The Gluteus Maximus
Introduction
The gluteus maximus is the largest and most superficial of the three gluteal muscles.
It makes up the shape and appearance of the buttocks.
Broad - thick - fleshy mass
Quadrilateral shape
The fibers are directed obliquely downward and lateralward;
Maintains the trunk in the erect posture.
Origin
Gluteal surface of ilium, lumbar fascia, sacrum, sacrotuberous ligament
Insertion
Gluteal tuberosity of the femur, iliotibial tract
Artery
superior and inferior gluteal arteries
Nerve
Iinferior gluteal nerve (L5, S1, S2 nerve roots)
Action
External rotation and extension of the hip joint
Supports the extended knee through the iliotibial tract
Its most powerful action is to cause the body to regain the erect position after stooping, by drawing the pelvis backward,
The gluteus maximus is also a main muscle used in many sports such as volleyball, hockey, basketball, soccer, and football.
Antagonists
Iliacus, Psoas major, Psoas minor
Bursae
Three bursae
one bursa separates it from the greater trochanter;
one bursa situated on the tuberosity of the ischium;
one bursa between its tendon and the tendon of the vastus lateralis.
Applied Anatomy
Trendelenberg sign - When the gluteus maximus muscle is paralysed, the hip on the opposite (normal) side drops instead of being lifted up when the opposite (normal) side foot is raised from the ground → waddling gait.