The joint between atlas and axis is-

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2022

Explanation

The joint between the first (atlas) and second (axis) cervical vertebrae is called the atlantoaxial joint.
It is structurally classified as a pivot (or trochoid) joint, which is a type of synovial joint.
In this joint, the dens (odontoid process) of the axis acts as a pivot that rotates within a ring formed by the atlas and the transverse ligament.
This specific articulation allows for rotation of the head, as in the motion of shaking one's head 'no'.

Option A: A ball and socket joint is multiaxial, allowing a wide range of motion including flexion, extension, abduction, adduction, and rotation. The atlantoaxial joint only permits rotation.
Option B: A saddle joint has reciprocally concavo-convex articular surfaces, allowing biaxial movement. The atlantoaxial joint does not have this shape.
Option D: Angular is a term used to describe a type of movement (like flexion or extension), not a structural classification of a joint. The question asks to identify the joint type.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of synovial joints as background academic context rather than a clinical decision trigger.
Understanding the atlantoaxial joint is crucial for nurses when assessing neck range of motion and caring for patients with cervical spine injuries.
Fractures of the dens (odontoid process) are a common and serious injury that can lead to instability of this joint, potentially causing spinal cord damage.
Nurses must use extreme caution and proper technique (e.g., log-rolling) when moving patients with suspected or confirmed cervical spine injuries to prevent catastrophic neurological damage.

How to Approach the Question

First, identify the key anatomical terms in the question: 'atlas' and 'axis'. Recall that these are the first two cervical vertebrae, C1 and C2, respectively.
Next, consider the primary movement that occurs between these two specific bones. The main function of the atlantoaxial joint is to allow the head to rotate from side to side.
Review the options, which are different types of synovial joints.
Match the movement (rotation around a central point) to the correct joint classification. A 'pivot' joint is defined by one bone rotating within a ring formed by another.
Eliminate the other options: 'Ball and socket' allows multi-axial movement (e.g., shoulder), 'saddle' allows biaxial movement (e.g., thumb), and 'angular' describes a type of motion, not a joint structure.

Concept Tested & Keywords

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E6 Osteology InderbirSingh 5e p. 24-26

E6 Anatomy Applied Ashalatha 4e p. 297-299

Practise the full RUHS, Jaipur, PB B.Sc Nursing Entrance-2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.