Cervical Lateral Flexion & Rotation BIOMECHANICS

Summary

In this video, Kevin Tokoff explores the biomechanics of lateral flexion and rotation in the cervical spine. He delves into how lateral flexion causes the spine to bend towards one side, creating varying effects on the facet joints. The video explains the concepts of down sloping and up sloping in relation to nerve root space and radiculopathy. Kevin also discusses type 2 mechanics, where lateral flexion and rotation occur in the same direction, and contrasts this with type 1 mechanics in the upper cervical spine. The video provides a detailed breakdown of cervical movement, including range of motion for lateral flexion and rotation.

Takeaways

• 😀 Lateral flexion, or side bending, involves bending the neck toward one side, with the left side lengthening and the right side shortening.
• 😀 In the lower cervical spine, lateral flexion and rotation occur together due to type 2 mechanics, where both movements happen in the same direction.
• 😀 The cervical spine from C2 to C7 is the primary area involved in lateral flexion and rotation, while the upper cervical spine (C0-C1-C2) does not significantly contribute to side bending.
• 😀 Lateral flexion to the right causes down sloping (posterior and inferior glide) on the right side, and up sloping (anterior and superior glide) on the left side.
• 😀 A radiculopathy on the right side may worsen during right lateral flexion, as the narrowing of the intervertebral foramina compresses the nerve root.
• 😀 In cases of left-side radiculopathy, right lateral flexion can provide relief by opening the left-side foramina and creating more space for the nerve root.
• 😀 Rotation of the cervical spine also causes ipsilateral down sloping and contralateral up sloping, contributing to narrowing and widening of the foramina, respectively.
• 😀 Type 1 mechanics in the upper cervical spine lead to lateral flexion and rotation occurring in opposite directions (contralateral side bending and rotation).
• 😀 The range of motion for lateral flexion in the cervical spine is about 35-40 degrees, with the majority coming from the lower cervical spine (C2-C7).
• 😀 The range of motion for rotation in the cervical spine is about 65-75 degrees, with the atlanto-axial joint contributing more than half of this movement (35-40 degrees).

Q & A

What is lateral flexion, and how is it typically described in the context of the cervical spine?

Lateral flexion, also known as side bending, refers to the movement of bending the head toward the right or left shoulder. In the context of the cervical spine, this is often described by which side the head bends toward (right or left), causing the cervical spine to elongate on one side and shorten on the other.

What happens to the cervical spine when performing right lateral flexion?

During right lateral flexion, the left side of the cervical spine becomes longer and more open, while the right side shortens and becomes more closed. The right side experiences down sloping of the facet joints, while the left side experiences up sloping.

What are the differences in the effects of ipsilateral and contralateral movements in lateral flexion?

Ipsilateral movements (same side as the flexion) cause down sloping, where the superior vertebra moves inferiorly and posteriorly. Contralateral movements (opposite side) cause up sloping, where the superior vertebra moves superiorly and anteriorly, creating more space in the intervertebral foramina.

How do the facet joints react to lateral flexion in the cervical spine?

The facet joints on the ipsilateral side undergo down sloping, causing them to move closer together, while the facet joints on the contralateral side undergo up sloping, causing them to move further apart.

How does lateral flexion relate to cervical rotation, especially in the lower cervical spine?

In the lower cervical spine, lateral flexion and rotation occur simultaneously, and they happen in the same direction due to type 2 mechanics. For example, right lateral flexion also causes right rotation.

What are type 2 mechanics, and how do they affect the cervical spine during lateral flexion and rotation?

Type 2 mechanics involve lateral flexion and rotation occurring in the same direction. This means when the head laterally flexes to the right, it also rotates slightly to the right in the lower cervical spine.

Why is it impossible to have lateral flexion without some rotation in the lower cervical spine?

Lateral flexion in the lower cervical spine automatically involves some rotation due to the orientation of the facet joints. The movements of the superior vertebrae during flexion also lead to a slight rotational effect.

What is the range of motion for lateral flexion and rotation in the cervical spine?

The range of motion for lateral flexion in the cervical spine is about 35 to 40 degrees, with the lower cervical spine contributing most of the movement. The range of motion for cervical rotation is around 65 to 75 degrees, with the lower cervical spine contributing nearly half of that, and the atlanto-axial joint contributing the rest.

How does the upper cervical spine differ from the lower cervical spine in terms of lateral flexion and rotation mechanics?

The upper cervical spine follows type 1 mechanics, meaning lateral flexion and rotation occur in opposite directions. For example, when the head laterally flexes to the right, it rotates to the left. In contrast, the lower cervical spine follows type 2 mechanics, where lateral flexion and rotation occur in the same direction.

Why might a person with a radiculopathy on the right side not want to perform right lateral flexion or rotation?

In right lateral flexion or rotation, the intervertebral foramina on the right side become narrower due to down sloping, which could compress the nerve root. This may cause pain or discomfort, making the individual less likely to perform these movements.