"The sacrum consists of five fused sacral vertebral and costal segments (S1-S5) that form a central sacral body and paired sacral alae (singular ala), which arise laterally from S1."
"The sacrum consists of five fused sacral vertebral and costal segments (S1-S5) that form a central sacral body and paired sacral alae (singular ala), which arise laterally from S1."
"Tarlov (perineural) cysts"
"As the sacrum develops, costal elements form the parts superior, lateral and inferior to the anterior sacral foramina. Posterior sacral foramina are wholly formed by the vertebral part, the costal elements lying lateral to the lateral sacral crest."
"sacroiliac ligaments: reinforce the sacroiliac joint - anterior, posterior and interosseous"
"sacrococcygeal ligaments: anterior, lateral and posterior ligaments. Superficial part of the posterior sacrococcygeal ligament closes the sacral hiatus. The anterior sacrococcygeal ligament is the terminal continuation of the anterior longitudinal ligament which blends into the periosteum of the coccyx"
"lumbosacral: superiorly, the sacrum articulates with the inferior endplate of L5 via the L5/S1 intervertebral disc; superior articular processes of S1 articulate with the L5 inferior articular facets to form the L5/S1 facet (zygapophyseal) joints"