Question

Joints of skull bones are
A. Synarthrosis
B. Amphiarthrosis
C. Hemarthrosis
D. Diarthrosis

Answer 1

Hint: The skeleton of the head is usually called a skull. It is placed and rests on the upper end of the vertebral column. The bony structure of the skull mainly consists of four parts that are named as cranium , facial bones , hyoid bones and last the ear bones.

Complete answer:
The joint of the skull should remain fixed and immovable as skull has to perform following function :- Functions of the Skull:
The most important function of the skull is to protect the brain. This function is mainly carried out by the cranium.
The skull bears jaws which help the animal in cutting and masticating its food.
Ear bones help in amplification of sound.
It protects and supports the special sense organs.
Now let us match this with the given option:
Synarthrosis :- it is non- movable and fixed. This type of joint is found between bones and is connected by fibrous tissue. Suture is a type of joint present in the skull and it is connected by fibrous tissue. Thus this option is correct.
Amphiarthrosis :- this type of joint has some mobility but mobility is limited and is found in two adjacent vertebrae. Thus this option is not correct.
Hemarthrosis :- it is a condition that occurs due to bleeding in the joint cavity. Thus it is not any kind of joint and the option is not correct.
Diarthrosis :- it is a kind of synovial joint. These kinds of joints are freely movable due to the presence of synovial fluid. But the skull needs a fixed joint. Thus, this option is not correct.

Our required answer is a) synarthrosis.

Note: Frontal bone forms anterior part of cranium and forms forehead. Parietal bone forms a greater portion of the sides and roof of the cranial cavity. Temporal bone forms an inferior lateral aspect of cranium and part of the cranial floor. Occipital bone forms the posterior part and most of the base of cranium.