Trunk
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno in Understanding Human Anatomy and Pathology, 2018
The spinal nerves divide into ventral rami and dorsal rami. The ventral rami form the intercostal nerves (T1–T12) in the thoracic region, as well as the cervical plexus, brachial plexus, lumbar plexus, and sacral plexus, thereby supplying the muscles and skin of the upper and lower limbs and part of the trunk. The lumbar plexus, sacral plexus, and pudendal plexus form the lumbosacral plexus. Intercostal nerves T1 to T11 lie together with the intercostal veins and intercostal arteries in the 11 intercostal spaces, while T12 is a subcostal nerve that courses below the 12th rib. The anterior end of an intercostal space is supplied by the anterior intercostal branches of the internal thoracic artery. The intercostal nerves supply the serratus posterior superior and serratus posterior inferior and the external intercostal muscle, internal intercostal muscle, and innermost intercostal muscle. The intercostal nerves also have cutaneous branches at the anterior (ventral) and lateral surfaces of the thoracic wall. The dorsal rami supply the paravertebral muscles (paraspinal muscles) and skin near the midline of the back.
Treatment planning
Jing Cai, Joe Y. Chang, Fang-Fang Yin in Principles and Practice of Image-Guided Radiation Therapy of Lung Cancer, 2017
The brachial plexus is a nervous network that arises from the four lower-most cervical nerves and the first thoracic nerves. This network controls the sensation and motor function of the upper extremities. Radiation injury of the brachial plexus, or brachial plexopathy, may manifest as pain, paresthesia, or motor weakness. A 2012 retrospective study of patients with NSCLC undergoing conventionally fractionated RT with concurrent chemotherapy examining rates of brachial plexopathy found a strong association and higher rates of brachial plexopathy with median brachial plexus doses greater than 69 Gy and doses to 0.1 cm3 of brachial plexus greater than 75 Gy [84]. In a retrospective study from Indiana University looking at apical lung lesions treated with SBRT, a maximum brachial plexus dose of 26 Gy or greater was associated with significantly higher rates of brachial plexopathy. Current clinical trials recommend a maximum dose ≤63–66 Gy [79] with conventional fractionation. For SBRT, brachial plexus dose constraints include 17.5 Gy if single fraction, 24 Gy (8 Gy/fx) max with 3-fraction regimens, 27.2 Gy (6.8 Gy per fraction with 4-fraction regimens, and 32 Gy max (6.4 Gy/fx) with 5-fraction regimens [66].
Anatomy
J. Richard Smith, Giuseppe Del Priore, Robert L. Coleman, John M. Monaghan in An Atlas of Gynecologic Oncology, 2018
The sacral plexus (S1−S5) also gives rise to nerves coursing through the pelvis that can be affected by cancers and surgical procedures. The main nerves are the sciatic (L4−S3), pudendal (S3−S4), and the superior (L4−S1) and inferior (L5−S2) gluteal nerves. Lesser nerves are the nerves to quadratus femoris (L4−S1), pirformis (S1−S2) and levator ani and coccygeus (S3−S4); a posterior cutaneous nerve to the buttocks and superior posteromedial thigh (S2−S3), and the nerve to obturator internus (L5−S2). Pelvic splanchnic (S2−S4) nerves supply pelvic viscera via the inferior hypogastric and pelvic plexuses. The sciatic nerve is located laterally to the internal iliac artery where anterior rami converge on the surface of the piriformis. Usually, the sciatic nerve leaves the pelvis along the inferior border of piriformis. However, branches may pass above and/or below (or through) the piriformis, and then merge to form the sciatic nerve. The sciatic nerve can be compromised by inadequate positioning during surgery and by lateral pelvic wall metastases.
Human inner ear blood supply revisited: the Uppsala collection of temporal bone—an international resource of education and collaboration
Published in Upsala Journal of Medical Sciences, 2018
Xueshuang Mei, Francesca Atturo, Karin Wadin, Sune Larsson, Sumit Agrawal, Hanif M. Ladak, Hao Li, Helge Rask-Andersen
The unique arterial plexus along the modiolus serves to supply the cochlea with a large amount of oxygenated blood. Levin (34) and Malan (49) described vascular convolutions with specialized arterio-venous connections. Schwalbe (40) has already described glomus-like structures and speculated on these functions to even out pulsatile pressure waves. Such pulses could negatively influence the sensitive mechanoreceptors and hearing. Furthermore, Balogh and Koburg (50) described a ‘plexus cochlearis’ in the modiolus with very high metabolic turnover rates, even higher than those of the spiral ganglion. This resembled the choroid plexus with extending spider-web-like connective tissue processes, and they speculated on a secretory function. We found that veins traversed the arterial system in close proximity before joining the inferior cochlear vein (ICV). We speculate that the vascular convolutes could monitor gas exchange and pressure alterations and thereby regulate cochlear blood flow via this well-vascularized zone. Thus, further analyses of the vascular plexus are indicated.
Radiation-induced brachial plexus toxicity after SBRT of apically located lung lesions
Published in Acta Oncologica, 2019
Karin Lindberg, Vitali Grozman, Sara Lindberg, Eva Onjukka, Ingmar Lax, Rolf Lewensohn, Peter Wersäll
The plexus is a fine structure directly adjacent to other soft-tissue structures, complicating the delineation of it. The conclusions of this study rely on the accuracy of the delineation of the plexus and on whether the doses extracted from the DVH:s (based on the planning CT) are representative of the doses actually delivered to the plexus. We used a modified version of the RTOG-contouring protocol [32], which has been criticized for inter-observer variability, however, only resulting in minimal inconsistency of maximum doses [33]. The greatest uncertainty in delineation prevailed in the lateral apical parts of the plexus, generally far from the high dose region in this study. Further, the accuracy of the delineation of the plexus could have been improved by using a contrast-enhanced treatment-planning CT and the usage of thin slices for delineation. Also, although knowing that apical structures of the lung have limited breathing motions, it cannot be ruled out that the plexus may have shifted positions during the breathing cycle, an uncertainty that we cannot foresee or correct for. Taking these uncertainties and limitations into consideration in addition to set-up- and intra-treatment-motion uncertainties, we believe that a planning organ at risk volume (PRV) to the plexus of 2 mm may be advisable to use, with a BED3,max planning constraint in the order of 170 Gy. The sparing of a PRV, however, has to be balanced in each case against the risk of tumor growth into the plexus, causing pronounced cancer morbidity symptoms.
MR neurography of the brachial plexus in adult and pediatric age groups: evolution, recent advances, and future directions
Published in Expert Review of Medical Devices, 2020
Alexander T. Mazal, Ali Faramarzalian, Jonathan D. Samet, Kevin Gill, Jonathan Cheng, Avneesh Chhabra
The Brachial plexus is a large network of peripheral nerves arising from the cervicothoracic spine which provides motor and sensory functions to the upper extremities. The clinical differentiation of brachial plexopathy from cervical spine-related radiculopathy or nerve injury has been a longstanding diagnostic challenge, as history, physical examination findings and electrodiagnostic testing are frequently indeterminate in this domain. MR neurography (MRN) of the brachial plexus has emerged in recent years as a useful modality for the identification of brachial plexopathies in both pediatric and adult populations. The article discusses the current state of brachial plexus MRN, including recent advances and future directions, as well as illustrate adult and pediatric brachial plexopathies that can be optimally characterized using these techniques.
Related Knowledge Centers
- Axon
- Brachial Plexus
- Lumbar Plexus
- Lymphatic Vessel
- Neuroanatomy
- Sacral Plexus
- Cervical Plexus
- Blood Vessel
- Nerve
- Nerve Plexus