Joints of the Pelvic Limb

Sacroiliac Joint: This joint connects the sacrum and the ilium.

• It is a tightly opposed synovial joint between the auricular surfaces of the ilium and sacrum.

• The auricular surface is covered by cartilage.

• Ligaments supporting this joint include ventral sacroiliac, interosseous sacroiliac, and dorsal sacroiliac ligaments.

• Carnivores: Have a sacrotuberous ligament that extends from the transverse processes of the last cervical vertebrae to the ischial tuber. However, this ligament is absent in cats. They also possess a dorsal sacroiliac ligament with short and long branches.

• Ungulates: Have a broad sacrotuberous ligament that extends from the lateral sacrum to the dorsal border of the ilium and ischium. They also have short and long branches of the dorsal sacroiliac ligaments, which run between the sacral tuber and spinous processes of the sacrum.

• Horse: The broad sacrotuberous ligament runs between the transverse processes of the first caudal vertebrae and the dorsal border of the ilium and ischium. They also have long and short branches of the sacroiliac ligaments.

Hip Joint (Coxal Joint): A spheroidal, ball-and-socket joint between the head of the femur and the acetabulum.

• Large Animals (Ungulates): Movement is mainly flexion and extension, with limited rotation, adduction, and abduction due to muscle mass and the shape of the femoral head.

• Dogs and Cats: Have a greater range of movement due to the shape of the femoral head and the presence of intraarticular ligaments.

• Ligaments include the ligament of the femoral head, the accessory ligament of the femur (present only in horses), and the transverse acetabular ligament.

Stifle Joint: A composite joint consisting of the femorotibial and femoropatellar joints.

• Femorotibial Joint: Formed between the condyles of the femur and the proximal end of the tibia. The incongruency of the articular surfaces is compensated by menisci. Primary movement is flexion and extension.

  • Meniscal ligaments support the menisci, including cranial and caudal tibial ligaments, and the femoromeniscal ligament.

  • Other ligaments supporting this joint include lateral and medial collateral ligaments and cranial and caudal cruciate ligaments.

• Femoropatellar Joint: Articulation between the patella and the femur. Supported by lateral and medial patellar ligaments and the intermediate patellar ligaments.

  • The patellar ligament is formed by the distal portion of the quadriceps femoris muscle tendon.

  • Horse and Ox: Have three patellar ligaments.

  • Carnivores, Small Ruminants, and Pigs: Have a single patellar ligament.

  • The stifle joint in the horse has a locking mechanism, which is an important part of the passive stay apparatus.

Tibiofibular Joint: Varies across species due to species-specific reduction of the fibula.

• Carnivores: Have well-developed fibula and tibia, with proximal and distal tibiofibular joints.

• Ruminants: Lack a proximal tibiofibular joint because the head of the fibula is fused to the lateral condyle of the tibia. They possess a distal tibiofibular joint.

• Horses: Only have a proximal tibiofibular joint. The distal end of the fibula is fused to the tibia, forming the lateral malleolus.

Tarsal Joint (Hock): Formed between the tibia, fibula, tarsal bones, and metatarsal bones, with four levels of articulation.

• The articulations include the tarsometatarsal joint, the centrodistal joint, the proximal intertarsal joints, and the tarsocrural joint.

• Supported by collateral ligaments, long plantar ligaments, and the talocentrotarsal ligament.

Metatarsophalangeal Joints: Similar to the corresponding joints of the thoracic limb.