An osteological study of supratrochlear foramen of humerus of south Indian population with reference to anatomical and clinical implications.

The supratrochlear foramen (STF) is an important and relatively common anatomic variation in the lower end of the humerus in humans. The present study on south Indian population is an attempt to highlight the incidence, morphological features and clinical importance of STF. The study was conducted on dried human humeri of unknown sex and free of pathological changes. The presence of a STF was noted for its shape and divided into three types (oval, round, and irregular). In bones where the foramen was absent the translucency of the septum between the coronoid and the radial fossa was noted by placing the lower end of the humerus against the X-ray view box. Out of the 142 humeri studied, 72 humeri (50.7%) were right sided and 70 humeri (49.2%) were left sided. In these 142 humeri, 38 humeri (26.7%) showed the presence of STF. The majority of STF were round shaped in 47.37%, followed by oval shaped in 42.11% and 10.53% were irregular in shape. The STF was absent in 36 humeri (25.35%) and 68 humeri (47.89%) showed the translucency of septum. The mean transverse diameter on right side was 4.50±3.183 mm and 3.32±3.222 mm on left side. The mean vertical diameter was 3.88±2.391 on right side and 3.68±3.532 mm on left side. Its existence is important to the orthopaedician in the preoperative planning of nailing fractures of the distal humerus and to the radiologist for differentiating it from an osteolytic or cystic lesion.