Ch 5, Words and Word parts pertaining to Body Structure Tools A B cephal/o head cervic/o neck thorac/o chest, thorax abdomin/o or celi/o abdomen lapar/o abdominal wall lumb/o lumbar region, lower back periton or peritone/o peritoneum acro extremity, end brachi/o arm cheir/o or chir/o hand ped/o or pod/o foot dactyl/o finger, toe circum- or peri- around intra- in, within epi- upon, over extra- outside infra- below sub- under, below inter- between juxta- or para- near, beside retro- behind, backward supra- above digit a finger or toe (adj. digital) epigastrium the epigastric region fundus the base or body of a hollow organ; the area of an organ farthest from its opening hypochondrium the hypochondriac region (left or right) lumen the central opening within a tube or vessel meatus a passage or opening orifice the opening of a cavity os mouth; any body opening septum a wall dividing two cavities sinus a cavity, as within a bone spincter a circular muscle that regulates an opening