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Home , Abdomen, Sagittal plane

Body Structure 6 Directional Terms

In describing the location or direction of a given point in the body, it is always assumed that the subject is in the anatomical position, that is, upright, with front, at the sides with palms forward, and feet par-allel, as shown in the small diagram in Figure 6-1. In this stance, the terms illustrated in Figure 6-1 and listed in Display 6-1 are used to designate relative position. Figure 6-2 illustrates planes of section, that is, direc-

Superior (cephalad)

Proximal

Anterior Posterior (ventral) (dorsal)

Distal

Medial

Lateral FIGURE 6-1. Directional terms. (Reprinted with per- mission from Cohen BJ, Wood DL. Memmler’s The in Health and Disease. 9th Ed. Philadel- phia: Lippincott Williams & Wilkins, 2000.)

Inferior 1 (caudal) BODY STRUCTURE 2

DISPLAY 5-1 Anatomical Directions

TERM DEFINITION anterior (ventral) toward the front (belly) of the body posterior (dorsal) toward the back of the body medial toward the midline of the body lateral toward the side of the body proximal nearer to the point of attachment or to a given reference point distal farther from the point of attachment or from a given reference point superior above inferior below cephalad (cranial) toward the head caudal toward the lower end of the spine (Latin cauda means “tail”) superficial (external) close to the surface of the body deep (internal) close to the center of the body

Frontal Sagittal Transverse (coronal) plane (horizontal) plane plane

FIGURE 6-2. Planes of division. (Reprinted with permission from Cohen BJ, Wood DL. Memmler’s The Human Body in Health and Disease. 9th Ed. Philadelphia: Lippincott Williams & Wilkins, 2000.) 3 MEDICAL TERMINOLOGY tions in which the body can be cut. A frontal plane, also called a , is made at right angles to the midline and divides the body into anterior and posterior parts. A sagittal (SAJ-i-tal) plane passes from front to back and divides the body into right and left portions. If the plane passes through the midline, it is a mid- sagittal or medial plane. A passes horizontally, dividing the body into superior and inferior parts.

Body Cavities

Internal organs are located within dorsal and ventral cavities (Fig. 5-3). The dorsal cavity contains the brain in the cranial cavity and the in the spinal cavity (canal). The uppermost ventral space, the tho- racic cavity, is separated from the by the diaphragm. There is no anatomical separation be- tween the abdominal cavity and the , which together make up the abdominopelvic cavity. The large_ membrane_ that lines the abdominopelvic cavity and covers the organs within it is the (per- i-to-NE-um).

Cranial cavity

Spinal cavity (canal) Dorsal Diaphragm cavity

Ventral Abdominal cavity cavity Abdominopelvic cavity Pelvic cavity

FIGURE 6-3. Side view of the body cavities. (Reprinted with permission from Cohen BJ, Wood DL. Memmler’s The Human Body in Health and Disease. 9th Ed. Philadelphia: Lippincott Williams & Wilkins, 2000.) BODY STRUCTURE 4

Body Regions

For orientation, the can be divided by imaginary lines into nine regions, which are shown in Fig- ure 5-4. The sections down the midline are the: • epigastric (ep-i-GAS-trik) region, located above the • umbilical (um-BIL-i-kal_ _ ) region, named for the umbilicus, or • hypogastric (hi -po -GAS-trik) region, located below the stomach The lateral regions are the: _ _ _ • right and left hypochondriac (hi -po-KON-dre-ak) regions, named for their position near the , specifically near the (root chondr/o) of the ribs, • right and left (LUM-bar) regions, which are located near the small of the back (lumbar region of the spine) _ • right and left iliac (IL-e-ak) regions, named for the upper bone of the , the . These regions are also called the (ING-gwi-nal) regions, with reference to the .

Right Left Epigastric hypochondriac hypochondriac region region region

Right Left Umbilical lumbar lumbar region region region

Right Left Hypogastric iliac iliac region region region

FIGURE 6-4. The nine regions of the abdomen. (Reprinted with permission from Cohen BJ, Wood DL. Memmler’s The Human Body in Health and Disease. 9th Ed. Philadelphia: Lippincott Williams & Wilkins, 2000.) 5 MEDICAL TERMINOLOGY

More simply, but less precisely, the abdomen can be divided by a single vertical line and a single horizontal line into four sections (Fig. 5-5), designated the right upper quadrant (RUQ), left upper quadrant (LUQ), right lower quadrant (RLQ), and left lower quadrant (LLQ). Additional terms for body regions are shown in Figures 5-6 and 5-7. You may need to refer to these illus- trations as you work through the book.

Positions

In addition to the anatomical position, there are other standard positions in which the body is placed for ex- amination or medical procedures. The most common of these are described in Display 5-2.

Right Left upper upper quadrant quadrant

Right Left lower lower quadrant quadrant

FIGURE 6-5. Quadrants of the abdomen, showing the organs within each quadrant. (Reprinted with permission from Cohen BJ, Wood DL. Memmler’s The Human Body in Health and Disease. 9th Ed. Philadelphia: Lippincott Williams & Wilkins, 2000.) BODY STRUCTURE 6

Cranium (frontal) (cranial) Head Eye (ocular) (cephalic) Face Mouth (oral) (facial)

Chest (thoracic) (mammary) Armpit (axillary) (brachial) Inner (antecubital) Upper extremity Navel (umbilical) (antebrachial) Groin (inguinal)

Wrist (pubic) (carpal)

Hand Palm (palmar)

Fingers (phalangeal)

Thigh (femoral)

Knee Kneecap (patellar)

Leg Lower (crural) extremity

Ankle (tarsal) (pedal) (phalangeal)

.FIGURE 6-6. Common terms for body regions, anterior view. Anatomical terms for regions are in parentheses 7 MEDICAL TERMINOLOGY

Crown (parietal)

Base of (occipital) (cervical) Deltoid Shoulder blade (scapular) Arm (brachial)

Small of back (lumbar)

Sacrum (sacral) Hip (iliac) Buttock (gluteal)

Back of (popliteal)

Calf

Ankle (tarsal)

Sole of foot (plantar)

.FIGURE 6-7. Common terms for body regions, posterior view BODY STRUCTURE 8

DISPLAY 5-2 Body Positions

POSITION DESCRIPTION anatomical position standing erect, facing forward, arms at sides, palms forward, legs parallel, toes pointed forward decubitus position _ _ lying down, specifically according to the part of the body resting on a flat de-KU-bi-tus surface, as in left or right lateral decubitus, or dorsal or ventral decubitus dorsal recumbent position on back, with legs bent and separated, feet flat Fowler position on back, head of bed raised about 18 inches, elevated Kraske (Jackknife) position _ prone with the raised KRAS-ke knee-chest position on knees, head and upper chest on table, arms crossed above head lateral recumbent position on the side with one leg flexed; arm position may vary lithotomy position _ _ on back, legs flexed on abdomen, apart li-THOT-o-me prone lying face down Sims position on left side, right leg drawn up high and forward, left arm along back, chest forward resting on bed supine*_ _ lying face up SU-pi-n Trendelenburg position on back with head lowered by tilting bed back at 45° angle tren-DEL-en-berg *To remember the difference between prone and supine, look for the word up in supine.

Key Terms

abdominal cavity The large ventral cavity below the diaphragm and above the ab-DOM-i-nal pelvic cavity

abdominopelvic_ cavity The large ventral cavity between the diaphragm and that ab-dom-i-no-PEL-vik includes the abdominal and pelvic cavities anatomic position Standard position for anatomical studies, in which the body is an-a-TOM-ik erect and facing forward, the arms are at the sides with palms forward, and the feet are parallel

cranial_ _ cavity The dorsal cavity that contains the brain KRA-ne-al diaphragm_ The muscle that separates the thoracic from the abdominal cavity DI -a-fram frontal_ (coronal) plane Plane of section that separates the body into anterior (front) and ko-RON-al posterior (back) portions pelvic cavity The ventral cavity that is below the abdominal cavity PEL-vik 9 MEDICAL TERMINOLOGY

The large that lines the abdominopelvic cavity peritoneum_ _ per-i-to-NE-um and covers the organs within it Plane that divides the body into right and left portions SAJ-i-tal spinal_ cavity (canal) Dorsal cavity that contains the spinal cord SPI-nal The ventral cavity above the diaphragm; the chest cavity thoracic_ cavity tho-RAS-ik transverse (horizontal) plane Plane that divides the body into superior (upper) and inferior trans-VERS (lower) portions

Word Parts Pertaining to Body Structure

TABLE 5-1 Roots for Regions of the Head and Trunk

ROOT MEANING EXAMPLE DEFINITION OF EXAMPLE cephal/o head abnormal smallness of the head microcephaly_ _ _ mi -kro-SEF-a-le cervic/o neck pertaining to the neck and face cervicofacial_ _ ser-vi-ko-FA-shal thorac/o outside the chest, thorax extrathoracic_ eks-tra-tho-RAS-ik abdomin/o abdomen intra-abdominal within the abdomen in-tra-ab-DOM-i-nal celi/o pertaining to the abdomen abdomen celiac_ _ SE-l e-ak lapar/o instrument for viewing the laparoscope_ _ -a-ro-skop through the abdominal wall lumb/o pertaining to the chest and lumbar region lumbar region, thoracolumbar_ _ lower back tho-rak-o-LUM-bar periton, pertaining to the peritoneum peritoneum peritoneal_ _ peritone/o per-i-to-NE-al BODY STRUCTURE 10

The human body consists of several structural and functional levels of organization. The complexity of each level increases from one to the next because the higher level incorporates the structures and functions of the previous level or levels. Eventually, all levels contribute to the structure and function of the entire -ism (see Figure 6–8). The levels of organization from the least to the most complex are the:

■ Cellular level, the smallest structural and functional unit of the body

■ Tissue level, groups of cells that perform a specialized function

■ Organ level, groups of tissues that perform a specifi c function

■ System level, groups of organs that are interconnected or that have similar or interrelated functions

■ Organism level, collection of body systems that makes up the most complex level—a living human being.

Organism level

Cellular level

Tissue level System level

Organ level

( Figure 6–8)

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