Question

Which of the following is called true joints?
A. Synovial joints
B. Synchondrosis
C. Syndesmosis
D. Symphysis

Answer 1

Hint: True joints are also known as the diarthrodial joint that is a freely moving joint characterized based on the mobility and the joint cavity within a synovial membrane that is kept inside the joint capsule. A layer of fibrocartilage or hyaline cartilage that lines the opposing bone surface, as well as lubricating synovial fluid, is seen in the synovial cavity of the true joints.

Complete answer:
Synovial joints are also known as diarthrosis, the characteristics of synovial joints include the ends of the bones are covered with the cartilage, space between two bones is known as the synovial cavity that contains the synovial fluid inside the synovial membrane, hence the option A is the correct answer.

Additional Information:
Synchondrosis is a cartilaginous joint where the hyaline cartilage completely joins the bones together and forms immovable joints, example includes the joint in between the diaphysis and epiphysis in long growing bone. As the joint is immovable it is not a true joint.
hence option B is incorrect.

A syndesmosis is a slightly movable joint obtained by linking two adjacent bones using ligaments, the joint is also known as a fibrous joint and is seen in the sutures or joints of the flat skull bones. As the joint is not freely movable and does not possess other characters of the true joint,
option C is incorrect.

Symphysis joint is also a form of cartilaginous joint, example includes pubic symphysis, hence option D is incorrect.

Note:
Synovial joints are of six different types – a. Ball and socket joint(shoulder joint),
b. Hinge joint (knee joint, elbow joint),
c. Pivot joint (ring-like atlas rotates around the peg-shaped process of axis or the second vertebra),
d. Gliding joint(joint between the carpal bones),
e. ellipsoid joint(joint between metacarpal and phalanges),
f. saddle joint( joint between the trapezium and the first metacarpal bone of thumb).