Pubic symphysis

Dr Henry Knipe et al.

The pubic symphysis (or symphysis pubis) is a midline secondary amphiarthrodial cartilaginous joint of the bony pelvis, uniting both pubic bodies.

Articulations

The pubic symphysis is a secondary cartilaginous joint, which means there is a wedge-shaped fibrocartilaginous interpubic disc situated between two layers of hyaline cartilage, which line the oval-shaped medial articular surfaces of the pubic bones 1-2

The width of the joint space differs at different ages:

  • ~10 mm at 3 years
  • ~6 mm at 20 years
  • ~3 mm at 50 years

For physiological reasons, women have a greater thickness of the fibrocartilaginous disc, allowing more mobility of the pelvic bones and thereby providing a larger pelvic diameter needed for childbirth.

Attachments
Ligaments

The pubic symphysis is reinforced by four strong ligaments 2-3:

  • superior pubic ligament: runs from pubic crest to pubic crest
  • inferior pubic (or subpubic or arcuate) ligament: runs from inferior pubic ramus to inferior pubic ramus
  • anterior pubic ligament: blends with periosteum laterally as well as the interpubic disc
  • posterior pubic ligament: blends with periosteum of both pubic bodies posteriorly

Other ligaments which attach to the pubic symphysis include:

  • suspensory ligament of the penis
  • pubocervical ligament
Musculotendinous
Relations
  • anteriorly
    • proximal ends of the penile/clitoral shafts
  • inferiorly
    • urethra
    • deep dorsal vein of penis/clitoris
  • posteriorly
    • bladder (separated from the pubic symphysis by the retropubic fat pad)
    • prostate and prostatic venous plexus

Normally very little movement: up to 2 mm shift and 1° rotation 2.

  • congenital widening of the pubic symphysis (rare) 5
CT/MRI
  • due to anteriorly-situated secondary ossification centres may appear "V-shaped" in adolescents on axial slices but will normally be parallel in adults 1
Abdominal and pelvic anatomy
Share article

Article information

rID: 28496
Section: Anatomy
Tags: pelvis, joint
Synonyms or Alternate Spellings:
  • Symphysis pubis

Support Radiopaedia and see fewer ads

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.