**Question:** Which of these disorders in neonates can best be excluded or diagnosed by anorectal manometry?

A. Hirschsprung disease
B. Anal fissure
C. Anal atresia
D. Anal stenosis

**Core Concept:** Anorectal manometry is a test used to measure the pressure within the anal canal and rectum. This test is performed to evaluate bowel function, especially in infants and children, to diagnose or exclude specific disorders.

**Why the Correct Answer is Right:** Anorectal manometry can be used to diagnose or exclude Hirschsprung disease, which is a congenital disorder characterized by the absence of ganglion cells in the distal colon and rectum, leading to impaired bowel motility. In Hirschsprung disease, anorectal manometry will show absent or reduced squeeze pressures, increased resting pressure, and absent propagated rectal contractions.

**Why Each Wrong Option is Incorrect:**

B. Anal fissure: An anal fissure is a tear in the anal mucosa due to severe constipation or manual maneuvers. Anorectal manometry will not be helpful in diagnosing anal fissure as it is a mucosal injury and not related to rectal motility.

C. Anal atresia: Anal atresia refers to a congenital absence of the anal canal, rectum, or both. Anorectal manometry will not be useful in diagnosing anal atresia as it is a structural anomaly. The test will not be able to detect the absence of anal canal or rectum.

D. Anal stenosis: Anal stenosis is a narrowing of the anal canal due to inflammation, scarring, or trauma. Anorectal manometry can be used to diagnose or exclude anal stenosis, as it shows reduced squeeze pressure, increased resting pressure, and delayed or absent propagated rectal contractions.

**Clinical Pearl:** Anorectal manometry is a non-invasive test that can help diagnose or exclude specific disorders affecting rectal motility in neonates, such as Hirschsprung disease. It is essential for proper diagnosis and management of these conditions.