Gluteal Region Flashcards
Outline how the muscles of the gluteal region can be grouped
Superficial abductors and extenders – A group of large muscles that abduct and extend the femur. It includes the gluteus maximus, gluteus medius, gluteus minimus and tensor fascia lata.
Deep lateral rotators – A group of smaller muscles, that mainly act to laterally rotate the femur. It includes the quadratus femoris, piriformis, gemellus superior, gemellus inferior and obturator internus.
Give the attachments, innervation and action of Gluteus Maximus
Attachments: Originates from the gluteal (posterior) surface of the ilium, sacrum and coccyx. It slopes across the buttock at a 45 degree angle, then inserts into the iliotibial tract and greater trochanter of the femur
Actions: It is the main extensor of the thigh, and assists with lateral rotation. However, it is only used when force is required, such as running or climbing.
Innervation: Inferior gluteal nerve.
Give the attachments, innervation and action of Gluteus Medius
Attachments: Originates from the gluteal surface of the ilium and inserts into the lateral surface of the greater trochanter.
Actions: Abducts and medially rotates the lower limb. During locomotion, it secures the pelvis, preventing pelvic drop of the opposite limb. (Note: the posterior fibres of the gluteus medius are also thought to produce a small amount of lateral rotation).
Innervation: Superior gluteal nerve.
Give the attachments, innervation and action of Gluteus Minimus
Attachments: Originates from the ilium and converges to form a tendon, inserting to the anterior side of the greater trochanter.
Actions: Abducts and medially rotates the lower limb. During locomotion, it secures the pelvis, preventing pelvic drop of the opposite limb.
Innervation: Superior gluteal nerve.
Give the attachments, innervation and action of Tensor Fascia Lata
Attachments: Originates the the anterior iliac crest, attaching to the anterior superior iliac spine (ASIS). It inserts into the iliotibial tract, which itself attaches to the lateral condyle of the tibia.
Actions: Abduction and medial rotation of the lower limb. It also plays a supportive role in the gait cycle.
Innervation: Superior gluteal nerve.
Describe the attachments, innervation and actions of Piriformis
Attachments: Originates from the anterior surface of the sacrum. It then travels infero-laterally, through the greater sciatic foramen, to insert into the greater trochanter of the femur.
Actions: Lateral rotation and abduction.
Innervation: Nerve to piriformis.
Describe the attachments, innervation and actions of Obturator Internus
The obturator internus forms the lateral walls of the pelvic cavity. In some texts, the obturator internus and the gemelli muscles are considered as one muscle – the triceps coxae.
Attachments: Originates from the pubis and ischium at the obturator foramen. It travels through the lesser sciatic foramen, and attaches to the greater trochanter of the femur.
Actions: Lateral rotation and abduction.
Innervation: Nerve to obturator internus.
Describe the attachments, innervation and actions of The Gemelli – Superior and Inferior
The gemelli are two narrow and triangular muscles. They are separated by the obturator internus tendon.
Attachments: The superior gemellus muscle originates from the ischial spine, the inferior from the ischial tuberosity. They both attach to the greater trochanter of the femur.
Actions: Lateral rotation and abduction.
Innervation: The superior gemellus muscle is innervated by the nerve to obturator internus, the inferior gemellus is innervated by the nerve to quadratus femoris.
Describe the attachments, innervation and actions of Quadratus Femoris
The quadratus femoris is a flat square shaped muscle. It is the most inferior of the deep gluteal muscles, located below the gemelli and obturator internus.
Attachments: It originates from the lateral side of the ischial tuberosity, and attaches to the quadrate tuberosity on the intertrochanteric crest.
Actions: Lateral rotation.
Innervation: Nerve to quadratus femoris.
