Pelvic Limb Joints: Vet Prep Structural and Functional Biology

Learning Goals

• Describe the actions of muscles on the pelvic limb joints (flexion and extension) according to the location of the muscles relative to the joints.
• Describe the bones and parts of the bones that form the coxofemoral joint.
• Describe the bones, parts of the bones, and individual joints that form the stifle joint.
• Name and identify the ligaments and structures associated with the coxofemoral and stifle joints and describe their functions.

Joints of the Pelvic Limb

• Coxofemoral (hip) joint
• Stifle joint
• Tarsus
• Sacroiliac joint
• Proximal and distal interphalangeal joints
• Metatarso-phalangeal joints
• Bones: ilium, ischium, pubis

Sacroilliac Joint

• Bones of the pelvis: ilium, ischium, pubis.
• Sacrum.

Coxofemoral Joint

• Head of the femur (ball) and acetabulum (socket) synovial joint.
• Primary movements are flexion and extension.
• Also allows for abduction, adduction, and circumduction.
• Bones: ilium, ischium, pubis, femur.
• Parts of the bones: acetabulum, head of femur.

Flexion and Extension Example: Quadriceps Femoris Muscle

• Four heads (only 2 heads shown).
• Origin of rectus femoris: ilium.
• Origin of vastus lateralis: proximal femur.
• Insertion of both: tibial tuberosity.
• Actions of both together:
  • Flex the hip.
  • Extend the stifle.

Extension and Flexion Example: Semitendinosus Muscle

• A hamstring muscle.
• Origin: pelvis (tuber ischii).
• Insertion: proximal, caudal tibia; calcaneus (a tarsal bone).
• Actions:
  • Extend the hip.
  • Flex the stifle.
  • Extend the hock.

Radiograph of Normal Canine Coxofemoral Joints

• Key anatomical features visible include:
  • Body of lumbar vertebra
  • Sacroiliac joint
  • Sacrum
  • Costal process of vertebra
  • Iliac bone
  • Caudal vertebra
  • Head of the femur
  • Greater trochanter
  • Neck of the femur
  • Lesser trochanter
  • Acetabulum
  • Pubis
  • Femur
  • Ischium

Coxofemoral Joint Structures

• Joint capsule: fibrous outer layer and synovial inner membrane that secretes synovial fluid for lubrication.
• Ligament of the head of the femur: courses from the acetabulum to the head of the femur.

Coxofemoral Luxation (Dislocation)

Stifle Joint

• Complex condylar synovial joint.
• Movements are limited to flexion and extension.
• Joints:
  • Femorotibial
  • Femoropatellar
  • Proximal tibiofibular
• Several ligaments associated with the stifle.

Menisci and Associated Ligaments

• Two C-shaped fibrocartilage discs – medial and lateral menisci.
• Located between the condyles of the femur and the condyles of the tibia.

Patellar Ligament

• Ligament between the patella and the tibial tuberosity.
• Tendon of quadriceps femoris m. connects to the patella.

Collateral Ligaments of the Stifle

• Located on the lateral and medial sides of the stifle – extra-articular.
• Help stabilize the stifle.
• Lateral collateral ligament:
  • Courses from the femur to the fibula and tibia.
  • Limits medial (varus) motion of the tibia.
• Medial collateral ligament:
  • Courses from the femur to the tibia.
  • Limits lateral (valgus) motion of the tibia.

Cruciate Ligaments

• Course between the femur and tibia; intra-articular.
• Named for where they attach to the tibia.
• Cranial cruciate ligament:
  • Attaches to the tibia cranially.
  • Prevents cranial movement of the tibia.
• Caudal cruciate ligament:
  • Attaches to the tibia caudally.
  • Prevents caudal movement of the tibia.

Cranial Cruciate Ligament Rupture

• Normal caudal cruciate on the right, torn cranial cruciate on the left.

Diagnosis of Cranial Cruciate Ligament Rupture

• Cranial drawer test
• Tibial compression test
• MRI
• Arthroscopy