Articular segment of sacroiliac joint is
(SI, 2) (427-BDC-2) (258-Snell 9th)The sacroiliac joint possesses all the characteristics of a true joint cavity containing synovial fluid adjacent bones having ligamentous connections cartilaginous surfaces which permit movements and and outer fibrous joint capsule with an inner synovial lining. The joint most commonly links the postero-superior part of the medial aspect of the iliac bones with the first, second and the upper part of the third segment of the sacrum.SACROILIAC JOINTSSynovial joints of the plain varietyThe strong posterior and interosseous sacroiliac ligaments suspends the sacrum between the two iliac bones, the anterior sacroiliac ligament is thin and lies in front of the joint.The rotatory movement is prevented by two strong sacrotuberous and sacrospinous ligamentThe primary function is to transmit the weight of the body form the vertebral column to the bony pelvisNerve supply1. Superior gluteal2. Ventral rami and the lateral branches of dorsal rami of the first and second sacral nerves1. Nervi-erigentes arises from ventral rami of S2 S3 S4 segments2. Ventral rami of L4 nerve takes part & both in formation of lumber plexus as well as sacral plexus is called nervi forcalis3. Spinal cord gives rise to 31 pairs of spinal nerves
S1-2
S3 l/2-s41/4
S 1/2 -4 1/2
None
Abdomen & Pelvis