The sacroiliac joint is what type of joint?

The sacroiliac joint is what type of joint?

• A. Amphiarthrosis
• B. Diarthrodial joint
• C. Fibrous joint
• D. Synarthrosis

Answer: (B)

Joints are grouped by how much they move and by their structure. Synovial joints have a joint cavity, a capsule, and fluid, which makes them diarthrodial—capable of movement (even if some are limited). The sacroiliac joint is a synovial, diarthrodial joint, though its movement is quite limited because of the strong ligaments and the way the ilium and sacrum fit together. That combination—a synovial joint with a capsule and fluid—places it in the diarthrodial category. It’s not fibrous or fibrous-like (which would be immovable), and it’s not a synarthrosis (which would have no movement) or an amphiarthrosis (which implies some limited movement without a synovial cavity).

Joints are grouped by how much they move and by their structure. Synovial joints have a joint cavity, a capsule, and fluid, which makes them diarthrodial—capable of movement (even if some are limited). The sacroiliac joint is a synovial, diarthrodial joint, though its movement is quite limited because of the strong ligaments and the way the ilium and sacrum fit together. That combination—a synovial joint with a capsule and fluid—places it in the diarthrodial category. It’s not fibrous or fibrous-like (which would be immovable), and it’s not a synarthrosis (which would have no movement) or an amphiarthrosis (which implies some limited movement without a synovial cavity).