A 50-year-old man has painless bleeding per rectum. Proctoscopy shows engorged vascular cushions arising above the pectinate (dentate) line. Which statement correctly applies to these lesions?

• A They are covered by stratified squamous epithelium and are somatically innervated
• B They drain into the inferior rectal veins
• C They drain lymph to the superficial inguinal nodes
• D They are covered by columnar epithelium and drain into the superior rectal vein ✓

Explanation

Above the pectinate line the anal canal is of hindgut endodermal origin, lined by columnar epithelium, supplied by the superior rectal vessels, drained by the superior rectal vein into the portal system, and innervated by visceral fibres, hence painless haemorrhoids. Below the line the mucosa is ectodermal, somatically innervated via the inferior rectal nerve, and drains to the inferior rectal veins and inguinal nodes.

Reference: Gray's Anatomy for Students, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.