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

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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.