Proximal Hindlimb

Functional Anatomy of the Proximal Hindlimb

  1. Nerve Supply: Describe the nerve supply to the pelvic limb and formation of the lumbosacral plexus.

  2. Palpation: Palpate bony prominences of the pelvis and describe the hip joint formation.

  3. Muscle Groups: Identify main muscle groups involved in hindlimb movements including their origins, insertions, and innervation.

  4. Bones of the Crus: Identify bones in the crus region and their centers of ossification.

  5. Radiographic Features: Recognize normal anatomical features of the tibia & fibula on radiographic film and interpret for abnormalities.

Hindlimb Nerve Supply

  • Spinal Nerves: Involves L5, L6, L7, S1, S2.

  • Dorsal Branches: Supply dorsal structures.

  • Ventral Branches: Contribute to the lumbosacral plexus.

  • Emerging Peripheral Nerves:

    • Gluteal Nerves: Cranial and caudal branches.

    • Obturator Nerve.

    • Femoral Nerve.

    • Sciatic Nerve: Key nerve supplying tibial and fibular/peroneal nerves.

Hip Joint (Coxo-femoral Joint)

Components:

  • Composed of:

    • Head of femur

    • Acetabulum of pelvis (lunate surface)

  • Acetabulum: Extended by labrum and completed ventrally by the transverse ligament.

Joint Capsule & Attachments:

  • Surrounds labrum and neck of femur.

  • Characteristics: Typical synovial joint but lacks collateral ligaments.

Stability:

  • Ligament of Head of Femur (teres ligament): Extends from fovea to acetabular fossa, providing stability, along with surrounding muscle mass.

Palpation of the Hindlimb

Pelvic Bony Prominences:

  • Dorsal iliac crest / wing of ilium

  • Tuber sacrale

  • Tuber coxae

  • Tuber ischium

Femur:

  • Greater trochanter: Aids in locating hip joint, formed by a triangle of three bony landmarks, bilaterally symmetrical for identification of hip dislocation or pelvic fractures.

Radiography & Clinical Considerations

Normal Radiographic Anatomy:

  • Conditions to consider:

    • Degenerative joint diseases like osteoarthritis.

    • Luzation/dislocation typically traumatic; subluxation may relate to hip dysplasia, especially in young dogs (e.g., Rottweilers).

Treatment Options:

  • Femoral head excision and hip replacement procedures.

Clinical Considerations: Surgical Approaches

Surgical Approach to Hip Joint:

  • Trochanteric Osteotomy: Involves removing greater trochanter while maintaining muscle attachments, with replaced sections secured by pins to minimize damage.

Blood Supply to the Hip Joint

Sources of Blood Supply:

  • Vessels from periosteum and medulla.

  • Joint capsule attachment around neck supplies vessels leading from neck to head.

Vulnerabilities:

  • Susceptible to damage which is relevant for:

    • Femoral neck fractures

    • Physeal separation

    • Avascular necrosis

  • Visual Aids: Detailed anatomical illustrations help visualize the vascular network of the proximal femur.

Hindlimb Movements

Extrinsic Muscles:

  • Function: Move limbs relative to the trunk with the sacroiliac joint being immovable. The pivotal movement occurs at the hip joint.

Movement Types:

  • Protraction: Hip flexion occurs cranial to the hip.

  • Retraction: Hip extension occurs caudal to the hip.

  • Abduction: Dorsal location in relation to the hip.

  • Adduction: Ventral location in relation to the hip.

Extrinsic Muscles Overview

Abductors (Gluteal Muscles):

  • Comprises superficial, middle, and deep gluteal muscles.

  • Originates from sacrum & pelvis; attaches to the greater trochanter, acting as a lever.

  • Innervation: By gluteal nerve.

Adductors (Ventral Surface Origin):

  • Includes gracilis, adductor, pectineus, and external obturator.

  • Innervation: By the obturator nerve.

Limb Protractors/Hip Flexors:

  • Key muscles include tensor fascia latae, iliopsoas muscle, sartorius, quadriceps muscle.

  • Innervation: By the femoral nerve.

Limb Retractors/Hip Extensors:

  • Muscles include biceps femoris, semitendinosus, semimembranosus.

  • Innervation: By the sciatic nerve.

Femoral Triangle

Boundaries:

  • Caudal: Pectineus & adductor muscles.

  • Cranial: Sartorius muscle.

  • Contains femoral neurovascular bundle (VAN) and palpable pulses.

Tibia and Fibula Anatomy

Crus Region:

  • Characteristics: The tibia is weight-bearing, while the fibula is reduced in size; both are long, paired, and parallel with interosseous space (no rotation).

Tibia’s Proximal End:

  • Triangular cross-section with medial and lateral condyles and smooth surfaces for articulation with femur.

  • Features include tibial crest and tuberosity (insertion for patellar ligament).

Distal End:

  • Oval shape with cochlea (concave surface for hock/tarsus); contains medial and lateral malleolus for ligament attachments.

Centers of Ossification

Tibia:

  • Four centers: proximal end, tibial tuberosity, body, and distal end.

Fibula:

  • Three centers: proximal end, body, and distal end.

Clinical Considerations: Tibial Fracture Repair

  • Repair techniques include intramedullary pinning, cerclage wire, and bone plates.

  • Fibula fractures: Less critical to overall limb stability.

Questions?

  • Open floor for discussion and inquiries regarding the content covered.