A morphological and morphometric study on supratrochlear foramen in human humerus with its clinical implication

Background: The supratrochlear foramen (STF) is an aperture present at the bony septum in the lower end of humerus that separates olecranon fossa from coronoid fossa. Although it holds significant clinical importance, it has not been extensively studied. Aim: The present study is carried out to assess incidence, morphologic and morphometric variation of the supratrochlear foramen (STF). Materials and Methods: The study was carried out on 200 dry, unpaired, adult human humeri of unknown sex, in the Anatomy Department, NRSMC, Kolkata. They were observed macroscopically for the incidence, location, shape & dimensions of the supratrochlear foramina. The opacity/ translucency of the bony septum was observed in those bones where the foramen was absent. Results: The supratrochlear foramen was present in 36 humerus (18%) and was more on the left side (26). The commonest shape observed was oval (19) followed by a circular & triangular shape (12 & 5 in number respectively). In majority of bones the supratrochlear septum was opaque. The mean transverse (MTD) and vertical diameter (MVD) of the foramen was measured separately on both sides. The mean distance of the foramen from lateral epicondyle of humerus was 23.08 ± 1.62 mm on left side and 21.59 ± 1.70 mm on right side. The mean distance of the foramen from medial epicondyle of humerus were found to be 21.59 ± 1.88 mm on left side & 20.59± 1.54mm on right side. Conclusions: This study was helpful not only for Orthopaedic Surgeons in preoperative planning of intramedullary nailing in Supracondylar fractures but also for Radiologists, Anatomists & anthropologists. The STF is radiolucent area in radiograph & the knowledge about this feature prevents from misinterpreting it as an osteolytic or cystic lesion.