title: Anatomy of the orbicularis oris muscle in incomplete unilateral cleft lip based on histological examination.
abstract: Histological sections of tissue removed from three incomplete cleft lips at the time of repair, a nature's scar line, and a noncleft lip were examined serially in the horizontal and saggital planes. The findings confirm previous data from electrical stimulation studies of clefts and a three-dimensional histological model of the orbicularis oris in a complete cleft lip. There is a disorganized mass of muscle fibers with numerous dermal insertions and no evidence of well-defined muscle bundles running parallel to the cleft margins. The fibers are somewhat hypoplastic and less abundant than those present in noncleft lips.
mesh_terms: D002648:Child; D002971:Cleft Lip / Q000473:pathology* / Q000601:surgery; D005152:Facial Muscles / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008046:Lip / Q000473:pathology* / Q000601:surgery; D008297:Male; D013518:Surgery, Plastic