A saddle joint: the carpometacarpal joint.
Birthmarks are skin blemishes, usually congenital. There are two main types: pigmented nevuses, or moles, which are usually brown or black and may be raised or flat; and vascular nevuses, local growths of small blood vessels, such as the "strawberry mark" and the "port-wine stain." Although harmless, they are sometimes removed for cosmetic reasons or if they show malignant tendencies. See also tumor.
Symptoms of birthmarks
Each type of birthmark has its own appearance:
Other symptoms of birthmarks:
Treatment for birthmarks
Treatment varies depending on the type of birthmark and related conditions. Usually no treatment is needed for the birthmark itself.
Large birthmarks that affect your appearance and self-esteem may be covered with special cosmetics.
Moles may be removed surgically if they affect your appearance or have an increased cancer risk. Discuss your options with your doctor to decide how and when to remove any moles.