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Anatomy overview
Published in Stephanie Martin, Working with Voice Disorders, 2020
The larynx is innervated by branches of the vague nerve on each side. Sensory innervations to the glottis and laryngeal vestibule is by the internal branch of the superior laryngeal nerve. The external branch of the superior laryngeal nerve innervates the cricothyroid muscles. There are eight extrinsic muscles, four of which lie above the level of the hyoid – the suprahyoid muscles, which act principally to elevate the larynx and support the hyoid bone. Four lie below the hyoid – the infrahyoid muscles, which act as laryngeal depressors. The latter are particularly important in lengthening the vocal tract, which has a significant effect on vocal resonance. Detailed descriptions of the extrinsic laryngeal muscles can be found in a number of texts, but for the purposes of this chapter an outline of the muscles, their function and innervation are given in Table 1.4.
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
Together with the hypoglossal nerve (CN XII) (Plate 3.19), the cervical nerves provide motor innervation for all neck and tongue muscles that are derived from somites, but not from the branchial arches—that is, it does not innervate branchiomeric muscles, which are the head muscles in an evolutionary and developmental context. The infrahyoid muscles are closely related developmentally and evolutionarily to the tongue muscles because they are somitic muscles formed by myoblasts that migrated ventrally, around the pharynx, then cranially to be secondarily incorporated into the head and neck. This migration is clearly seen during development, where these muscles migrate via the hypoglossal cord (chorda hypobranchialis) (Plate 3.2). This somitic origin is why the infrahyoid and tongue muscles are both part of the so-called hypobranchial group of muscles. Therefore, it is not surprising that axons of the spinal nerve C1 are carried by the hypoglossal nerve to innervate a tongue muscle (the geniohyoid) and an infrahyoid muscle (the thyrohyoid, via the nerve to the thyroid muscle). The other three infrahyoid muscles (omohyoid, sternothyroid, and sternohyoid) receive motor innervation from the ansa cervicalis, which is formed by the first, second, and third cervical nerves. The other three true tongue muscles (genioglossus, hyoglossus, and styloglossus) receive motor innervation from the hypoglossal nerve (CN XII).
Muscles, Blood Vessels, and Craniofacial Growth: Some Experimental Approaches
Published in D. Dixon Andrew, A.N. Hoyte David, Ronning Olli, Fundamentals of Craniofacial Growth, 2017
The infrahyoid muscles lie below the hyoid bone. They pull the hyoid bone downwards or hold it in place, thus acting as indirect jaw openers. They are also involved in the act of swallowing. As cranial extensions of the rectus system of the anterior abdominal wall they are innervated from the ansa cervicalis, this being made up of cervical nerves one to three.
Endotracheal Tube Electrode Neuromonitoring for Placement of Vagal Nerve Stimulation for Epilepsy: Intraoperative Stimulation Thresholds
Published in The Neurodiagnostic Journal, 2022
Gennadiy A. Katsevman, Darnell T. Josiah, Joseph E. LaNeve, Sanjay Bhatia
Once the carotid sheath is opened, a nerve stimulator is used to test any structure appearing to be a nerve within the sheath. The ansa cervicalis and its branches may then be identified by observable contractions of the infrahyoid muscles. These branches are dissected and preserved, and the dissection is then deepened between the IJV and the CCA. If the vagal trunk is then identified, it is stimulated and the minimal stimulation intensity that produces a detectable response in the vocal cords is recorded. If vocal cord stimulation is seen, then the nerve is confirmed to be the vagus nerve. If no nerve is identified between the CCA and the IJV, the stimulation intensity is increased up to 2 mA and stimulation is performed posterior to the CCA or IJV to locate the nerve. Once vocal cord stimulation is identified, then further dissection is performed in the area of stimulation to fully isolate the nerve. This technique reduces the amount of dissection necessary in the posterior aspect of the carotid sheath and can avoid injury to the phrenic nerve and the sympathetic trunk, which are located posterior to the carotid sheath. Once the vagus nerve is correctly identified and dissected free, minimum stimulating intensity is again recorded. The nerve is then tented up with a yellow vessel loop and stimulated again at the middle to cranial end of the dissection. The minimum stimulation intensity is again recorded. The VNS electrodes are then placed in usual fashion and the nerve is allowed to lay flat. The minimum stimulating intensity proximal to the spiral electrodes is again recorded.
Voice rehabilitation after total laryngectomy with the infrahyoid musculocutaneous flap
Published in Acta Oto-Laryngologica, 2021
Changjiang Li, Yi Fang, Haitao Wu, Min Shu, Lei Cheng, Peijie He
Surgical re-establishment of the laryngeal function is of significant importance for patients who have undergone laryngectomy. The materials currently used for reconstructing the phonation pathway mainly include neoglottis and free or pedicled tissue transfer, other than TEP [9,10]. Besides offering the benefits of tracheal-esophageal speech, tracheopharyngeal phonation has the advantage of precluding the need for prosthesis, although the surgery per se is technically complex. Therefore, investigations and practical application of this method has been relatively less. Some investigators have used free ileocolonic and jejunal flaps to reestablish laryngeal function. Although this approach provide excellent swallowing function, the voice quality and speech fluency were unsatisfactory because intestinal mucosa has a secretive function and has mobility [11,12]. One study used a radial forearm free flap for patients who have undergone laryngectomy; however, the phonation efficacy was reported to be about 70%–90% in that study, and speech intelligibility was poor [13]. The infrahyoid musculocutaneous flap used in the current study is nourished from the superior thyroid vessels and can be harvested relatively easily. The infrahyoid region can provide a skin island of size 8 × 4 cm from the central part of the anterior neck. This flap is multifunctional since it is thin and pliable and has plasticity, thereby allowing for good motility of the preserved structures around the resected area. The infrahyoid muscles fill the deep tissue defect caused by the en block resection with neck dissection [14]. Therefore, it is widely used in head and neck cancer surgery [15,16].
Effects of behavioural swallowing therapy in patients with Parkinson’s disease: A systematic review
Published in International Journal of Speech-Language Pathology, 2023
This review included two device-driven therapies, namely NMES and EMST. NMES delivers electrical stimulation through surface electrodes to increase muscle strength and sensory awareness (Baijens et al., 2012). Park et al. (2018) firstly provided stimulation on the infrahyoid muscles, not suprahyoid muscles, to improve swallowing function in PD. This is based on the idea that depressed hyoid bone with stimulation on the infrahyoid muscles makes a patient experience a greater resistance to hyo-laryngeal elevation during swallowing. In this study, NMES combined with effortful swallowing was effective to improve antero-superior movement of hyoid bone and reduce aspiration in the PD group. Participants also received conventional dysphagia therapy with NMES. Thus, the results need to be interpreted from the lens of combined treatment; nonetheless, the synergistic effect of NMES with both effortful swallowing and conventional therapy was positive on swallowing function. Further research is required to understand the isolated contribution of NMES in PD swallowing treatment. The second device-driven therapy, EMST has been shown to be an effective treatment method for swallowing in PD as shown in the study of Claus et al. (2021), although no studies have described the detraining effects of EMST to identify the need for maintenance programs after the training periods. The EMST by Troche et al. (2014) investigated the detraining effects of EMST on swallowing in PD to identify maintenance training for swallowing function. In this study, participants with more impaired swallowing function detrained at a greater rate than did those who had less impaired swallowing function. There, we speculate that the maintenance EMST training may also be necessary for patients with neurodegenerative diseases to manage and optimise swallowing function with disease progression, and requires more investigation, particularly as EMST is considered a cost-effective swallowing therapy in PD.