Pubic symphysis
Updates to Article Attributes
The pubic symphysis (or symphysis pubis) is a midline secondary amphiarthrodial, fibrocartilaginous 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 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 fibrocartialginous 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: blends with periosteum of both pubic bodies posteriorly
Musculotendinous
- adductor longus, adductor brevis and rectus abdominis muscles attach to the anterior pubic ligament and interpubic disc 2
- external oblique aponeurosis also reinforces the pubic symphysis anteriorly 3
Relations
- anteriorly
- proximal ends of the penile/clitoral shafts
- inferiorly
- urethra
- deep dorsal vein of penis/clitoris
- posteriorly
Movement
Normally very little movement - up: up to 2mm2 mm shift and 1 degree rotation 2.
Blood supply
- mainly supplied by branches of obturator and inferior epigastric arteries 2
Nerve supply
- supplied by branches of the pudendal and/or genitofemoral and/or iliohypogastric/ilioinguinal nerves 2
Variant anatomy
- congenital widening of the pubic symphysis (rare) 5
Radiographic appearance
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
Related pathology
-<li>superior pubic ligament - runs from pubic crest to pubic crest</li>-<li>inferior pubic (or subpubic or arcuate) ligament - runs from inferior pubic ramus to inferior pubic ramus</li>-<li>anterior pubic ligament - blends with periosteum laterally as well as the interpubic disc</li>-<li>posterior pubic ligament - blends with periosteum of both pubic bodies posteriorly</li>- +<li>superior pubic ligament: runs from pubic crest to pubic crest</li>
- +<li>inferior pubic (or subpubic or arcuate) ligament: runs from inferior pubic ramus to inferior pubic ramus</li>
- +<li>anterior pubic ligament: blends with periosteum laterally as well as the interpubic disc</li>
- +<li>posterior pubic ligament: blends with periosteum of both pubic bodies posteriorly</li>
-</ul><h4>Movement</h4><p>Normally very little movement - up to 2mm shift and 1 degree rotation <sup>2</sup>. </p><h4>Blood supply</h4><ul><li>mainly supplied by branches of <a href="/articles/obturator-artery">obturator</a> and <a href="/articles/inferior-epigastric-artery">inferior epigastric arteries</a> <sup>2</sup>-</li></ul><h4>Nerve supply</h4><ul><li>supplied by branches of the <a title="Pudendal nerve" href="/articles/pudendal-nerve-1">pudendal</a> and/or <a href="/articles/genitofemoral-nerve">genitofemoral</a> and/or <a href="/articles/iliohypogastric-nerve">iliohypogastric</a>/<a href="/articles/ilioinguinal-nerve">ilioinguinal</a> nerves <sup>2</sup>- +</ul><h4>Movement</h4><p>Normally very little movement: up to 2 mm shift and 1 degree rotation <sup>2</sup>. </p><h4>Blood supply</h4><ul><li>mainly supplied by branches of <a href="/articles/obturator-artery">obturator</a> and <a href="/articles/inferior-epigastric-artery">inferior epigastric arteries</a> <sup>2</sup>
- +</li></ul><h4>Nerve supply</h4><ul><li>supplied by branches of the <a href="/articles/pudendal-nerve-1">pudendal</a> and/or <a href="/articles/genitofemoral-nerve">genitofemoral</a> and/or <a href="/articles/iliohypogastric-nerve">iliohypogastric</a>/<a href="/articles/ilioinguinal-nerve">ilioinguinal</a> nerves <sup>2</sup>