Lymph nodes draining area superior to pectinate line of anal canal drain to which nodal groups?

Lymph nodes draining area superior to pectinate line of anal canal drain to which nodal groups?

• A. Paraaortic
• B. Internal iliac only
• C. Internal iliac, inferior mesenteric
• D. Superficial inguinal

Answer: (C)

Lymph drainage in the anal canal is divided by the pectinate line, reflecting different embryologic origins and arterial supplies. The portion above the pectinate line is part of the hindgut and its lymphatics drain to both internal iliac nodes and inferior mesenteric nodes. The pathway to the inferior mesenteric nodes follows the superior rectal lymphatics accompanying the superior rectal artery, while drainage to the internal iliac nodes follows the middle rectal lymphatics accompanying the middle rectal artery. Because this region uses both routes, the nodal groups involved are internal iliac and inferior mesenteric. (Below the pectinate line, drainage shifts to superficial inguinal nodes.)

Lymph drainage in the anal canal is divided by the pectinate line, reflecting different embryologic origins and arterial supplies. The portion above the pectinate line is part of the hindgut and its lymphatics drain to both internal iliac nodes and inferior mesenteric nodes. The pathway to the inferior mesenteric nodes follows the superior rectal lymphatics accompanying the superior rectal artery, while drainage to the internal iliac nodes follows the middle rectal lymphatics accompanying the middle rectal artery. Because this region uses both routes, the nodal groups involved are internal iliac and inferior mesenteric. (Below the pectinate line, drainage shifts to superficial inguinal nodes.)