Coccyx

Function

Our vestigial tail — three to five fused segments anchoring the pelvic floor muscles, the anal sphincter and the anococcygeal ligament that supports the rectum.

Landmarks

• Base and apex
• Cornua
• Transverse processes (vestigial)

Articulations (joints)

• Sacrum (sacrococcygeal joint)
• Anococcygeal ligament attachments

Clinical relevance

Coccydynia follows falls onto the tailbone or childbirth; the coccyx is deliberately removed in rare refractory cases (coccygectomy) and is a route for presacral tumour spread.