The spinous process is an extension of the vertebral arch, which starts at the point of greatest flexion and points centrally backwards. Depending on which vertebra the spinous process is located, it can have different shapes. At the cervical vertebrae, the spinous process is usually forked and kept short except for the 7th cervical vertebra, which is clearly palpable at the transition between neck and back.
In the thoracic vertebrae, the spinous process is clearly longer and points diagonally downwards. This shape is often compared with roof tiles that are lobed on top of each other. The spinous processes of the lumbar spine in turn, point straight backwards. They are used for orientation when a lumbar puncture is performed to remove cerebrospinal fluid.
Function
The spinous process has essentially two important functions. On the one hand, ligaments and muscles arise and attach to it. This function can be described as a lever, which serves to convert the contraction of a muscle into a movement, in particular the extension of the spinal column backwards or the flexion to the side. The ligaments that connect the spinous processes longitudinally are the interspinous ligament, which runs between the spinous processes, and the supraspinal ligament, which covers only the tips of the spinous processes. On the other hand, the spinous processes of the thoracic vertebrae, which, similar to roof tiles, are lobed obliquely downwards, provide additional protection for the spinal cord and indirectly prevent the spinal column from being stretched too far backwards.
Symptoms
Symptoms that can emanate from a spinous process are pain caused by a fracture, an inflammation or in the context of Baastrup’s disease. These are usually linked to certain movements and can be triggered by direct pressure on the spinous process. In addition, the spinous processes can indicate a malposition of the spinal column if they deviate from the midline.
Pain of the spinous process is usually felt in the midline of the back. They can be sharp or dull and can get worse or better through certain movements. Lying on the back can be experienced as unpleasant.
Pain that affects the spinous process can be explained by an injury, such as a compression or a fracture, of the same as a result of an enormous force or violence. On the other hand, there is a clinical picture in which the pain at the spinous processes of the lumbar spine is in the foreground, the so-called “Baastrup’s disease“. The interaction of large, roughly shaped spinous processes and excessive extension of the lumbar spine to the back, more rarely the reduced height of the vertebral bodies, causes the spinous processes to touch each other. The pain then occurs primarily when the lumbar spine is additionally stretched and when direct pressure is applied to the spinous processes. Inflammation of the vertebrae, for example in “spondylitis”, can also cause the inflammatory reaction to spread to such an extent that the spinous processes become pain-sensitive to knocking.
