Pathophysiology of the Sympathetic System
Hooshang Hooshmand in Chronic Pain, 2018
The sympathetic pain, phylogenetically a more primitive and hyperpathic pain (Figures 10 and 13), follows a different route in CNS (medial pain system) than the more sophisticated somatic pain (lateral pain system). The c fibers carrying nociceptive afferent impulses end up in layer 1 (superficial layer) (Figures 11,13, and 14) of the posterior horn of the spinal cord. From there (Figures 11b, 13b, and 14b) they stimulate a wide dynamic rang415,416 of adjacent levels of the spinal cord, resulting in a diffuse nociceptive pain. They eventually end up in the prefrontal cortex, inducing anxiety (Figure 12). This is in contrast with the A–δ fibers, which end up in the deeper layers of the posterior horn and relay to the lateral spinothalamic tract. The pain transmission in this tract is a discrete focalized pain that ends up in the sensory cortex of the contralateral parietal lobe, and it is not accompanied by hyperpathia and its emotional connotations (Table 5).
The spinal cord
Nan Stalker in Pain Control, 2018
Anterior or motor roots consist of fibre coming from motor cells of the anterior horns. Posterior or sensory roots consist of sensory fibres bringing in sensory stimuli from the skin and, to a lesser extent, from other tissue. The fibres run into the vetrectial canal and from the posterior roots of spinal nerves. On each root is a ganglion which is visible as a marked swelling and which is called the posterior root ganglion. This consists of the cells of these fibres which have the protection of the spinal column and which are joined by a T-shaped branch to the fibre. From the ganglion the fibre runs on and enters the posterior horn of the spinal cord, where it ends in a widely spread tree-like branching. This branching passes on the stimuli brought in by the fibre to the sensory cells of the cord on the same or opposite side.
The nervous system
Peter Kopelman, Dame Jane Dacre in Handbook of Clinical Skills, 2019
Afferent fibres convey stimuli to the spinal cord. They enter the spinal cord via the posterior root ganglia and posterior roots. The majority of afferent fibres terminate in the grey matter of the posterior horn, at or near the level at which they enter. The second-order sensory neurone fibres arise from these cells in the posterior horn (Fig. 6.3). Sensations of pain and temperature ascend in the lateral spinothalamic tract, with fibres from the lower part of the body being placed laterally and those from the upper part medially. These fibres cross immediately, or within a few segments, to the opposite lateral and anterior columns of the cord, and ascend to the brainstem as the anterior and lateral spinothalamic tracts. Simple touch also follows this route, largely in the anterior spinothalamic tract. The other afferent fibres do not synapse in the grey matter of the posterior horns of the spinal cord, but ascend in the ipsilateral posterior columns (Fig. 6.4) (transmitting joint position sense, size, shape, discrimination and vibration sense).
Spinal cord involvement in Lewy body-related α-synucleinopathies
Published in The Journal of Spinal Cord Medicine, 2020
Raffaele Nardone, Yvonne Höller, Francesco Brigo, Viviana Versace, Luca Sebastianelli, Cristina Florea, Kerstin Schwenker, Stefan Golaszewski, Leopold Saltuari, Eugen Trinka
An involvement in lamina I of the spinal cord dorsal horn has been found in all PD patients36 (Fig. 3). The pathological changes were to a lesser extent in the cervical segments, and density gradually increased caudally. In a subsequent study the spine has been examined in 23 neurologically asymptomatic subjects (seven with ILBD), 17 patients with PD, 9 with DLB, 19 with AD with LB, and 19 with AD without LB.37 In 16 out of 17 patients with PD, LB were detected in all gray matter regions of the spinal cord. The lesions were predominantly located in the Th/IML horn at the base of the posterior horn of the sacral cord. Although the sample size is rather limited, these reports strongly suggest that the spinal cord and particularly of the IML columns are frequently involved. However, available data do not allow us to specify whether the involvement of the spinal cord precedes or follows LBAS of the brain or of the ganglia.
Biomechanical study of medial meniscus after posterior horn injury: a finite element analysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Peishi Jiang, Juncheng Cui, Zhiwei Chen, Zhu Dai, Yangchun Zhang, Guoliang Yi
In this study, the maximum contact pressure of normal meniscus under 760 N axial compression load was 11.81 MPa (Figure 3(a)). Mononen et al. (2013) simulated the gait cycle in the finite element analysis of knee joint and obtained the peak meniscus stress value of 29 MPa. Although differences existed in the respective results, the magnitude of the peak meniscus stress value was consistent. Previously, we used this model to perform two other verification experiments: Verification Experiment 1, apply a 134 N forward load to the upper tibia, observe the anterior displacement distance of the tibial plateau and the stress of the anterior and posterior cruciate ligaments; Verification Experiment 2, apply upward loads to the lower tibia in different directions and magnitudes in turn and record the maximum equivalent stress of the tibial cartilage. Results of the two experiments are consistent with the results of in vitro experiments and finite element numerical calculations of the knee joint by other scholars, thus verifying the model is valid. Related literature has been published (Peishi et al. 2018). In our analysis model, we found that the displacement of anterior and posterior horn of meniscus was mainly downward axial displacement in the displacement nephogram and the meniscus body had both axial and radial displacement.
Assessment of spinal cord relative vulnerability in C4–C5 compressive cervical myelopathy using multi-modal spinal cord evoked potentials and neurological findings
Published in The Journal of Spinal Cord Medicine, 2021
Yasuaki Imajo, Tsukasa Kanchiku, Hidenori Suzuki, Norihiro Nishida, Masahiro Funaba, Toshihiko Taguchi, Takashi Sakai
We previously electrophysiologically evaluated the functional integrity of three spinal tracts (lateral corticospinal tract and the lateral parts [Burdach tract] and medial parts [Goll tract] of the posterior column).6 We reported on the correlation between the progression of spinal tract lesions in cervical spondylotic myelopathy (CSM) at the C3–C4 intervertebral level, as estimated by multi-modal spinal cord evoked potentials (SCEPs) and neurological findings.6 Multi-modal SCEPs were SCEPs following median nerve stimulation (MN-SCEPs), transcranial electric stimulation (TCE-SCEPs), and spinal cord stimulation (SC-SCEPs). At the C3–C4 intervertebral level, we found that MN-SCEPs are mediated by Burdach tract, TCE-SCEPs by lateral corticospinal tract, and the N2 component of SC-SCEPs by Goll tract. According to these results, the involvement of long tracts in CSM start in the Burdach tract, followed by the lateral corticospinal tract, and eventually, the Goll tracts. Hattori et al. reported that the posterior horn was involved with mild stage CCM.7 However, it is unclear when the posterior horn is electrophysiologically involved or how the spinal cord lesions including the posterior horn progress from a mild to severe stage. The median and ulnar nerves are formed by the union of the C6–T1 nerve roots and C8/T1 nerve roots, respectively.8 Therefore, MN-SCEPs and UN-SCEPs at the C4–C5 intervertebral level are mediated by the posterior horn (laminae IV–V) and the ascending tract, respectively.9,10 Ueta et al. reported the origin of the UN-SCEPs was mainly the posterior funiculus (the Burdach tract).10Table 1 shows the relationships between type of SCEPs, area of spinal cord, and neurological findings (Fig. 1). Here, we aimed to electrophysiologically evaluate the function of three spinal tracts and the posterior horn in patients with CCM at the C4–C5 intervertebral level in addition to SCEPs which stimulated the ulnar nerve. Moreover, we aimed to correlate the progression of spinal cord lesions with neurological findings.
Related Knowledge Centers
- Dorsal Root Ganglion
- Proprioception
- Somatosensory System
- Spinal Cord
- Grey Column
- Transverse Plane
- Rexed Laminae
- Marginal Nucleus of Spinal Cord
- Substantia Gelatinosa of Rolando
- Nucleus Proprius of Spinal Cord