An Anthropometric Study of Cadaveric Human Scapula Bone in the Odisha Population: Implications for Orthopaedic Implants and Surgical Interventions.

The human scapula, a triangular, flat, paired bone on the posterolateral thoracic wall, acts as the biomechanical foundation for the upper extremity. It provides critical attachment sites for 17 muscles that stabilize and drive the glenohumeral joint—the most mobile joint in the human body. Because the humeral head is significantly larger than the shallow glenoid fossa, the joint possesses an inherent instability, making it susceptible to subluxation, impingement, and degenerative rotator cuff lesions.

 

Pathology of the shoulder is currently the third most common cause of musculoskeletal disease, with approximately 2% of the global population experiencing varying degrees of shoulder instability. Understanding the geometric variations of the coracoid process and glenoid fossa is fundamental to treating glenohumeral osteoarthritis, subcoracoid impingement, and recurrent dislocations. Furthermore, traumatic scapula injuries, while accounting for only 1% of all fractures, are typically the result of high-energy trauma and are frequently accompanied by severe associated injuries to the thorax and upper extremities.

 

In cases of significant displacement, surgical intervention via open reduction and internal fixation (ORIF) is required to restore congruence and prevent chronic pain and stiffness. However, there is a documented lack of demographically specific shoulder-related literature in India.

 

Implants designed based on Western anthropometric data often lead to geometric mismatches in Indian populations, resulting in altered biomechanics and hardware failure. Based on the protocols established in THESIS S11.docx, this study evaluates the specific morphometry of the scapula in the Odisha population to provide accurate reference data for orthopaedic surgeons and implant manufacturers.

The study was conducted using dry, mature cadaveric human scapulae obtained from the Osteology Museum of the Department of Anatomy, S.C.B. Medical College, Cuttack, Odisha.

 

Inclusion Criteria:

·         Mature, dry, structurally intact cadaveric scapulae (male and female, left and right).

 

Exclusion Criteria:

·         Immature bones (unfused epiphyses).

·         Broken, damaged, or pathologically deformed bones.

 

Measurement Techniques:

·         Linear Measurements: Recorded using sliding digital Vernier calipers (accurate to 0.01 mm) and standard measuring scales. Metrics included scapular length/width, glenoid cavity dimensions, acromion/coracoid lengths, acromio-coracoid distance, and suprascapular notch depths.

·         Angular Measurements: Recorded using standard protractors and goniometers (1-degree resolution). Metrics included the glenopolar angle, medial angle, lateral angle, and inferior angle.

·         Thickness Measurements: Recorded at specific anatomical zones (glenoid fossa, lateral border, scapular spine) to identify optimal screw purchase sites for fracture fixation.

 

Statistical analysis was performed to calculate means and standard deviations. Independent sample t-tests were utilized to evaluate sexual dimorphism, with a p-value of <0.05 considered statistically significant.

The fundamental dimensions of the scapula demonstrated significant sexual dimorphism, with male specimens exhibiting larger overall parameters.

 

Table 1: Linear Measurements of the Scapular Body

 

Accurate glenoid cavity dimensions are crucial for shoulder arthroplasty. All linear glenoid parameters were significantly larger in males.

 

Table 2: Morphometry of the Glenoid Cavity

 

The spatial relationship between the acromion and coracoid process is a primary determinant in subacromial impingement syndromes.

 

 

Table 3: Coracoid Process, Acromion, and Spatial Distances

 

Variations in the suprascapular notch are directly linked to suprascapular nerve entrapment neuropathies.

 

Table 4: Suprascapular Notch Dimensions

 

Mapping bone thickness dictates the optimal trajectory and placement of screws during open reduction and internal fixation of scapular fractures.

 

Table 5: Regional Scapular Bone Thickness

 

The morphometric evaluation of the scapula is a cornerstone for advancing orthopaedic interventions of the shoulder. Our findings in the Odisha population confirm that the scapula is a highly sexually dimorphic bone, aligning with the forensic and anatomical assessments previously reported by Oliveira Costa et al. and Polguj et al.

 

The structural dimensions of the glenohumeral joint observed in this cohort emphasize the necessity for population-specific prostheses. The mean glenoid cavity length and width were significantly smaller than those reported in Western demographic studies. If standard Western implants are utilized in this demographic without modification, patients are at a higher risk for component overhang, altered soft-tissue tensioning, and accelerated polyethylene wear.

 

Furthermore, the regional thickness mapping strongly supports the surgical approaches advocated by Burke et al. The central portion of the scapular body proved to be uniformly thin (mean 2.85 mm), rendering it entirely unsuitable for screw fixation. Conversely, the lateral border and the base of the scapular spine demonstrated robust cortical thickness, making them the most biomechanically sound regions for contoured reconstruction plates during the management of displaced scapular body and neck fractures.

 

The varied spatial relationship between the acromion and coracoid process recorded in this study also sheds light on the pathomechanics of subcoracoid impingement. A reduced acromio-coracoid distance, noted predominantly in the lower percentiles of the female cohort, limits the subacromial space, predisposing these individuals to early-onset rotator cuff tendinopathy. Accurate preoperative imaging and awareness of these regional baseline values will allow surgeons to better anticipate the need for concurrent acromioplasty or coracoplasty during reconstructive procedures.

1.       Matsumura N, Ikegami H, Nakamichi N, Nakamura T, Nagura T, Imanishi N, Aiso S, Toyama Y. Effect of shortening deformity of the clavicle on scapular kinematics: a cadaveric study. The American Journal of Sports Medicine. 2010;38(5):1000-1006.

2.       Masih C, Francis A, Shriwastava A, Diwedi N, Tiwari P, Nareliya R, Kumar V. Biomechanical evaluation of human humerus and scapula bone: a review. Journal of Biomedical and Bioengineering. 2012;3(1):63-66.

3.       Polguj M, Jędrzejewski KS, Topol M. Sexual dimorphism of the suprascapular notch–morphometric study. Archives of Medical Science. 2013;9(1):177-183.

4.       Campoli G, Weinans H, van der Helm F, Zadpoor AA. Subject-specific modeling of the scapula bone tissue adaptation. Journal of Biomechanics. 2013;46(14):2434-2441.

5.       Sharma R, Singla RK, Kullar JS, Sharma R, Sharma T. A Cadaveric Study of Different Angles of Scapula and Their Role in its Kinesiometrics and Muscle Morphology. Journal of Nepal Medical Association. 2013;52(191).

6.       Tuček M, Naňka O, Malík J, Bartoníček J. The scapular glenopolar angle: standard values and side differences. Skeletal Radiology. 2014;43:1583-1587.

7.       Contreras J, Gil D, de Dios Errázuriz J, Ruiz P, Díaz C, Águila P, Rosselot A, Espinoza R, Beltrán M, Liendo R, Soza F. Scapular balance angle reference values in a healthy population. Revista Española de Cirugía Ortopédica y Traumatología. 2014;58(1):24-30.

8.       Jacobson A, Gilot GJ, Greene A, Flurin PH, Wright TW, Zuckerman JD, Roche CP. Glenohumeral anatomic study: a comparison of male and female shoulders with similar average age and BMI. Bulletin of the NYU Hospital for Joint Diseases. 2015;73(1):S68.

9.       Grohmann I, Raith S, Mücke T, Stimmer H, Rohleder N, Kesting MR, Hölzle F, Steiner T. Biomechanical loading test on reconstructed mandibles with fibular, iliac crest or scapula graft: a comparative study. British Journal of Oral and Maxillofacial Surgery. 2015;53(8):741-747.

10.    Lingamdenne PE, Marapaka P. Measurement and analysis of anthropometric measurements of the human scapula in Telangana region, India. International Journal of Anatomy and Research. 2016;4(3):2677-2683.

11.    Burke CS, Roberts CS, Nyland JA, Radmacher PG, Acland RD, Voor MJ. Scapular thickness—implications for fracture fixation. Journal of Shoulder and Elbow Surgery. 2016;15(5):645-648.

12.    Oliveira Costa AC, de Albuquerque PP, de Albuquerque PV, de Oliveira BD, de Albuquerque YM, Caiaffo V. Morphometric Analysis of the Scapula and Their Differences between Females and Males. International Journal of Morphology. 2016;34(3).

13.    Chavan SR, Bhoir M, Verma S. A study of anthropometric measurements of the human scapula in Maharashtra, India. International Journal of Anatomy. 2017;1(2):23-26.

14.    Donders JC, Prins J, Kloen P, Streekstra GJ, Cole PA, Kleipool RP, Dobbe JG. Three-dimensional topography of scapular nutrient foramina. Surgical and Radiologic Anatomy. 2020;42:887-892.

15.    Rodriguez S, Mancini MR, Kakazu R, LeVasseur MR, Trudeau MT, Cote MP, Arciero RA, Denard PJ, Mazzocca AD. Comparison of the coracoid, distal clavicle, and scapular spine for autograft augmentation of glenoid bone loss: a radiologic and cadaveric assessment. The American Journal of Sports Medicine. 2022;50(3):717-724.