Surgical Procedures for Perianal Sepsis: Ischiorectal Abscesses, Fistulas, and Pilonidal Sinus

Abstract

• Internal sphincter = smooth muscle

• External sphincter = striated muscle

• Mucosa of upper third of anal canal: no somatic sensation

• Mucosa of lower two-thirds of anal canal: somatic innervation from inferior rectal nerves

• Anal glands occur in the intersphincteric plane and open at the level of the dentate line within the anal canal

Before any anorectal surgical procedure is performed, digital and sigmoidoscopic examinations are mandatory. Since these examinations may be painful in patients with local inflammation, it may be necessary to perform them with the patient under some kind of anaesthesia. Digital examination should always precede sigmoidoscopy and proctoscopy as it relaxes the sphincters and detects any obstruction that may cause injury during proctosig-moidscopy. It also provides helpful information on the strength and muscular symmetry of the sphincter muscles.