Pubic symphysis

Laparoscopic

Approach to Inguinal Disruption in Athletes: a Retrospective 13-Year Analysis of 198 Patients in a Single-Surgeon Setting. Scheme of the musculotendinous and aponeurotic attachments of the anterior pubis. Ellipse—prepubic aponeurotic complex (P-PAC); a—rectus abdominis, b—gracilis, c—adductor longus, d—adductor brevis. The arrows schematize the shearing forces with P-PAC as fulcrum

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

Gross anatomy

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 .

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 :

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

adductor longus, adductor brevis and rectus abdominis muscles attach to the anterior pubic ligament and interpubic disc
external oblique aponeurosis also reinforces the pubic symphysis anteriorly
remaining anterior abdominal wall muscles (internal oblique, transversus abdominis)
remaining thigh adductor muscles (adductor magnus, pectineus, gracilis)
pyramidalis muscle

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

Movement

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

Arterial supply

mainly supplied by branches of obturator and inferior epigastric arteries

Innervation

supplied by branches of the pudendal and/or genitofemoral and/or iliohypogastric/ilioinguinal nerves

Variant anatomy

congenital widening of the pubic symphysis (rare)

Radiographic features

CT/MRI

due to anteriorly-situated secondary ossification centers may appear "V-shaped" in adolescents on axial slices but will normally be parallel in adults

Related pathology