Thorax
David Heylings, Stephen Carmichael, Samuel Leinster, Janak Saada, Bari M. Logan, Ralph T. Hutchings in McMinn’s Concise Human Anatomy, 2017
Phrenic nerves - descending from the neck (p. 88), the left phrenic nerve (Figs. 5.4A, 5.5A) runs caudally over the left side of the arch of the aorta and the pericardium overlying the left ventricle to pierce the muscular part of the diaphragm. The right phrenic nerve (Fig.5.6) runs caudally beside the superior vena cava and the pericardium overlying the right atrium to pass through the right side of the vena caval foramen in the tendon of the diaphragm. Both phrenic nerves spread out on the abdominal surface of the diaphragm as the motor supply to the muscle fibres of their respective halves. Although the peripheral part of the diaphragm receives fibres from lower intercostal nerves, these are afferent only; the only motor supply is from the phrenic nerves. The phrenic nerves also have a large afferent area of supply: diaphragm, mediastinal and diaphragmatic pleura, pericardium and subdiaphragmatic peritoneum (hence referred pain from these areas is commonly to the C4 dermatome just superior to the shoulder; Fig. 3.17).
Forensic Pathophysiology of Asphyxial Death
Sudhir K. Gupta in Forensic Pathology of Asphyxial Deaths, 2022
It supports the muscles of inspiration and expiration. Respiration is regulated by two different neural mechanisms: the first one is for voluntary control and the second for autonomic control. The cerebral cortex is the seat controlling the voluntary respiratory movements via transmission of regulating impulses through the corticospinal tracts to the respiratory motor neurons. The autonomic control system is orchestrated by a group of pacemaker cells in the medulla oblongata, which activate the motor neurons in cervical and thoracic spinal cord controlling the inspiratory muscles. Phrenic nerve originates from the cervical roots C2–C4 and controls the diaphragm, while external intercostal muscles are controlled by the thoracic nerves of the spinal cord.
Technical aspects of treating aortic aneurysms
Peter A. Schneider in Endovascular Skills: Guidewire and Catheter Skills for Endovascular Surgery, 2019
The most common of these procedures is the left carotid-to-subclavian artery bypass (Figure 28.16). This is because type B aortic dissection is increasingly being treated with stent–graft coverage to manage short-term complications, enhance long-term remodeling, and prevent aneurysm degeneration. Because the pathology of type B aortic dissection usually initiates at the level of the left subclavian artery, it is common for this area to require coverage in order to have graft sealing in healthy aorta proximal to the dissection site. The left carotid-to-subclavian artery bypass is best performed by using a transverse supraclavicular incision. The proximal left common carotid artery is exposed. The anterior scalene muscle is divided. The phrenic nerve is located on the anterior surface of the muscle and must be preserved. Just posterior to the muscle is the left subclavian artery. The jugular vein is located slightly anterior and lateral to the common carotid artery. The graft is usually tunneled posterior to the jugular vein. Either anastomosis may be performed first. After the carotid-to-subclavian bypass has been carried out, the aortic stent–graft is placed. Lastly, a plug is placed in the proximal left subclavian artery. The proximal left subclavian artery can also be ligated, but it must be ligated proximal to the origin of the left vertebral artery. This can be difficult when the origin of the vertebral artery is quite proximal.
Stimulation of abdominal and upper thoracic muscles with surface electrodes for respiration and cough: Acute studies in adult canines
Published in The Journal of Spinal Cord Medicine, 2018
James S. Walter, Joseph Posluszny, Raymond Dieter, Robert S. Dieter, Scott Sayers, Kiratipath Iamsakul, Christine Staunton, Donald Thomas, Mark Rabbat, Sanjay Singh
There is a continuing need to develop improved methods to assist with ventilation and cough following SCI, particularly in individuals with tetraplegia.27 Current results with surface electrodes and the 12-Channel Neuroprosthetic Platform extends our prior findings toward this goal.11,25–31 Further study is needed, because some of the current studies were limited to only two or three animals and other limitations cited above. Clinical testing of some of the current methods, however, is warranted because surface electrode stimulation is widely used in patients with SCI.19–23 Such testing depend on the level of spinal cord injury because the stimulation has to be applied in non-sensate areas. For SCI at low spinal cord levels, surface stimulation is limited to lower thoracic and abdominal muscles. For individuals with cervical level SCI, surface stimulation could be applied to both extradiaphragmatic muscles for expiration. For individuals receiving phrenic nerve stimulation for diaphragmatic inspiration, stimulation of the extradiaphragmatic muscles could be coordinated with the diaphragm. Monitoring during upper thorax stimulation should include EKG recording to assess the occurrence of heart arrhythmia, which, if observed, would mandate stopping stimulation.
Thoracoscopic intercostal to phrenic nerve transfer for diaphragmatic reanimation in a child with tetraplegia
Published in The Journal of Spinal Cord Medicine, 2021
Jacob Latreille, Erika B. Lindholm, Dan A. Zlotolow, Harsh Grewal
The phrenic nerve receives input from the ventral rami of C3, C4, and C5 and descends superficially to the anterior scalene towards the diaphragm where it separates into three branches to provide innervation inferiorly.2,13 It is the only nerve to supply motor innervation to the diaphragm. Dysfunction of the phrenic nerve therefore leads to pneumonia, sleep disorders, pulmonary effusion, atelectasis, and ventilator dependency.9 These injuries can often be assessed by NCS and needle electromyography in conjunction with M-mode ultrasound.14,15 If spinal cord levels C3, C4, or C5 are all within the zone of injury to the spinal cord, pacing the phrenic nerve is impossible due to Wallerian degeneration of the nerve distally and inability to propagate electrical signals.13 To overcome the loss of axons in the phrenic nerve, multiple nerve transfers have been recommended. The goal is to achieve ventilator independency; an outcome associated with increased mobility, speech, quality of life, and reduced health care costs.9
End-to-side neurotization with the phrenic nerve in restoring the function of toe extension: an experimental study in a rat model
Published in Journal of Plastic Surgery and Hand Surgery, 2018
Xiaotian Jia, Chao Chen, Jianyun Yang, Cong Yu
The function of toe extension was lost due to the surgery, while the function of wrist extension existed. None of the rats of these two groups experienced tachypnea. End-to-side neurotization with the phrenic nerve proved that it could preserve the function of the phrenic nerve and do not affect the respiratory. Furthermore, no ulcerations were discovered on the surgical side in two groups, which means there was no obvious sensory disturbance on the surgical side. The motion of slight toe extension was observed in Group A between 32 to 43 days (average 37.94 ± 3.51 days). Besides, the motion showed a same rhythm as the respiratory rate and didn't disappear under anesthesia. These proved that the motion of toe extension was innervated by the phrenic nerve. The motion of toe extension was identified in Group B between 25 to 30 days (average 27.33 ± 2.06 days).
Related Knowledge Centers
- Brachial Plexus
- Muscle
- Spinal Nerve
- Cervical Plexus
- Respiratory System
- Nerve
- Thoracic Diaphragm
- Cervical Spinal Nerve 4
- Central Tendon of Diaphragm
- Pulmonary Pleurae