“A Study of Morphology and Pattern of Talar Articular Facets in Human Calcanei of Jodhpur Region of Western Rajasthan”

Original Research Article There are total three facets on upper side of talocalcaneal joint: anterior talar facet, middle and posterior. There are considerable variations in the number and arrangement of these articular facets. Present study was done to determine patterns of the talar facets of calcanei of Jodhpur Region of Western Rajasthan.


INTRODUCTION
Calcaneum is the longest, strongest and biggest of all the tarsal bones of the proximal row. It forms talocalcaneal joint with talus. This joint maintains eversion and inversion of foot and named as subtalar joint. There are three facets over upper side of talocalcaneal joint: anterior talar facet, middle and posterior [1]. It is also referred to as heel bone and forms a major component of theskeleton of the hindfoot and prominence of the heel. This bone is unique, since it is the first tarsal bone to ossify. The purpose of the calcaneus is to transmit the weight of the body to the ground and act as a strong lever for the calf muscles [2]. It is well designed to sustain high tensile, bending andcompressive forces. However, high instantaneous loads often result in fracture [3]. It is located poster inferior to the talus, providing support to the ankle joint. It measures about 3.5 inches in length and about 1.5 inch at its widest point [4]. The anterior and the posterior facets are situated on the body and the middle is situated on the sustentaculum tail. There are considerable variations in the number and arrangement of these facets. Using parameters such as degree of separation, fusion, and shape, several workers have described types and preponderance of articular facets on the anterior third of the calcaneus incertain population groups like African, Indian, British, Egyptian, and Spanish [5-7. Bunning and Barnett have observed that there are three types of variations in the arrangement of facets. They have classified these variations as follows: Type-A: There are three facets separated by variable intervals. Type-B: There are two facets, anterior and middle which are either continuous or have a notch between them.
Type-C: There is only one facet i.e. the three forms a continuum [8]. Few Indian workers have also worked on this subject. Jha et al. have reported that type-B calcanei are common amongst the population in Uttar Pradesh and also have classified type-B calcanei into four subgroups: Group-1: Anterior and middle articular facets completely fused and form a single facet.
Group-2: Anterior and middle articular facets incompletely separated from each other by means of a notch.
Group-3: Anterior and middle articular facets separated from each other but with no non-particular area intervening.
Group-4: Absence of anterior articular facet. Only middle and posterior articular facets were being present [9].   Further, in type II, three subtypes were found i.e. Subtype A includes -with narrow separation (<2mm), Subtype B-with moderate separation (2-5mm), Subtype C-with wide separation (>5). Further, in Type II (A) was found to be present in 23.07% cases, Type II (B) in 38.46% cases and Type II (C) in 38.46% cases.
In the present study, the incidence of type III calcanei was not found in any of the case and this result is in close resemblance to the result of Mini Mol et al. [11]. It was highest 7.04% in studies of Priyaety et al. [15] followed by Gupta et al. (5%). In other studies it ranged between 1.3%-1.5%. The incidence of type IV calcanei in the present study was 0% which is in resemblance with study of Mini Mol et al. [10] and Nagar S K et al. [16]. Type V was observed by Nagar S K et al. [16] in 0.18% and Rohin Garg et al. [11] in 0.32% while it was not observed in any of case in present study.

CONCLUSION
The present study has showed wide range of variations in the incidences of various types of calcanei compared to previous workers in different regions of India. These variations may arise due to population differences, type of gait and built of an individual or the region to which they belong like whether it is a plane or a hilly area.