Symphysis

A symphysis is a type of cartilaginous joint, a secondary cartilaginous joint where bones are connected by a disc or plate of fibrocartilage. It is a slightly movable joint (amphiarthrosis) that provides both stability and flexibility. Symphyses are strong and capable of withstanding significant compression and shear forces. They often lie in the midline of the body, contributing to its structural integrity and facilitating coordinated movement in the axial skeleton. The fibrocartilage acts as a shock absorber and allows limited motion, such as bending, twisting, or gliding. Symphyses provide articulation with limited motion in contrast to synovial joints or synarthroses.

Symphysis meaning with examples

• The pubic symphysis, located at the anterior midline of the pelvis, is crucial during childbirth, allowing for some expansion of the pelvic girdle to facilitate the passage of the infant's head. The robust fibrocartilaginous disc permits limited movement, crucial for the proper function of the lower extremities and transferring the weight from the torso down the body, which promotes upright posture and ambulation.
• The intervertebral discs connecting the vertebral bodies are symphyses. These discs act as cushions, absorbing shock and permitting slight movements between adjacent vertebrae. These movements are critical for spinal flexion, extension, and rotation, providing flexibility to the spine during everyday activities. This also prevents significant friction or bone-on-bone contact that could lead to discomfort.
• The manubriosternal joint, connecting the manubrium and the body of the sternum, is a symphysis. This joint provides a flexible connection, and some limited movement, which is essential for the expansion and contraction of the ribcage during breathing. The fibrocartilage allows the chest to expand and retract, supporting respiratory function by increasing the capacity of the thoracic cavity and proper air intake.
• During the development of the mandible, the two halves of the mandible are initially connected by a mandibular symphysis. The presence of this symphysis allows for slight growth and expansion of the mandible before fusing into a single bone later in development, which facilitates the growth to accommodate the adult set of teeth. The joint allows for expansion for proper teeth alignment.