Neurological manifestations of West Nile virus
Avindra Nath, Joseph R. Berger in Clinical Neurovirology, 2020
Another important subset of WNV neuroinvasive disease is “acute flaccid paralysis,” or West Nile paralysis (WNP). WNP results from infection and injury or death of motor neurons in the anterior horn cells of the spinal cord. It is estimated to occur in about 5%–10% of those with encephalitis, but may also occur as the sole or major manifestation of neuroinvasive disease. The onset of weakness is often abrupt and may occur within 72 hours from the onset of systemic symptoms [48]. The pattern of weakness is generally asymmetrical and frequently involves the legs more often than the arms. The spectrum of weakness can range from monoplegia to dense quadriplegia. Sejvar et al. reported on the patterns of weakness in 32 patients with WNP and found that 64% had quadriplegia, 24% had bilateral arm or leg weakness, and 20% had monoplegia [48]. In severe cases, there can be paralysis of the diaphragmatic and intercostal muscles leading to respiratory failure. In the previously mentioned study, 11/25 patients (44%) with WNP required intubation and mechanical ventilation. Compared with those without respiratory failure, these patients tended to be immunosuppressed (33% vs. 0%), have bulbar dysfunction leading to dysarthria and dysphagia (92% vs. 15%), and have concurrent encephalitis (100% vs. 25%) [48].
The Intercostal Muscles
Alan D. Miller, Armand L. Bianchi, Beverly P. Bishop in Neural Control of the Respiratory Muscles, 2019
Histological and electrophysiological studies have revealed the structural and functional intricacy of the intercostal muscles. It seems obvious that the rib cage is nonhomogeneous in that it is composed of motor components that vary according to their location in the intercostal spaces of the rostral part or of the base of the thorax. Furthermore, in each intercostal space, the same intercostal muscles (internal or external intercostal muscles) can be functionaly different according to their dorsal, lateral, or ventral position (Figure 4). For each intercostal muscle, the “postural-respiratory” functional duality results from the complex combination of its architecture (slow and fast motor units), the density of its spindles, and the spatial pattern of distribution of central and segmental afferents that control its motoneuron output. This complexity of organization of the central nervous control of the intercostal muscles is also illustrated by a “functional” somatotopy of the intercostal motoneurons in the thoracic spinal cord.
A to Z Entries
Clare E. Milner in Functional Anatomy for Sport and Exercise, 2019
The muscles of the thorax itself are the internal and external intercostals, subcostals, transverse thoracis, levatores costarum, inferior and superior serratus posterior, and the diaphragm. The 11 intercostal muscles lie between the ribs and draw adjacent ribs together. When the first rib is braced by the scalene muscles that run between it and the cervical vertebrae, the external intercostals increase the volume of the thoracic cavity by raising the ribs on contraction. Conversely, when the last rib is braced by the quadratus lumborum muscle in the lumbar region, the internal intercostals decrease the volume of the thoracic cavity. Similarly, the action of transversus thoracis is to draw the anterior part of the ribs distally and decrease the volume of the thoracic cavity. The levatores costarum and superior serratus posterior raise the ribs and increase the thoracic volume. The inferior serratus posterior draws the distal ribs outwards and downwards, counteracting the inward pull of the diaphragm.
“Undercutting of the corresponding rib”: a novel technique of increasing the length of donor in intercostal to musculocutaneous nerve transfer in brachial plexus injury
Published in British Journal of Neurosurgery, 2023
Kuntal Kanti Das, Jeena Joseph, Jaskaran Singh Gosal, Deepak Khatri, Pawan Verma, Awadhesh K Jaiswal, Arun K Srivastava, Sanjay Behari
Intercoastal nerves are frequently used for neurotization procedures in brachial plexus injuries. Due to a number of concerns, the upper intercostal nerves T3-T5 are favored as donors. The upper intercostal nerves (T3-T6) run parallel to the corresponding ribs in between the middle and the innermost intercostal muscles. For musculocutaneous nerve neurotization, ICNS 3rd to 5th are used as these 3 nerves combined not only provide a perfect size match but also the requisite number of motor axon available in these otherwise mixed nerves.6,7 The intercostal nerves are harvested starting proximally from the anterior axillary line, from the point of origin of serratus anterior muscle digitations to the costochondral junction distally. The general recommendation is to dissect as distally as possible to have a long donor nerve. However, the ICN becomes thinner as it moves towards the midline, with most of the motor branches leaving the nerve to supply the muscles. More proximally, the ICN remains hidden beneath the rib in the costal groove, which is itself covered by serratus anterior digitations. This anatomical fact was utilized by us and undercutting of the rib provided us with a few extra centimeters of ICN to obtain a tensionless co-aptation of ICN-MCN (Figure 3(B)).
Long COVID – respiratory symptoms in non-hospitalised subjects – a cross-sectional study
Published in European Journal of Physiotherapy, 2022
Monika Fagevik Olsén, Louise Lannefors, Malin Nygren-Bonnier, Ewa-Lena Johansson
Details, per patient, are presented in supplement. Concerning spirometry six of the subjects had a reduced FVC and seven reduced FEV1. PEF was below normal values in one subject (data not shown). Sixty-four percent had reduced MIP and 17% reduced MEP. Physical capacity (6MWT n = 14 and TST n = 38) was reduced in 69% of the subjects, desaturation during the test (SpO2 < 92) was found in 10%. Thoracic expansion was reduced in 26% of the subjects, and of those, four subjects showed <20% of the predicted value. Secretions were reported during auscultation in one and ronchi was detected in 15 of the subjects. Pain was found in 67% of the subjects in either the sternocostal joints, the intercostal muscles, or both. Breathing pattern was found divergent in 57 of the 60 subjects (95%) and most common was breathing predominantly in the upper and lower thoracic level with no or minor abdominal movement (diaphragmatic breathing) in sitting and standing (see Table 2).
Ultrasonographic evaluation of diaphragm thickness and excursion in patients with cervical spinal cord injury
Published in The Journal of Spinal Cord Medicine, 2021
Zhizhong Zhu, Jianjun Li, Degang Yang, Feng Gao, Liangjie Du, Mingliang Yang
Diaphragm excursion was also seen as an index of diaphragmatic contractile activity19,20 and mainly related to the inspired volume.21 Ultrasound imaging measurement is useful to accurately evaluate diaphragm excursions at the end of tidal breathing.22 In tetraplegia, distortion of the respiratory system causes inefficient ventilation. During spontaneous breathing, the lack of activity in the external intercostal muscles causes distortion where the upper anterior rib cage moves inward during inhalation diminishing the extent of rib-cage expansion that the diaphragm can contribute to.23 This study confirms this: at the end of quiet tidal breathing, diaphragm excursion in patients with cervical SCI was greater than control participants when compensating for insufficient tidal volume. Meanwhile, during maximal inspiration, no diaphragm excursion difference was found.
Related Knowledge Centers
- Breathing
- Exhalation
- External Intercostal Muscles
- Internal Intercostal Muscles
- Muscle
- Thoracic Wall
- Inhalation
- Thoracic Cavity
- Rib Cage
- Innermost Intercostal Muscle