Where are internal hemorrhoids located in relation to the pectinate line?

Internal hemorrhoids are characterized by their development above the pectinate line, which is a critical anatomical landmark in the anal canal. The pectinate line demarcates the change from the rectal mucosa to the anal mucosa and serves as a boundary that distinguishes the upper two-thirds of the anal canal from the lower third.

Internal hemorrhoids arise from the rectal venous plexus and are located within the rectal cavity, above the pectinate line. Due to their location, they are typically not visible on inspection and do not induce pain unless they become prolapsed or result in complications such as thrombosis. This positioning correlates with sensitivity to different types of stimuli; the area above the pectinate line is innervated by visceral nerves, making internal hemorrhoids generally painless unless significant issues develop.

In contrast, the external hemorrhoids form below the pectinate line, where the skin is innervated by somatic nerves. This distinction is crucial in understanding the clinical presentation and management of hemorrhoidal disease. The differentiation also affects how these conditions are treated and what symptoms may be reported by patients.

Thus, understanding that internal hemorrhoids exist above the pectinate line is fundamental for diagnosing and managing related disorders effectively.