If you’re considering getting a horse, you’ve probably heard of hind leg problems. After all, these structures should function properly, right? Wrong! Here’s a little background on the hind leg. Continue reading to learn more about this important part of your horse’s anatomy. Let’s start with the anatomy: What is the hind leg? Where does it originate? What are its muscles and veins?
Anatomy
The hind leg comprises bones in the hip, thigh, and pes. It exhibits general similarities to the forelimb, whereas it is somewhat different in structure from the limbs of equids. The leg’s muscles, including the hamstrings, are located on the posterior side. These muscles are responsible for constraining extension during the first half of the stance. Several other muscles support the foot.
The femur is the bone at the rear of the pelvis. The thickened end is called the tuber ischii. It is a strong bone and is the attachment point for the hindquarter muscles. The tarsus consists of six or seven short, flat bones that attach to the femur. Each tarsus has a distinct function in walking and running, and their arrangement is important for movement.
Functions
The muscles of the hind limb vary in structure throughout the order, but are often closely related to the function of the leg. There are three sclerites that articulate the femur to the fifth tarsomere: the unguitractor, the basipulvilli, and the pulvilli, which act as claws. These tendons are attached to bones directly or via short tendons.
During walking and running, the body weight of a standing horse acts on the hip joint and ground reaction force, generating a compressive force on the hind limb. The extensor muscles of the hind limb maintain the joints in extension, which increases with body mass and joint angulation. In contrast, equines and other smaller animals tend to adopt a crouched posture, while larger animals generally exhibit upright limb angulations.
Muscles
The muscles of the hind leg play a critical role in jumping. The levator and depressor muscles of the hind leg activate proprioceptors to track joint movements. The levator moves the trochanter and occupies more of the metathorax than the depressor. The depressor muscle increases the lever arm when the hind leg is fully levated, whereas the levator decreases as the leg is lowered.
During a fully levated hind leg movement, the hairs on the medial edge of the coxa may be stimulated. In contrast, when walking on a horizontal surface, the femur is not in contact with the hairs. In addition, the hairs on the medial edge of the coxa are about 10mm long and 5mm wide at their base. The hairs on this part of the coxa serve as proprioceptors and may contribute to the leg’s jumping performance.
Veins
The superficial veins of the hind leg were first discovered in the macaque, where the saphenous vein was the prior known surface vein. Later, researchers studied the topography of these veins in gorillas and baboons, finding that the saphenous vein of these animals resembled the great saphenous vein of humans. In addition, the saphenous vein in macaques and baboons had a distinct physiology, with a long saphenous vein that opened into the femoral vein.
In addition to cosmetic appearance, the varicose veins of the hind leg can also cause pain and discomfort. Larger varicose veins may lead to other complications, such as leg ulcers and skin discoloration. Many people want to undergo treatment for this condition, however, due to aesthetic reasons. Surgery for varicose veins in the leg is available to reduce pain and improve appearance. Surgery to remove varicose veins involves the use of general anesthesia. This surgery can be performed on both legs and may require one night in the hospital.
Symptoms
There are several different causes of hind leg weakness in dogs, and some of them are exercise-induced or episodic. While the severity of the problem varies from dog to dog, the most common cause is arthritis, which causes deterioration of the cartilage in the hind legs. Symptoms of arthritis in dogs include pain and inflammation in the hind legs, lethargy, and reluctance to play. Older dogs and large breeds are more susceptible to the disease.
Many different underlying conditions can cause hind limb problems in cats. These conditions can include inherited abnormalities, congenital conditions, and parasite-borne diseases. Regardless of the cause, your pet should be checked out by a veterinarian as soon as possible. You should also check the condition of the other parts of the body, since a weakened hind leg can affect other parts of the body. If you suspect an underlying heart problem, consult a veterinarian as soon as possible.