Question

Metacarpophalangeal joint allows the movement in two directions, it is an example of which type of joint?
A) Angular ellipsoidal joint
B) Ball and socket joint
C) Gliding joint
D) Pivotal join

Answer 1

Hint: A joint is a place where two bones meet. Due to the presence of a number of joints, the movement of the different body parts and the whole body is possible. All the mentioned above joints belong to the synovial joint or movable joint.

Complete answer:
A metacarpophalangeal joint is placed between the metacarpals and proximal phalanges of the finger. This joint plays an important role in the movement of the hand. Let us explore all the mentioned kinds of joints and then decide which joint fits the metacarpophalangeal joint.
A) Angular ellipsoidal joint- this joint allows the movement of articulating bones around two axes, for example the metacarpophalangeal joint and the carpels. This joint does not move at a $360^\circ$ angle but only shows upward and downward movement.
B) Ball and socket joint – this kind of joint is formed by a ball or knob in a socket, admitting a degree of rotatory movement in every direction, for example the joint between the femur and the pelvis.
C)Gliding joint- this is a kind of synovial joint in which articulation of contiguous bones allows only gliding movements, as in the wrist and the ankle, and between the articulation facets of adjacent vertebrae.
D) Pivotal joint- In this kind of joint one bone rotates around the other, for example, the Atlas of the skull on the axis.

From the above discussion, it becomes quite clear that the metacarpophalangeal joint is an angular ellipsoidal joint. So, option (A) is the correct answer.

Note:
- In synovial joints, a space between the bones is present called the synovial cavity. A slippery fluid fills this space.
- According to the mobility of joints, they are classified as fixed, slightly movable and freely movable.
- The structure of a joint plays a vital role in the mobility of the joint.