Muscles of the Hip and Thigh

Introduction

• Overview of lecture topics:
  • Muscles of the hip
    • Anterior hip muscles
    • Posterior hip muscles (Gluteal muscles)
  • Muscles of the thigh
    • Anterior compartment
    • Medial compartment
    • Posterior compartment
  • Clinical notes on hip and thigh muscles

Muscles of the Hip

Anterior Hip Muscles

1. Psoas Major

   • Origin: Bodies of vertebrae T12 to L4, costal processes of L1 to L5
   • Function: Powerful flexor of the thigh at hip joint
   • Innervation: Femoral nerve, lumbar plexus
   • Blood supply: Iliolumbar artery, medial femoral circumflex artery

2. Iliacus

   • Origin: Iliac fossa
   • Part of: Iliopsoas (combined with psoas major)
   • Innervation: Femoral nerve

3. Psoas Minor

   • Often absent (40-70% of people)
   • Innervation: Lumbar plexus (if present)

Posterior Hip Muscles (Gluteal Muscles)

Superficial Gluteal Muscles

1. Gluteus Maximus

   • Origin: Ilium posterior to posterior gluteal line, sacrum, coccyx
   • Function: Defines buttocks, used in twerking
   • Innervation: Inferior gluteal nerve
   • Blood supply: Superior and inferior gluteal arteries

2. Gluteus Medius

   • Origin: Gluteal surface of ilium
   • Insertion: Greater trochanter
   • Innervation: Superior gluteal nerve

3. Gluteus Minimus

   • Origin: Gluteal surface of ilium
   • Insertion: Greater trochanter of femur
   • Innervation: Superior gluteal nerve

4. Tensor Fasciae Latae

   • Origin: Anterior superior iliac spine
   • Insertion: Iliotibial tract
   • Function: Stabilizes pelvis

Deep Gluteal Muscles

1. Piriformis

   • Origin: Pelvic surface of sacrum
   • Insertion: Greater trochanter of femur

2. Obturator Internus

   • Origin: Obturator membrane
   • Insertion: Greater trochanter, trochanteric fossa

3. Superior Gemellus

   • Origin: Ischial spine
   • Insertion: Greater trochanter

4. Inferior Gemellus

   • Origin: Tuberosity of ischium
   • Insertion: Greater trochanter

5. Quadratus Femoris

   • Origin: Tuberosity of ischium
   • Insertion: Intertrochanteric crest

Muscles of the Thigh

Anterior Compartment

1. Sartorius

   • Longest muscle in the human body
   • Origin: Anterior superior iliac spine
   • Function: Flexion of thigh and knee, abduction, lateral rotation of thigh

2. Quadriceps Femoris (4 muscles)

   • Rectus Femoris: Originates from anterior inferior iliac spine
   • Vastus Lateralis: Originates from linea aspera, greater trochanter
   • Vastus Intermedius: Originates from shaft of femur
   • Vastus Medialis: Originates from linea aspera, intertrochanteric line
   • Function: Primarily extensors of the leg at knee joint
   • Innervation: Femoral nerve
   • Blood supply: Femoral artery, deep femoral artery

3. Articularis Genu

   • Origin: Anterior distal femoral shaft
   • Insertion: Knee joint capsule

Medial Compartment

1. Obturator Externus

   • Origin: Obturator foramen, membrane
   • Insertion: Trochanteric fossa

2. Pectineus

   • Origin: Iliopubic eminence, pectineal line
   • Insertion: Linea aspera, pectineal line of femur

3. Gracilis

   • Origin: Inferior pubic ramus
   • Insertion: Proximal medial surface of tibia

4. Adductor Group (Adductors)

   • Adductor Brevis: Short muscle, originates from inferior pubic ramus
   • Adductor Longus: Longer muscle, originates from pubic symphysis
   • Adductor Magnus: Largest, multiple origins including inferior pubic ramus
   • Adductor Minimus: Distinct section of adductor magnus
   • Function: Adduction of thigh at hip joint
   • Innervation: Obturator nerve, with variations
   • Blood supply: Obturator artery, deep femoral artery

Posterior Compartment (Hamstrings)

1. Biceps Femoris

   • Origin: Sacro-tuberous ligament, linea aspera, tuberosity of ischium
   • Insertion: Head of fibula

2. Semitendinosus

   • Origin: Sacro-tuberous ligament, tuberosity of ischium
   • Insertion: Proximal tibia, medial to tibial tuberosity

3. Semimembranosus

   • Origin: Tuberosity of ischium
   • Insertion: Medial condyle of tibia, oblique popliteal ligament

4. Function: Primarily flexion at knee joint, extensors of thigh at hip joint (except short head of biceps femoris)

   • Innervation: Mainly tibial nerve, short head by common fibular nerve
   • Blood supply: Deep femoral artery

Clinical Notes

• Pulled Hamstring: Strain of posterior compartment muscles, common in sports.
  • Symptoms: Pain, swelling in back of thigh
  • Treatment: RICE (rest, ice, compression, elevation), ibuprofen, physical therapy if needed.
  • Prevention: Warm-up and stretching before exercise.

Summary

• Reviewed the muscles of the hip and thigh:
  • Hip muscles divided into anterior and posterior (gluteal) muscles.
  • Gluteal muscles further divided into superficial and deep.
  • Thigh muscles organized into anterior, medial, and posterior compartments.
  • Discussed clinical relevance of hamstring strains.