Facts on File Encyclopedia of Health and Medicine

posture. A child may need to wear a scoliosis
brace only at night or all the time, depending on
the severity of the scoliosis. Severe scoliosis or sco-
liosis that persists despite treatment may require
surgery, in which the surgeon realigns the verte-
brae, sometimes bracing them with steel or tita-
nium rods to maintain them in proper position.
Most scoliosis, when detected early, responds very
well to treatment and is gone by the time the child
reaches late ADOLESCENCE.

Risk Factors and Preventive Measures

Because doctors do not know what causes most
scoliosis, there are no known risk factors or pre-
ventive measures. Scoliosis often accompanies
other conditions such as CEREBRAL PALSY, MUSCULAR
DYSTROPHY, andSPINA BIFIDA. Health experts urge
women of childbearing age to take folic acid sup-
plements, which can prevent many NEURAL TUBE
DEFECTSsuch as spina bifida. It also tends to run in
families, leading doctors to suspect there are
hereditary factors at play.
See also KYPHOSIS; LORDOSIS; SURGERY BENEFIT AND
RISK ASSESSMENT.

skeletal dysplasia Dysfunctional growth of the
SKELETONsuch that the person is of significantly
short stature. There are numerous forms of skele-
tal dysplasia, commonly and collectively called
dwarfism, most of which are hereditary. Skeletal
dysplasia may also occur as a result of HORMONE
deficiencies during childhood. Each type of skele-
tal dysplasia presents characteristic symptoms. In
general, skeletal dysplasias result in extremely
short stature. The structures of the skeleton are
nearly always disproportionate. Disorders of
growth that are metabolic cause proportionate
smallness. HORMONE THERAPYmay increase skeletal
growth when the cause is endocrine or metabolic.
There are no treatments to alter the skeleton
when the cause of the dysplasia is genetic.
See also ACHONDROPLASIA; GENETIC DISORDERS;
INHERITANCE PATTERN; OSTEOGENESIS IMPERFECTA; RICK-
ETS; SCURVY.

skeleton The organization of the bones in the
body. The skeleton has two primary organizational
divisions: the axial skeleton and the appendicular
skeleton. The axial skeleton consists of the bones

that form the body’s axis or perpendicular line,

which include the head, rib cage, and spine. It

contains 80 bones. The remaining 126 bones—

arms, hands, legs, feet, shoulders, pelvis, hips—

form the appendicular skeleton.

The primary functions of the skeleton are to

give the body structure, support and protect the

body’s internal organs, and enable mobility.

Within certain bones is the BONE MARROW, which

produces the body’s BLOODcells. The skeleton also

serves as the body’s “calcium bank,” storing cal-

cium when levels in the blood circulation are ade-

quate and pulling calcium from the bones when

blood levels of calcium drop too low.

For further discussion of the skeleton within

the context of the structures and functions of the

musculoskeletal system, please see the overview

section “The Musculoskeletal System.”

See also BONE; CALCIUM AND BONE HEALTH; OSTEO-

MALACIA; OSTEOPOROSIS.

sprains and strains Acute, traumatic injury to

muscles, tendons, and ligaments, typically as a

consequence of rapid and unexpected stretching

such as may occur with a stumble, sudden twist-

ing movement, or fall. A sprain is an injury to a

LIGAMENT; ligaments connect bones to each other.

A strain is an injury to a MUSCLEor TENDON; ten-

dons extend from muscles to connect them to

bones. Sprains and strains nearly always occur in

or near joints. A muscle, tendon, or ligament may

rupture (tear completely) under the force of a

sudden stretch. Though immediate treatment—

RICE(rest, ice, compression, elevation)—remains

the same, a rupture may later require surgical

repair.

A severe strain or sprain often is diffi-

cult to distinguish from a FRACTUREand

should be treated as a fracture until

medical assessment determines it is not.

Symptoms and Diagnostic Path

The main symptoms of a sprain or strain are PAIN

and swelling following a sudden movement that

involves a JOINT. Both are often immediate, and it

may be difficult to use the limb. Grade 1 sprains

and strains are painful but minor and do not nec-

essarily require a visit to the doctor. However, it is

sprains and strains 355