Body Structure. Directional Terms

Transcription

1 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 face front, arms 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 (ventral) Posterior (dorsal) Distal Medial Lateral FIGURE 6-1. Directional terms. (Reprinted with permission from Cohen BJ, Wood DL. Memmler s The Human Body in Health and Disease. 9th Ed. Philadelphia: Lippincott Williams & Wilkins, 2000.) 1 Inferior (caudal)

2 BODY STRUCTURE 2 DISPLAY 5-1 Anatomical Directions TERM anterior (ventral) posterior (dorsal) medial lateral proximal distal superior inferior cephalad (cranial) caudal superficial (external) deep (internal) DEFINITION toward the front (belly) of the body toward the back of the body toward the midline of the body toward the side of the body nearer to the point of attachment or to a given reference point farther from the point of attachment or from a given reference point above below toward the head toward the lower end of the spine (Latin cauda means tail ) close to the surface of the body close to the center of the body Frontal (coronal) plane Sagittal plane Transverse (horizontal) 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 3 MEDICAL TERMINOLOGY tions in which the body can be cut. A frontal plane, also called a coronal plane, 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 midsagittal or medial plane. A transverse plane 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 contains the brain in the cranial and the spinal cord in the spinal (canal). The uppermost ventral space, the thoracic, is separated from the abdominal by the diaphragm. There is no anatomical separation between the abdominal and the pelvic, which together make up the abdominopelvic. The large membrane that lines the abdominopelvic and covers the organs within it is the peritoneum (peri-to _ -NE _ -um). Cranial Thoracic Diaphragm Spinal (canal) Dorsal Ventral Abdominal Abdominopelvic Pelvic 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.)

4 BODY STRUCTURE 4 Body Regions For orientation, the abdomen can be divided by imaginary lines into nine s, which are shown in Figure 5-4. The sections down the midline are the: epigastric (ep-i-gas-trik), located above the stomach umbilical (um-bil-i-kal), named for the umbilicus, or navel hypogastric (hi _ -po _ -GAS-trik), located below the stomach The lateral s are the: right and left hypochondriac (hi _ -po _ -KON-dre _ -ak) s, named for their position near the ribs, specifically near the cartilages (root chondr/o) of the ribs, right and left lumbar (LUM-bar) s, which are located near the small of the back (lumbar of the spine) right and left iliac (IL-e _ -ak) s, named for the upper bone of the hip, the ilium. These s are also called the inguinal (ING-gwi-nal) s, with reference to the groin. Right hypochondriac Epigastric Left hypochondriac Right lumbar Right iliac Umbilical Hypogastric Left lumbar Left iliac FIGURE 6-4. The nine s 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 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 s are shown in Figures 5-6 and 5-7. You may need to refer to these illustrations 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 examination or medical procedures. The most common of these are described in Display 5-2. Right upper quadrant Right lower quadrant Left upper quadrant Left lower 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.)

6 BODY STRUCTURE 6 Head (cephalic) Cranium (cranial) Face (facial) Forehead (frontal) Eye (ocular) Mouth (oral) Upper extremity Chest (thoracic) Arm (brachial) Forearm (antebrachial) Wrist (carpal) Hand Thigh (femoral) Knee Breast (mammary) Armpit (axillary) Inner elbow (antecubital) Navel (umbilical) Groin (inguinal) Pubis (pubic) Palm (palmar) Fingers (phalangeal) Kneecap (patellar) Lower extremity Leg (crural) Foot (pedal) Ankle (tarsal) Toes (phalangeal).figure 6-6. Common terms for body s, anterior view. Anatomical terms for s are in parentheses

7 7 MEDICAL TERMINOLOGY Crown (parietal) Shoulder Base of skull (occipital) Neck (cervical) Deltoid Shoulder blade (scapular) Arm (brachial) Flank Hip (iliac) Small of back (lumbar) Sacrum (sacral) Buttock (gluteal) Back of knee (popliteal) Calf Ankle (tarsal) Sole of foot (plantar).figure 6-7. Common terms for body s, posterior view

8 BODY STRUCTURE 8 DISPLAY 5-2 Body Positions POSITION anatomical position decubitus position de _ -KU _ -bi-tus dorsal recumbent position Fowler position Kraske (Jackknife) position KRAS-ke _ knee-chest position lateral recumbent position lithotomy position li-thot-o _ -me _ prone Sims position supine* SU _ -pi _ -n Trendelenburg position tren-del-en-berg DESCRIPTION standing erect, facing forward, arms at sides, palms forward, legs parallel, toes pointed forward lying down, specifically according to the part of the body resting on a flat surface, as in left or right lateral decubitus, or dorsal or ventral decubitus on back, with legs bent and separated, feet flat on back, head of bed raised about 18 inches, knees elevated prone with the buttocks raised on knees, head and upper chest on table, arms crossed above head on the side with one leg flexed; arm position may vary on back, legs flexed on abdomen, thighs apart lying face down on left side, right leg drawn up high and forward, left arm along back, chest forward resting on bed lying face up on back with head lowered by tilting bed back at 45 angle *To remember the difference between prone and supine, look for the word up in supine. Key Terms abdominal ab-dom-i-nal abdominopelvic ab-dom-i-no _ -PEL-vik anatomic position an-a-tom-ik cranial KR A-ne -al diaphragm DI _ -a-fram frontal (coronal) plane ko-ro _ N-al pelvic PEL-vik The large ventral below the diaphragm and above the pelvic The large ventral between the diaphragm and pelvis that includes the abdominal and pelvic cavities Standard position for anatomical studies, in which the body is erect and facing forward, the arms are at the sides with palms forward, and the feet are parallel The dorsal that contains the brain The muscle that separates the thoracic from the abdominal Plane of section that separates the body into anterior (front) and posterior (back) portions The ventral that is below the abdominal

9 9 MEDICAL TERMINOLOGY peritoneum per-i-to _ -NE _ -um sagittal plane SAJ-i-tal spinal (canal) SPI _ -nal thoracic tho _ -RAS-ik transverse (horizontal) plane trans-vers The large serous membrane that lines the abdominopelvic and covers the organs within it Plane that divides the body into right and left portions Dorsal that contains the spinal cord The ventral above the diaphragm; the chest Plane that divides the body into superior (upper) and inferior (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 microcephaly mi _ -kro _ -SEF-a-l _ abnormal smallness of the head e cervic/o neck cervicofacial ser-vi-ko _ -FA _ pertaining to the neck and face -shal thorac/o chest, thorax extrathoracic eks-tra-tho _ outside the thorax -RAS-ik abdomin/o abdomen intra-abdominal within the abdomen in-tra-ab-dom-i-nal celi/o abdomen celiac SE _ -l e _ pertaining to the abdomen -ak lapar/o abdominal wall laparoscope LAP-a-ro _ -sko _ instrument for viewing the peritoneal p through the abdominal wall lumb/o lumbar, thoracolumbar lower back tho _ -rak-o _ pertaining to the chest and lumbar -LUM-bar periton, peritoneum peritoneal peritone/o per-i-to _ -NE _ pertaining to the peritoneum -al

10 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 organ-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 specific 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 System level Tissue level Organ level ( Figure 6 8)