Anatomy · Bones

Pelvis

Latin for 'basin'

Trunk and lower limb · pelvic girdle

The bony pelvis is the basin-shaped ring formed by the two hip bones in front and at the sides, the sacrum and the coccyx behind. It transfers the weight of the upper body to the lower limbs, protects the pelvic organs and, in women, forms the birth canal. A brim divides the shallow upper 'false' pelvis from the deeper, ring-like 'true' pelvis.

How to spot them

▸A basin-shaped ring of bone: two large, flaring hip bones joined to the sacrum behind and to each other in front
▸The pelvic brim (inlet) separates the greater (false) pelvis above from the lesser (true) pelvis below
▸Female pelvis: wider, shallower, with a round or oval inlet and a subpubic angle greater than 80 degrees; male pelvis: narrower, deeper, heart-shaped inlet and an angle less than 70 degrees
▸The anterior superior iliac spines and the pubic tubercles lie in the same vertical plane when standing

What to know

Its name is Latin for a basin, and it is formed of four bones: two large paired bones, the sacrum and the coccyx

Pelvis — the two hip bones, sacrum and coccyx.

A ring of bone that transfers the weight of the upper body to the legs and protects the bladder and other organs within it

Pelvis — its primary role is weight transfer.

A brim divides a shallow 'false' upper part from a deeper 'true' lower part that contains the bladder and rectum

Pelvis — the greater (false) and lesser (true) pelvis, divided by the pelvic brim.

An angle beneath the front joint greater than 80 degrees points to a woman; less than 70 degrees, to a man

Pelvis — the subpubic angle.

Its shapes are classified as gynaecoid, android, anthropoid and platypelloid

Pelvis — the Caldwell–Moloney classification.

Two ligaments running from the sacrum to spines and tuberosities of its hip bones turn its greater and lesser notches into foramina for nerves and vessels to the lower limb

Pelvis — the sacrospinous and sacrotuberous ligaments.

In a standing person its front is tilted so that the two anterior spines and the tubercles of the front joint lie in one vertical plane

Pelvis — the anatomical position of the pelvis.

Key ideas

Unlike the mobile pectoral girdle, the pelvis is a strong, largely immobile structure, giving the upper body a stable foundation on the mobile legs.
The female pelvis is wider and shallower, with a larger subpubic angle and a rounder inlet, adaptations for childbirth.

Quick-fire facts

•The bony pelvis consists of four bones: the two hip bones, the sacrum and the coccyx.
•The pelvic girdle is formed by the two hip bones alone; the sacrum and coccyx are added to make the pelvis.
•The pelvic brim (pelvic inlet) runs from the sacral promontory along the arcuate line of the ilium and the pectineal line of the pubis to the top of the pubic symphysis.
•The greater (false) pelvis is bounded by the flaring ilia and contains loops of intestine; the lesser (true) pelvis contains the bladder, rectum and the reproductive organs.
•The subpubic angle is greater than 80 degrees in females and less than 70 degrees in males (OpenStax).
•The Caldwell–Moloney classification (1933) recognises four female pelvic types: gynaecoid, android, anthropoid and platypelloid.
•The sacroiliac joints, pubic symphysis and hip joints link the pelvis to the spine, to its opposite side and to the legs.
•The name pelvis comes from the Latin for a basin.

Drill it — 7 cards

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Sources

OpenStax — Anatomy and Physiology 2e — 8.3 The Pelvic Girdle and Pelvis
TeachMeAnatomy — The Pelvic Girdle — Bones of the Pelvis