The joint structure is composed of bones that are separated by cartilage which acts as a pad for adjacent bones. Ligaments are attached to the bones around the joint and there are fluid filled sacs which provide gliding surface for adjacent tendons.
A sty or stye is a tender, painful red bump located at the base of an eyelash or under or inside the eyelid. A sty results from a localized infection of the glands or a hair follicle of the eyelid.