Chapter 9: Articulations
• The body is adapted to movement, which occurs only at joints where 2 bones
connect (articulations). Joints have different structures that determine the
direction and distance they can move. Joints always compromise strength to
increase mobility.
I. The Classification of Joints, p. 259
Objectives
1. The major categories of joints, and the structure and function of each category.
2. The basic structure of a synovial joint, the common accessory structures and their
functions.
♣ The distance and direction a joint can move is called range of motion. Joints can
move a little (amphiarthrosis), a lot (diarthrosis) or not at all (synarthrosis).
Table 9-1
Functional classification
♣ Joints can be divided into functional groups:
- Synarthroses, or immovable joints, are bound together by fibrous or
cartilaginous connections, which may fuse over time.
- Amphiarthroses, or slightly moveable joints, may have fibrous or cartilaginous
connections.
- Diarthroses, or synovial joints, are freely moveable, and are subdivided by type
of motion.
Table 9-2
Structural Classification
♣ Joints can also be classified by structure:
- bony
- fibrous
- cartilaginous
- synovial
Synarthroses (Immovable Joints), p. 260
♣ Synarthroses are very strong. At a synarthrosis, the edges of the bones may touch
or interlock. The 4 types of synarthrotic joints are:
1. suture:
- bones are interlocked and bound by dense fibrous connective tissue
- found only in the skull
2. gomphosis:
- a fibrous connection (periodontal ligament)
