Amphiarthroosi

Amphiarthroosi, also known as amphiarthrosis, is a category of joint in the skeletal system characterized by limited, or slightly movable, articulation. It sits between the more rigid synarthroses (immobile) and the freely movable diarthroses (synovial joints). The movement at amphiarthrotic joints is constrained but not absent, providing a balance between stability and mobility.

Structurally, amphiarthroses can be fibrous or cartilaginous. Fibrous amphiarthroses connect bones with ligaments and allow only modest motion, as seen in bepaalde syndesmoses. Cartilaginous amphiarthroses join bones by cartilage, often fibrocartilage, and permit more movement than fibrous joints while still limiting motion compared with diarthroses. The composition and arrangement of the connective tissue influence the degree of mobility and load distribution.

Common examples include the joints between adjacent vertebral bodies, where intervertebral discs and associated cartilage allow limited flexion, extension, and slight rotation. The pubic symphysis is another classic amphiarthrosis, a fibrocartilaginous joint that provides modest movement during gait and childbirth. The distal tibiofibular joint, a syndesmosis, is a fibrous amphiarthrosis that affords stability with only slight giving way during ankle motion.

Clinical relevance lies in the need to balance stability with flexibility in these joints. Degenerative changes, trauma, or overuse can reduce their mobility or cause pain, underscoring the functional role of amphiarthroses in everyday movement.