Birth Definitions

Pelvis Definition


Pelvis is a term used in the pregnancy and birthing industry to refer to the lower section of the abdomen, located between the hips. It is a basin-shaped structure of the bones and joints of the lower limb consisting of four bones: the two hip bones, the sacrum, and the coccyx (tailbone). It is bounded above by the pelvic girdle or hip bones, below by the knees, and behind by the sacrum and coccyx.

The pelvis serves to support the weight of the upper body keeping it upright, transmit body weight to the lower limbs, protect the pelvic organs, and provide attachments for muscles, tendons, and ligaments. The pelvis also helps to absorb shock during walking and running. During pregnancy, the pelvis serves as the attachment point for the uterus, and also houses the birth canal.

The pelvis is subject to a number of disorders such as pelvic inflammatory disease, endometriosis, pelvic organ prolapse, and others. Pelvic pain is a common symptom of these disorders.


The term “pelvis” is often used interchangeably with “pelvic girdle.” However, the pelvis is actually a part of the pelvic girdle. The pelvic girdle consists of the two hip bones, the sacrum, and the coccyx. The pelvic girdle attaches the lower limbs to the axial skeleton and provides support for the upper body.

The term “pelvic floor” refers to the muscles and connective tissue that support the pelvic organs and span the bottom of the pelvis. The pelvic floor muscles include the pubococcygeus muscle and the levator ani muscle. These muscles are important for urinary and fecal continence.

Other Related Terms

There are several terms that are closely associated with pelvis, including:

  • perineum (the area between the anus and vulva/scrotum),
  • pubic symphysis (the joint between the two pubic bones), and
  • Ischial Spines (bony protrusions on either side of the pelvis).

This image shows how often the term ‘Pelvis’ is used in relation to other, similar birth terms:

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