In the adult, the pelvis (os coxae) is formed by the fusion of three bones: ilium, ischium, and pubis (Figure 6-1A and B). The union the these 3 bones occurs at the acetabulum. The paired os coxae articulate posteriorly through the sacrum and anteriorly v the pubic symphysis.

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Each os coxa is formed by the combination of 3 bones: ilium, ischium, and also pubis. The following landmarks are linked within the unify os coxa (Figure 6-1A–C): Acetabulum. A cup-shaped socket into which the ball-shaped head that the femur articulates.

Obturator foramen. A feet in the os coxa the is covered by a level sheet the connective tissue dubbed the obturator membrane. A tiny opening situated at the height of the membrane gives a path through i beg your pardon the obturator nerve, artery, and also vein course.

Greater sciatic notch. Located in between the posterior worse iliac spine and the ischial spine. The sacrospinous ligament counter the notch into the greater sciatic foramen, wherein the piriformis muscle, sciatic nerve, and pudendal neurovascular structures course.

Lesser sciatic notch. Located between the ischial spine and the ischial tuberosity. The sacrotuberous ligament counter the notch right into the lesser sciatic foramen.

Pubic symphysis. Fibrocartilage connecting the 2 pubic skeletal in the anterior midline of the pelvis.

Pelvic inlet. The exceptional aperture that the pelvis. The pelvic inlet is oval shaped and also bounded by the ala the the sacrum, arcuate line, pubic bone, and symphysis pubis. The pelvic inlet is traversed by structures in the abdominal muscle and pelvic cavities.

Pelvic outlet. The inferior aperture that the pelvis. The pelvic outlet is a diamond-shaped opening formed by the pubic symphysis and also sacrotuberous ligaments. Terminal components of the vagina and the urinary and gastrointestinal tracts traverse the pelvic outlet. The perineum is inferior to the pelvic outlet.


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The ilium has the following bony landmarks: Iliac crest. Thickened premium rim.

Iliac fossa. Concave surface on the anteromedial surface.

Anterior exceptional iliac spine (ASIS). Anterior importance of the iliac crest. Serves together an attachment site for the sartorius and also tensor fascia lata muscles.

Anterior inferior iliac spine (AIIS). Serves as an attachment website for the rectus femoris muscle.

Posterior exceptional iliac spine. Posterior prestige of the iliac crest.

Posterior worse iliac spine. develops the posterior border of the ala that the sacrum.


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The ischium has the adhering to bony landmarks: Ischial tuberosity.

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A big protuberance on the inferior facet of the ischium because that attachment of the hamstring muscles and for supporting the body once sitting.