region
[re´jun] a plane with more or less definite boundaries; called also
regio. adj.,
adj re´gional.
abdominal r's the areas into which the anterior surface of the abdomen is divided, including the epigastric, hypochondriac (right and left), iliac (right and left), lumbar (right and left), hypogastric, and umbilical.

Nine abdominopelvic regions. From Applegate, 2000.
See illustration.
AN region the area of the heart where the atrial fibers merge with the atrioventricular node.
facial region that comprising the various anatomical regions of the face, divided into
buccal (side of oral cavity),
infraorbital (below eye),
mental (chin),
nasal (nose),
oral (lips),
orbital (eye),
parotid (angle of jaw), and
zygomatic (cheek bone) regions.
H region the area of the bundle of His from its connection with the atrioventricular node to its branching portion.
homology r's looped structures, comprising approximately 100 amino acid residues and fastened by disulfide bonds, that show similarities in primary structure from one region to another. They represent the building blocks or units of immunoglobulin molecules.
hypochondriac region either of the abdominal regions that are in superior lateral locations, one on the left (
left hypochondriac region) and one on the right (
right hypochondriac region) of the
epigastric region; called also
hypochondrium.
I region that part of the major histocompatibility complex where immune response genes are present.
lateral region either of the abdominal regions that are in central lateral locations, one to the left (
left lateral region) and one to the right (
right lateral region) of the
umbilical region; called also
flank and
lumbar region.
lumbar region 1. the region of the back lying lateral to the lumbar vertebrae. See also
loin.
N region [nodal region] the region of the atrioventricular node consisting of the body of the node.
NH region [nodal-His region] the area where the atrioventricular node becomes the bundle of His.
precordial region the part of the anterior surface of the body covering the heart and the pit of the stomach.
urogenital region the part of the
perineal region that surrounds the external genital organs and the urethral orifice,
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.