Lecture Notes: Muscles of the Hip and Thigh

Overview

• Focus: Muscles involved in defining the booty (hip and thigh muscles)
• Structure:
  • Hip muscles (anterior and posterior/gluteal)
  • Thigh muscles (anterior, medial, and posterior compartments)
  • Clinical notes on the muscles

Muscles of the Hip

Anterior Hip Muscles

• Main Muscles:
  1. Psoas Major
     • Origin: Vertebrae T12-L4, L1-L5
     • Insertion: Lesser trochanter of the femur
     • Innervation: Femoral nerve, lumbar plexus
     • Blood Supply: Iliolumbar artery, medial femoral circumflex artery
  2. Iliacus
     • Origin: Iliac fossa
     • Insertion: Lesser trochanter (as iliopsoas)
     • Innervation: Femoral nerve
  3. Psoas Minor (often absent)
     • Origin: Surface of psoas major
     • Innervation: Lumbar plexus
• Function: Most powerful flexor of the thigh at the hip joint

Posterior Hip Muscles (Gluteal Muscles)

Superficial Gluteal Muscles

• Main Muscles:
  1. Gluteus Maximus
     • Origin: Ilium, sacrum, coccyx
     • Insertion: Gluteal tuberosity, iliotibial tract
     • Innervation: Inferior gluteal nerve
     • Function: Extension, abduction, rotation, and stabilization of thigh/pelvis
  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
     • Innervation: Superior gluteal nerve
  4. Tensor Fasciae Latae
     • Origin: Anterior superior iliac line
     • Insertion: Iliotibial tract
     • Innervation: Superior gluteal nerve

Deep Gluteal Muscles

• Main Muscles:
  1. Piriformis
     • Origin: Pelvic surface of sacrum
     • Insertion: Greater trochanter
  2. Obturator Internus
     • Origin: Obturator membrane
     • Insertion: Greater trochanter, trochanteric fossa
  3. Superior & Inferior Gemellus
     • Superior: Origin from ischial spine
     • Inferior: Origin from tuberosity of ischium
     • Insertion: Greater trochanter
  4. Quadratus Femoris
     • Origin: Tuberosity of ischium
     • Insertion: Intertrochanteric crest
• Function: Lateral rotation of the thigh at the hip
• Innervation: Sacral plexus

Muscles of the Thigh

Anterior Compartment

• Main Muscles:
  1. Sartorius
     • Origin: Anterior superior iliac spine
     • Insertion: Medial surface of tibia
     • Function: Flexion of thigh/knee, abduction, rotation
  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 femoral shaft
     • Vastus Medialis: Originates from linea aspera, intertrochanteric line
  3. Articularis Genu
     • Origin: Anterior distal femoral shaft
     • Insertion: Knee joint capsule
• Function: Extensors of the leg at the knee joint
• Innervation: Femoral nerve

Medial Compartment

• Main Muscles:
  1. Obturator Externus
     • Origin: Obturator foramen
     • Insertion: Trochanteric fossa
  2. Pectineus
     • Origin: Iliopubic eminence
     • Insertion: Linea aspera femoris
  3. Gracilis
     • Origin: Inferior pubic ramus
     • Insertion: Proximal medial surface of tibia
  4. Adductors (Brevis, Longus, Magnus, Minimus)
     • Common origin from pubic regions
     • Insertions on linea aspera femoris
• Function: Adduction of the thigh at the hip
• Innervation: Mainly obturator nerve, with contributions from femoral and tibial nerves

Posterior Compartment (Hamstrings)

• Main Muscles:
  1. Biceps Femoris
     • Origin: Sacrotuberous ligament, linea aspera, tuberosity of ischium
     • Insertion: Head of fibula
  2. Semitendinosus
     • Origin: Sacrotuberous ligament, tuberosity of ischium
     • Insertion: Medial tibia
  3. Semimembranosus
     • Origin: Tuberosity of ischium
     • Insertion: Medial condyle of tibia, oblique popliteal ligament
• Function: Flexion of leg at knee, extension of thigh at hip
• Innervation: Mainly tibial nerve, exception for the short head of biceps femoris (common fibular nerve)

Clinical Notes

• Pulled Hamstring:
  • Strain in one/more posterior compartment muscles
  • Symptoms: Pain, swelling in back of thigh
  • Treatment: RICE, ibuprofen, possible physical therapy
  • Prevention: Warm-up, stretching

Conclusion

• Summary of muscle groups and their subdivisions
• Muscles targeted for exercises like squats to enhance gluteal aesthetics

Additional Resources: 3D muscle function video series for detailed visualization.