often called Sinuses
Place ref this link to sinus(es)sinus-anatomy
The diaphragm is a thick muscle separating the thoracic and abdominopelvic cavities.
All bones of a newborn start as cartilage therefore has no cavities. As the baby grows up, they turn into bones through ossification.
marrow
The maxilla is the keystone of the face and all other facial bones articulate with them. They form part of the lateral walls and most of the floor of the nasal cavity, part of the floor of the orbital cavities and three fourths of the roof of the mouth, or hard palate. If you break these, your face will collapse.
sinuses.
The face consists of 14 individual bones, which fuse to house the orbits of the eyes, nasal and oral cavities, as well as the sinuses. The frontal bone, typically a bone of the calvaria, is sometimes included as part of the facial skeleton.
Thick and strong bones are not very heavy primarily due to their unique structural composition. Bones are made of a combination of mineralized tissue and a lightweight collagen matrix, which provides strength without excessive weight. Additionally, the internal structure of bones includes a network of hollows and cavities, like the trabecular (spongy) bone, which reduces overall mass while maintaining structural integrity. This design allows bones to support the body's weight effectively without being overly heavy.
The mucous membrane-lined cavities found in several bones surrounding the nasal cavities are called paranasal sinuses. These sinuses include the frontal, maxillary, ethmoid, and sphenoid sinuses. They help to lighten the skull, produce mucus, and regulate the resonance of the voice.
How many bones are in the face
only in the spinal cavity all of the others the bones are the borders of the cavities.
The teeth. Maybe the bones too? But generally when people say cavities without a qualifier, they mean in their teeth.