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Understanding Hip and Thigh Muscles

May 4, 2025

Lecture Notes: Muscles of the Hip and Thigh

Overview

  • Focus on understanding the muscles involved in shaping the hip and thigh.
  • Breakdown of hip muscles (anterior and posterior) and thigh muscles (anterior, medial, and posterior compartments).
  • Clinical notes on related common injuries.

Muscles of the Hip

Anterior Hip Muscles

  • Psoas Major

    • Origin: Vertebrae T12 to L4, L1 to L5.
    • Innervation: Femoral nerve, lumbar plexus.
    • Blood Supply: Iliolumbar artery, medial femoral circumflex artery.
    • Function: Flexor of the thigh at the hip joint.
  • Iliacus

    • Origin: Iliac fossa.
    • Innervation: Femoral nerve.
    • Function: Part of the iliopsoas muscle group, major flexor of the thigh.
  • Psoas Minor (often absent)

    • Origin: Along psoas major.
    • Innervation: Lumbar plexus.

Gluteal Muscles (Posterior Hip Muscles)

  • Superficial Gluteal Muscles

    • Gluteus Maximus

      • Origin: Ilium, sacrum, coccyx.
      • Insertion: Gluteal tuberosity, iliotibial tract.
      • Innervation: Inferior gluteal nerve.
      • Function: Extension, abduction, rotation of the thigh.
    • Gluteus Medius & Gluteus Minimus

      • Origin: Gluteal surface of the ilium.
      • Insertion: Greater trochanter.
      • Innervation: Superior gluteal nerve.
    • Tensor Fasciae Latae

      • Origin: Anterior superior iliac line.
      • Insertion: Iliotibial tract.
  • Deep Gluteal Muscles

    • Piriformis: Lateral rotation of the thigh.
    • Obturator Internus: Lateral rotation.
    • Gemellus (Superior & Inferior)
    • Quadratus Femoris: Lateral rotation.
    • Innervation: Sacral plexus.
    • Blood Supply: Superior and inferior gluteal arteries.

Muscles of the Thigh

Anterior Compartment

  • Sartorius

    • Longest muscle, flexes thigh and knee.
    • Origin: Anterior superior iliac spine.
    • Insertion: Medial surface of the tibia.
  • Quadriceps Femoris Group

    • Rectus Femoris, Vastus Lateralis, Vastus Intermedius, Vastus Medialis.
    • Function: Extensor of the leg at the knee.
    • Innervation: Femoral nerve.

Medial Compartment

  • Obturator Externus, Pectineus, Gracilis
    • Function: Adductors of the thigh.
    • Innervation: Obturator nerve, femoral nerve (pectineus), tibial nerve (adductor magnus).

Posterior Compartment (Hamstrings)

  • Biceps Femoris, Semitendinosus, Semimembranosus
    • Function: Flexion of the leg at the knee, extension of the thigh at the hip.
    • Innervation: Tibial nerve (except short head of biceps femoris by common fibular nerve).

Clinical Notes

  • Pulled Hamstring: Common sports injury, involves pain and swelling at the back of the thigh.
    • Treatment: Rest, ice, compression, elevation (RICE), and physical therapy if necessary.

Summary

  • Hip muscles: Anterior and Posterior (Gluteal) division.
  • Thigh muscles: Anterior, Medial, and Posterior compartments.
  • Clinical relevance of hamstring injuries.