At what age does the odontoid process ossify?
The odontoid process forms in utero from two separate ossification centers that fuse in the midline by the 7th fetal month. A secondary ossification center appears at the apex of the odontoid process (os terminale) between 3 and 6 years of age and fuses by age 12 years.
Does C2 have a bifid spinous process?
The axis is formed by a body with the attached dens, two lateral masses, a posterior neural arch (formed by the pedicle and a thick lamina), and a large spinous process, which is commonly bifid.
What is the significance of odontoid process?
The odontoid process, or dens, is a superior projecting bony element from the second cervical vertebrae (C2, or the axis). The first cervical vertebrae (atlas) rotates around the odontoid process to provide the largest single component of lateral rotation of the cervical spine.
Why do cervical vertebrae have bifid spinous processes?
Another feature unique to the cervical vertebrae is the bifid spinous process (See “physiologic variants” section), which may serve to increase surface area for muscle attachment.
What is a bifid process?
Bifid spinous process – this is where the spinous process splits into two distally. Transverse foramina – holes in the transverse processes. They give passage to the vertebral artery, vein and sympathetic nerves[2]. The main role of the cervical spine is to support and promote the movement of the head and neck.
Which structure does the odontoid process of C2 articulate with?
transverse ligament
This tooth-like elevation serves a stable point around which the atlas bone rotates. Posteriorly the Odontoid process is flattened where it articulates with the transverse ligament.
What is the odontoid process called?
Dens. The dens, also called the odontoid process or the peg, is the most pronounced projecting feature of the axis. The dens exhibits a slight constriction where it joins the main body of the vertebra.
What does the odontoid process articulate with the occipital bone?
Occipital-Cervical and Upper Cervical Spine Fractures The atlas, in turn, articulates with the axis anteriorly via the odontoid process, and laterally via the lateral masses, with associated synovial capsules at each articulation.
Where do bifid spinous process occur and what are they?
The spinous process of a typical cervical vertebra is short and bifid posteriorly. It is bifid because it develops from two separate secondary centers of ossification. This morphology is unique to cervical spinous processes.
What is the odontoid process?
The odontoid process (also dens or odontoid peg) is a protuberance (process or projection) of the Axis (second cervical vertebra). It exhibits a slight constriction or neck, where it joins the main body of the vertebra. On its anterior surface is an oval or nearly circular facet for articulation with that on the anterior arch of the atlas.
What is odontoid morphology and why is it important?
A sound understanding of the development of the odontoid process, both in normal and in variant forms, as well as its phenotypical morphology is a prerequisite for the diagnosis and treatment of patients presenting with disorders affecting the cranio-cervical spine.
What is os odontoideum?
Os odontoideum It is the most common developmental anomaly of odontoid. The definition of an os odontoideum is uniform throughout the literature: An ossicle with smooth circumferential cortical margins representing the odontoid process that has no osseous continuity with the body of C2.[25]
Can the odontoid process fracture?
The odontoid process can fracture (Fig. 5-13 ), and any fracture of the odontoid is serious because of the close relationship between the odontoid process and spinal cord. Fracture of the odontoid superior to its attachment to the body of C2 is known as a type I fracture.