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LIF101 Anatomy. Lecture 12: Gluteal and Thigh Muscles. Gluteal Muscles. Gluteus maximus largest, most superficial Gluteus medius medium size, under gluteus maximus Gluteus minimus smallest, under gluteus medius. Gluteus Maximus. Originates at sacrum and coccyx
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LIF101Anatomy Lecture 12: Gluteal and Thigh Muscles
Gluteal Muscles • Gluteus maximus • largest, most superficial • Gluteus medius • medium size, under gluteus maximus • Gluteus minimus • smallest, under gluteus medius
Gluteus Maximus • Originates at sacrum and coccyx • Inserts on posterior femur and iliotibial band
Gluteus Maximus • FUNCTION: • Extends thigh backward, rotates it outward
Gluteus Medius • Originates at lateral surface of ilium, under iliac crest • Inserts on greater trochanter of femur
Gluteus Medius • FUNCTION: • Abducts the thigh
Muscles of the Thigh • Three Groups, Three Compartments: • Extensor group (in anterior compartment) • Adductor group (in medial compartment) • Flexor group (in posterior compartment) • Abductor group (in lateral compartment) • Also: • Ilium-to-knee “muscle window”
Ilium-to-Knee Muscle Window • Sartorius • Tensor Fasciae Latae (with iliotibial band) • Proximal meeting of these two muscles creates anatomical landmark (and window.) • Extensor group looks out the window.
Ilium-to-Knee Muscle Window • Sartorius • Origin: A.S.I.S. • Insertion: medial tibia • Rotates thigh inward and outward • Longest muscle in the human body
Ilium-to-Knee Muscle Window • Tensor fasciae latae • Origin: A.S.I.S. • Insertion: iliotibial band on lateral thigh • FUNCTION: • Provides tension for iliotibial band • Also abducts thigh
Extensor Group of Thigh • A.K.A. “quadriceps” • “Looks out” through ilium-to-knee muscle window • Includes: • Rectus femorus • Vastus lateralis • Vastus medialis • Forms suprapatellar bulge Function of thigh extensor group: All muscles above extend leg
Adductor Group of Thigh • A.K.A. “groin muscles” • Pectineus • Adductor longus • Adductor magnus • Gracilis (gracilis = L. slender) FUNCTION: All muscles listed above adduct thigh
Flexor Group of Thigh • On posterior surface of thigh • A.K.A. “hamstrings” • Include (from left to right on right leg): • Semimembranosus • Semitendinosus • Biceps femoris (long and short heads) All above muscles flex leg
Flexor Group of Thigh • Insertion tendons of the two medial muscles form medial wall of popliteal fossa. • Insertion tendon of lateral muscle forms lateral wall of popliteal fossa.
On lateral side of the leg, tendons of iliotibial band and biceps femoris form distinct surface landmarks.
Surface Landmarks of the Thigh • Anterior: • Hollow notch just below A.S.I.S. (formed by?) • Suprapatellar bulge (distal end of vastus medialis ) • Posterior • Popliteal fossa (padded with adipose tissue) • Tendons on either side • Lateral • Iliotibial band (inserts on lateral tibia) • Biceps femoris tendon (inserts on head of fibula)
Assignments • Reading: • Peck, pp. 128 – 137