Biceps Femoris Muscle in Dogs Diana Powell 11/25/2016 The Biceps Femoris is the largest muscle in the muscle group that makes up the hamstring. The Biceps Femoris is covered only by fascia and skin and can be easily palpated on most dog breeds. The Biceps Femoris has two heads of origin. The first is described as the long head. This head starts at the back part of the ischial tuberosity. The second, short head, begins at the linea aspera and extends nearly to the point of insertion for gluteus maximus muscle. (1) The two muscle sections of the biceps come together at a layer of tendons attached to the stifle and crural fascia and this fascia then inserts on the patella, patella ligament, and tibial tuberosity. A distal tendon of the muscle separates from the main muscle belly and passes under the adductor and along the gastrocnemius. It moves in front of the calcaneal tendon and combining with a tendon of the semitendinous muscle inserts on the calcaneal tuberosity. (2) The Biceps Femoris is a composite muscle. The short head develops in the flexor compartment of the thigh and is thus innervated by the common fibular branch of the sciatic nerve. The long head is innervated by the tibial branch of the sciatic nerve. (3) The blood supply to the Biceps Femoris comes from a connection between the deep femoral artery and several smaller arteries: the perforating branches of the profunda femoris artery, the inferior gluteal artery, and the popliteal artery. (1) The function of the Biceps Femoris muscle is to extend the hip joint. It also flexes and extends the stifle joint. This muscle allows the dog to lift its leg to urinate. If the limb is fixed on the ground, the Biceps Femoris produces a powerful thrust on the trunk to propel in walking/running. (4) In 2012, there was a study published in the Journal of Veterinary Science on Biceps Femoris muscle transposition for treatment of cranial cruciate ligament rupture in small breed dogs. The purpose of the study was to determine the efficacy of a new surgical technique used to treat cranial
cruciate ligament ruptures. The cranial cruciate ligament rupture is the most common cause of lameness in dogs. The goal of surgery is to stabilize the stifle joint, preserve range of motion and prevent osteoarthritis. The study describes a new surgical technique for the extracapsular stabilization of the cranial cruciate ligament rupture through transposition of a strip of the Biceps Femoris muscle. Nine small breed dogs with cranial cruciate ligament ruptures were used in the study. A portion of the Biceps Femoris muscle was sutured on the patellar ligament. The transposed Biceps Femoris muscle acts on the tibial tuberosity with the force directed caudally and externally. The study reported no intraoperative complications. All nine dogs had complete healing with good post-operative results at three months. At 1,3 and 12 month check-ups, there were no recurrences of stifle instability. The table below shows the health scores of the nine dogs pre-and post- operation. (5) Total patient score: for each patient, the mean value obtained from the six subscale scores Score evaluation: excellent (81~100), good (61~80), poor (41~60), and failed (0~4). All data are represented as the mean ± SD for score. Significant improvement was shown at 1 month (mo) p.o.; at 12 mo, follow-up showed excellent scores for all dogs.
As previously mentioned, the Biceps Femoris muscle in often easily palpated on most dogs. The muscle is smooth in texture. In certain dogs like Dobermans, Boxers and other long legged breeds with muscular legs, the Biceps Femoris muscle appears prominent and can easily be identified. Canine massage can be beneficial to the Biceps Femoris. Massage can help improve circulation to the muscle promoting proper movement and use. Massage can also be used to help heal an injury or a recovery from surgery. Massage can help identify any areas of pain or discomfort and possibly alert the practitioner to any possible health concerns. Figure 1
Figure 2 Figure 3
References 1. www.wikipedia.com 2. www.wikivet.com 3. Clinical Anatomy and Physiology for Veterinary Technicians by Thomas Colville and Joanna M. Bassert 2002 by Mosby, Inc. 4. www.onlineveterinaryanatomy.net 5. Pubmed.gov Journal of Veterinary Science volume 13 2012 Mar 6. Figure 1 www.studyblue.com 7. Figure 2 - www.vanat.cvm.umn.edu 8. Figure 3 www.answers.com