Section VI. SESAMOID BONES
4-13. GENERAL
The sesamoid bones are another kind of bone. Sesamoid bones develop in
place within tendons of skeletal muscles where the tendons sustain excessive
pressures. Since the sesamoid bone absorbs these pressures, it protects the tendon
from wear and tear.
4-14. EXAMPLE-PATELLA
The primary example of sesamoid bones is the patella (kneecap). In the form of
a simple pulley mechanism, the tendon of the quadriceps femoris muscle passes over
the distal end of the femur. Located at this point within the tendon is the patella.
Section VII. DEFINITION AND TYPES OF JOINTS
4-15. INTRODUCTION
a. Where two bones meet each other, this junction is referred to as a joint or
articulation.
b. The joints of the human skeleton may be characterized, in general, in three
different ways.
4-16. MATERIAL HOLDING JOINT TOGETHER
First, they are characterized by the type of material that holds the bones together
at the joint.
a. If the bones are fused together with bony tissue, the articulation is called a
synosteosis.
b. Thus, in a synchondrosis, the bones are held together by cartilage tissue.
c. In a syndesmosis, the bones are held together by FCT.
NOTE:
A synovial articulation is somewhat different and will be described in detail in
the next section.
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