REGIONS, OF THE BODY, various portions of the surface of the human body into which it has been divided by anatomists for convenience of description. The system of division varies, sometimes being general, sometimes more or less specific, or minute. Thus, in general terms, we may speak of the thoracic region, implying the whole surface of the thorax, anterior, posterior, and lateral, or that portion of the body inclosed by the ribs, sternum, and dorsal vertebrse. A further division of the thorax includes that just named, as, anterior thoracic region, lateral thoracic regions, and posterior thoracic regibn. The anterior thoracic region is again subdivided into the sternal, or that part covered by the sternum bone (see SKELETON); two clavicular, those parts indicated by the collar bones, or clavicles; two subclavian, or those parts just below the clavicles; i,wo mammary, or those regions corresponding to the breasts, and two infra-mammary, or legions just, below the breasts (of course these double regions are named respectively right and left, as left mammary, right mammary region, etc.). The sternal region is again subdivided into upper and lower, and sometimes into upper, middle, and lower regions. The lateral thoracic regions are each subdivided into axillarv, lateral, and lower lateral, and the posterior thoracic region is subdivided on each side of the spine into scapular, corresponding to the shoulder-blade; and inter-scapular, between the shoulder-blade and the spine. Sometimes another region is added, called the dorsal, corresponding to the base of the lung on each side, but sometimes the dorsal region is used in a more general sense, including a great portion of the posterior thoracic, on each side of the spine; and it may be remarked. here that we are only sketching the most commonly adopted topog raphy. These regions are not always very sharply defined, but the subclavian region may be said accurately to comprise that portion of either side of the thorax embraced between the clavicle, or collar bone, and the upper part of the fourth rib, and included laterally by the deltoid muscle and the sternum. Beneath it lies the upper lobe of the lung and the main bronchial tube, and on the right side, beside this, the descending vena-cava (see CruculanoN), and a portion of the arch of the aorta. The mammary region extends from the fourth to the seventh rib, on either side, bounded laterally by the sternum and a line drawn vertically about 2 in. outside of the nipple. Beneath this region, on the right side, the lung occupies the whole space, and the sounds on percus sion given by a healthy lung are clear, except at the very lower border, where the liver and diaphragm are very near and produce dullness. On the left side the lung is partly displaced by the heart, and consequently at this portion percussion elicits dullness of sound. This sketch of the thoracic regions will suffice for the use of the general reader, and to show the utility of such divisions. The lower part of the body is usually divided, i u a general way, into abdominal, lumbar, and sacral regions, and in a still more general way may be added a pelvic region, although this would include portions of other regions. If a horizontal line is drawn round the body in a level with the lower end of the sternum (the ensiform cartilage) it will mark the superior boundary of the abdomen; and if another horizontal line is drawn on a level with the cartilages of the last false ribs, and still another on a level with the crests of the hip bones (ilia), three horizontal divisions or zones will be formed, one of them being below the lower (third) line. If now two lines, one on each side, are drawn from the upper horizontal line vertically downward to the end of the trunk, and between 3 and 4 in. on each side of tire center (technically inter secting the middle of Poupart' s ligament), each of the zones will be divided into three sub-regions. The three central re ions, from above downwards are named epigastric, umbilical, and hypogastric, the cprgastrie lying over the stomach, and the hypogastric, (sometimes called the pubic) being the lowest central region. Ou each side of this cen
tral tier of regions there are, from above downward, the hypochondriac, the lumbar (sometimes called the iliac), and inguinal regions. These regions are of great importance" in descriptive anatomy, and must be familiar to the surgeon as well as the physician. They ought also to be recognized by every well-educated person. Beneath the right hypochondriac region (called hypochondriac because beneath the cartilages of the false or floating ribs) is tire right lobe of the liver, tire gall bladder, the duodenum (see DIGES TION), the pancreas, and the upper part of the right kidney. Beneath the right lumbar region lies that part of the large intestine called the ascending colon, and also some con volutions of the small intestines. The ascending colon, and its pouch-like commence ment at the termination of the ilium, the last division of the small intestines, are impor tant divisions of the alimentary canal. Beneath the right inguinal region lies the lower, pouch-like end of the ascending colon (its commencement) before mentioned, and its attachment, the appendix vermiformis. Beneath the left hypochondriac region are the greater or splenic cud of the stomach, the spleen (q.v.) and extremity of tire pancreas (q.v.), the splenic flexure of the colon and the tipper half of the left kidney. Beneath the left lumbar region lies the descending colon, the lower part of the left kidney, and some convolutions of the small intestines. Beneath the left inguinal region lies the sigmoid flexure of the colon (that part of it which is next the commencement of the rectum) and ureter. See URETERS. The sacral region of the body corresponds to that portion of the pelvis called the sacrum, the lower portion of the spinal column. Besides the regions enumerated, there is the general cervical region (region of the neck), divided into anterior, posterior, and lateral cervical regions, whose locations are obvious. The head is generally divided into a cranial and a facial region. The cranial region is again divided into frontal, corouid, occipital, parietal, and temporal regions. Leaving the surface we also have the basilar region of the cranium, the floor of the skull, upon which the brain rests. See SKELETON. The facial region is divided into upper and lower facial. Passing to the upper extremities there are the acromial, or shoulder region, corresponding to the deltoid muscle; the anterior humeral region, corresponding to the front of the arm; and the posterior humeral region, corresponding to the back of the arm. We may also speak of the external and internal lateral humeral regions, to aid description. The bra chial regions, anterior and posterior, are terms applied principally to the anterior and pos terior aspects of the fore-arm, although the word brachium means the whole arm, from the shoulder to the wrist. 'We also have a radial region, corresponding to the radius, and au ulnar region, corresponding to the ulna. At the wrist is the carpal region. anterior and posterior; in the hand the dorsal or metacarpal (back of the hand), and the palmar regions. Passing to the lower extremities, in the hip there is the &teal region (the buttocks), a portion of the iliac region (the hip and thigh joint), the anterior femoral region (the fore part of the thigh), the posterior femoral region (the posterior surface of the thigh), internal and external (lateral) femoral regions; popliteal region, immediately behind the knee joint; the anterior tibio-filmlar region, the front aspect of the .eg, cor responding to the shin: the posterior tibio-flbular region, corresponding to the calf and posterior aspect of the leg; the dorsal region of the foot, corresponding to the instep; and the plantar region, corresponding to the sole of the foot.