Anatomy 25 KEY ANATOMICAL TERMINOLOGY Guthrie

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1 THE FOLLOWING TERMS ARE COMMONLY USED IN ANATOMY. YOU MUST KNOW THEM IN ORDER TO FIND YOUR WAY AROUND THE BODY. CADAVER : A dead human body A NATOMICAL POSITION : The standard reference position of the body. The body stands facing you; the upper limbs hang by the sides with the palms of the hands facing forward; the feet are directed straight ahead. All anatomical descriptions are given as if the body were in this position, regardless of its actual disposition. ANATOMICAL SURFACES Anterior Surface. The "front" surface of the body in the anatomical position. Also called the ventral surface. Posterior Surface. The "back" surface of the body in the anatomical position. Also called the dorsum or the dorsal surface. Palmar Surface. The palm of the hand. Also called the volar ("throwing") surface. The back of the hand is called the dorsum or dorsal surface. Plantar Surface. The sole of the foot. The top of the foot is called the dorsum or dorsal surface. External Surface. The "outer" surface of a structure. Internal Surface. The "inner" surface of a structure. A NATOMICAL PLANES Technically, a plane is a surface that entirely contains every straight line joining any two points lying in it. In anatomy, you can think of a plane as an imaginary sheet of glass that cuts through the body. Median (midsagittal ) Plane Runs through the body from head to toe. Divides the body into right and left halves. There is only one median plane. Midline: An imaginary line created by the junction of the median plane with the anterior and posterior surfaces of the body. Sagittal (parasagittal) Planes Planes parallel to the median plane. Divide the body into unequal right and left parts. Theoretically, there are an unlimited number of possible sagittal planes. Frontal (coronal ) Planes Run through the body from head to toe at right angles to the median plane. Divide the body into front and back parts.theoretically, there are an unlimited number of possible frontal planes. Horizontal (transverse) Planes Run through the body parallel to the ground at right angles to the median, sagittal, and frontal planes. Divide the body into upper and lower parts. Theoretically, there are an unlimited number of possible horizontall planes. ANATOMICAL SECTIONS When a body or body part is sliced along an anatomical plane, the resulting slice is called a section. Therefore, a slice made through the median plane creates a median section; one through a sagittal plane, a sagittal section; one through a frontal plane, a frontal or coronal section; and one through a horizontal plane, a horizontal, transverse, or cross section. Sagittal sections A25lab.terminology.mjg.2009 page 1 of 5

2 have medial and lateral surfaces; frontal sections, anterior and posterior surfaces; and horizontal sections, superior and inferior surfaces. TERMS USED TO DESCRIBE DIRECTIONS AND RELATIONSHIPS Superior (cranial): The head end of the body or towards the head end of the body. Relative to another structure, closer to the head end of the body. For example: structure A is superior to structure B. Inferior (caudal): The foot end of the body or towards the foot end of the body. Relative to another structure, closer to the foot end of the body. For example: structure B is inferior to structure A. Anterior (ventral): The front surface of the body or toward the front surface of the body. Relative to another structure, closer to the front surface of the body. For example: structure C is anterior to structure D. Posterior (dorsal): The back surface of the body or toward the back surface of the body. Relative to another structure, closer to the back surface of the body. For example: structure D is posterior to structure C. Medial: Toward the median plane. Relative to another structure, closer to the median plane. For example: structure E is medial to structure F. Lateral: Away from the median plane. Relative to another structure, farther from the median plane. For example: structure F is lateral to structure E. Proximal: In general, toward the origin or beginning of a structure. Relative to another structure, closer to the origin or beginning of a structure. In the limbs, toward the shoulder or the hip joint. Relative to another structure, closer to the shoulder or the hip joint. For example: structure G is proximal to structure H. (Note that in the limbs, proximal is synonymous with superior.) Distal: In general, away from the origin or beginning of a structure. Relative to another structure, farther from the origin or beginning of a structure. In the limbs, away from the shoulder or the hip joint. Relative to another structure, farther from the shoulder or the hip joint. For example: structure H is distal to structure G. (Note that in the limbs, distal is synonymous with inferior.) Superficial: In general, toward the outer surface of the body or an organ. Relative to another structure, closer to the outer surface of the body or an organ. For example, structure I is superficial to structure J. Deep: In general, away from the outer surface of the body or an organ. Relative to another structure, farther from the outer surface of the body or an organ. For example, structure J is deep to structure I. Combined Directional Terms: Since the body is three-dimensional, it is sometimes necessary to combine directional terms to describe one structure's position relative to another. For example. if structure A is both closer to the head end of the body and closer to the front surface than structure B, then A is anterosuperior to B. Conversely, B is posteroinferior to A. A25lab.terminology.mjg.2009 page 2 of 5

3 ASPECT (VIEW) Lateral Aspect: A structure as it appears when viewed from the "side" or laterally. Medial Aspect: A structure as it appears when viewed from the median plane or medially. Superior Aspect: A structure as it appears when viewed from "above" or superiorly. Inferior Aspect: A structure as it appears when viewed from "below" or inferiorly. Anterior Aspect: A structure as it appears when viewed from the "front" or anteriorly. Posterior Aspect: A structure as it appears when viewed from "behind" or posteriorly. Superficial Aspect: A structure as it appears when viewed from the "outside." Deep Aspect: A structure as it appears when viewed from the "inside." External Aspect: A structure as it appears when viewed from the "outside." Internal Aspect: A structure as it appears when viewed from the "inside." SOMA AND VISCUS Soma (adj. = somatic). The "body wall:" bone, muscle, and skin. Viscus (pl. = viscera; adj. = visceral). The "soft organs" or structures of the body. BODY CAVITIES Cranial Cavity. The space enclosed by the cranium. Major Contents: the brain; its connective tissue coverings, the meninges; and cerebrospinal fluid (CSF). Vertebral Canal. The tubular space enclosed by the vertebrae. Major contents: the spinal cord; its connective tissue coverings, the meninges; the spinal nerves; and cerebrospinal fluid (CSF). Thoracic Cavity. The space enclosed by the thorax. Limited inferiorly by the Diaphragm. Major Contents: heart, great vessels, lungs, trachea, esophagus, thymus Mediastinum. The wall between the lungs. It is actually a space filled with the heart, trachea, esophagus, thymus, blood vessels, nerves, and connective tissues. Abdominal Cavity. The space limited superiorly by the diaphragm and continuous inferiorly with the pelvic cavity. Major Contents: Most of the digestive system (liver, pancreas, stomach, small intestine, most of large intestine), kidneys and upper ureters, adrenal glands, spleen. Pelvic Cavity. The space surrounded by the pelvis (hip bones + sacrum). Superiorly, it is continuous with the abdominal cavity. Inferiorly its floor is the pelvic diaphragm (a sheet of muscles). It is divided into two parts: an upper pelvis major or false pelvis and a lower pelvis minor or true pelvis. Since the abdominal and pelvic cavities are continuous with each other, they are sometimes referred to as the abdominopelvic cavity. A25lab.terminology.mjg.2009 page 3 of 5

4 SOME COMMONLY USED REGIONAL TERMS Head (n. = caput; adj. = capitis). The bones of the skull surrounding the brain form the cranium (adj. = cranial); the rest of the bones form the foundation for the face (adj. = facial). Neck (n. = cervix; adj. = cervical) Thorax (adj. = thoracic). The "rib cage:" ribs + sternum + thoracic vertebrae. Pectoral. The "chest." Abdomen (adj. = abdominal). In anatomy, the abdomen is divided into four more or less equal parts called quadrants by two imaginary lines: a vertical line from the sternum ("breastbone") to the pubic symphysis and a horizontal line through the umbilicus ("navel" or "belly button"). The quadrants are named upper right, upper left, lower right, and lower left. In medicine, the abdomen is divided into nine regions: epigastric, umbilical, hypogastric, right and left hypochondriac, right and left lumbar, right and left iliac. Lumbar. The "small of the back." Pelvis (adj. = pelvic). A "basin," formed by the two hip bones + the sacrum and coccyx. Perineum (adj. = perineal). The diamond-shaped area located between the thighs that contains the external genitals and the openings of the vagina, anus, and urethra. Gluteal (n. = glutes, the buttocks). The "buttock" region. Upper Limb Scapular: The region of the "shoulder blade." Axilla (adj. = axillary): A pyramidal space between the arm and the thorax. The "armpit" is its floor. Deltoid: The "shoulder" region. The area covered by the Deltoid muscle. Brachium (adj. = brachial): The "arm." The part of the upper limb between the shoulder and elbow joints. Antebrachium (adj. = antebrachial): The "forearm." The part of the upper limb between the elbow and the wrist joints. Carpus (adj. = carpal): The "wrist." Manus: The "hand." Digits (adj. = digital): The fingers. Pollex: The "thumb." Lower Limb Thigh (adj. = femoral): The part of the lower limb between the hip and the knee joints. Knee (n. = genu; adj. = genicular) Patellar. Region of the "kneecap." Popliteal. The diamond-shaped area behind the knee. Leg (n. = crus; adj. = crural). The part of the lower limb between the knee and the ankle joints. Tarsal (n. = tarsus). The posterior half of the foot. Pes (adj. = pedal). The "foot." Digits. The toes. Hallux. The big toe." A25lab.terminology.mjg.2009 page 4 of 5

5 MEMBRANES Mucous Membranes or Mucosae (sing. = mucosa). Lining membranes producing a film of mucus that covers their surfaces. Mucus is mostly a mixture of the mucins (proteins) plus water. Examples: nasal mucosa, oral mucosa, stomach mucosa, intestinal mucosa, urethral mucosa, etc. Serous Membranes or Serosae (sing. = serosa). Membranes producing a watery solution. They typically are arranged in two layers: an outer parietal layer and an inner visceral layer separated by a cavity filled with the watery fluid produced by the membranes. Pericardia(sing. = pericardium; adj. pericardial). Serous membranes enveloping the heart: parietal pericardium + visceral pericardium + pericardial cavity filled with serous fluid. Peritoneum(pl. = peritonea; adj. peritoneal). Serous membranes lining the walls of the abdominopelvic cavity and covering the outer surfaces of the soft organs that occupy it: parietal peritoneum + visceral peritoneum + peritoneal cavity filled with serous fluid. Pleurae(sing. = pleura; adj. pleural). Serous membranes that line the thoracic cavity walls and cover the lungs: parietal pleura + visceral pleura + pleural cavity filled with serous fluid. Meninges (sing. = meninx). Connective tissue membranes that line the cranial cavity and envelop the brain. A25lab.terminology.mjg.2009 page 5 of 5