Cranio-Vertebral Joints

C1 Vertebra

The C1 vertebra is below the skull bone. It has no body and gets fused to C2. The Altanto occipital joint is for yes movement. It is a type of Ellipsoid joint or condylar. The transverse foramen is for the passage of the vertebral artery.

The relation between the vertebral artery and atlas vertebra is that they have a groove and pass through that groove to enter the cranial cavity. The vertebral artery comes from the transverse foramen and arches towards the superior surface of the atlas vertebra (posterior arch). Then it enters the foramen magnum and cranial cavity upward. Anterior tubercle and posterior tubercle are present. The superior articular facet is for the cervical vertebra or is directed backward and upward. No lateral and medial.

C2, Axis Vertebra

C2, the axis vertebra may get the body of the upper vertebra. The Odontoid process or dens of the axis is the body of the C1 vertebra. The body of the C1 vertebra is fusing with the body of the C2 vertebra. It produces an elevation called the Odontoid process of the dens of the axis. The axis vertebra has its own body. The other body is attached to its own body. Projection is seen in other views. Transversarium, the vertebral artery is passing.

Yes Movement of the Head

While doing the yes movement of the head, the atlanto occipital joint moves. This joint is ellipsoid or condylar because there are occipital condyles.

Atlanto Occipital Joint

C1 and C2 are atlas and axis joints. Dens or the Odontoid process, the body of C2, is seen. The odontoid process appears to be the body of the C1 vertebra fusing with the C2 vertebra. The assumption is that it got broken from there and fused here. It goes to the anterior arch of the atlas. The transverse ligament holds the Odontoid process. C2 gives the Odontoid process held by the transverse ligament of the C1 vertebra anteriorly.

No movement of the head

No movement happens at C1 and C2 vertebrae. The Skull and atlas vertebrae rotate together on the axis vertebra. The occipital and atlas become a unit that rotates on the axis vertebra.

Atlantoaxial joint

The Atlantoaxial Joint is a rotatory joint. It has a central axis, and rotation occurs here. It is called a pivot or trochoid synovial joint. The skull and atlas rotate on the axis vertebra.

As the skull moves, the atlas also moves. The transverse ligament holds the Odontoid process of the axis on the anterior arch of the atlas vertebra. The atlantoaxial joint is for yes movement. The pivot or Trochoid is for no movement.

Also Read: Diaphragm: Development and Openings

Frequently Asked Questions:

Q: Which joint is responsible for the “yes” movement of the head?

Answer: The atlanto occipital joint is responsible for the yes movement of the head.

Q: Which joint is responsible for the “no” movement of the head?

Answer: No movement happens at C1 and C2 vertebra. As a unit, the Skull and atlas vertebra rotate on the axis vertebra.

Q: What is different about the C1 vertebra?

Answer: The C1 vertebra has no body.

Q: What is the Transverse foramen?

Answer: The transverse foramen is a hollow structure that is used to pass the vertebral artery.

Q: What type of joint is an atlantoaxial joint?

Answer: The atlantoaxial joint is a pivot or trochoid synovial joint.

Q: How many vertebrae are there in the human body?

Answer: 33

Also Read: Hematopoiesis: The Journey Of Blood Cell Production

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