Intervertebral foramina

The spinal cord ends at about the level of the second lumhar vertebra. Lower nerve roots run caudally and laterally to exit from the intervertebral foramina. This termination of the cord into a spray of nerve roots is known as the cauda equina. Disk herniation disturbs the nerve root of the lower of the vertebrae involved. Therefore, an L5-S1 herniated disk will cause dysfunction of the first sacral nerve root. 

In addition, other elements such as epineuriem and supportive fet may be directly affected by protruded disc and in turn directly affect the contents of the intervertebral foramina. Besides the segmental nerve, arteries and veins may likewise be compressed, bringing about vascular stasis. The loss of shock absorption, inflammation, and edema may lead to back pain. Impingement on a nerve root may lead to a radiculopathy into an extremity. 

In preganglionic injuries, pseudomeningoceles can be appreciated as hypoanechoic collections located in proximity to the intervertebral foramina instead ofthe nerve roots. In our experience, however, US seems less sensitive than MR imaging for detecting them. At least in part, this could be explained by the fact that these collections are not extruded so far outside the neural foramina. In addition, avulsed frayed roots without pseudomeningoceles can have a very similar US appearance. The examiner must also be aware that nerve root avulsions can occur without traumatic pseudomeningoceles... 

Since vessel diameters of the described spinal arteries may be of submillimeter size, and the fact that these arteries go through (intervertebral foramen) or run adjacent to the vertebrae, CTA of the spinal arteries is one of the most challenging tasks within the field of CT ap-pHcations. Furthermore, a bidirectional flow along the ASA may be present, causing unpredictable opacifica-... 

Fig. 6.17a,b. Vertebral anatomy neural foramina, a Schematic drawing of the cervical spine illustrates the anatomic correspondence between transverse processes and nerve roots. Each root (in yellow) leaves the intervertebral foramen sliding on the transverse process of its corresponding vertebral level. Because there are eight cervical nerves and only seven cervical vertebrae, the C8 root lies at the level of the T1 vertebra. The position f the vertebral artery (in red) relative to the bony tubercles b Photograph of the cervical spine shows the typical appearance of transverse processes, which exhibit prominent anterior (star) and posterior (asterisks) tubercles. Note the absence of the anterior tubercle at C7 level, whereas the lateral aspect of T1 is flat without any bony prominence... 

The upper cervical vertebral bodies are 15-16 mm high (C2 is 5-6 mm higher), 23-25 mm wide and 17-19 mm deep on average. The average distance from the midline to the intervertebral foramen where the roots leave the spinal canal is 12-13 mm. The foramen transversaria, creating a canal for the vertebral artery, are found 25 mm from the midline at C 20 mm at C2, and 15 mm at C3 respectively. 

R.T. was a 48-year-old man who came to the clinic with a report of numbness and "pins and needles" in his right forearm and hand. This had been present for several months. He gave a history of an automobile accident approximately 1 year previously. He had undergone an MRl 1 month previously that demonstrated a herniation ofthe intervertebral disc between C6-C7, with apparent impingement on the foramen. He had a history of a mild elevation of his blood pressure, which was controlled with verapamil. He had been scheduled for surgery for the cervical disc for the following week and requested that a trial of manipulation be performed in an attempt to prevent surgery. 

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