A foramen is a term used to describe a natural hole or opening in certain areas within the body. These spaces serve as a passageway for vital structures such as blood vessels, nerves and the spinal cord. These tunnel-like cavities are commonly located in a bone and can be found throughout the body.
The magnum foramen, for example, is one of several openings located at the base of the skull in the bone called the occiput. Its primary purpose is to allow the spinal cord to connect to both the cranium and the body. The spinal cord then travels the length of the vertebral column, also known as the spine or backbone, through a series of vertebral spaces. This sequence of circular openings is commonly referred to as the vertebral canal.
However, the spine is only one of several holes or tunnels located within the body. There are additional openings located within the skull to allow for the passage of nerves. The foramen ovale is an example of one of the cranial openings which allows for nerves to transmit or pass signals within the skull. There is also a foramen ovale present in the heart between the right and left atria in the heart at birth which seals itself within the first two years of life.
There is also an opening situated in the mandible or lower jaw bone known as the mandibular foramen. This allows a channel for nerves through the teeth, lower lip and a portion of the jaw and face area. The foramen spinosum, on the other hand, is the passageway for nerves for the upper jaw region.
When there is a problem within these spaces, such as seen with spinal stenosis — a narrowing of the vertebral canal, impingement or entrapment of the nerves and spinal cord can occur. This can lead to symptoms of numbness and tingling or pain, typically radiating the length of the nerve. Sciatica is an example of the compression of the sciatic nerve due to a reduction of the foramen space resulting in pain which travels from the mow back through the buttocks and down the posterior leg. Occasionally, with severe cases, this pain can be felt in the ankle or foot area.
Treatment for stenosis or narrowing of the vertebral foramen often involves a procedure called a laminectomy, in which the lamina or the arch of the spinal bone is removed to allow for more space. This can reduce the pressure on the nerves and spinal cord and allow for the cessation of further damage.