HEAD AND NECK ANATOMY
Basic knowledge of the skull, facial bones, jaws,
and muscles of the head and neck region are
fundamental for a Dental Technician. It is important to
understand the relationship of the bones and muscles
as they work together to provide support for the
dentition (teeth) and movement for mastication
STRUCTURE OF BONE
The bones of the human skeleton provide rigid
support for muscles and skin, and serve to protect the
easily injured organ systems of the body. Bone itself is
a living, highly vascular tissue, which is made up of
both inorganic (minerals) and organic (cells &
connective tissue fiber) elements. The inorganic
component of bone serves as a warehouse for calcium
and phosphorous, two essential minerals for the body.
Bone consists of a hard outer shell called cortical or
compact bone and an inner spongy, porous portion
referred to as cancellous bone (fig. 3-1). Within this
cancellous area are the bone marrow spaces responsible
for manufacturing blood cells. The majority of blood
cells are made by the bone marrow found in the long
bones, such as the femur or thigh bone.
A thin layer of connective tissue, called
periosteum, surrounds each bone and provides
nourishment through many vascular vessels. The
periosteum also contains many nerve endings that
respond to trauma with the sensation of pain. When a
bone breaks, it is the periosteum that hurts, not the
bone itself. When new bone is required, such as when a
break occurs, it is the periosteum which provides the
cells that make the new bone.
Bone can be classified as to how it develops, its
location, and its shape.
Membraneous bone forms
from the periosteum in successive layers and is usually
flat such as those of the skull. The long bones of the
arms and legs are cartilaginous bones, which develop
BONES OF THE SKULL
The skull consists of 28 bones that form the
framework of the head and provide protection for the
Figure 3-1.Structure of a typical flat bone.
brain, eyes, and ears. It can be divided into two parts:
the cranium and the bones of the face. The cranium is
primarily involved in housing and protecting the brain.
The bones of the face are a complex framework that
helps to form facial features, the upper jaw (maxilla)
and lower jaw (mandible). With the exception of the
mandible and the bones of the inner ear, all skull bones
are joined together firmly along seams called sutures.
An example of sutures is shown in figure 3-2. Sutures
are sometimes considered immovable; however, they
do permit a small amount of movement and provide
mechanical protection for the brain by absorbing much
of the force if a blow to the head occurs.
The cranium is formed by eight cranial bones,
which form the foundation for attachment of many of
the muscles necessary for head movements and
chewing. Figure 3-3 show the cranial bones, and Table
3-1 lists them as either single or paired bones.
The frontal bone forms the front part of the skull
above the eyes, which includes the forehead and part of