Classification
- Type: Secondary cartilaginous joint (symphysis — fibrocartilaginous disc between hyaline cartilage-covered surfaces)
- Degrees of freedom: Minimal — <2 mm of movement in any direction (vertical shear, AP compression, slight rotation)
- Region: Anterior pelvis (forms the anterior pelvic ring with the anatomy/joints/sacroiliac joints forming the posterior ring)
Articular Surfaces
- Pubic body articular surfaces (×2): The medial surfaces of each pubic body are covered with a thin layer of hyaline cartilage. The surfaces are oval and slightly convex.
- Interpubic disc: A fibrocartilaginous disc between the two articular surfaces. It may contain a small cavity (especially in females), which enlarges during pregnancy. The disc transmits compressive forces and allows the minimal movement that occurs.
Movements and ROM
| Movement |
Normal ROM |
Mechanism |
| Vertical shear |
<2 mm |
One pubic bone slides superiorly relative to the other during single-leg stance |
| AP compression |
<2 mm |
The two pubic bones compress during loading |
| Separation |
<1 mm (up to 10+ mm in pregnancy) |
The symphysis widens under hormonal influence (relaxin) during pregnancy |
Pregnancy-related changes. Relaxin hormone loosens the pubic symphysis ligaments during pregnancy, allowing the joint to widen for delivery. Normal widening is up to 10 mm. Widening >10 mm is considered symphysis pubis dysfunction (SPD) / diastasis symphysis pubis, producing significant pelvic girdle pain.
Capsular Pattern
Not applicable — this is a symphysis, not a synovial joint. No capsular pattern exists.
Resting and Close-Packed Positions
Not applicable for a symphysis joint.
Ligaments
Superior Pubic Ligament
- Attachments: Connects the superior surfaces of both pubic bones across the top of the symphysis
- Function: Resists superior displacement and vertical shear
Inferior (Arcuate) Pubic Ligament
- Attachments: Connects the inferior surfaces of both pubic bodies, forming an arch below the symphysis
- Function: Resists inferior displacement and provides a sturdy inferior frame for the pelvic outlet. The strongest pubic symphysis ligament.
Anterior and Posterior Pubic Ligaments
- Attachments: Anterior and posterior surfaces of the symphysis
- Function: Reinforce the joint capsule anteriorly and posteriorly
Mobilization Techniques
The pubic symphysis is not a joint that is typically mobilized with the same glide techniques used for synovial joints. Treatment of pubic symphysis dysfunction focuses on:
- Muscle energy techniques (METs): The patient performs isometric hip adduction or abduction against resistance while the clinician stabilizes the pelvis. This normalizes pubic position through muscular contraction. METs are the primary manual intervention for pubic symphysis malalignment.
- SI joint and hip treatment: Pubic symphysis dysfunction almost always accompanies SI joint or hip dysfunction. Addressing the SI joints and hip mobility often resolves the symphysis malalignment indirectly.
- Pelvic floor and adductor management: The adductors (especially adductor longus) and the pelvic floor muscles attach to the pubic rami. Hypertonia in these muscles increases symphyseal stress. Release of the adductors and pelvic floor (when within scope) reduces symphyseal loading.
Muscles Attaching to the Pubic Symphysis Region
Conditions Affecting This Joint
- Osteitis pubis — chronic inflammation of the pubic symphysis producing anterior pelvic pain; common in runners, soccer players, and hockey players; progressive onset, worsened by single-leg activities (running, kicking)
- Athletic pubalgia ("sports hernia") — tearing or attenuation of the rectus abdominis and/or adductor longus attachments near the pubic symphysis; deep groin pain worsened by sprinting, kicking, and sit-ups; no true hernia is present
- Symphysis pubis dysfunction (SPD) — pregnancy-related anterior pelvic pain from excessive symphyseal widening; pain with walking, stair climbing, turning in bed; typically resolves postpartum
- Diastasis symphysis pubis — separation >10 mm; may occur during or after delivery; significant pelvic instability and pain
- Pubic stress fracture — inferior pubic ramus stress fractures are common in distance runners and military recruits; insidious onset groin/pelvic pain worsened by weight bearing
Clinical Notes
- The pubic symphysis is the "anterior keystone" of the pelvic ring. Together with the two SI joints posteriorly, it forms a closed ring. Dysfunction at any point (SI joint, pubic symphysis, or hip) affects the entire ring. Always assess the pubic symphysis when treating SI joint or hip pathology.
- Athletic pubalgia involves the rectus-adductor interface. The rectus abdominis and adductor longus share attachments at the pubic body. In athletes who sprint, kick, and perform sudden directional changes, the opposing forces (rectus pulls up, adductor longus pulls down) create shear stress at the pubic symphysis. This interface is where tissue failure occurs. Treatment must address both muscle groups.
- Pubic symphysis tenderness is a red flag in certain populations. In a postpartum woman, tenderness suggests SPD or diastasis. In an immunocompromised patient or IV drug user, pubic symphysis tenderness may indicate septic arthritis (osteomyelitis pubis) — a rare but serious condition requiring referral.
- Pelvic floor assessment is essential in pubic symphysis dysfunction. The pelvic floor muscles attach to the pubic rami and directly affect symphyseal loading. Pelvic floor dysfunction (hypertonicity or weakness) perpetuates pubic pain. Pelvic floor physiotherapy is an important component of management.
Key Takeaways
- The pubic symphysis has virtually no movement under normal conditions — it is a weight-transmitting, force-absorbing joint, not a mobile joint.
- The rectus abdominis-adductor longus interface at the pubic body is the site of athletic pubalgia — opposing forces produce shear at the symphysis.
- Symphysis dysfunction always accompanies SI joint and/or hip dysfunction — assess and treat the entire pelvic ring.
- Pregnancy-related SPD results from hormonal ligament laxity — widening >10 mm causes significant pelvic girdle pain.
