ampharthrosis

Amphiarthrosis is a type of joint that permits limited movement, occupying an intermediate position between synarthrosis (no movement) and diarthrosis (free movement). Depending on the joint, amphiarthrosis can be fibrous or cartilaginous, with stability provided by ligaments or fibrocartilaginous discs that restrict motion while allowing small excursions.

Examples include the intervertebral joints between adjacent vertebral bodies, where the fibrocartilaginous intervertebral discs and facet joints permit bending and limited twisting; and the pubic symphysis, a cartilaginous joint that unites the left and right pubic bones with modest motion. Fibrous amphiarthroses occur at the distal tibiofibular joint, where ligaments connect the tibia and fibula with slight give, contributing to ankle stability.

Clinical relevance: amphiarthroses provide a balance of stability and flexibility essential for load transmission and modest mobility. Mobility at these joints tends to decrease with age as connective tissues and cartilage wear. They are distinct from synarthroses (no movement) and diarthroses (free movement).