A 32-year-old postpartum woman presents with bilateral sacroiliac joint pain. Which statement about the sacroiliac joint is correct?
- A It is a synovial joint in adults, and the sacral surface is covered by hyaline cartilage while the iliac surface is fibrocartilage ✓
- B It is a synchondrosis in adults, and movement is essentially nil
- C It is a synovial plane joint in adults, and the articular surface of the sacrum is covered by fibrocartilage
- D It is a fibrous syndesmosis in adults with no synovial component
Correct answer: A. It is a synovial joint in adults, and the sacral surface is covered by hyaline cartilage while the iliac surface is fibrocartilage
Explanation
The sacroiliac joint is a true synovial joint in adults. The sacral articular surface is covered by hyaline cartilage (thicker, approximately 2 to 3 mm), while the iliac surface is covered by thinner fibrocartilage. This asymmetry is characteristic. The joint permits small gliding and rotatory movements that increase during pregnancy due to relaxin-mediated ligamentous laxity.
Reference: Gray's Anatomy, 42nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.