Pubic symphysis !
The pubic symphysis is the joint at the front of the pelvis where the two pubic bones meet; it closes the pelvic ring.
Opens in the Durgical app, no sign-up needed.
What it is
The joint at the front of the pelvis where the two pubic bones meet, joined by a disc of fibrocartilage.
What it does
Closes the pelvic ring in front and allows a tiny amount of movement, a little more during pregnancy.
Key facts
- Where
- Midline, between the bodies of the two pubic bones, front of the pelvic ring
- Attaches
- Hyaline-covered pubic surfaces joined by fibrocartilaginous interpubic disc; superior pubic and inferior (arcuate) pubic ligaments
- Function
- Secondary cartilaginous joint (symphysis); closes the pelvic ring in front; very little movement, slightly more in pregnancy (hormonal loosening)
Relations
- In front
- Rectus abdominis and pyramidalis insert on the pubic crest beside it; adductor longus arises just below the pubic tubercle; their tendons blend with the anterior pubic ligament
- Behind
- Retropubic space (of Retzius) with the bladder and its venous plexus; the prostate in men and the urethra lie just behind the lower part
- Above
- Superior pubic ligament between the pubic tubercles; the linea alba ends here; the spermatic cord or round ligament emerges from the superficial inguinal ring above and lateral
- Below
- Arcuate (inferior) pubic ligament forms the apex of the pubic arch; the deep dorsal vein of the penis or clitoris passes just below it into the pelvis
How to find it
Felt as a firm midline ridge at the lower end of the abdomen, under the mons pubis, just above the external genitalia; the pubic tubercles lie a short distance to each side.
Examination
- Adductor squeeze test: groin pain or weakness when squeezing the knees together against resistance points to osteitis pubis or adductor-related groin pain
- Active straight leg raise (pregnancy-related pelvic girdle pain): lifting a straight leg while lying supine is hard and becomes easier when the pelvis is compressed
On imaging
AP pelvis shows the width and any step; single-leg standing (flamingo) views show vertical shift when the joint is unstable. MRI in osteitis pubis shows bone edema on both sides and sometimes a secondary cleft; CT for fractures of the pelvic ring.
Common problems
- Pain during or after pregnancy (symphysis pubis dysfunction).
- Osteitis pubis: groin pain in kicking and running sports.
- Widening in pelvic ring injuries.
How it is diagnosed
Exam; X-rays (sometimes standing on one leg) and MRI.
Treatment
- Rest, physical therapy and a pelvic belt; surgical plating for traumatic widening.
Clinical notes
- Osteitis pubis and athletic groin pain in kicking sports reflect repeated pull of the adductors and rectus abdominis in opposite directions across the pubis
- A full bladder rises above the symphysis and lifts the peritoneum, which lets a suprapubic catheter enter the bladder without crossing the peritoneal cavity
- Pelvic binders are centred over the greater trochanters to close an open-book injury and reduce bleeding
- In pregnancy hormones such as relaxin soften the joint and it widens slightly; a larger separation around delivery (peripartum diastasis) causes pain over the pubis and a waddling, painful gait
Anatomical variants
- The pubic arch below the joint is wider in women (subpubic angle commonly quoted above 80°) than in men (under about 70°), one of the most reliable signs of sex on a pelvis
Development
The symphyseal face changes with age, from ridged to smooth and rimmed, which forensic anthropology uses to estimate age at death.
Related conditions
Test yourself
Think of the answer, then tap the question to see it.
In an open-book pelvic injury, what does widening of the pubic symphysis beyond about 2.5 cm suggest?
That the anterior sacroiliac ligaments are torn as well.
Which organs are at risk when the pubic symphysis is disrupted?
The bladder and, in men, the urethra (blood at the meatus), which lie right behind and below the joint.
What type of joint is the pubic symphysis?
A secondary cartilaginous joint: hyaline-covered pubic surfaces joined by a fibrocartilaginous interpubic disc, with very little movement.
Where is a pelvic binder centred to close an open-book injury of the pubic symphysis?
Over the greater trochanters, to close the ring and reduce bleeding.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- symphysis pubica TA2 1855
- Official Spanish (DeCS)
- Sínfisis pubiana DeCS D011631
- English (TA2)
- Pubic symphysis
- Also called
- symphysis ossium pubis
Related
Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Bony Pelvis and Lower Limb: Pelvic Joints; 8.3 The Pelvic Girdle and Pelvis (OpenStax (Rice University), 2022) · adapted, CC BY 4.0; 17.8 Gonadal and Placental Hormones (OpenStax (Rice University), 2022) · adapted, CC BY 4.0.
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.
