Natural instability of the cervical spine in children

Cervical spine injuries in children usually occur in the upper cervical spine from the occiput to C3.

This fact may be explained by the unique biomechanics and anatomy of the paediatric cervical spine.

The fulcrum of motion in the cervical spine in children is at C2-3 level. In the adult cervical spine, the fulcrum is at C5-6 level.

Therefore, a child in a supine position is always better positioned with the head a little bit lower than the thorax.

The immature spine is hypermobile because of ligamentous laxity, shallow and angled facet joints, underdeveloped spinous processes, and physiologic anterior wedging of vertebral bodies, all of which contribute to high torque and shear forces acting on the C1-2 region.

Incomplete ossification of the odontoid process, a relatively large head, and weak neck muscles are other factors that predispose to instability of the paediatric cervical spine.

The child's cervical spine differs from the adults in a number of ways:

• The vertebral bodies may appear wedged on the lateral view, secondary to the shape of the ossified body.

• The planes of the facet joints of the lower cervical in the new-born is 30°, progressing to 65° in the adult.

• The C1-2 angles change from 55 to 70 degrees.

• The flatter facet angles in young children contribute to the pseudo-subluxation of the younger child's cervical spine, most marked at C2-3. This level is hypermobile in 40% of children less than 8 years old.

This is one of the reasons not to manipulate the cervicals in children.

Luc Peeters, MSc.Ost.