Atlanto-Occipital and Atlanto-Axial Joint Movements

Question 1

What are the Atlanto-Occipital and Atlanto-Axial Joints for?

Answer 1

Antlanto-occipital-allow nodding and lateral flexion movements of the head

Atlanto-axial- rotation of the head

Question 2

Where are the Atlanto-occipital joints?

Answer 2

synovial joints between convex occipital condyles and concave facets on the lateral mass of the atlas

Question 3

How are the Atlanto-occipital joints adapted for there function?

Answer 3

Curved surfaces-adapted for head flexion and extension and abduction of the skull on the atlas of the vertebra

Question 4

When the head is erect what muscles are involved?

Answer 4

head held in position by the the tone of the EXTENSOR MUSCLES (postvertebral group of muscles) in the back of the neck

Question 5

When the head is flexed what muscles are involved ?

Answer 5

The extensor muscles relax and further flexion is produced by the bilateral contraction of sterno-mastois and pre-vertbral muscles. These muscles contract uni laterally

Question 6

How can you test the movements at the atlanto-occipital joints?

Answer 6

1-Patient has head held in erect position looking straight ahead.
2- The examiner stands behind the patient and holds the neck just below the jaws with one hand, and instructs the patient to nod the head up and down, as if to say “yes”
3-meanwhile the examiner keeps check of the rest of the cervical spine does not bend.

Question 7

Where are the Atlanto-axial joints?

Answer 7

Synovial joints between the ATLAS and the dense of the AXIS and the LATERAL MASSES OF BOTH VERTEBRAE.

Question 8

What is the dens of the axis?

Answer 8

Part of the axis that rises/ sticks out perpendicularly from the body of the bone

Question 9

What holds the dens of the axis in position?

Answer 9

The transverse limb of the Cruciate ligament

Question 10

How does the head rotate?

Answer 10

The atlas rotates along a vertical axis passing through the dens and the head rotates with the atlas

Question 11

What muscles are responsible for the rotation of the head?

Answer 11

STERNO MASTOIDS and SUB-OCCIPITAL muscles (splenius capitis, inferior oblique)

Question 12

How can you test the movements at the atlanto-axial joints:

Answer 12

1- Patient has head held in erect position looking straight ahead.
2-The examiner stands behind the patient and holds the neck just below the jaws with one hand, and instructs the patient to rotate their head side to side, as if to say “no”
3-meanwhile the examiner checks the rest of the cervical spine does not bend.