medical College Hospital & Research Centre, Chennai 600067, Tamil Nadu
India

Abstract

Introduction: Morphometric study of spinoglenoid notch, coracoacromial arch, and another measurement of the scapulae are required to understand the reason for spasms of common muscle due to supraspinatus tendinitis, nerve compression over the spinoglenoid notch. Therefore, the aim of this study was to discuss the subcoracoacromial arch, deviation of the spinous process, and measurement of the spinoglenoid notch. Materials and Methods: This study was conducted at the Department of Anatomy, Sri Venkateshwaraa Medical College Hospital & Research Centre, Chennai, Tamil Nadu, India on 70 scapulae that include 58 non-articulated scapulae and 12 articulated scapulae. All the measurements were performed with a vernier caliper and the alignment of the spinous process of the scapula was measured with a goniometer. All the measurements are compared on both sides. Results: All the measurements were performed and presented as mean with standard deviation. We found the variation of diameter between the left and right sides. Spinoglenoid notch diameters were noted as anterior to posterior right 2.97 ± 0.37 cm, left 3.06 ± 0.56 cm and medial to lateral right 1.36 ± 0.14 cm, left 1.4 ± 0.08 cm. Subcoracoacromial arch was observed as right 1.85 ± 0.23 cm and left 1.92 ± 0.4 cm. The direction of the spinous process of the scapula was noted as right 21.50º ± 8.50 and left 18.8º ± 7.89. Conclusion: The present morphometric study findings may give a different approach to supraspinatous tendinits, shoulder instability, and dislocation cases due to morphometric changes present in the spinous process, acromion process, glenoid cavity, and spinoglenoid notch of the scapula. These morphometric studies on scapula can help radiologists, orthopedicians, and physiotherapists to plan patient management.

How to cite this article:
Kannappan SG, Bagoji IB, Kumar S. A morphometric study of spinoglenoid notch, subcoracoacromial arch, and spinous process of the scapula on shoulder impingement.MGM J Med Sci 2022;9:459-464

How to cite this URL:
Kannappan SG, Bagoji IB, Kumar S. A morphometric study of spinoglenoid notch, subcoracoacromial arch, and spinous process of the scapula on shoulder impingement. MGM J Med Sci [serial online] 2022 [cited 2023 Mar 28 ];9:459-464
Available from: http://www.mgmjms.com/text.asp?2022/9/4/459/365985

Full Text

INTRODUCTION

Upper limb shoulder issues are the most frequent musculoskeletal problems. It is mostly caused by the supraspinatus muscle tendon pressing against the coracoacromial arch, rotator cuff muscle tears, and compression of the suprascapular nerve as it runs through the suprascapular notch or spinoglenoid notch of the scapula.[1] The glenoid fossa and humeral head combine to generate the multiaxial shoulder joint. The glenoid fossa is smaller than the head of the humerus, and the articulated ends are covered with hyaline cartilage. Ligaments and the rotator cuff muscles can play a major role to determine the stability of the joint. After passing beneath the coracoacromial arch of the scapula, the supraspinatus tendon of the rotator cuff muscle attaches to the larger greater tubercle of the humerus. The aforementioned tendon travels between the coracoacromial arch and the glenohumeral articulation. Therefore, the area beneath the coracoacromial arch plays a crucial in supraspinatus tendinitis. The projection of the acromion, the morphology of the coracoid and spinous process, and the size of the glenoid cavity form the subcoracoacromial arch. To determine the size of the spinoglenoid notch, suprascapular notch, and subcoracoacromial arch, morphometric examinations of the aforementioned scapular components are essential.

The suprascapular nerve (C5 and C6) is one of the branches of the brachial plexus from Erb’s point.[2] In the suprascapular region, it passes through the notch beneath the trapezius and the suprascapular muscles. Furthermore, it continues to descend into the spinoglenoid notch that is located between the lateral border of the spinous process and the glenoid cavity and beneath the spinoglenoid ligament.[3] The muscles of the supraspinatus and infraspinatus receive motor supply from it.[4] This suprascapular nerve is most likely to compress at the osteofibrous tunnel of the spinoglenoid notch and suprascapular notch.[5] To overcome shoulder pain syndrome,[6] early detection and precise treatment selections are necessary.

MATERIALS AND METHODS

The Department of Anatomy at Sri Venkateshwaraa Medical College Hospital & Research (SVMCH & RI), Chennai conducted the current morphometric study using 70 dry scapulae from the right and left sides of the body. Of 70 scapulae, 12 scapulae from the articulated group and 58 from the non-articulated group were chosen. Studies were included to evaluate the morphometrics of the glenoid cavity, suprascapular notch, spinoglenoid notch, subcoracoacromial arch, and angle of the spinous process of the scapula. Bones without any fractures or missing bony processes were included in the study. Vernier calipers are used to measure distance and depth. Goniometers are used to measure the angle of the spinous process of the scapula in the osteometric examination of bone.

All parameter results were analyzed using Microsoft Excel 2010 and presented as means with standard deviation (SD). In this study, a comparison of data between two sites was performed using a sample-paired t test.

RESULTS

Measurement of the shape of the glenoid cavity

Glenoid cavity measurements were evaluated using three parameters. Between the upper wide parts of the glenoid rim, there is an elongated AB line, and in the lower wide part of the glenoid, there is an elongated CD line. The EF line extends between the supraglenoid and infraglenoid tubercle. The mean and SD of the glenoid cavity was AB 1.59 ± 1.5 cm, CD 2.48 ± 0.26 cm, and EF 3.67 ± 0.30 cm. The mean and SD of the right glenoid were AB 1.61 ± 0.1 cm, CD 2.53 ± 0.3 cm, and EF 3.81 ± 0.2 cm. The mean and SD of the left glenoid were 1.58 ± 0.1 cm, 2.45 ± 0.2 cm, and 3.53 ± 0.3 cm (P = 0.69) [Figure 1].{Figure 1}

Measurement of the shape of the suprascapular notch

Different type of suprascapular notch was identified during the study and measured the maximum width of the notch and depth of the notch was with a vernier caliper. The mean and SD of the suprascapular notch were h 0.42 ± 0.12 cm and W 0.75 ± 0.28 cm. The mean and SD of the right suprascapular notch were h 0.42 ± 0.1 cm and W 0.84 ± 0.3 cm. The mean and SD of the left side of the suprascapular notch were h 0.42 ± 0.1 cm and W 0.65 ± 0.1 cm, with P value of height 1 and P value of the width of 0.28 [Figure 2].{Figure 2}

Measurement of spinoglenoid notch

Acromioglenoid (AP) diameter is extending from the supraglenoid tubercle to the highest concavity of acromion. Lateral diameter (ML) is extending between the posterior rim of the glenoid cavity to the center of the lateral border of the spine of the scapula. The mean and SD of the spinoglenoid notch were AP 3.01 ± 0.4 cm and ML 1.4 ± 0.1 cm. The mean and SD of the spinoglenoid notch on the right side were AP 2.97 ± 0.3 cm and ML 1.36 ± 0.1 cm. The mean and SD of the spinoglenoid notch on the left side were AP 3.06 ± 0.5 cm and ML 1.43 ± 0.1 cm, with P value of (acromioglenoid) AP diameter 0.66 and P value of ML diameter 0.14 [Figure 3].{Figure 3}

Measurement of subcoracoacromial arch

Measurement of the subcoracoacromial arch has calculated the distance between A and B points. Point A is the center of the imaginary line between the coracoid and acromian process. Point B is the supraglenoid tubercle. The mean and SD of the subcoracoacromial arch were 1.8 ± 0.3 cm. The mean and SD of the subcoracoacromial arch on the right side were 1.85 ± 0.2 cm. The mean and SD of the subcoracoacromial arch on the left side were 1.92 ± 0.4 cm (P = 0.61) [Figure 4].{Figure 4}

Measurement of the angle of the spinous process of the scapula

The direction of the spinous process was measured by using a goniometer. Measurement was taken by placing a fulcrum at the root of the spinous process, the stationary arm was kept horizontal, and the moving arm was kept on the spinous process. The angle of the spinous process was noted from all scapulae.

The mean and SD of the angle of the spinous process of the scapula were 20.09º ± 7.9. The mean and SD right side of the angle of the spinous process of the scapula were 21.5º ± 8.5. The mean and SD of the left side angle of the spinous process of the scapula were 18.8º ± 7.8 (P = 0.46) [Figure 5] and [Table 1].{Figure 5} {Table 1}

DISCUSSION

This study was conducted to determine the parameters of the reported and unreported parts of the scapula. Some of the parameters were performed by several authors in their course of study. The results obtained from this study are compared with those of other studies and mentioned their differences as well as similarities with our findings.

The narrow space of the subcoracoacromial arch was bounded above by acromion, coracoid process, coracoacromial ligament, and inferiorly limited by rotator cuff muscles that attach to the head of the humerus.[7] Owing to biomechanical factors or the morphological configuration of the scapula’s process, the part of the rotator muscle tendon may be inappropriately compressed when the arm is raised in this small area. Intrinsic and extrinsic factors are the two main causes of these subcoracoacromial impingements. The morphological alignment of bony projections is an extrinsic component, whereas the supraspinatus tendon rupture is an intrinsic factor.[8] For supraspinatus impingement, the bony constellations of the coracoacromial arch are of particular importance.[9] Not every scapula has the same protrusion of the spinous process. A variable angle range of 7°–30° is displayed in our study. None of the scapula marphometric studies have documented the scapulae spinous process projections. The spinoglenoid notch space and subcoracoacromial space can shift as a result of this variable projection angle. The rotator cuff muscle may be impacted by this change in the subcoracoacromial area. The compression of the suprascapular nerve may be affected by this change in the spinoglenoid notch.

Two perspectives were used to measure the spinoglenoid notch in our investigation. Acromioglenoid (AP) diameter ranged from 2 to 3.5 cm, whereas lateral (ML) diameter ranged from 1.2 to 1.6 cm. Numerous other earlier studies showed the spinoglenoid notch of acromioglenoid diameter.[10],[11] Vinay et al.[12] study on acromioglenoid measurement showed the identical to our present study on acromioglenoid measurement. It has mentioned right 29.79 ± 4.04 and left 30.36 ± 4.1. Dhindsa et al.[13] study on acromioglenoid measurement of right side 3.0 ± 3.6 cm, left side 3.02 ± 4.6 cm. Mansur et al.[14] reported a mean of right 31.83 mm and left 31.97. The earlier studies mentioned only about acromioglenoid diameter of the spinoglenoid notch. This study discussed the distance between the lateral border of the spinous process and the margin of the glenoid cavity.

The subcoracoacromial arch and spinoglenoid notch spaces may change depending on how the glenoid cavity is shaped. Previous research study on the vertical diameter of the glenoid cavity was reported by Coskun et al., with a mean value of 3.63 ± 3 cm, Mamta et al., with a mean value of 3.3 ± 2.8 cm, Azhagiri et al., with a mean value of 3.51 ± 2.6 cm, Akhtar et al., 3.58 ± 3.1, Neeta al., 3.87 ± 3.03.[10],[15],[16],[17],[18] Coskun et al. and Akhtar et al. study findings on vertical diameter of glenoid cavity were showed almost identical to our current study findings.

The transverse diameter of the upper part of the glenoid was presented by Mamta et al., with a mean of 1.62 ± 2.01 cm, and Azhagiri et al., with a mean of 1.79 ± 2.573 cm, Akhtar et al., a mean of 1.61 ± 2.24 cm, Neeta et al. mean of 1.86 ± 2.13 cm. Mamtha et al. and Akhtar et al. study on transverse diameter of upper part of glenoid cavity were showed almost similar findings to our present study on glenoid cavity. The transverse diameter of the lower part of the glenoid was presented by Coskun et al., with a mean of 2.46 ± 2.5, Mamta et al., a mean of 3.36 ± 2.8, Neeta et al. a mean of 2.49 ± 2.55, Azhagiri et al., mean of 2.41 ± 1.9 cm, Akhtar et al., mean of 2.36 ± 2.50 cm. Mamtha et al., and Akhtar et al., study on transverse diameter of upper part of glenoid cavity were showed almost similar findings to our present study on glenoid cavity.

According to Ostör et al.,[19] shoulder disorders are most commonly caused by rotator cuff tears (85%) and shoulder impingement (74%). Through the acromiohumeral index and critical shoulder angle in radiological results, these shoulder diseases can be evaluated.[20] By measuring the height of the subcoracoacromial arch, which extends from the supraglenoid tubercle to the coracoacromial arch, Edelson and Taitz[21] studied the degeneration of the coracoacromial arch. According to their study, subcoracoacromial arch distances of less than 12 mm are connected with degenerative alterations of acromion and coracoid process. In his investigation, degenerative causes were found in 75% of coracoacromial arches. However, the subcoracoacromial arch measured in our study had a mean value of 18 mm and a range of 13–22 mm. These differences in the subcoracoacromial arch can play an important role in rotator cuff tears.

The angle of the spinous process of the scapula in this study was shown to range between 7° and 35°. This enormous difference in spinous process angle on different individuals may alter the space of the spinoglenoid notch and coracoacromial arch space. None of the previous studies was done on the angle of spinous process projection by a goniometer.

CONCLUSION

In this study, numerous characteristics were examined from the glenoid cavity, suprascapular notch, spinoglenoid notch, coracoacromial arch, and spinous process orientation. The findings of this study were unique and distinct from those of earlier research studies by other authors. No author reported complete morphometry of the spinoglenoid notch, subcoracoacromial arch, and angle of the spinous process. This study deals with the morphometry of various scapular components and elucidates the importance of the normal morphology variation present in the scapula. The subcoracoacromial arch and angle of the spinous process show a huge range variation between different dry scapula. The morphometry of this study guides us to better understand the anatomy and pathology of the rotator cuff tear, shoulder impingement, and suprascapular nerve compressions occurring in the shoulder regions. It helps professionals such as orthopedic surgeons, radiologists, physiotherapists, and others to understand the disorder with clarity.

Ethical policy and institutional review board statement

The study was conducted with dry scapulae. Hence, it does not require any ethical consideration.

Financial support and sponsorship

Not applicable.

Conflicts of interest

There are no conflicts of interest.

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