Biomedical Engineering Reference
In-Depth Information
A.2 Bone Types Based on Region
Based on the region where bones locate, we have two bone types. The human
skeleton can be divided into two main parts; the first part is the axial skeleton
and second is the appendicular skeleton.
The axial skeleton consists of the bones in the head and trunk of the human
body. This area can be further divided into four main parts: the skull, the
hyoid bone of the throat, the chest, and the vertebral column. The appen-
dicular skeleton consists of 126 bones in the human body that make motion
possible and protect the organs of digestion, excretion, and reproduction.
The word “appendicular” refers to an appendage or anything attached to a
major part of the body, such as the upper and lower extremities. The axial
skeleton and the appendicular skeleton together form the complete skeleton.
A.2.1 Bones of the Axial Skeleton
The axial skeleton forms the central axis of the body. It consists of the
80 bones along the central axis of the human body. It is composed of four
parts: the human skull, the hyoid bone of the throat, the vertebral column,
and the thoracic cage
A.2.1.1 Skull
The skull consists of 28 different bones (including the ossicles of the ear).
The bones of the skull can be divided into three main groups: the cranium,
the facial bones, and the middle ear.
• Cranium (8)
• Frontal bone (1) forms the forehead and the superior surface of
the orbits.
• Parietal bones (2) are found on both sides of the skull, posterior
to the frontal bone. They are bones in the human skull that, when
joined together, form the sides and roof of the cranium. Each
bone is roughly quadrilateral in form and has two surfaces, four
borders, and four angles.
• Occipital bone (1) forms the posterior and inferior portions of the
cranium.
• Temporal bones (2) are found below the parietal bones, contrib-
uting to the sides and base of the cranium.
• The sphenoid bone (1) forms part of the floor of the cranium.
The sphenoid bone is an unpaired bone situated at the base
of the skull in front of the temporal bone and basilar part of the
occipital bone. It is one of the seven bones that articulate to form
