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Morphometric Study of Scapular Index in South Indian Population: An Observational Study |
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MS Somesh, Sanjaykumar B Revankar, Mutyalapati Venkata Ramulu 1. Professor and Head, Department of Anatomy, Father Muller Medical College, Mangalore, Karnataka, India. 2. Assistant Professor, Department of Anatomy, Father Muller Medical College, Mangalore, Karnataka, India. 3. Associate Professor, Department of Anatomy, Apollo Institute of Medical Sciences and Research, Chittoor, Andhra Pradesh, India. |
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Correspondence Address : Dr. MS Somesh, Professor and Head, Department of Anatomy, Father Muller Medical College, Father Muller Road, Kankanady, Mangalore-575002, Karnataka, India. E-mail: drsomeshms@fathemuller.in |
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ABSTRACT | ||||||||||||||||||||||||||||||||||||||||||
: Introduction: Scapula is a flat, triangular bone forming very important shoulder joint and with the evolution it has undergone modifications especially in its shape. It can be best studied with the help of Scapular Index (SI)-which denotes the relationship of breadth of the scapula to the length of the scapular bone. Aim: To determine the morphometric dimensions and SI in South Indian population and to compare it with various ethnic groups and laterality. Materials and Methods: The present retrospective observational study utilised a total of 98 scapulae of both right and left sides from South Indian population available over a period of one year in the Department of Anatomy of tertiary care centre. The relationship of Scapular Length (SL) with its breadth was expressed as the SI. The obtained values are analysed using Statistical Package for Social Sciences (SPSS) Software version 21.0. Mean, ratio, percentage and standard deviations were applied and results were analysed. Results: The breadth of the scapula ranged from 83-112 mm and the mean value was 96.71±6.98 mm. The length of scapula ranges from 104.5-165 mm and the mean value was 136±13.52 mm. The SI was ranging from 55.62-87.08 and the mean value was 71.46±5.64. The Infraspinous Index (IB), ranged from 68.42-121.33 and the mean value was 94.14±10.98. Conclusion: The morphometric data of the present study can be not only in comparative anatomy between the different races, but also between the subpopulations of our country also. The data of the present study can be useful for manufacturing various prosthetic products, for procedures such as prosthetic positioning of scapula and also in various surgical maneuvers such as screw fixations, replacements of the shoulder joint in our subset of population for various medical fields such as Orthopaedics. | ||||||||||||||||||||||||||||||||||||||||||
Keywords : Infraspinous index, Morphology, Scapular region, Shoulder | ||||||||||||||||||||||||||||||||||||||||||
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DOI and Others :
10.7860/IJARS/2021/48941:2678
Date of Submission: Feb 09, 2021 Date of Peer Review: Mar 25, 2021 Date of Acceptance: May 03, 2021 Date of Publishing: Jul 01, 2021 AUTHOR DECLARATION: • Financial or Other Competing Interests: None • Was Ethics Committee Approval obtained for this study? Yes • Was informed consent obtained from the subjects involved in the study? NA • For any images presented appropriate consent has been obtained from the subjects. NA PLAGIARISM CHECKING METHODS: |
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INTRODUCTION | ||||||||||||||||||||||||||||||||||||||||||
Scapula is a flat, triangular bone of the pectoral girdle, situated on the posterior side of the rib cage, extending from T2 to T7. Scapula has a body with subscapular fossa on its costal aspect and supraspinous and infraspinous fossa on its dorsal aspect. The triangular spine, the acromion process and the coracoid process also lies in its dorsal aspect. It consists of three angles, superior, inferior and lateral; the lateral angle is truncated and bears the glenoid cavity (1). With evolution two parts of human scapula, the dorsal component representing scapula proper and the ventral component representing coracoids are fused together (2). Various studies on the development of scapula agreed to that, the peculiar shape of scapula is a mammalian characteristic as against the forces applied by the surrounding muscles (3). With the evolution, scapula has undergone modifications especially in its shape. These modifications can be best studied with the help of SI-which denotes the relationship of breadth of the scapula to the length of the scapular bone. In previous studies, it is noted that, in quadrupeds the scapula is long and narrow and the SI is very high and it progressively falls as we approach the mammals, which walks with body upright position such as humans, where the forelimb is completely free (4). The measurements of scapula can give a lot of valuable information to Orthopaedic surgeons in cases like chronic shoulder dislocation and surgeries like shoulder arthroplasty. It also is of utmost importance in solving many medicolegal cases for forensic experts and also for comparative anatomy purposes like anthropologists (5). Since the available information in the literature was less, we made a sincere effort for scapular measurements in south Indian population (6),(7). Authors tried to compare the morphometry of scapula with various other populations not only in our subcontinent, but also with distant ethnic origins. The aim of the present study was to compare the scapular indices between right and left sides in our population and also among various ethnic origins which were not done in the previous studies. | ||||||||||||||||||||||||||||||||||||||||||
Material and Methods | ||||||||||||||||||||||||||||||||||||||||||
The present retrospective observational study was performed for a period of one year between January 2019 to December 2019. The study was conducted on dry human scapulae available at Department of Anatomy, Father Muller Medical College Mangalore, Karnataka, India after the approval of Institutional Ethics Committee (FMMCIEC/CCM/56/2019). Inclusion criteria: Adult intact human dry scapulae of undetermined sex of both sides which were of good quality without any damages were included in the study. Exclusion criteria: Scapulae which were deformed and damaged were excluded. Also, scapulae of infants and children were exempted from the study. Study Procedure A total of 98 scapulae of both right and left sides were taken out of which 47 were of right sided and 51 were left sided. The scapulae were fixed to the osteometric board and measurements were taken in mm with the help of the Vernier Caliper. Each measurement was recorded twice to minimise the observational error. Based on the findings of Nazir M et al., the scapular measurements were estimated using the following points (Table/Fig 1) (8). The Scapular measurements taken were as follows: Scapular Breadth (SB): Measurement between the points E and F (Table/Fig 2)a. Scapular Length (SL): Measurement between the points G and H (Table/Fig 2)b. Infraspinous Length (IL): Measurement between the points E and H. The Scapular Index (SI) and Infraspinous Index (IB) by using the formulae (5): SI=(100×SB)/SL Also, IB=(100×SB)/IL STATISTICAL ANALYSIS The observational findings were tabulated in Excel sheet and analysed. The results were tabulated and expressed in terms of mean, ratios, percentage and standard deviation was derived using SPSS software version 21.0. Scapular indices were also analysed between right and left sides. A comparison was made between the obtained means of both sides using the student‘s t-test and p-value less than 0.05 was considered statistically significant. | ||||||||||||||||||||||||||||||||||||||||||
Results | ||||||||||||||||||||||||||||||||||||||||||
In the present study, breadth of the scapula ranged from 83-112 mm and the mean value is 96.71 mm and 6.98 as standard deviation, respectively. The maximum number of scapula (24.49%) is in the range of 101-105 mm, followed by 23.47% in the range of 91-95 mm and only 2.04% of the scapula was in the range of 111-115 (Table/Fig 3). The length of the scapula ranges from 104.5-165 mm and the mean value is 136 mm and 13.52 mm as standard deviation. The maximum of scapula (31.63 %) was in the range of 131-140 mm, followed by 25.51% in the range of 141-150 mm and only 5.11% of the scapula was in the range of 100-110 (Table/Fig 4). The relationship of SL with its breadth is expressed as SI and it ranges from 55.62-87.08 and the mean value is 71.46 with 5.64 as standard deviation respectively. The maximum scapula (43.88%) is in the range of 71-75 followed by 27.56% in the range of 66-70 and only 1.02% of the scapula is in the range of 86-90 (Table/Fig 5). Regarding the IB, it ranges from 68.42-121.33 and the mean value is 94.14 and 10.98 as standard deviation respectively. The maximum number of scapula (33.67%) is in the range of 96-105 followed by 31.64% in the range of 86-95. Only 2.04% of the scapula is in the range of 116-125 (Table/Fig 6).' The SB and length (in mm) were slightly increased in left scapulae as compared to the right-side, whereas scapular indices such as SI and IB were marginally increased on the right-side. However, there was no statistical significant difference for these parameters (Table/Fig 7). | ||||||||||||||||||||||||||||||||||||||||||
Discussion | ||||||||||||||||||||||||||||||||||||||||||
The present study deals with the scapular indices like its breadth, length, IL, SI and IB in south Indian population in Karnataka region. Similar studies have been carried out by a number of workers in other races and other groups of population and sincere effort were made to compare the findings with the studies done in the past. Scapular Breadth (SB): In the present study, the SB was ranging from 83-112 mm, while in other ethnic studies it was ranging between 83-126 mm. The mean SB in various past studies in other ethnic populations ranges between 92-104 mm (4),(9),(10),(11). Mean SB of 96.71±6.98 mm in the present study was very much comparable to the study done by Singal G et al., in Saurashtra region among Gujarat population, where the values were 96.4 mm (5). However, mean SB were10.2±0.81cm in Tamil Nadu population, 105.59±50.8 mm in Andhra population and 98.16 mm in Kashmiri populations (7),(8). So, the mean SB in South Indian population is very nearer to that of Saurashtra region of Gujarat population (5). Scapular Length (SL): The SL in present study was ranging from 104.5-165 mm and mean SL was 136.08±13.52 mm which was lower than past studies in other ethnic populations, where it was ranging from 155-157 mm (4),(9),(10),(11). However, mean scapula length was 141.7 in Gujarat, 12.5±1.01cm in Tamil Nadu and 143.27±11.14 in Andhra populations [5-7]. The present values were comparable with that of Kashmiri population, in which the mean SL was 137±20.09 mm (8). Scapular Index (SI): These values in the present study was ranging from 55.62-87.08 and the mean SI in the present study was 71.46±5.64 and about 44% of them were in the range of 71-75 (Table/Fig 5). The mean values in the studies from other ethnic races varied from minimum of 57.3 in Peruvian population to a maximum of 71.7 in that of Negroes (Table/Fig 8) (4),(5),(6),(8),(9),(12),(13). However, the values of mean SI in our subcontinent were 68.5±4 mm in Gujarat, 74.0±4.18 in Tamil Nadu, 73.99±4.6 mm in Andhra and 72±11.41 in Kashmiri populations (5),(6),(7),(8). So, the SI values of current study are very close to that of Kashmiri population of our ethnic race and also to that of Negroid Population in other ethnic races. Similar observations were made by Nithya V et al., 2020 in Tamil Nadu populations which is comparable with the present study (Table/Fig 8) (6). Infraspinous Index (IB): These values observed in the present study were ranging from 68.42-121.33. About 33.67% were in the range of 96-105 followed by 31.64% in the range of 86-95, (Table/Fig 6). However, the mean IB observed in the present study is 94.14 with the standard deviation of 10.98. The mean value varies from 75.1-120 mm in many other different races (Table/Fig 9) (4),(5),(7),(8),(9),(12),(13). However, the values of mean IB in ethnic race were 94.6±7.6 in Gujarati people, 98.33±5.86 mm in Andhra region and 92.83±15.86 in Kashmiri populations (5),(7),(8). So, the IB in the present study are very close to that of Gujarat population in saurashtra region in our ethnic race and also to that of Negroid Population in distant ethnic races (Table/Fig 9) (5). Limitation(s) The current study was done on human dry scapulae to determine the various scapular indices. However, the sexual dimorphism of scapulae was not determined. Further in depth, detailed studies can be done to explore various human scapular measurements and indices with respect to age, sex and radiological findings. This may further help in determining the race just by using these indices which can be of importance to forensic experts and anthropologists. | ||||||||||||||||||||||||||||||||||||||||||
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Original article / research
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