Muscles of the hip region (part 1)

Muscles of the hip region are divided in two groups with the following muscles:

NOTE: tensor fasciae latae, piriformis, obturator muscle, gemellus muscles and quadratus femoris are shown in the next slides.


Iliopsoas

The iliopsoas muscle consists of two muscles, the psoas major and iliacus muscles, which have different areas of origin but common insertion. The iliacus is a flat skeletal muscle of the pelvis, filling the iliac fossa. The psoas major is a long muscle of the pelvis that joins with the iliacus to form the iliopsoas. 


Origin: iliacus - iliac fossa, psoas major - transverse processes of the twelfth thoracic and first four lumbar vertebrae (T12 - L4) and lateral sides of the intervertebral discs between them. 

Insertion: both muscles insert on the lesser trochanter of the femur. 

Function: the main actions of the iliopsoas include flexion of the hip joint and external rotation of the thigh, as well as flexion of the trunk, if the leg is fixed. 


Psoas minor

The psoas minor is a long, slim skeletal muscle lying anterior to the psoas major muscle.

Origin: lateral surface of the twelfth thoracic (T12) and first lumbar (L1) vertebrae. 

Insertion: iliopubic eminence. 

Function: stabilizing of the pelvis and the hip joint, flexion of the trunk.


Gluteus maximus

The gluteus maximus is the largest and most superficial of the three gluteal muscles and forms the surface anatomy of the gluteal region or buttocks. 

Origin: outer surface of the ileum behind the posterior gluteal line, posterior surface of the sacrum and coccyx, sacrotuberous ligament, and thoracolumbar fascia.

Insertion: iliotibial band of the fascia lata and gluteal tuberosity between the adductor magnus and vastus lateralis muscles.

Function: extends and externally rotates the hip, it also supports the hip joint.


Gluteus medius

The gluteus medius is one of the three paired gluteal muscles and it is situated beneath the gluteus maximus.

Origin: between the anterior and posterior gluteal lines of the ileum. 

Insertion: along with the gluteus minimus, this muscle inserts at the greater trochanter of the femur. 

Functions: abducts and internally rotates the hip. The contractions of anterior fibers of the gluteus medius muscle result into flexion and internal rotation, while the contractions of the posterior fibers result into external rotation of the hip.


Gluteus minimus

The gluteus minimus is the smallest of the three gluteal muscles and it is situated below the gluteus medius. 

Origin: between the anterior and inferior gluteal lines of the ileum. 

Insertion: along with the gluteus medius, it inserts at the greater trochanter of the femur. 

Function: abducts and internally rotates the hip. The contractions of the anterior fibers of the gluteus minimus result into flexion and internal rotation, while the contractions of the posterior fibers result into external rotation of the hip.