L16- The Muscular System III

Lecture Overview

• Lecture Title: The Muscular System - III

• Instructor: Dr. Nicole M. Ventura, PhD.

• Institution: York University, School of Kinesiology & Health Sciences

Learning Objectives

• Identify and describe:

  • Major origins and insertions for gluteal and thigh muscles.

  • Major functions of gluteal and thigh muscles.

  • Fasciae of the lower extremity.

  • General blood supply of the lower extremity.

Fasciae of the Lower Limb

• Fascia Lata: Deep fascia surrounding the thigh, forming compartments.

• Crural Fascia: Deep fascia of the leg, continuous with fascia lata.

• Popliteal Fascia: Surrounds the knee region.

• Fascia Compartment Layout:

  • Anterior Compartment

  • Medial Compartment

  • Lateral Compartment

  • Posterior Compartment

The Gluteal Region: Muscles

Gluteus Maximus

• Origin: Ilium, sacrum, and coccyx.

• Insertion: Gluteal tuberosity of the femur and iliotibial band.

• Function: Extends and laterally rotates the thigh.

Tensor Fascia Lata

• Origin: Anterior superior iliac spine (ASIS).

• Insertion: Lateral tibial condyle via IT band.

• Function: Abducts and medially rotates thigh; tenses IT band.

Gluteus Medius and Minimus

• Origin: Posterior ilium.

• Insertion: Greater trochanter of the femur.

• Function: Abducts and medially rotates the thigh.

Lateral Rotators of the Thigh

• Includes: Piriformis, Superior Gemellus, Obturator Internus, Inferior Gemellus, Quadratus Femoris.

• Function: Lateral rotation of the thigh at the hip.

Anterior Compartment of the Thigh

Major Muscles

• Psoas Major: Originates from T12-L5, inserts onto lesser trochanter.

• Iliacus: Originates from iliac fossa, forms iliopsoas with psoas major.

• Sartorius:

  • Origin: ASIS

  • Insertion: Anteromedial tibia (pes anserinus)

  • Function: Hip and knee flexion.

Quadriceps Femoris Group

• Includes: Rectus Femoris, Vastus Lateralis, Vastus Medialis, Vastus Intermedius.

• Insertion: Via quadriceps tendon to patellar ligament to tibial tuberosity.

• Function: Performs knee extension, hip flexion (Rectus Femoris).

Medial Compartment of the Thigh

Major Muscles

• Pectineus, Adductor Longus, Gracilis.

• Common Origin: Pubis.

• Common Function: Adduction of the thigh and some flexion.

• Pes Anserinus: Insertion point for Sartorius, Gracilis, and Semitendinosus.

Posterior Compartment of the Thigh (Hamstrings)

Major Muscles

• Biceps Femoris: Long head from ischial tuberosity; short head from femur. Inserts at head of fibula.

• Common Action: Hip extension and knee flexion.

• Semitendinosus & Semimembranosus: Both originate from ischial tuberosity; insert on medial tibia.

Blood Supply to the Lower Extremity

• External Iliac Artery: Continuation of common iliac artery, supplies lower extremity.

• Internal Iliac Artery: Supplies gluteal region and medial thigh.

• Femoral Artery: Major artery for thigh, extends from inguinal ligament.

• Deep Femoral Artery: Supplies posterior thigh and hip joint.