Janet Fogel, age 14, of Vancouver, Wash., for her question:

WHAT DOES THE CLAVICLE DO?

Clavicle is the technical name for the long, slender, curved bone that connects the breastbone with a hooklike projection on the shoulder blade. It is more commonly called the collarbone.

The collarbone forms an important part of the shoulder.

Humans have two collarbones, one directly in front of each shoulder. The bones are shaped somewhat like the italic latter "F." They hold the arms in proper position at the sides of the body.

When a person breaks a collarbone, his shoulder drops downward and forward toward the chest. Most broken collarbones are caused by falling on outstretched arms. A hard blow on the shoulder may dislocate the outer end of a collarbone.

Just as the collarbone is technically called the clavicle, the breastbone is properly called the sternum. Also, the hookiike projection is called the acromion and the shoulder blade is called the scapula.

Animals that walk on four legs, such as dogs, have no collarbones. Those that hang from trees, such as monkey, have large collarbones.