Accordion-Like Tethers – elbow, knee and finger joints

Tethers at the midaxial (lateral) lines of hinge joints are tight and deeply anchored around the joint capsules. They form the origin of the creases and folds in the skin seen around the knees, elbows, wrists and finger joints. Like an accordion or Roman shade, these lateral tethers help store redundant skin as folds in extension that can then be used when you bend or flex your joints. Look down at the top or dorsal surface of your fingers and knees. Flex and extend the joints and pull on the skin. You can feel and almost see rigid tethers laterally and looser tethers directly over the joints. Tight lateral elbow tethers work in concert with loose, filmy dorsal tethers allowing motion and preventing shear. Short, rigid tethers between the skin and the tibial tuberosity or proximal shin bone further anchor the skin distally at the knee allowing for stretching of the looser thigh skin when you bend your knees. This complex array of accordion-like attachments again demonstrates how appearance and function are interdependent.