Although the cranium—the largest section of the skull—might
seem like one solid bone, there are actually 22 bones that house the brain.
Twenty-one of those pieces are fused together by sutures, nearly rigid, fibrous
joints found only in the skull. Similar connective fibers are found in teeth
and the spine.
These sutures give the appearance of cracks. These are easiest
to see on the side of the head where the temporal bone meets the parietal bone
and in the back where the occipital bone adjoins the temporal and parietal
bones.
The skull consists of the cranium and the mandible, or jawbone. It is the
semi-circular bone at the bottom of the skull and attached to the cranium at
the jaw. The mandible is responsible for the up and down motion of the jaw.
The mandible also holds the bottom row of teeth; the maxilla
holds the upper row. Mammals, including humans, develop two sets of teeth
during their lives.
The shape and structure of human teeth serve many purposes.
As most humans are omnivores (eat both plants and animals), their teeth must
serve many functions to ensure proper chewing of food. The thin incisors and
pointed canines help rip and tear meat, and the premolars and molars help grind
down substances so they are easy to swallow.
Because teeth play a role in the way your body receives
nutrients, proper tooth care is important. Common tooth ailments include:
- Plaque and
buildup: Accumulation of mouth bacteria that can lead to cavities
- Cavities:
Areas of decay that develop in the teeth
- Gingivitis:
Irritation of the gum line that can result in tooth loss
The skull also provides housing for the eye and optic nerve.
This portion of the skull is called an orbit, but it is more commonly known as
the eye socket. Seven different bones make up the eye socket:
- Frontal bone
- Lacrimal bone
- Ethmoid bone
- Zygomatic bone
- Maxillary bone
- Palatine bone
- Sphenoid bone
The eye is protected from
the hard edges of the bone by fat tissue, which makes movement of the eye
smooth. Nerves, blood vessels, ligaments, and other important tissues occupy
the rest of the orbit.
