Iris sphincter muscle Iris sphincter muscle The iris sphincter muscle (pupillary sphincter, pupillary constrictor, circular muscle of iris, circular fibers) is a muscle in the part of the eye called the iris. It encircles the pupil of the iris, appropriate to its function as a constrictor of the pupil. It is found in vertebrates and some cephalopods. Initially, all the myocytes are of the smooth muscle type but, later in life, most cells are of the striated muscle type. Its dimensions are about 0.75 mm wide by 0.15 mm thick. In humans, it functions to constrict the pupil in bright light (pupillary light
Muscle imbalance with the joint centered, thus accomplishing human movement Muscles that have become imbalanced are usually result of either adaption or dysfunction, they can be classed as functional or pathological. Classic symptoms of muscle imbalances are usually pain associated with the affected joint. Symptoms can vary depending on what stage their muscular imbalance is, functional or pathological, but commonly exhibit small tissue damage or lesions accompanied by a change in muscle movement patterns. Symptoms may occur after injury or surgery, where the recuperation of the joint affected is left untreated causing either tension or restriction to flexibility and strength of the