The spinous processes are bony protrusions that come from the back of the vertebrae. These vertebral views are easily palpable on physical examination of the back.
All vertebrae, with the exception of the first cervical or atlas, have a spinous process, but the characteristics of this vary depending on the location in which it is found.
By Jmarchn - Own work, CC BY-SA 3.0, The main function of these structures is to serve as an attachment surface for the muscles and ligaments of the neck, head and back. They are also an additional bone protection mechanism for the spinal cord.
Injury to these bone processes is not a common pathology; however, it can be observed in the polytraumatized patient, with the spinous processes of the dorsal vertebrae being the most frequently fractured.
Treatment is generally conservative and fractures improve without sequelae. However, when there is injury to several vertebrae, it is a complicated fracture that can cause spinal cord injury.
Anatomy and Features
The vertebrae are the irregular bony structures that make up the spine. Its structure consists of a body, an arch, a foramen or orifice and seven processes or processes.
The vertebral processes are distributed as follows: two transverse processes, four articular, also called facets, and one spinous.
By Fabianamun - Own work, CC BY-SA 4.0, The spinous processes are odd protrusions of the vertebral lamina found at the back of the vertebrae.
These bony protrusions are usually elongated and slightly sharp, however these characteristics vary depending on their location on the spine.
With the exception of the first cervical vertebra known as the atlas, all vertebrae have a spinous process.
The spinous processes have some differences depending on the type of vertebra to which they belong and the height of the column in which they are located.
Cervical
The spinous processes of the cervical vertebrae are bifid, that is, they are divided into two asymmetric parts.
By Anatomist90 - Own work, CC BY-SA 3.0, Up to the fifth cervical vertebra (C5) the length of the spinous processes is short and they are reinforced by the cervical splenius and trapezius muscles and by the nuchal ligament, which uses them as an insertion surface.
This is a very strong and tough ligament that attaches to the spinous processes of all cervical vertebrae and to the posterior tubercle of the atlas.
The seventh cervical has a different spinous process than the rest of the cervical vertebrae. In the first place it is not bifid; it is thick and almost horizontal.
The spinous process of C7 is the longest in approximately 70% of people. For this reason, it is easily identified on palpation on the skin of the back.
By Anatomography - en: Anatomography (setting page of this image), CC BY-SA 2.1 jp, The atlas is the first cervical vertebra, it is directly articulated with the occipital bone and it is a vertebra with atypical characteristics.
By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See «Book» section below) Bartleby.com: Gray's Anatomy, Plate 86, Public Domain, https://commons.wikimedia.org/w/index. php? curid = 792296
It is a cylindrical bony body that resembles a ring. Contrary to the rest of the vertebrae, it does not have a body without a spinous process.
Dorsal
The dorsal or thoracic vertebrae have prominent and thick spinous processes. The higher ones, between the first and the fifth (T1 and T5) are almost horizontal and progressively take an oblique direction.
Starting at T6, the spinous processes become totally oblique and overlap each other until reaching T11.
By Gray, Henry, 1825-1861; Carter, HV, ill; Westmacott, John Guise, Dr, ill - https://www.flickr.com/photos/internetarchivebookimages/14764287872/Source book page: https: // archive. org / stream / b20386424 / b20386424 # page / n49 / mode / 1up, No restrictions, In this vertebra the spinous process is considerably shorter than the rest and in T12 it acquires the characteristics of those of the lumbar vertebrae.
Lumbar
The lumbar spinous processes are strong and thick structures. In the upper lumbar vertebrae they are slightly longer than in the lower ones.
By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See «Book» section below) Bartleby.com: Gray's Anatomy, Plate 92, Public Domain, https://commons.wikimedia.org/w/index. php? curid = 792302
They have a wide surface and an almost square shape, their height being similar to their width. They end in an asymmetrical edge that may have a small notch in the lower lumbar vertebrae.
Sacrococcygeas
The sacrum is a set of five fused vertebrae. In this structure the spinous processes are small and very rudimentary, they are observed in the central part of the bone as five tuberosities without a defined structure.
By Dr Johannes Sobotta - Sobotta Atlas and Text-book of Human Anatomy 1909, Public Domain, The coccyx is also a structure of four to five fused vertebrae that is articulated with the sacrum.
In this bone, the spinous processes are almost non-existent, the most prominent being that of the first vertebra, which has a shape and size similar to those of the sacrum.
Features
The spinous processes serve a supportive role by providing a firm surface for the attachment of the muscles and ligaments of the neck and back.
In addition to this, they are thick and strong structures that protect the spinal cord that is located towards its anterior face, passing through the spinal canal of the vertebrae.
On the other hand, spinous processes are used as anatomical landmarks to identify vertebral bodies and intervertebral spaces.
During physical examination of the spine, the prominent spinous process of the seventh cervical vertebra (C7) is easily palpable on the back below the nape. The next palpable process is the first thoracic (T1).
By Mikael Häggström. When using this image in external works, it may be cited as: Häggström, Mikael (2014). "Medical gallery of Mikael Häggström 2014". WikiJournal of Medicine 1 (2). DOI: 10.15347 / wjm / 2014.008. ISSN 2002-4436. Public Domain.orBy Mikael Häggström, used with permission. - Image: 432px-Gray-back.PNG & Anatomy Compendium (Godfried Roomans and Anca Dragomir), Public Domain, The spinous process of T11 can be identified by following the path of the last rib, which is articulated with this vertebra.
Knowing these guidelines is extremely important for the performance of some procedures such as lumbar puncture, in which a sample of cerebrospinal fluid is taken through the intervertebral space between L3 and L4.
By BruceBlaus. When using this image in external sources it can be cited as: Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI: 10.15347 / wjm / 2014.010. ISSN 2002-4436. - Own work, CC BY 3.0,
Injuries
Spinous processes can present fractures in polytrauma patients, usually from a fall, car accident, or gunshot wound. The processes of the dorsal vertebrae are injured more frequently than the rest.
Symptoms depend on the degree of the fracture. In those small and not displaced that involve a single vertebra, the patient presents pain on mobilization and a decrease in the range of movements.
Contrary to the case of displaced or unstable fractures, there may be spinal cord injury presenting with symptoms such as decreased muscle strength or inability to control sphincters. Spinal symptoms will depend on the level at which the injury occurred.
When a spinous process fracture is suspected, the spine should be completely immobilized with a rigid collar and brace.
By Internet Archive Book Images - https://www.flickr.com/photos/internetarchivebookimages/14597323339/Source book page: https://archive.org/stream/chicagomedicaljo3618unse/chicagomedicaljo3618unse#page/n383/mode/1up, No restrictions, Once the level and degree of the fracture and the presence or absence of spinal cord damage have been identified, the appropriate treatment can be decided.
Simple fractures improve with immobilization and rehabilitation, while complex fractures require surgical treatment.
References:
- Vargas, M. (2012). Anatomy and physical examination of the cervical and thoracic spine. Legal Medicine of Costa Rica. Taken from: scielo.sa.cr
- Cui, X; Wang, G. (2017). Radiographic anatomical relationship between spinous process and pedicle in thoracolumbar and lumbar spine. Medicine. Taken from: ncbi.nlm.nih.gov
- Aylott, C. E; Puna, R; Robertson, P. A; Walker, C. (2012). Spinous process morphology: the effect of aging through adulthood on spinous process size and relationship to sagittal alignment. European spine journal: official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. Taken from: nlm.nih.gov
- Cruz, L; Athié, J. M; Martínez, V. A; Martínez, FR (2017). Proper location of the L3-L4 intervertebral space by palpation according to ultrasound in healthy volunteers. Grupo Ángeles medical report. Taken from: scielo.org.mx
- Ludwisiak, K; Podgórski, M; Biernacka, K; Stefańczyk, L; Olewnik, Ł; Majos, A; Polguj, M. (2019). Variation in the morphology of spinous processes in the cervical spine-An objective and parametric assessment based on CT study. PloS one. Taken from: nlm.nih.gov