Prevertebral space is a space in the neck region defined by the anterior part of the cervical spine and the deep layer of the deep cervical fascia running between the transverse processes of the spine.
It extends from the skull base into the mediastinum and ends at the level of the fourth thoracic vertebra.
The prevertebral space contains
- The prevertebral muscles (longus colli and longus capitis)
- Vertebral vessels
- Scalene muscles
- Phrenic nerve
- Proximal part of the brachial plexus.
On lateral cervical spine x-ray, the normal prevertebral space looks like this.
Normal dimension in the adult is 4 mm at C3 level. Greater than 7 mm value is definitely abnormal and the cause should be looked for.
If the values lie in between, a clinical correlation must be sought.
Prevertebral space may get enlarged due to the pathology of the cervical spine that leads to accumulation of fluid, blood or pus in the space.
This space is evaluated on the lateral view of the cervical spine as seen above. It is one of the important components of the cervical spine x-ray evaluation.
Many a time, enlargement of the space is the finding that raises the doubt about pathology. Infections particularly tuberculosis may otherwise not produce much symptoms and suspicion may be raised from the examination of prevertebral space.
Hematoma accumulation in prevertebral space can lead to its enlargement following an injury to the neck. Tumors and metastases may spread to this space to cause enlargement.
The conditions that lead to enlargement of prevertebral space and the consequent increase of its width in x-ray are following –
- Trauma of the cervical spine
- Vertebral osteomyelitis
- Vertebral metastasis.
- Hodgkin lymphoma
- Posterior spread of squamous cell carcinoma head and neck
- Primary tumors arising from tissues belonging to this space.
If space is increased a computed tomogram or MRI should be done for further evaluation of pathology.