Final answer:
The aneurysm detectable as a pulsating mass around the umbilicus is the abdominal aortic aneurysm.
Step-by-step explanation:
The type of aneurysm that is detectable on palpation as a pulsating mass in an area around the umbilicus is the abdominal aortic aneurysm (AAA). An AAA occurs when the part of the aorta that runs through the abdomen becomes enlarged or bulges due to weakening in the artery wall. This condition can be life-threatening if the aneurysm bursts, leading to internal bleeding. The abdominal aorta provides oxygenated blood to many abdominal organs through its many branches, such as the celiac trunk and the mesenteric arteries, therefore rupture of an aneurysm in this area can have profound effects.