Daily Anatomy 1.0 Part 1
The human skeleton comprises 206 bones. They are under the control of hundreds of skeletal muscles, which in turn are controlled by nerve impulses received from the CNS ( Central Nervous System ).
Anatomically, the skeleton is divided into:
- axial skeleton (consisting of 80 bones): bones of the central axis of the body (skull, spine, thoracic cage and hyoid bone); Virtually all bones of the head and trunk are Axial bones.
- appendicular skeleton (consisting of 126 bones): bones of the upper and lower limbs (peripheral bones) and bones allowing them to attach to the body (belts).
Bone Markings ( To be continued in the next post ) :
Bone markings are very important since they allow for identification of bones and bony pieces, enable joints to form, enable bones to slide past each other, enable bones to lock in place, and provide places for muscle and connective tissues to attach and provide structural support. Bone markings also provide stabilization, protection and a pathway to nerves, vessels, and other structures.
The surface features of bones vary considerably, depending on the function and location in the body. There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together (articulus = “joint”). These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape is an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points.
Angle - Sharp bony angulations which may serve as bony or soft tissue attachments.
Example : superior, inferior, and acromial angles of the scapula; superior, inferior, lateral angles of the occipital bone; angle of the mandible
1 - angle of the mandible ; 2 - superior angle of the scapula
Body - Usually refers to the largest most proeminent segment of the bone.
Example : diaphysis or shaft of long bones like the femur and humerus; body of the mandible
Canal - Passageway through a bone.
Example : optic canal