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Head and Neck
Published in Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno, Understanding Human Anatomy and Pathology, 2018
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno
The retropharyngeal space is situated posterior to the cervical viscera and anterior to the vertebrae. It extends from the basilar part of the occipital bone to the superior mediastinum and forms a dangerous route for the spread of infection from the pharyngeal wall down to the thorax. Lateral to this space is the sympathetic trunk. Along the trunk, swellings of the superior, middle, and inferior cervical sympathetic ganglia are found (often the inferior cervical ganglion and the 1st thoracic ganglion fuse into one stellate ganglion, or cervicothoracic ganglion). Gray rami communicantes connect these ganglia to the cervical spinal nerves. Superiorly, the internal carotid nerve carries postganglionic fibers from the superior cervical ganglion to all the structures of the head (Plate 3.20). The prevertebral fascia covers the prevertebral muscles (longus colli and longus capitis) and the lateral vertebral muscles (anterior, middle, and posterior scalene muscles).
Anatomical considerations
Published in Hemanshu Prabhakar, Charu Mahajan, Indu Kapoor, Manual of Neuroanesthesia, 2017
Each spinal nerve is connected to the spinal cord by anterior (ventral) and posterior (dorsal) roots (Figure 1.10). The anterior root consists of efferent (motor) nerve fibers while the posterior root consists of afferent (sensory) nerve fibers. The posterior root contains a ganglion known as the posterior or dorsal root ganglion, which contains the cell body of the sensory neurons. The two nerve roots unite to form the spinal nerve. The spinal nerve divides into a large anterior (ventral) ramus and a small posterior (dorsal) ramus (Figure 1.11). The posterior ramus passes posteriorly to supply the skin and muscles of the back. The anterior ramus continues anteriorly and further divides into the anterior and lateral cutaneous branches to supply the muscles and skin over the anterior and lateral wall of the body (thorax and abdomen) and the muscles and skin of the limbs (cervical, lumbar, and sacral spinal nerves). The thoracic and upper 2 or 3 lumbar spinal nerves also give rise to branches to the paravertebral sympathetic trunk called white and gray rami communicantes.2,9
Quantitative Clinical, Sensory, and Autonomic Testing of Chronic Neuropathic Pain
Published in Gary W. Jay, Practical Guide to Chronic Pain Syndromes, 2016
Shortly thereafter, these fibers separate from the roots and proceed toward the paravertebral sympathetic chain. Their myelination gives rise to their color and thus the segments of these pathways between the root and the chain ganglia are known as the white rami communicantes. After synapsing with neurons in the respective ganglia that are destined to become part of the final common sudomotor path, the postganglionic fibers exit and, due to their unmyelinated state, become identifiable as the gray rami communicantes. They return to join the main (mixed) nerve roots which pass through the neural foramina of the spinal column, proceeding to individual territories of skin where clinical and subclinical (electrophysiological) functions are controlled locally. Pathological processes affecting these pathways either (a) create regional hypohidrosis by interrupting normal sweating locally, or (b) irritate such fibers in a manner that forces them to drive the effectors excessively, creating local increases in sweating (hyperhidrosis).
High field structural MRI in the management of degenerative cervical myelopathy
Published in British Journal of Neurosurgery, 2018
Dan Wright, Sean Martin, Erlick AC Pereira, Yazhuo Kong, Irene Tracey, Thomas Cadoux-Hudson
Axial neck pain is thought to derive from the richly innervated disc and facet joint. The posterior disc, ligament and dura are innervated by the sinovertebral nerve as it enters the canal via the nerve root exit foramen. The anterior disc and ligament are innervated by the sympathetic trunk and recurrent branches of the gray rami communicantes. The facet (zygapophyseal diarthrodial) joints are rich in nociceptors and are supplied by the dorsal rami of the cervical nerve roots. Clearly, any disc disruption or abnormal axial loading of the facet joints has the potential to cause pain. This pain is typically worsened with flexion and relieved by lying down
Comprehensive review on intravertebral intraspinal, intrajoint, and intradiscal vacuum phenomenon: From anatomy and physiology to pathology
Published in Modern Rheumatology, 2021
Francesco Cianci, Gianfranco Ferraccioli, Edoardo Sean Ferraccioli, Elisa Gremese
The cells of the annulus tend to be fibroblast-like and aligned parallel to collagen fibers. Cells of the disc, both in the annulus and nucleus, can have several long, thin cytoplasmatic projections. Their function in disc are unknown, but it has been suggested that they act as sensors and communicators of mechanical strain within the tissue [35]. The cartilage endplate, a thin horizontal layer, usually less than 1 mm thick, of hyaline cartilage interfaces the disc and the vertebral body. The cartilaginous endplate, like other hyaline cartilages, is normally total avascular and aneural in the healthy adult. Instead, the disc has few (if any) blood vessels, but it has some nerves, mainly restricted in the outer lamellae. These nerves can derive from gray rami communicantes or from a meningeal branch of the spinal nerve, known as the recurrent sinovertebral nerve, which it’s divided into a major ascending and a lesser descending branch. It has been shown in animal studies that further afferent contribution to the sinovertebral nerve arises via the rami communicantes from multiple superior and inferior dorsal root ganglia and via branches originating in the dorsal root ganglion from the anterior longitudinal ligament. The posterior longitudinal ligament is richly innervated by nociceptive fibers from the ascending branches of the sinovertebral nerve; these fibers also innervate the adjacent outer layers of the annulus fibrosus [36]. The intervertebral disc is the one of the largest avascular structures in the body, with cells in the center of the adult disc lying as far as 8 mm from the nearest blood supply. The nutrient supply to the cells in the outer annulus derives from the capillaries in the neighboring tissues, whereas in the inner annulus and nucleus it’s provided by diffusion from capillaries in the cartilaginous endplate [37]. These capillaries originate in the vertebral body from the ‘marrow contact channels’ which penetrate the subchondral bone [38] and can get occluded as a result of the aging-related endplate calcification [39]. These alterations can modify the permeability and the fluid transport in the disc, affecting his metabolic exchanges. In fact, convective transport plays an important role in fluid exchanges to and from the disc, increasing the penetration of molecules greater than 40 kDa (e.g., the aggrecan) [40].