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Portrait of Pubis

Anatomy · Bones

Pubis

The anterior part of the hip bone

Pelvic girdle · hip bone

The pubis is the anterior, medial part of the hip bone. Its body meets the pubis of the opposite side at the pubic symphysis, a fibrocartilaginous joint in the midline, and a superior and an inferior ramus pass out from the body to join the ilium and ischium. It forms about one-fifth of the acetabulum and the front of the pelvic brim.

How to spot them

  • ▸The front and lower part of the hip bone, with a body, a superior ramus and an inferior ramus
  • ▸Bodies of the two sides meet in the midline at the pubic symphysis
  • ▸A small pubic tubercle on the upper surface of the body, where the inguinal ligament attaches
  • ▸The inferior ramus joins the ischial ramus, and the two sides form an inverted V, the subpubic angle, below the symphysis

What to know

The most anterior of the three bones that fuse to make the hip bone, made of a body and two branches that enclose the front of the large opening below the socket

Pubis — body, superior ramus and inferior ramus, forming the front of the obturator foramen.

It contributes about one-fifth of the hip socket, the other four fifths coming from its two neighbours

Pubis — acetabulum: ilium and ischium two-fifths each, pubis one-fifth.

A small bump on its upper surface gives attachment to the inguinal ligament

Pubis — the pubic tubercle.

Its lower branch joins a branch of the sitting bone, and the two sides form an inverted V beneath the midline joint of the pelvis

Pubis — the inferior pubic ramus joins the ischial ramus; the subpubic angle lies below the symphysis.

Fractures of its branches are typical low-energy injuries of older people who fall onto the hip

Pubis — pubic ramus fractures.

Its superior ramus carries a ridge along its upper edge that forms part of the pelvic brim, the pectineal line

Pubis — the pectineal line.

It fuses with the ilium and ischium in the Y-shaped cartilage of the acetabulum in the late teens

Pubis — the triradiate cartilage.

Key ideas

  • The two pubic bones are united by a fibrocartilaginous disc at the pubic symphysis, a secondary cartilaginous joint that allows slight movement, which increases in pregnancy under the influence of hormones such as relaxin.
  • The pubic arch and subpubic angle are wider in females, part of the pelvic adaptations for childbirth.

Quick-fire facts

  • •It forms the anterior part of the hip bone, consisting of a body and superior and inferior rami.
  • •The two pubic bones meet at the pubic symphysis, a joint with a fibrocartilage disc.
  • •The pubic tubercle is the attachment of the inguinal ligament; the pubic crest lies medial to it.
  • •The pectineal line runs along the superior pubic ramus and is part of the pelvic brim.
  • •The inferior pubic ramus joins the ischial ramus to make the ischiopubic ramus.
  • •The subpubic angle is greater than 80 degrees in females and less than 70 degrees in males (OpenStax).
  • •Pubic ramus fractures are common in older women after a low-energy fall.
  • •It forms one fifth of the acetabulum; the ilium and ischium form two fifths each.

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