In a patient with a gallbladder present, the CBD is considered dilated when the diameter is greater than:

In a patient with a gallbladder present, the CBD is considered dilated when the diameter is greater than:

• A. >5 mm
• B. >6 mm
• C. >8 mm
• D. >10 mm

Answer: (C)

The main idea is knowing what diameter of the common bile duct is considered normal versus dilated when a gallbladder is present. In adults with a gallbladder, the CBD should be relatively small, and a common upper normal limit is around 6–7 mm. When the diameter exceeds about 8 mm, it is regarded as dilated, suggesting possible obstruction or pathology such as stones, a stricture, or a mass blocking bile flow. Values like 5–6 mm are within normal range for many patients, while 10 mm represents more pronounced dilation and is more concerning in someone without special circumstances. Therefore, a CBD diameter greater than 8 mm is the threshold used to define dilation in a patient who still has the gallbladder.

The main idea is knowing what diameter of the common bile duct is considered normal versus dilated when a gallbladder is present. In adults with a gallbladder, the CBD should be relatively small, and a common upper normal limit is around 6–7 mm. When the diameter exceeds about 8 mm, it is regarded as dilated, suggesting possible obstruction or pathology such as stones, a stricture, or a mass blocking bile flow. Values like 5–6 mm are within normal range for many patients, while 10 mm represents more pronounced dilation and is more concerning in someone without special circumstances. Therefore, a CBD diameter greater than 8 mm is the threshold used to define dilation in a patient who still has the gallbladder.