AmeriCorps Health Blog

Axial Region

The axial region consists of the head, neck (cervical2 region), and trunk. The trunk is further divided into the

2cervic = neck thoracic region above the diaphragm and the abdominal region below it.

One way of referring to the locations of abdominal structures is to divide the region into quadrants. Two perpendicular lines intersecting at the umbilicus (navel) divide the abdomen into a right upper quadrant (RUQ), right lower quadrant (RLQ), left upper quadrant (LUQ), and left lower quadrant (LLQ) (fig. A.6a, b). The quadrant scheme is often used to describe the site of an abdominal pain or abnormality.

The abdomen also can be divided into nine regions defined by four lines that intersect like a tic-tac-toe grid (fig. A.6c, d). Each vertical line is called a midclavicular line because it passes through the midpoint of the clavicle (collarbone). The superior horizontal line is called the subcostal3 line because it connects the inferior borders of the lowest costal cartilages (cartilage connecting the tenth rib on each side to the inferior end of the sternum). The inferior horizontal line is called the intertubercular4 line because it passes from left to right between the tubercles (anterior superior spines) of the pelvis—two points of bone located about where the front pockets open on most pants. The three lateral regions of this grid, from upper to lower, are the hypochondriac,5 lateral (lumbar), and inguinal6 (iliac) regions. The three medial regions from upper to lower are the epigastric,7 umbilical, and hypogastric (pubic) regions.

4inter = between + tubercul = little swelling

5 hypo = below + chondr = cartilage

6inguin = groin

Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition

Upper extremity:

Acromial r.-

(shoulder) Axillary r. (armpit) Brachial r. (arm)

Cubital r. (elbow)

Antebrachial r. (forearm)

Carpal r. (wrist)

Lower extremity: Coxal r. (hip) Patellar r. (knee)

(a)

Cephalic r. (head)

Cervical r. (neck)

Thoracic r. (chest): Sternal r. Pectoral r.

Umbilical r.

Abdominal r. Inguinal r. (groin) Pubic r.: Mons pubis External genitalia Penis Scrotum Testes

Lower extremity: Femoral r. (thigh)

Plantar surface (sole)

Nuchal r. (back of neck)

Interscapular r. Scapular r.

Tarsal r. Calcaneal r. (heel)

Cranial r.

Nuchal r. (back of neck)

Interscapular r. Scapular r.

Vertebral r.

Lumbar r. Sacral r.

Gluteal r. (buttock)

Dorsum of hand Perineal r. Femoral r.

Popliteal r.

Crural r.

Tarsal r. Calcaneal r. (heel)

Cranial r.

Popliteal r.

Crural r.

Figure A.5 The Adult Female and Male Bodies. (a and fa) Ventral aspect (c and d) dorsal aspect (r. = region).

Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition

34 Part One Organization of the Body

Figure A.6 Four Quadrants and Nine Regions of the Abdomen. (a) External division into four quadrants. (b) Internal anatomy correlated with the four quadrants.

Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition

Atlas A General Orientation to Human Anatomy 35

Figure A.6 Four Quadrants and Nine Regions of the Abdomen (continued). (c) External division into nine regions. (d) Internal anatomy correlated with the nine regions.

Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition

Atlas A General Orientation to Human Anatomy

Text

© The McGraw-H Companies, 2003

36 Part One Organization of the Body