European Journal of Cardiovascular Medicine

The scapula is a large, flat and triangular bone situated postero-laterally on the thoracic cage between the second to sixth ribs [1]. It has three surfaces; costal and dorsal, three borders; medial, lateral and superior and three angles; superior, inferior and lateral. Its lateral angle is truncated and broad which provides socket for articulation of head of humerus forming the head of humerus. The shallow glenoid cavity and relatively larger head of humerus in combination with lax capsule make the joint more mobile but unstable [2]. There are various shapes of glenoid cavity like oval, pear and inverted comma shapes are reported due to presence of notch on its anterosuperior aspect [3,4]. There are many factors which provide the stability of shoulder joint such as coraco-acromial arch, glenoid labrum and musculotendinous cuff. Most commonly shoulder joint is dislocated inferiorly because there are very few supports at inferior region [5]. The main purpose of this study was to collect the data of glenoid cavity of scapula and identify the different shapes in population of Bihar and compare this data with those of other study. These data will help the orthopedic surgeon for better understanding and management of gleno-humeral instability, shoulder replacement and rotator cuff tear management in population of Bihar.

This is a cross-sectional type of study carried on 120 dry adult human scapulae of unknown age and sex in which 60 belongs to right side and 60 belongs to left side were obtained from, MBBS students, department of anatomy and forensic medicine of Indira Gandhi Institute of Medical Sciences, Patna. The fully ossified, dried, macerated bones which were complete in all respects included in this study. The scapulae that were damaged or had any pathological deformity were excluded from this study.

The following parameters were studied:

1. Shape of glenoid cavity- Trace the slightly raised rim of glenoid cavity on white paper with lead pencil.
2. Maximum scapular length- The distance measured from summit of superior angle to inferior angle.
3. Maximum scapular breadth- The distance measured from where the spine intersects the medial border to the posterior rim of glenoid cavity.
4. Supero-inferior diameter of Glenoid cavity (SI)- Maximum distance between most prominent point of supra-glenoid tubercle to most inferior point on glenoid margin.
5. Antero-posterior diameter of Glenoid cavity AP)- Maximum breadth of articular margin of glenoid cavity
6. Glenoid cavity index- GCI) Anterio-posterior Glenoid diameter ÷ Superio inferior glenoid diameter) × 100

Figure 1. Measurement of Scapula [AB - Maximum scapular length, CD - Maximum scapular width]

Figure 2. Measurement of Glenoid cavity [EF- Supeo-inferior diameter and GH- Antero-posterior diameter]   

comma-shaped (31.67%). The least common shape was oval (14.16%). The mean scapular length was observed as 137.11±8.72 mm, the mean breadth of the scapula was 98.73±10.92 mm, the mean supero-inferior glenoid diameter was 36.34±3.91 mm, the mean anteroposterior glenoid diameter was 24.95±4.58 mm and mean glenoid cavity index was 68.82±10.33.

Table 1. Various shapes of Glenoid cavity of the Scapula

Table 2. Morphometric parameter of Scapula

      Figure 3. Different shapes of Glenoid cavity (A-Pear, B- Inverted comma, C- Oval)

Table 3. Comparison of Incidence of different shapes of Glenoid cavity

Table 4. Comparison of morphometric value of glenoid fossa

In our study pear shape was most common shape of glenoid cavity followed by inverted comma and oval shaped. Most of the authors reported pear shaped glenoid cavity as a common shaped. D. Santosh Kumar Ankush rao et al., Akhtar MJ et al. and Rajput HB et al., reported in their study that pear shaped glenoid cavity as a common shape followed by inverted comma and oval shaped while Coskun N et al. reported oval shaped glenoid cavity was the most common followed by pear shaped in Turkish population. In present study supero-inferior diameter of scapula was 36.34±3.91 mm in total scapula, 36.15±4.00 on right side and on left side it was 36.53±3.85mm. The supero-inferior diameter values measured by Archana Singh et al., Akhtar MJ et al., Aigbogun E O et al. were very similar with the present study [10,1,13], while the study done by Neeta et al. and W.A.Nasr El-Din et al. reported higher value. In present study, the mean values of antero-posterior diameter of glenoid cavity were as 24.95±4.58 mm in total, 24.75±4.63 mm on the right and 25.15±4.56 mm on the left side. This value was very closely to the study done by Archana Singh et al., Akhtar MJ et al., Neeta et al. [10,1,11]. The study done by W.A.Nasr El-Din et al. in Egyptian population and Aigbogun E O et al. in Nigerian population reported higher value than this study. In present study, the mean values of Glenoid cavity index on right side 66.66±9.15, on left side 67.22±6.11 and in total glenoid fossa 66.98±7.80. Values of GCI of present study were found very close to the study done by Akhtar MJ et al., Neeta et al. [1,11].  While the values of GCI reported by Archana Singh et al. [10] were higher than the present study.

Morphological and morphometric analysis of glenoid cavity of scapula is very important during designing and fitting of glenoid component in total shoulder arthroplasty and its associated shoulder pathology

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