Enthesopathies

Excerpt

Entheses are boney insertion sites of tendons and ligaments. Enthesopathies are defined as the pathologies that affect the entheses. Although somewhat controversial, there appear to be two main classifications of entheses: 1) fibrous and 2) fibrocartilaginous. The difference is that fibrous entheses insert directly onto the periosteum, whereas fibrocartilaginous enthesis lack periosteum.

Anatomically, the entheses are usually found outside the joint capsule with exceptions, including the sacroiliac, sternoclavicular, and distal interphalangeal joints. Entheses have two main roles: stability of the joint, and to transduce mechanical forces. A unique aspect of the entheses is also the relative lack of vascularity. Enthesitis, a subset of enthesopathy, is the inflammation of the insertion sites for the tendons and ligaments on the bone. It is associated with diffuse inflammatory disorders such as psoriatic arthritis (PsA) and spondyloarthropathies (SpA).