Bones Of The Human Skull

Naming, location and description of the bones that create the human skull.

The entire framework of the human body is known as the skeleton. It is made up of two primary groups of bones;

1. Axial skeleton - This group of bones are the ones that make up the head and actual trunk of the body.

2. Appendicular skeleton - This is the group of bones that make up the body's extremities (arms and legs).

The entire group of bones that make up the head is called the skull and it too can be divided into two primary groups:

1. Cranium- This is the rounded area that houses and protects the brain. It is comprised of eight distinct bones that are fused together in an adult.

2. Facial area - The facial area is made up of fourteen separate bones, which include those that make up the jaws, cheeks and nasal area.

The eight bones that make up the cranium are:

1. Frontal bone-The frontal bone is the one that comprises the forehead, the upper orbit of the eye and the forward parts of the cranium. The frontal bone also contains two air spaces that are called sinuses. The frontal bone is fused with the parietal bones at the top, the sphenoid bones, maxilla and nasal bones.

2. Parietal bones- There are two parietal bones which form the largest portion of the top and sides of the cranium. They are fused down the middle at the top of the skull. In addition to the frontal bones, the parietal bones are also fused to the sphenoid, temporal and occipital bones.

3. Temporal bones-Like the parietal bones, there are two distinct temporal bones. These bones are what form the lower, central sides of the skull. The temporal bones also hold the mastoid sinuses as well as parts of the ears.

4. Ethmoid bone- There is only one ethmoid bone and it has a different consistency that the other bones in the head. Where they are hard and dense, the ethmoid bone is a delicate, spongy bone that is located between the eyes. It also forms a part of the frontal floor area of the cranium.

5. Sphenoid bone-There are two sphenoid bones and they sit behind the eyes and run back towards the temporal bones.

6. Occipital bone-There is only one occipital bone. It forms the back base of the skull.

The facial bones include:

1. Mandible- The mandible (lower jaw) is the only moveable bone in the skull.

2. Maxillae - There are two maxillae bones. They are what comprise the upper jaw and each one of them contains a large "maxillary" sinus.

3. Zygomatic-There are two zygomatic bones and they sit on either side of the skull and comprise the higher area of the cheek.

4. Lacrimal bones- There are two small lacrimal bones that sit at the inside corner of each eye.

5. Vomer-There is only one vomer bone and it is what forms the lower portion of the nasal septum.

6. Nasal bones- The nasal bones are a pair of small, slender bones that support the actual bridge of the nose. They are fused at the top to the frontal bone and to the maxillae at the area that completes the inside orbit of the eye.

In addition to the previous bones, there are six tiny bones (three pairs) called ossicles that are located in the ears. These are joined in such a way as to amplify the sound waves received by the eardrum (tympanic membrane).

1. Malleus- Often called the hammer are the two malleus bones (one in each ear).They are the first bones in the inner ear and appear similar in shape to a hammer. The "handle" part attaches to the tympanic membrane and the "head" portion attaches to the incus.

2. Incus-The incus is also called the anvil and it is the middle of the three bones.

3. Stapes- The stapes is the innermost bone and it appears very similar to a tiny stirrup. In fact, the stapes is often called the stirrup.

There is one final bone of the human skull. It is a single U-shaped bone to which the tongue attaches to and it is called the hyoid bone. The hyoid is located underneath the skull and forms the boundary between the head and neck.

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