Question

In human beings, the second cervical vertebra helps in rotatory movements of the head through a knob-like process called
A.Prezygapophysis
B.Olecranon process
C.Odontoid process
D.Metaphysis

Answer 1

Hint:
The second cervical vertebra is the axis. It has a big bony projection that highlights its vertebral body and is placed into an atlas above it. The atlas is ring-shaped in shape.

Complete answer:
The cervical spine is made up of two anatomically and functionally different segments. To create rotation, flexion, lateral flexion, and extension of the neck and head these two segments work together.
It is made up of 7 vertebrae. C1 and C2, the first two vertebrae are highly exclusive and known as the atlas and axis respectively. C3-C7 have a body, pedicles, laminae, spinous processes, and facet joints.
The great degree of mobility for the skull is provided by a set of unique articulation forms by C1 and C2. The skull is placed on C1 which performs as a ring or washer. Almost half flexion-extension of the neck happens between the occiput and C1; 50% of the rotation of the neck happens between C1 and C2.
Hence the correct answer is Odontoid process.

Option ‘C’ is correct

Note:
The cervical spine functions to provide mobility and stability to the head while connecting it to the relatively immobile thoracic spine. The movement rotating the head left and right happens almost entirely at the joint between the atlas and the axis, the atlantoaxial joint.