The classification of joints having no separation or articular cavity is:
A Diarthosis
B Carrtilaginous
C Ligamentous
D Synarthosis
The correct answer and explanation is:
Correct Answer: D. Synarthrosis
A synarthrosis is a type of joint that allows no movement between the articulating bones. These joints have no separation or articular cavity, meaning the bones are directly connected either by fibrous tissue or cartilage and are tightly joined.
Synarthroses are typically found in areas where stability is more important than mobility. A good example is the sutures in the skull. These sutures hold the bones of the skull tightly together, protecting the brain and maintaining the shape of the head. The edges of the bones interlock and are bound together by fibrous tissue, which restricts any form of movement.
There are different types of synarthroses, depending on the tissue connecting the bones. The most common form is fibrous joints, such as the skull sutures. Another type includes cartilaginous joints that permit very little to no movement, like the joint between the first rib and the sternum. However, when classifying joints strictly based on movement and the absence of an articular cavity, synarthrosis is the most accurate term for immovable joints.
Now, looking at the other options:
- A. Diarthrosis refers to freely movable joints such as the shoulder or knee. These joints have a joint cavity filled with synovial fluid, allowing a wide range of motion. This is the complete opposite of a synarthrosis.
- B. Cartilaginous joints allow limited movement. They are connected by cartilage and are not completely immovable. Examples include intervertebral discs.
- C. Ligamentous is not a standard category for joint classification. Ligaments are connective tissues that support joints, but the term “ligamentous” does not classify joints based on their mobility or cavity structure.
In conclusion, synarthrosis is the correct classification for joints that have no separation and allow no movement, making option D the right answer.