Question

The characteristics and an example of a synovial joint in human is

(A) Fluid cartilage between two bones, limited movements	(1) Knee joints
(B) FluiD - filled between two joint, provides cushion	(2) Skull bones
(C) FluiD - filled synovial cavity between two bones	(3) Joint between atlas and axis
(D) Lymph filled between two bones, limited movement.	(4) Gliding joint between carpals

(a) A - 1, B - 2, C - 3, D - 4
(b) A - 1, B - 3, C - 2, D - 4
(c) A - 1, B - 3, C - 4, D - 2
(d) A - 1, B - 2, C - 4, D - 3

Answer 1

Hint: The inferior articular surface of the atlas is circular and forms the two lateral atlantoaxial joints. These two joints together with the joint between the dens of the axis and the anterior small arch of atlas, allow once to say no to the lateral rotation of the face.

Complete step by step answer:
- The atlanto occipital joint where the base of the skull articulates with the vertebral column which is the articulation between the atlas and the occipital bone consists of a pair of condyloid joints.
- The atlanto occipital joints are synovial socket- type joints where the sockets are shallow in infancy and deepen with age.
- The joint formed between atlas and axis in the upper part of the neck which is synovial in nature.
- The atlantoaxial joint is of complicated nature and consists of three distinct joints-
One which is found between the dens of the axis and the anterior arch of the atlas.
Two are located between the lateral masses of the first cervical vertebra and
Three on the superior articular facets of the second cervical vertebra.
- The following four ligaments stabilize these joints:
Apical ligament: Which connects the dens to the foramen magnum of the occipital bone.
Alar ligaments: Which connect the dens to the lateral margins of the foramen magnum.
Cruciate ligament: Which attaches the dens to the anterior arch of the atlas and the body of the axis to the foramen magnum of the occipital bone.
Tectorial membrane: Which starts at the skull and becomes the posterior longitudinal ligament.
So, the correct answer is ‘A - 1, B - 2, C - 3, D - 4.’

Additional Information:
- The atlas is the topmost vertebra and chief peculiarity of the atlas is that it has nobody, it is ring- like and consists of the anterior and posterior arch and two lateral masses.
- Axis, the 2nd cervical vertebra has a concave underside and convex from side to side. The most distinctive characteristic of this bone is a strong odontoid process, the dens.
- The movements allowed in this joint are flexion and extension in the sagittal axis, which give rise to the ordinary forward and backward nodding of the head. Slight lateral motion, lateral flexion to one or other side in the frontal axis or tilting of head. It's where the nodding action of the head takes place.

Note:
- The ligaments connecting the bones are two articular capsules posterior atlanto- occipital membrane: extend from anterior arch of the atlas to posterior margin of the foramen magnum.
- Anterior atlanto-occipital membrane: extend from anterior arch of the atlas to anterior margin of the foramen magnum.