AST Surgical Technologist Practice Exam

Which of the following is an abnormal tract between two epithelium-lined surfaces that is open at both ends?

1. Fistula

2. Sinus

3. Adenoma

4. Cyst

The correct answer is: Fistula

A fistula is defined as an abnormal connection or tract that forms between two epithelium-lined surfaces, allowing for the passage of fluids or materials between these surfaces. This type of structure is characterized by being open at both ends, which distinguishes it from other formations that may be encapsulated or closed. For instance, a sinus is typically a cavity or channel leading to a space, but it does not necessarily connect two distinct surfaces. An adenoma is a benign tumor formed from glandular tissue and does not refer to a tract or connection. A cyst, on the other hand, is a sac-like structure that can be filled with fluid or tissue, but it is typically closed and does not form the open connections that characterize a fistula. Therefore, the identification of a fistula as the correct answer is based on its unique structural properties and functional implications in the human body.