When you receive a medical imaging report, such as an MRI or CT scan of your spine, you may encounter the phrase “neural foramina are patent.” This technical term is a positive finding, meaning the small passageways where nerves exit the spinal column are clear and unobstructed. Understanding this terminology requires a look at the anatomy of the spine and what happens when these openings are not clear.
Anatomy of the Neural Foramina
The spine is a complex structure made up of individual bones called vertebrae, which are stacked one upon the other from the neck down to the pelvis. Between each pair of adjacent vertebrae, there are openings on both the left and right sides, and these openings are known as the neural foramina. The term “foramen” is Latin for hole or opening, and “neural” refers to the nerves.
These foramina serve as protective exit tunnels for the spinal nerve roots, which branch off the main spinal cord. At each level, a pair of nerve roots exits through a foramen to travel to the body’s limbs and organs. These nerve roots carry signals for sensation and movement, connecting the brain to the rest of the body. The size of the neural foramina is determined by the relative positions of the surrounding vertebrae and the cushioning discs between them.
What Does “Patent” Mean in This Context?
In medical language, the word “patent” means open, unobstructed, or unrestricted. When a radiologist reports that the neural foramina are patent, they are confirming that these bony tunnels are wide enough. This finding suggests that the spinal nerve roots passing through them have sufficient space.
A patent foramen indicates a healthy condition where the nerve root is not being compressed or irritated by surrounding tissues. This is the normal state for these structures to function correctly. The positive implication is that any symptoms a patient may be experiencing are unlikely to be caused by pressure on the spinal nerve at that specific location.
When Foramina Are Not Patent: Spinal Stenosis
The opposite of a patent foramen is a narrowed or obstructed one, a condition medically known as foraminal stenosis. Stenosis is a term that refers to the abnormal narrowing of a body channel. Foraminal stenosis occurs when the space within the neural foramen shrinks, which can then pinch or compress the exiting spinal nerve root.
This narrowing is often a result of degenerative changes linked to the natural aging process. One frequent cause is the growth of bone spurs, also called osteophytes, which are bony projections that can grow into the foramen and reduce its size. Degenerative disc disease can also contribute, as the intervertebral discs lose height and bulge or herniate, pushing into the nerve root pathway.
Thickening of the ligaments and arthritis in the facet joints further restrict the available space. When the nerve root becomes compressed in the narrowed foramen, the resulting condition is called radiculopathy, often described as a pinched nerve. Symptoms typically include pain that radiates along the path of the affected nerve.
For example, compression in the lower back (lumbar spine) can cause sciatica, a sharp pain, numbness, or tingling that travels down the buttocks and legs. In the neck (cervical spine), symptoms may manifest as pain, numbness, or weakness in the shoulders, arms, and hands.