The anal valves or valves of Ball are small valve-like folds at the lower ends of the anal sinuses in the rectum. The anal valves join together the lower ends of the anal columns. The anal sinuses are located between them. The valves and sinuses form the pectinate line.
- Standring, Susan (2008). Gray's Anatomy - The Anatomic Basis of Clinical Practice, 40th Edition. Section 8: Elsevier Health Sciences UK. p. 1156. ISBN 9780702047534.
- Anatomy photo:43:11-0107 at the SUNY Downstate Medical Center — "The Female Pelvis: The Rectum"