Suitable Alternative for Human Cadaver Temporal Bone Dissection: Comparative Micro Ear Anatomy of Cattle, Pig and Sheep with Human.

The study was undertaken to compare the micro ear anatomy of three commonly available animal models which are expected to have similar anatomy to human and to find out suitable model among them as an alternative for human cadaver temporal bone dissection. This is an observational study of comparison of micro ear anatomy of the three animal models with human. Decapitated heads of cattle, pig and sheep were collected from slaughter houses, soft tissues along with brain were removed and preserved in commercially available formalin preservative. CT scan was taken for the three specimens and 3D reconstructions were done. Each specimen was subjected to micro dissection and the anatomical features were studied and compared with human. Among the three animal models sheep is found to be an ideal model for a beginner because of ease of exposure of bone, very thin cortical bone, and no cellularity, good exposure of all the middle ear structures and similar interrelations of middle ear structures with human. Pig may not be an ideal model because of abundant fatty soft tissues, thick periosteum very narrow space occupied by the middle ear, difficulty in accessing cellularity small fragile ossicular chain and overhanging facial nerve.