Lecture on Thigh Muscles

Introduction

• Focus on thigh muscles, part of the lower limb muscles.
• Muscles of the lower limb are divided into 4 parts:
  1. Hip Joint muscles
  2. Thigh muscles
  3. Leg muscles
  4. Foot muscles

Thigh Muscles Overview

• Divided into three groups based on anatomical location:
  1. Anterior group
  2. Medial group
  3. Posterior group

Anterior Group

• Characteristics: Covers entire anterior surface of the thigh, innervated by the femoral nerve.
• Main Muscles: Quadriceps Femoris & Sartorius

Quadriceps Femoris

• Composed of 4 parts:
  • Rectus Femoris: Originates from the anterior inferior iliac spine.
  • Vastus Lateralis: Originates at the lateral lip of the Linea aspera.
  • Vastus Medialis: Originates at the medial lip of Linea aspera.
  • Vastus Intermedialis: Originates from the anterior surface of the thigh.
• Insertion: Tibial tuberosity via the patellar ligament.
• Function: Extend the leg and flex the femur.

Sartorius Muscle

• Origin: Anterior superior iliac spine.
• Insertion: Tibial tuberosity.
• Function: Flexes thigh and leg, externally rotates thigh, internally rotates leg.

Medial Group

• View: Medial view of the thigh.
• Muscles: Pectineus, Adductor Brevis, Adductor Longus, Adductor Magnus, Gracilis.

Pectineus

• Origin: Pecten pubis.
• Insertion: Pectineal line of the femur.
• Function: Adduction, flexion, and external rotation of the thigh.

Adductor Brevis

• Origin: Inferior pubic ramus.
• Insertion: Medial lip of linea aspera.
• Function: Adduction, flexion, and external rotation of the thigh.

Adductor Longus

• Origin: Between pubic symphysis and pubic tubercle.
• Insertion: Medial lip of linea aspera.
• Function: Adduction, flexion, and external rotation of the thigh.

Adductor Magnus

• Origin: Inferior pubic ramus, Ischial Ramus, Ischial Tuberosity.
• Insertion: Medial lip of linea aspera, medial epicondyle of the femur.
• Function: Adduction, extension, and internal rotation of the thigh.

Gracilis

• Origin: Inferior pubic ramus.
• Insertion: Tibial tuberosity.
• Function: Adduct thigh, flex leg, and internally rotate leg.

Posterior Group

• Characteristics: Extensors of the hip joint, flexors of the knee joint.
• Common Innervation: Sciatic nerve.
• Muscles: Biceps Femoris, Semitendinosus, Semimembranosus

Biceps Femoris

• Composition: Long head (originates from ischial tuberosity), Short head (originates from lateral lip of linea aspera).
• Insertion: Head of the Fibula.
• Function: Flexion and external rotation of the leg, extension of the thigh (long head only).

Semitendinosus

• Origin: Ischial tuberosity.
• Insertion: Tibial Tuberosity.
• Function: Flexion, internal rotation of the leg, and extension of the thigh.

Semimembranosus

• Location: Behind semitendinosus, larger.
• Origin: Ischial tuberosity.
• Insertion: Medial condyle of the tibia.
• Function: Flexion and internal rotation of the leg, extension of the thigh.

Conclusion

• Comprehensive coverage of thigh muscles.
• Next lecture: Muscles of the Leg.