51. Body, Human

See also 14. ANATOMY ; 50. BODILY FUNCTIONS .

acrocephaly

Medicine. having a high, pointed skull. Also called oxycephaly. —acrocephalic, acrocephalous, adj.

acromegaly

Medicine. a disease resulting from abnormal activity of the pituitary gland in which bones of the extremities are enlarged. —acromegalic, adj., n.

adiposity

the state of being obese. —adipose, adj.

anatomy

the study of the body and its parts. —anatomist, n. —anatomical, adj.

androgynism, androgyny

the possession of the characteristics of both sexes; hermaphroditism. Also androgyneity. —androgynous. adj.

ankylophobia

a dread of stiff or immobile joints.

atonicity, atony

lack of tone or tonus in the body; poor muscular condition. Cf. tonicity. —atonic, adj.

bioastronautics

the science that studies the effects of space travel on life, especially human life and the human body.

bionics

1. the science or study of how man and animals perform tasks and solve certain types of problems involving use of the body.

2. the application of this study to the design of computer-driven and other automated equipment.

3. the application of this study to the design of artificial limbs, organs, and other prosthetic devices. —bionic, adj.

biophysiology

the branch of biology that studies the growth, morphology, and physiology of organs. —biophysiologist, n.

biopsy

the removal of a fragment of living tissue from the body for medical study. —bioptic, adj.

bisexualism, bisexuality

the condition of combining male and female sexual characteristics in one body. See also 364. SEX . —bisexual, adj.

callipygia, callipygy

the state of having well-shaped buttocks. Cf. steatopygia. —callipygian, callipygous. adj.

carnosity

Obsolete, fleshiness; obesity.

caseation

the change in consistency of tissue to a soft, cheeselike form, as in tuberculosis.

claudication

a limp or limping movement.

clonism

a state or condition in which the muscles undergo clonus, or rapid flexion and extension. —clonic, adj.

coenesthesia, coenesthesis, cenesthesia, cenesthesis

the combination of organic sensations that comprise an individual’s awareness of bodily existence. —coenesthetic, cenesthetic, adj.

deuteropathy

an affection of the body that is secondary to and resulting from another affection.

diarthrosis

a joint or articulation, as that at the knee, which allows maximum movement.

ectomorphy

the condition or state of being an ectomorph, i.e., having a light, slender body structure. —ectomorphic , adj.

emaceration

Obsolete, the act of making or becoming lean; emaciation.

endomorphy

the condition or state of being an endomorph, i.e., having a rounded, stocky body structure with a tendency to obesity. Also called pyknic. —endomorphic , adj.

epicenism

the state or quality of combining characteristics of both sexes. —epicenity , n. —epicene , adj.

excrescence

1. a normal outgrowth of the body, as hair, fingernails.

2. an abnormal outgrowth, as a corn, wart, etc. —excrescent , adj.

formication

a body sensation that feels as if ants are crawling over the skin.

gynandrism, gynandry

hermaphroditism. Also gynandry . —gynandroid , n., adj.

gynecomastism

an excessive development of mammary glands in males. Also gynecomastia, gynecomasty .

hermaphroditism

the presence on an individual body of both male and female sex organs. Also called androgynism, gynandrism, gynandry. —hermaphrodite, n. —hermaphroditic, adj.

hyperkinesia, hyperkinesis

a condition of the body in which muscular movement is abnormally agitated. —hyperkinetic, adj.

hypertrophy

excessive growth of tissue or of an organ, independent of and out of proportion to the rest of the body. Cf. hypoplasia. —hypertrophic , hypertrophical, hypertrophous , adj.

hypoplasia

a condition in which tissue or an organ of the body fails to grow to normal size. Cf. hypertrophy . —hypoplastic , adj.

hypothermia

a condition in which the body temperature is abnormally low. —hypothermal, adj.

ichor

a thin watery substance discharged from wounds or ulcers. See also 183. GOD and GODS . —ichorous , adj.

ictus

Medicine. 1. a stroke or beat, as the beat of the pulse. See also 409. VERSE .

2. a paralytic stroke.

jactitation

Medicine. twitching of the muscles or of other parts of the body. Also called jactation.

kinesiology

Medicine. the study of the motions of the human body, especially as they apply to therapy through corrective exercise. Also called kinestherapy . —kinesiologic, kinesiological, adj.

kyphosis

an abnormal condition of the spine in which it has a hump, kyphos, or curvature. —kyphotic , adj.

leptosomy

ectomorphy. —leptosome , n. —leptosomic, leptosomatic, adj.

lordosis

any abnormal curvature of the bones, especially forward curvature of the spine, resulting in a hollow in the back. —lordotic, adj.

macrosomatia

the condition of having an abnormally large body. —macrosomatous, adj.

marasmus

1. a wasting away or atrophying of the body in the absence of disease.

2. the progressive emaciation that results from malnutrition. —marasmic , adj.

mesomorphy

the condition or state of being a mesomorph, i.e., having an athletic body structure. —mesomorphic , adj.

microcephalism

the condition of having an abnormally small head. Also microcephaly. —microcephalous , microcephalic , adj.

myoatrophy

atrophy or wasting away of the muscles.

myotonia

a condition of tonic muscle spasm or rigidity of the muscles. —myotonic, adj.

necrosis

the death or decay of body tissue, the result of loss of blood supply or trauma. —necrotic, adj.

neoplasia

the growth or formation of aneoplasm. —neoplastic, adj.

neoplasm

any abnormal formation or growth of tissue, as a tumor. —neoplastic, adj.

orthopraxy, orthopraxis

the use of mechanical apparatus or devices to correct bodily deformities.

orthosis

the process of correcting bodily or mental distortion. —orthotic, adj.

osmidrosis

an abnormal condition in which the sweat has a very strong odor.

osteoporosis

the rarefaction of bone, resulting in abnormally porous and weak bony tissue.

oxycephaly

acrocephaly. —oxycephalic, oxycephalous, adj.

oxygeusia

extreme acuteness or sensitivity of the sense of taste.

paralysis

abnormal loss of muscle function or of sensation. —paralytic, n., adj.

paresis

a state or process of partial paralysis. —paretic, adj.

paresthesia, paraesthesia

any abnormal physical sensation, as itching, a tickling feeling, etc. —paresthetic, paraesthetic, adj.

pectoriloquism, pectoriloquy

the transmission of the voice through the chest wall, so that it can be picked up by direct listening against the chest or with a stethoscope. It frequently indicates an abnormality in the lungs. —pectoriloquial, pectoriloquous, adj.

phocomelia, phocomely

a deformity, usually congenital, in which the extremities of the limbs are abnormally short.

pinguidity

the state or quality of being fat or unctuous. —pinguid, adj.

pneumology

the scientific study of the human respiratory system. —pneumological, adj.

polymastism

the condition of having more than two breasts. Also polymastia. —polymastic, adj.

psychroesthesia

an abnormal condition in which part of the body, though actually warm, is felt as cold.

pulsimeter, pulsometer

an instrument for measuring the rate of the pulse.

radiosensibility

sensitivity to the effects of radiation, as of parts of the body. Also radiosensitivity . —radiosensible, adj.

rhigosis

the feeling or sensation of coldness.

rictus

the opening of the mouth, especially in a grimace or expression of pain.

rotundity

the state or quality of being roundor plump. —rotund, adj.

schematomancy

divination of a person’s future from observation of physical appearance.

sclerosis

a hardening of body tissues or other parts, as by an excessive growth of fibrous connective tissue. See also 319. PLANTS . —sclerotic, adj.

scoliosis

lateral curvature of the spine. —scoliotic, adj.

somatology

the branch of anthropology that studies man’s physical characteristics. Also physical anthropology, somatics. —somatologie, somatological, adj.

somatotype

a particular type of human physique. Cf. ectomorphy, endomorphy, mesomorphy.

steatopygia, steatopygy

excessive fatness of the hips and buttocks. Cf. callipygia. —steatopygic , adj.

syntexis

the wasting of the body, as in consumption. —syntectic, syntectical , adj.

tabes

any disease that wastes the body; atrophy. —tabetic , n., adj.

tabescence

1. the process of emaciation or wasting of the body.

2. the condition of being wasted or in decay, especially as a gradual process. —tabescent , adj.

tabitude

the state of being affected by tabes or by gradual wasting or decay.

tonicity

the state or quality of muscular tone or tension. —tonic, adj.

torticollis

a condition characterized by involuntary contraction of the cervical muscles, causing a twisting of the neck; wryneck.

tricrotism

the condition of having three arterial beats for every one heart-beat, as in certain pulses. —tricrotic , adj.

turgescence, turgescency

1. the process of swelling.

2. the state of being swollen. —turgescent , adj.

valgus

1. an abnormally turned condition of a bone in part of the human body, especially the leg.

2. the condition of being bow-legged.

vellication

a twitching, as of a part of the body; convulsive movement of a muscle.

ventripotence

obesity, particularly in the region of the stomach. —ventripotent, adj.

ventrosity

Rare. largeness of the belly; corpulence, especially in the abdominal region.

xeransis

a dried or desiccated condition of the body. Also xerosis. —xerantic , adj.

xerotes

a dry condition or tendency to dryness of the body. —xerotic , adj.

zonesthesia

a feeling or sensation of constriction in the body, as from wearing a tight belt.

zooplasty

the process of surgically grafting tissue from a lower animal onto the human body. —zooplastic , adj.

Human Body

Humans come in different shapes and sizes. There is no shape or size that is considered "right." Medical professionals have created healthy guidelines for people. When a baby is born, doctors track many variables to make sure it is developing correctly. These charts and guidelines are not perfect, but they form a framework from which to assess a person's health.

Tracking Growth

Over the years, physicians have developed various methods for tracking growth. Keeping a record of a child's growth patterns helps doctors determine if the child is developing properly. As a person ages, doctors continue to monitor growth, helping patients maintain a healthy weight. Physicians also review height to check for problems of the spine, bone, and other medical conditions.

Growth Charts. Pediatric growth charts have been used by medical professionals since 1977. The charts are used for many measurements of growth in a child. For example, when a child's height is measured, she is then placed into a percentile. If a child is in the seventy-fifth percentile in height, it means that she would be taller than 75 percent of all other children in her age group.

Originally, the sampling for growth charts was taken from a small portion of the population. These children were primarily Caucasian, formula-fed, and middle-class. This sample was problematic because it did not reflect the diversity of the United States. To help make charts that were representative of the whole, and in turn were more accurate, samples were taken from a much larger portion of the population and from people with varying backgrounds.

There are various mathematical concepts behind growth charts. Scaling is one important factor in charting growth in an infant. Though often associated with architecture, humans also undergo scaling. While an infant is much smaller than an adult, the support material remains the same: bone. Bone is a type of tissue that can only support a limited degree of force due to strain. This is evident in the number of broken bones humans can experience when faced with too much strain—for instance, as a result of activities such as sports. As humans grow, their bones also grow but only with a narrow tolerance for strain.

"Average" Height. The determination of "average" human dimensions is based on statistics and illustrates the statistical concepts of sampling , central tendency, and outliers . For example, rare genetic or medical conditions can cause a small percentage of the human population to be very tall or very short. Persons diagnosed with gigantism* may reach adult heights of more than 8 feet, whereas persons with dwarfism are commonly less than 4 feet, 10 inches tall.

*The tallest man in documented medical history was Robert Wadlow, who at 22 years old stood 8 feet, 11.1 inches tall, weighed 440 pounds, and wore a size 37AA shoe.

Because the heights of "average" people are statistically determined by excluding individuals with these rare conditions, the physical dimensions of tall or short people are therefore deemed "disproportionate" or "outside the average." Yet if the sampling set included only individuals with these special conditions, and excluded everyone else, then their statures would be considered well within average. Hence, what is considered average depends on the sampling and calculation methods by which it is derived.

Many consumer products are built for "average" people—they are constructed for persons within an average height and weight range and who are not physically challenged. Such construction can cause difficulties for those who are not "average." As a result, some manufacturers offer products to help people make the necessary adjustments. For example, some people could not drive automobiles comfortably without enhancements like adjustable foot pedals, which bring the brake and accelerator pedals closer or farther away from drivers. This allows shorter and taller people to drive more easily, keeping a safe distance from the car's steering wheel airbag. Gadgets also exist to help disabled drivers, including hand controls that can be used to brake or accelerate.

Allometry. Another mathematical principle known as allometry (from the Greek word alloios, which means different) is especially important in the study of how humans grow. Biological allometry and human anatomy are concerned with the different growth rates that an organism experiences throughout its lifetime. A human infant does not have the same proportions of limb-to-head-to-body ratios as a human adult. The head of an infant compared to its body size is much different from an adult's. As a human grows, limbs and body size increase considerably while the head does not. This change in ratio occurs in all kinds of animals. A baby horse is born with extraordinarily long legs compared to its body. As it grows, the body catches up with the legs.

An entire branch of science deals with the allometric changes of organisms. One of the modern methods of observing allometric change is to place imaginary points on the organism, in this case, a human infant's head. A computer scans for the imaginary points and constructs a grid system. As the infant grows, these points are continually tracked, and the points shift in position relative to one another. When the infant reaches adulthood, it is possible to see how the skull grew, where it grew the fastest and the slowest, and how the proportions have changed. The initial square grid looks wavy and distorted. Changes in body shape and physiology, such as in bone structure, breathing rate, and muscle strength can be expressed as variables and tracked. The basic allometric equations used to monitor these changes are as follows:

y = a × x ^b and logy = loga + b logx.

This equation is used by biologists to plot two variables on logarithmic coordinates (using logarithmic scales on the x and y axes of a Cartesian coordinate system). The result is a straight line. Many biological measurements that relate to change in body size use this general equation. The exponent b represents the slope of the line. This equation can help biologists track the changes in variables (the arbitrary points used to make an initial grid). Computers can track the three-dimensional (3-D) changes that occur with growth and produce allometric 3-D scaling grids.

How Much Should a Person Weigh?

The new indicator used for weight measurements is the Body Mass Index (BMI). Formerly, weight-for-stature charts had been used when assessing weight. With this type of chart, a person's weight was evaluated only in relation to one variable, his or her height. When looking at a person's BMI, other factors, such as age, are considered.

A BMI is the fraction of a person's weight divided by his height squared. If a person is between the range of 20–25, then he is said to fall within a healthy weight range. Once a person goes above a BMI of 25, he may suffer from weight-related health problems. Additionally, people with a BMI of less than 20 may also suffer health problems from being underweight. The BMI is the preferred way to chart weight because it looks at more variables than how much a person weighs and what his height is. The body mass index can also help doctors be aware of people who may be more predisposed to being either overweight or underweight.

While all growth charts are helpful in determining development, they really serve only as guidelines. There is no one correct height or weight for a person, only a range of what is healthy. Growth charts do not serve the purpose of locating an "ideal." Instead, they help to indicate whether someone is healthy.

see also DÜrer, Albrecht; Leonardo da Vinci; Logarithms; Ratio, Rate, and Proportion; Scale Drawings and Models.

Brook E. Hall

Bibliography

Hildebrand, Milton. Analysis of Vertebrate Structure, 3rd ed. New York: John Wiley & Sons, 1988.

Kardong, Kenneth. Vertebrates: Comparative Anatomy, Function, and Evolution. Dubuque, IA: William C. Brown Publishers, 1995.

Schmidt-Nielsen, Knut. Scaling: Why Is Animal Size So Important? New York: Cambridge University Press, 1984.

Serway, Raymond, and Jerry Faughn. College Physics. Philadelphia: Saunders College Publishing, 1985.

Internet Resources

CDC Growth Charts: United States. Texas Medical Association. <http://www.texmed.org/has/prs/cdcbackground.asp>.

human body Physical structure of a human. It consists of water, protein and other organic compounds, and some minerals. The skeleton consists of more than 200 bones, sheathed in voluntary muscle to enable movement. A skull surrounds the large brain. The body is fuelled by nutrients absorbed from the digestive system and oxygen from the lungs, which the circulatory system pumps around the body by Metabolic wastes are eliminated mainly by excretion. Sexual reproduction enables continuation of the species. The nervous system, working closely with the endocrine system, exerts overall control. A protective layer of skin covers the body's surface.