Thigh and Lower Leg Muscle Anatomy

Oct 16, 2024

Lecture Notes: Muscles of the Thigh and Lower Leg

Anterior Thigh Muscles

Superficial Muscles

  • Sartorius
    • Location: Lateral aspect of the thigh
    • Characteristics: Broad, band-like (thin in humans)
    • Actions: Lateral knee rotation, knee flexion
  • Gracilis
    • Location: Medial aspect of the thigh
    • Actions: Knee flexion

Deep Muscles

  • Tensor Fasciae Latae
    • Associated with the IT band (iliotibial tract)
    • Actions: Stabilizes the thigh, assists in knee stabilization
  • Quadriceps Group
    • Rectus Femoris
    • Vastus Lateralis
    • Vastus Medialis
    • Vastus Intermedius (deepest muscle)
    • Actions: Knee extension, aids in trunk flexion

Medial Aspect Muscles

  • Adductor Femoris (cat) / Adductor Magnus (human)
    • Actions: Adducts thigh
  • Adductor Longus
    • Actions: Adducts thigh, medially rotates femur
  • Pectineus
    • Actions: Adducts thigh

Iliopsoas

  • Actions: Thigh flexion, aids in trunk flexion

Crural Region Muscles

  • Gastrocnemius
    • Location: Superficial muscle of the calf
    • Actions: Plantar flexes foot, connects to calcaneus via calcaneal tendon
  • Soleus
    • Actions: Synergist to gastrocnemius, plantar flexes foot
  • Fibularis Longus (Peroneus Longus)
    • Actions: Everts the foot
  • Extensor Digitorum Longus
    • Actions: Extends digits
  • Tibialis Anterior
    • Actions: Dorsiflexes the foot, antagonist to gastrocnemius and soleus

Posterior Thigh Muscles (Hamstring Group)

  • Biceps Femoris
  • Semitendinosus
  • Semimembranosus
    • Actions: Flex the knee (opposes quadriceps group)
    • Note: Sciatic nerve located deep to these muscles

Key Points

  • Clear distinction between cat and human muscles (e.g., Adductor Femoris vs. Adductor Magnus)
  • Importance of learning the muscle groups and their primary actions for both identification and understanding of movement mechanics.