Anatomical review of canine biceps femoris muscle

The biceps femoris (BF) muscle plays a fundamental role in the biomechanics of the canine pelvic limb, acting in flexion - extension on knee articulation and abduction of the limb. Correct evaluation plays an important role in veterinary clinic. There are controversial issues among the authors consulted about the morphology of this muscle. The present study aims to discuss the various descriptions proposed for this muscle, considering insertions, structure and innervation. Bilateral dissections of 12 animals were carried out. Pieces conservation was done by immersion in pools with 10% formaldehyde and 4% carbolic acid in water. Different techniques were used in order to achieve various observations of muscle structures. It was found that BF muscle originates by two heads, as is implicit in its name, a craneal head, bulkier and a smaller caudal head. The first takes origin in the sacrotuberal ligament and the lateral surface of the ischial tuberosity. The caudal head, originates from the ischial tuberosity. These parts are closely linked but they can be identified at the level of the muscle bellies through a thin layer of connective tissue that extends to the distal part of the muscle. Regarding the innervation, we found that no caudal gluteal nerve branches reach this muscle.