Pelvic girdle

Cingulum pelvicum

  • Latin synonym: Cingulum membrorum inferiorum; Cingulum membri inferioris; Cingulum extremitatum inferiororum; Cingulum extremitatum pelvinarum
  • Synonym: Lower limb girdle

Definition

The pelvic girdle is a ring-like structure comprising two hip bones, a sacrum, and a coccyx. Each hip bone consists of three sub-parts: the ilium, ischium, and pubis.

The hip bones connect anteriorly through the pubic symphysis, a secondary cartilaginous joint, and posteriorly with the sacrum at the sacroiliac joints, which are synovial joints.

The bony pelvic girdle connects the axial skeleton (vertebral column) with the appendicular skeleton (bones of the lower limb). In an upright position, it plays an important role in transferring the weight of the upper body to the lower limbs.

An important anatomical feature of the pelvic girdle is the pelvic inlet (a.k.a. the superior pelvic aperture or pelvic brim). It is a heart-shaped ring formed by the promontory and lateral parts of the sacrum, the arcuate lines, and the upper borders of the pubic bones. The pelvic brim separates the false pelvis (above the pelvic inlet) from the true pelvis (below the pelvic inlet).

The lower margins of the pelvic girdle form the pelvic outlet (a.k.a. inferior pelvic aperture). The boundaries of the pelvic outlet consist of various bones and ligaments, including the sacrum and coccyx posteriorly, sacrotuberous ligaments laterally, and the pubic arch anteriorly.

Muscles located in the lateral pelvic wall provide support to the pelvic girdle, such as the obturator internus and piriformis muscles. They originate from the lateral pelvic wall and exit the pelvis through the sciatic foramina to act on the hip joint. The inner aspect of the pelvic wall also contains important structures like the lumbosacral plexus of nerves. Above all, the bony pelvic girdle serves as a protective enclosure for pelvic viscera, including the bladder, uterus, and rectum.

Text written by Muhammad A. Javaid, MD, PhD © 2023 IMAIOS.

  • Burgess, M.D. and Lui, F. Anatomy, Bony Pelvis and Lower Limb: Pelvic Bones. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551580/


Comparative anatomy in animals

Translations

Translations