Christine Obermann, age 7, of St. Francis, Wis., for her question:

WHAT ARE SINUSES?

A sinus is a cavity in the front of the skull. Every human has four groups and they are all connected to the nasal cavity. Each set takes its name from the bones of the skull in which it is found.

If the front of the skull were solid bone, it is very possible that the face would be so very heavy that it would tend to rest on the chest. The sinuses lighten the skull and make it easier to hold up the head and to balance it on the neck.

Each sinus is lined with the same membranes as those that line the nose. It is possible for infections of the nose to spread to the sinuses. Painful pressure can build up in the sinuses. Pain relieving drugs, a liquid diet and lots of rest help often to solve sinus problems.