ULTRASOUNDcan confirm the diagnosis though usu-
ally are not necessary unless the doctor suspects a
complete rupture and needs to assess the extent
and location of damage before surgery to repair it.
Most Achilles tendon injuries heal with ice,
rest, and NONSTEROIDAL ANTI-INFLAMMATORY DRUGS
(NSAIDS) to reduce inflammation and pain. The
doctor may choose to cast the lower leg and foot
to immobilize the ankle when the injury is severe.
Surgery is usually necessary to repair significant or
total Achilles tendon rupture. HEALINGis complete
when the person can move the injured foot with
the same ease and range of motion as the unin-
jured foot, which may take six weeks to three
months for repair and six months for rehabilita-
tion, depending on the injury’s severity. Swim-
ming is an excellent activity for rehabilitation, as it
allows full range of motion and use of the Achilles
tendon without impact.
Stretching andWARM-UPbefore athletic activi-
ties, including WALKING FOR FITNESS, are the most
effective methods for reducing the risk of injury to
the Achilles tendon. People who have tight calf
muscles or previous Achilles tendon injury benefit
from regular stretching (once or twice daily)
regardless of athletic activity.
See also ANKLE INJURIES; ATHLETIC INJURIES; BONE
SPUR; SPRAINS AND STRAINS.
achondroplasia A genetic disorder in which the
rate CARTILAGEcells (chondrocytes) convert to BONE
cells is greatly slower than normal, resulting in
skeletal abnormalities such as shortened limbs and
diminished height. Achondroplasia is the most
common cause of SKELETAL DYSPLASIA, commonly
called dwarfism. Though achondroplasia can occur
as an autosomal dominant inherited genetic disor-
der, it more commonly occurs as a spontaneous
MUTATIONof a GENEon CHROMOSOME4 that encodes
fibroblast growth factors, the proteins that regu-
late cartilage cell conversion. Prenatal testing can
identify whether a FETUS has achondroplasia,
though doctors generally offer the test only when
there is reason to suspect the condition could be
present or along with other GENETIC TESTING.
Because infants born with achondroplasia have
distinctive physical features, the disorder is obvi-
ous at birth.
The characteristics of achondroplasia include
- enlarged head and prominent forehead
- short arms and legs
- short hands and short, thick fingers with a dis-
tinct separation between the middle and ring
fingers - abnormalities in the opening at the base of the
BRAIN, the foramen magnum, and in the verte-
brae that compress the SPINAL CORD, affecting
BREATHING - craniofacial anomalies such as narrow nasal
passages, flat NOSE, and short jaw
Evaluation for an infant born with achon-
droplasia typically includes COMPUTED TOMOGRAPHY
(CT) SCAN, ULTRASOUND, or MAGNETIC RESONANCE
IMAGING(MRI) to evaluate the extent of skeletal
anomalies, especially those that may affect the
spinal cord and thus vital functions such as
breathing. Some infants also have or develop
HYDROCEPHALY(fluid accumulation within the cra-
nium), which may require a shunt for draining
the excess fluid. As they grow, children who have
achondroplasia are vulnerable to KYPHOSIS(a hump
in the upper back) and LORDOSIS(curvature of the
lower spine). They are also susceptible to frequent
OTITISmedia (middle EAR INFECTION) because the
shortened facial structures mean the eustachian
tubes, valvelike structures between the middle ear
and the THROAT, are also shorter than normal and
do not function properly.
Though some children may benefit from bone-
lengthening operations, in most situations there
are no treatments to normalize the development of
bone. Bone-lengthening surgery is extensive and
expensive, has significant risk for side effects (such
as infection and permanent damage to the bones),
and is controversial among medical experts. Some
specialists use HUMAN GROWTH HORMONE(HGH) SUP-
PLEMENTearly in the child’s life, though this is also
controversial and does not produce predictable
results. Adults who have achondroplasia generally
reach a maximum height of about four feet.
See also EUSTACHIAN TUBE; GENETIC COUNSELING;
GENETIC DISORDERS; INHERITANCE PATTERN; OPERATION;
SURGERY BENEFIT AND RISK ASSESSMENT.adhesive capsulitis A condition in which the
JOINTcapsule of the shoulder joint fuses (adheres)298 The Musculoskeletal System