the anteroposterior diameter of the pelvic outlet, movements in the sacrococcygeal joint can further increase this diameter. Palpation The joint is palpable deep within the natal cleft, and can be felt as a horizontal groove. With the palpating finger on the dorsal surface of the coccyx, a degree of rotation can be produced with an applied forward pressure. See also Anococcygeal raphé Coccydynia (coccyx pain, tailbone pain) Ganglion impar Rump (croup) Notes References (A good illustration of the posterior and lateral ligaments.) External links Pelvis Joints Bones of the vertebral column