The pectinate line is also important in the understanding of hemorrhoid disease. External hemorrhoids are located below the pectinate line, internal hemorrhoids above the pectinate line. Sensory innervation is present below the pectinate line only which explains why it is possible to perform banding internal hemorrhoids without local anesthesia. Note the induration and erythema of the left buttocks with the point of the perirectal abscess occurring just lateral to the anus. Such an abscess may drain per rectum or spontaneously drain through an opening in the skin of the buttocks.
Surgical treatment involves prompt incision and drainage.
The probe is passed through both the external opening at the skin level and the internal opening at the pectinate line. Patients present with complaints of scant to moderate drainage through the skin opening. Pain is not usually a presenting symptom. Surgical management involves opening the fistula tract overlying the probe as shown. The wound is allowed to heal by secondary intention.