Understanding the perionychium.

The fingernail and toenail are unique to primates. The anatomy and physiology of the nail must be understood for nail care to be effective. The most common cause of deformity of the nail bed is trauma, which requires careful suturing and postoperative care if the desired results are to be achieved. Congenital anomalies, tumors, and infection can also cause nail deformities and can frequently be corrected or improved surgically.