Coccyx

Posterior (both): sacrum and coccyx, sacral vessels and nerves, piriformis, coccygeus and levator ani, presacral fascia and lymph nodes.

What our notes say

• Posterior (both): sacrum and coccyx, sacral vessels and nerves, piriformis, coccygeus and levator ani, presacral fascia and lymph nodes. (Master First-Year Anatomy: Must-Know Essays & Key Concepts)