What condition is referred to as "clergyman's knee"?

The condition referred to as "clergyman's knee" is prepatellar bursitis. This condition occurs when the bursa in front of the kneecap (patella) becomes inflamed, often due to repetitive kneeling or direct trauma to the knee. The term "clergyman's knee" derives from the historical association of clergymen who kneel frequently during prayers and services, leading to this specific type of bursitis.

In assessing the other conditions listed, infrapatellar bursitis affects the bursa located below the kneecap and is not specifically linked to the act of kneeling in the same way. Anserine bursitis involves inflammation of a different bursa located on the inner side of the knee, which is also unrelated to the activities that lead to prepatellar bursitis. Iliotibial band syndrome is a different disorder characterized by pain and inflammation along the outer part of the knee, typically associated with running or other repetitive leg movements.

Thus, prepatellar bursitis stands out as the condition known as "clergyman's knee," specifically connected with the demands placed on the knee through kneeling.