Lecture Notes: Muscles of the Leg

Introduction

• Overview of leg muscles from top to bottom.
• Anatomical position reference.

Upper Leg Muscles

Hip Flexors

• Psoas Major:
  • Function: Flexion at the hip.
• Iliacus:
  • Function: Flexion at the hip.
• Synergists: Psoas Major and Iliacus.

Sartorius Muscle

• Longest muscle in the body.
• Functions:
  • Flexion at the hip.
  • Flexion at the knee.
  • Lateral (external) rotation.

Tensor Fasciae Latae

• Functions:
  • Flexion at the hip.
  • Medial (internal) rotation.
  • Tenses the iliotibial tract (IT band).

Quadriceps Femoris Group

• Four muscles:
  • Rectus Femoris:
    • Flexion at the hip.
    • Extension at the knee.
  • Vastus Medialis:
    • Extension at the knee.
  • Vastus Lateralis:
    • Extension at the knee.
  • Vastus Intermedius (deep to Rectus Femoris):
    • Extension at the knee.

Gluteal Muscles

Gluteus Maximus

• Functions:
  • Extension at the hip.
  • Lateral rotation at the hip.

Gluteus Medius and Minimus

• Functions:
  • Abduction of the hip.

Lateral Rotators

• Include:
  • Piriformis
  • Superior Gemellus
  • Obturator Internus
  • Inferior Gemellus
  • Quadratus Femoris
• Function: Lateral rotation of the hip.

Hamstring Muscles

Biceps Femoris

• Two heads: Short and Long.
• Functions:
  • Extension at the hip.
  • Flexion at the knee.

Semitendinosus and Semimembranosus

• Functions:
  • Extension at the hip.
  • Flexion at the knee.

Synergies and Antagonists

• Synergists with Gluteus Maximus for hip extension.
• Antagonists to Quadriceps Femoris for knee extension.

Adductor Muscles

Adductor Magnus

• Function: Adduction at the hip.

Adductor Brevis

• Function: Adduction at the hip.

Gracilis

• Functions:
  • Adduction at the hip.
  • Flexion at the knee.
  • Medial rotation.

Adductor Longus

• Function: Adduction at the hip.

Pectineus

• Function: Flexion at the hip.

"Sergeant Muscles"

• Sartorius, Gracilis, Semitendinosus.
• Insertion: PES anserine.

Lower Leg Muscles

Anterior Compartment

Tibialis Anterior

• Functions:
  • Dorsiflexion of the ankle.
  • Inversion of the ankle.

Extensor Digitorum Longus

• Functions:
  • Extension of digits.
  • Dorsiflexion.
  • Inversion of the ankle.

Lateral Compartment

Peroneus (Fibularis) Longus and Brevis

• Function: Eversion of the ankle.

Posterior Compartment

Gastrocnemius

• Two heads: Lateral and Medial.
• Function: Plantar flexion.

Soleus

• Function: Plantar flexion.

Plantaris

• Functions:
  • Flexion at the knee.
  • Plantar flexion.

Popliteus

• Function: Flexion at the knee.

Flexor Hallucis Longus

• Function: Flexion of the big toe.

Tibialis Posterior

• Functions:
  • Plantar flexion.
  • Inversion of the ankle.

Flexor Digitorum Longus

• Functions:
  • Flexion of digits.
  • Inversion at the ankle.
  • Plantar flexion.

Conclusion

• Comprehensive overview of the muscles of the entire leg.