Bma Illustrated Medical Dictionary

lower forehead; 2 ethmoidal sinuses be-
tween the eyes; 2 maxillary sinuses in
the cheekbones; and the sphenoidal
sinuses in the skull behind the nose.
Mucus drains from each sinus along a
channel that opens into the nose. Infec-
tion of a sinus causes sinusitis.
sinusitisInflammation of the membrane
lining the facial sinusescaused by infec-
tion, usually spread from the nose. The
maxillary and the ethmoidal sinuses are
most commonly affected.
Sinusitis may cause a feeling of fullness
in the affected area, fever, a stuffy nose,
and loss of the sense of smell. A com-
mon complication is the formation of
pus in the affected sinuses, causing
pain and nasal discharge.
Treatment of sinusitis is is usually
with antibiotics and a decongestant.
Steam inhalationsmay also be helpful. If
sinusitis persists despite treatment,
surgical drainage of the affected sinuses
may be performed.
sinus tachycardiaA fast, but regular,
heart-rate (more than 100 beats per
minute) caused by increased electrical
activity in the sinoatrial node. Such a
heartbeat is normal during sudden
stressful moments or exercise. Persis-
tentsinus tachycardia at rest may be
caused by fever or hyperthyroidism.
situs inversusAn unusual condition in
which the internal organs are situated
in the mirror image of their normal posi-
tions. No treatment is needed provided
all the organs are functioning normally.
Sjögren’s syndromeA condition in
which the eyes and mouth are excessively
dry. The nasal cavity, throat, and vagina
may also be affected. The syndrome
tends to occur with certain autoimmune
disorders, such as rheumatoid arthritis
and systemic lupus erythematosus. Most
sufferers are middle-aged women.
skeletonThe framework of bones that
gives the body shape and provides
attachment points for the muscles and
underlying soft tissues of the body. The
average human adult skeleton has 213
bones (counting each of the 9 fused ver-
tebrae of the sacrum and coccyx as
individual bones) joined with ligaments
and tendonsat points called joints.The
skeleton plays an indispensable role in

movement by providing a strong, stable

but mobile framework on which mus-

cles can act. The skeleton also supports

and protects internal body organs.

skinThe outermost covering of body tis-

sue, which protects internal organs from

the environment. Skin has 2 layers: the

outer epidermis, and the inner dermis.

The outermost epidermis is composed

of dead cells and the protein keratin.As

these dead cells are worn away, they are

replaced by new ones from the inner epi-

dermis.Some epidermal cells produce

the pigment melanin, which protects the

body from ultraviolet lightin sunlight.

The dermis is composed of connective

tissueinterspersed with hairfollicles,

SINUSITIS SKIN

SKELETON

Frontal bone

Mandible

Parietal bone

Temporal bone

Occipital bone

Zygomatic arch

Scapula Clavicle

Sternum

Rib

Vertebral

column

Ilium

Pubis

Ischium

Phalanges

Calcaneus

Carpals

Humerus

Ulna

Radius

Femur

Patella

Tibia

Fibula

Tarsals

Metatarsals

Phalanges

Metacarpals

S