Gross anatomical study on humerus of tiger (Panthera tigris)

In recent years the number of tigers is continuously decreasing due to poaching, diseases and destruction of habitat. The poaching is considered as one of the most important cause for reduction of their population and bringing them at the verge of extinction. So the present study was planned to record the characteristic features of the humerus in the tiger. The study was conducted on humerus of five adult tigers. Which was comprised of shaft and two extremities. The shaft was compressed antero-posteriorly in its upper third, cylindrical in middle third and compressed medio-laterally in its remaining part. It had tricipital lines, deltoid tuberosity, brachial groove and supracondyloid foramen similar to other felines. Tricipital line was in the form of oblique crest which formed the upper boundary of the brachial groove and terminated into deltoid tuberosity. The distal extremity had two separate coronoid and radial fossae which was 2:1 in ratio. Humerus bone of both the sides were morphologiocally similar but a non significant difference was observed in right and left side bones in all the skeletons (t < 0.05). Right humerus of the tiger weighed 381.22 + 5.55 g and the mean total length was 31.36 + 0.31 cm where as left humerus was weighing 384.94 + 5.54g and 31.08 + 0.29 cm. The mean circumference of the shaft on its upper, middle and lower part was 13.58 + 0.12 cm, 10.62 + 0.15 cm and 11.04 + 0.12 cm, respectively in the right humerus where as they were 13.20 + 0.08 cm, 10.44 + 0.12cm and 10.90 + 0.12 cm, respectively in left humerus. These differences may be of some biomechanical importance.