1
|
Neuromuscular Specializations of the Human Hypopharyngeal Muscles. Dysphagia 2020; 36:769-785. [PMID: 33159539 DOI: 10.1007/s00455-020-10212-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/03/2020] [Indexed: 10/23/2022]
Abstract
The hypopharyngeal muscles in humans play a vital role in swallowing, speech, and respiration. Increasing evidence indicates that these muscles are specialized to perform life-sustaining upper aerodigestive functions. This review aims to provide current knowledge regarding the key structural, physiological, and biochemical features of the hypopharyngeal muscles, including innervation, contractile properties, histochemistry, biochemical properties, myosin heavy chain (MyHC) expression and regulation, and age-related alterations. These would clarify the unique neuromuscular specializations of the human hypopharyngeal muscles for a better understanding of the functions and pathological conditions of the pharynx and for the development of novel therapies to treat related upper airway disorders.
Collapse
|
2
|
Hong YT, Hong KH, Jun JP, Hwang PH. The effects of dynamic laryngeal movements on pitch control. Am J Otolaryngol 2015; 36:660-5. [PMID: 26095529 DOI: 10.1016/j.amjoto.2015.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/04/2015] [Accepted: 05/26/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Extralaryngeal structures have been known to not only play an important role in swallowing, but also have a significant influence on the voice during phonation. The aim of this study is to evaluate the effect of dynamic laryngeal movements on pitch control. SUBJECTS AND METHODS Videofluoroscopic examinations were analyzed. To accurately analyze the sequence of these movements, the recorded images were digitized using a computer program. The moving distances of the hyoid bone, thyroid cartilage, and cricoid cartilage were analyzed, and they were compared to the cricothyroid distance during pitch elevation. RESULTS The vertical movements of the hyoid bone, and cricoid and thyroid cartilages had an impact on the increase in the pitch with a decrease in the cricothyroid distance. All Ad-R(2) values for distance of the hyoid bone, and cricoid and thyroid cartilages were above 0.9, which showed a higher explanatory power than the cricothyroid distance, showing an Ad-R(2) value of 0.4. CONCLUSIONS Upward movements of the larynx had a more dominant effect on pitch elevation than the cricothyroid distance. We suspect that the pitch is more affected by the antero-vertical movements of the larynx than the horizontal movement by cricothyroid muscle in human study.
Collapse
|
3
|
Cheetham J, Jones A, Martin-Flores M. Effect of inhaled carbon dioxide on laryngeal abduction. J Appl Physiol (1985) 2015; 118:489-94. [DOI: 10.1152/japplphysiol.00469.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypercapnia produces a profound effect on respiratory drive and upper airway function to maintain airway patency. Previous work has evaluated the effects of hypercapnia on the sole arytenoid abductor, the posterior cricoarytenoid (PCA), using indirect measures of function, such as electromyography and direct nerve recording. Here we describe a novel method to evaluate PCA function in anesthetized animals and use this method to determine the effects of hypercapnia on PCA function. Eight dogs were anesthetized, and a laryngeal mask airway was used, in combination with high-speed videoendoscopy, to evaluate laryngeal function. A stepwise increase in inspired partial pressure of CO2 produced marked arytenoid abduction above 70-mmHg end-tidal CO2 (ETCO2) ( P < 0.001). Glottic length increased above 80-mmHg ETCO2 ( P < 0.02), and this lead to underrepresentation of changes in glottic area, if standard measures of glottic area (normalized glottic gap area) were used. Use of a known scale to determine absolute glottic area demonstrated no plateau with increasing ETCO2 up to 120 mmHg. Ventilatory parameters also continued to increase with no evidence of a maximal response. In a second anesthetic episode, repeated bursts of transient hypercapnia for 60 s with an ETCO2 of 90 mmHg produced a 43–55% increase in glottic area ( P < 0.001) at or shortly after the end of the hypercapnic burst. A laryngeal mask airway can be used in combination with videoendoscopy to precisely determine changes in laryngeal dimensions with high temporal resolution. Absolute glottic area more precisely represents PCA function than normalized glottic gap area at moderate levels of hypercapnia.
Collapse
|
4
|
Reesink HL, Hermanson JW, Cheetham J, Mu L, Mitchell LM, Soderholm LV, Ducharme NG. Anatomic and neuromuscular characterisation of the equine cricothyroid muscle. Equine Vet J 2013; 45:630-6. [DOI: 10.1111/evj.12023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 11/09/2012] [Indexed: 11/25/2022]
Affiliation(s)
- H. L. Reesink
- Department of Clinical Sciences; College of Veterinary Medicine; Cornell University; Ithaca New York USA
| | - J. W. Hermanson
- Department of Biomedical Sciences; College of Veterinary Medicine; Cornell University; Ithaca New York USA
| | - J. Cheetham
- Department of Clinical Sciences; College of Veterinary Medicine; Cornell University; Ithaca New York USA
| | - L. Mu
- Upper Airway Research Laboratory; Department of Research; Hackensack University Medical Center; Hackensack New Jersey USA
| | - L. M. Mitchell
- Department of Clinical Sciences; College of Veterinary Medicine; Cornell University; Ithaca New York USA
| | - L. V. Soderholm
- Department of Clinical Sciences; College of Veterinary Medicine; Cornell University; Ithaca New York USA
| | - N. G. Ducharme
- Department of Clinical Sciences; College of Veterinary Medicine; Cornell University; Ithaca New York USA
| |
Collapse
|
5
|
An X, Yue B, Lee JH, Lee MS, Lin C, Han SH. Intramuscular distribution of the phrenic nerve in human diaphragm as shown by Sihler staining. Muscle Nerve 2012; 45:522-6. [PMID: 22431085 DOI: 10.1002/mus.22141] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Intramuscular innervation of the human diaphragm has not been well described. The goal of this study was to elucidate the detailed intramuscular distribution of the phrenic nerve in the human diaphragm. METHODS Fifteen human diaphragms were visualized using modified Sihler staining, and the detailed intramuscular phrenic nerve distribution was photographed and recorded. RESULTS Three types of primary phrenic nerve branches were noted. Each type of primary branch innervated a confined muscular subvolume of the diaphragm, and the intramuscular branches in each subvolume anastomosed largely with one another and formed a characteristic "net" of nerve branches. A few small nerve filaments were seen entering the peripheral diaphragm. The directions and locations of nerve branches innervating the hiatal diaphragm were not symmetrical between sides. CONCLUSION These findings may offer useful information for anatomists, physiologists, and clinicians.
Collapse
Affiliation(s)
- Xiaochun An
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, 505, Banpo-dong, Seocho-gu, Seoul 137-701, Korea
| | | | | | | | | | | |
Collapse
|
6
|
Mu L, Sanders I. Sihler's whole mount nerve staining technique: a review. Biotech Histochem 2010; 85:19-42. [PMID: 19572223 DOI: 10.3109/10520290903048384] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sihler's stain is a whole mount nerve staining technique that renders other soft tissue translucent or transparent while staining the nerves. It permits mapping of entire nerve supply patterns of organs, skeletal muscles, mucosa, skin, and other structures after the specimens are fixed in neutralized formalin, macerated in potassium hydroxide, decalcified in acetic acid, stained in Ehrlich's hematoxylin, destained in acetic acid, and cleared in glycerin. The unique advantage of Sihler's stain over other anatomical methods is that all the nerves within the stained specimen can be visualized in their three-dimensional positions. To date, Sihler's stain is the best tool for demonstrating the precise intramuscular branching and distribution patterns of skeletal muscles, which are important not only for anatomists, but also for physiologists and clinicians. Advanced knowledge of the neural structures within mammalian skeletal muscles is critical for understanding muscle functions, performing electrophysiological experiments and developing novel neurosurgical techniques. In this review, Sihler's stain is described in detail and its use in nerve mapping is surveyed. Special emphasis is placed on staining procedures and troubleshooting, strengths and limitations, applications, major contributions to neuroscience, physiological and clinical significance, and areas for further technical improvement that deserve future research.
Collapse
Affiliation(s)
- L Mu
- Upper Airway Research Laboratory, Department of Research, Hackensack University Medical Center, Hackensack, NJ 07601, USA.
| | | |
Collapse
|
7
|
Mu L, Sanders I. Newly revealed cricothyropharyngeus muscle in the human laryngopharynx. Anat Rec (Hoboken) 2008; 291:927-38. [PMID: 18521893 DOI: 10.1002/ar.20727] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Humans have a uniquely curved pharynx and tongue that is believed to have evolved for speech. The most inferior part of the pharynx consists of the laryngopharynx, the critical crossroad where swallowing, breathing, and phonation overlap. We hypothesized that the human laryngopharynx has unique neuromuscular specializations that may be speech related. Laryngopharynx specimens from 15 humans and 20 nonhuman mammals (dog, pig, rabbit, and rat) were studied. Microdissection revealed that only human specimens had a muscle originating from the anterior arch of the cricoid cartilage, and coursing between the inferior pharyngeal constrictor and cricopharyngeus muscles to insert into the median raphe at the posterior midline of the pharynx. On the basis of these anatomic features, we termed it the "cricothyropharyngeus" (CTP). The structure, innervation, and muscle fiber types of the human CTP were further investigated by histological methods, Sihler's stain, and myosin heavy chain (MHC) immunocytochemistry. The innervation and muscle fiber types of the CTP were found to differ from those of neighboring muscles. The laryngeal portion of the CTP was innervated by the external superior laryngeal nerve, whereas the pharyngeal portion of the muscle was supplied by the pharyngeal plexus. Most notable was that the CTP contained specialized muscle fibers expressing some unusual MHC isoforms (i.e., slow-tonic, alpha-cardiac, neonatal, and embryonic). In conclusion, the CTP appears to be a newly described and uniquely human muscle with characteristics suggesting a specialized function that may be speech related.
Collapse
Affiliation(s)
- Liancai Mu
- Department of Otolaryngology, Upper Airway Research Laboratory, Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
| | | |
Collapse
|
8
|
Mu L, Sanders I. The human cricothyroid muscle: three muscle bellies and their innervation patterns. J Voice 2008; 23:21-8. [PMID: 18191374 DOI: 10.1016/j.jvoice.2007.08.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 08/07/2007] [Indexed: 11/19/2022]
Abstract
We hypothesized that the phonatory and respiratory functions of the human cricothyroid (CT) muscle are subserved by separately controlled muscle bellies. In this work, 30 autopsied adult human hemilarynges were used to determine the neuromuscular organization of the CT muscle using microdissection, histology, and Sihler's stain. The results showed that the human CT was composed of three bellies: rectus, oblique, and horizontal. External superior laryngeal nerve (ESLN) was found to enter into the CT muscle as a single trunk (37.5%) or multiple (two to five) branches (62.5%). Within the CT muscle, the ESLN gave off three to seven branches to innervate the rectus belly and one or two branches to supply the oblique and horizontal bellies, respectively. Notably, ESLN also gave off branches to innervate the ipsilateral thyroarytenoid muscle (46%) and subglottic mucosa (67%) or connect with the recurrent laryngeal nerve (25%). These findings suggest that the CT bellies appear to be functionally designed for different motor tasks. The data are also useful for further clarifying the functions of the CT bellies and the ESLN branches and for developing belly-based reinnervation procedures to treat laryngeal paralysis.
Collapse
Affiliation(s)
- Liancai Mu
- Upper Airway Research Laboratory, Department of Otolaryngology, Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
| | | |
Collapse
|
9
|
Numasawa T, Shiba K, Nakazawa K, Umezaki T. Membrane potential changes in vocal cord tensor motoneurons during breathing, vocalization, coughing and swallowing in decerebrate cats. Neurosci Res 2004; 49:315-24. [PMID: 15196780 DOI: 10.1016/j.neures.2004.03.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2004] [Accepted: 03/26/2004] [Indexed: 11/25/2022]
Abstract
We studied the patterns of membrane potential changes in vocal cord tensor motoneurons, i.e. cricothyroid muscle motoneurons (CTMs), during fictive breathing, vocalization, coughing, and swallowing in decerebrate paralyzed cats to determine the nature of central drives to CTMs during these behaviors. CTMs were identified by antidromic activation from the superior laryngeal nerve. During breathing, CTMs always depolarized during the inspiratory phase, and sometimes depolarized during the expiratory phase as well. During vocalization, CTMs strongly depolarized. During coughing, CTMs exhibited depolarizations during both inspiratory and expiratory phases, but it was interrupted by a transient repolarization between the last part of the inspiratory phase and the first part of the abdominal burst during which chloride-dependent inhibitory postsynaptic potentials were revealed. During swallowing, most CTMs hyperpolarized, and this hyperpolarization was sometimes followed by a weak depolarization. We conclude that the main role of the cricothyroid muscle is vocalization but the functional roles in coughing and swallowing are minor, and that the CTM activity during resting breathing and vocalization are primarily controlled by excitatory inputs, while during coughing and swallowing, inhibitory inputs play roles in shaping membrane potential trajectories.
Collapse
Affiliation(s)
- Tamaki Numasawa
- Department of Otolaryngology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chiba 260-8670, Japan.
| | | | | | | |
Collapse
|
10
|
Abstract
Although a tremendous volume of energy and literature has been devoted to laryngeal paralysis in the past decade, there are still substantial gaps in our understanding of fundamental issues. Oddly enough, controversy remains regarding the actual innervation pathways of the larynx and whether the paralyzed larynx is truly denervated or dysfunctionally reinnervated. An appreciation of these basic issues is prerequisite to making prudent decisions regarding the most appropriate type of intervention. The purpose of this article is to provide a brief overview of basic laryngeal anatomy and neurophysiology to prepare the reader for a subsequent discussion of futuristic research for treatment of laryngeal paralysis.A novel approach is described, which can induce selective reinnervation of individual laryngeal muscles by their original motor fibers within the recurrent laryngeal nerve.
Collapse
Affiliation(s)
- David L Zealear
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University School of Medicine, S2100 Medical Center North, Nashville, TN 37232, USA.
| | | |
Collapse
|
11
|
Hong KH, Kim HK, Kim YH. The role of the pars recta and pars oblique of cricothyroid muscle in speech production. J Voice 2001; 15:512-8. [PMID: 11792027 DOI: 10.1016/s0892-1997(01)00051-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
To evaluate the functional difference of the pars recta and pars oblique during speech production, the electromyographic activities of these muscles were measured in thyroidectomized patients. The hooked wire electrodes were inserted into the normal side of the bellies of the pars recta and pars oblique bundles. Two kinds of sentences were used to obtain pitch changes, a simple interrogative sentence and a complex sentence with stress contrasts. The pars recta and pars oblique were simultaneously activated for initial lengthening and tensing of vocal folds to produce speech. The pars oblique might be initially more active than the pars recta at the initial task of speech and the pars recta might be more active at the pitch elevation in the interrogative sentence and the stress contrast of the complex sentence. The maximum electromyographic activity range of the pars recta and pars oblique seemed to be nearly equal. These results demonstrated that the patterns of electrical activities of the two bellies are different during speech and the combined activities of the pars recta and pars oblique are important in the adjustment of the vocal fold length during speech.
Collapse
Affiliation(s)
- K H Hong
- Department of Otolaryngology-Head and Neck Surgery, Chonbuk National University, Medical School, Institute for Speech Science, Chonju, Korea.
| | | | | |
Collapse
|
12
|
Mu L, Sanders I. Neuromuscular specializations of the pharyngeal dilator muscles: II. Compartmentalization of the canine genioglossus muscle. THE ANATOMICAL RECORD 2000; 260:308-25. [PMID: 11066041 DOI: 10.1002/1097-0185(20001101)260:3<308::aid-ar70>3.0.co;2-n] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The genioglossus (GG) muscle is divided into horizontal and oblique compartments that are the main protrusor and depressor muscles of the tongue, respectively. In humans the GG plays an important role in speech articulation, swallowing, and inspiratory dilation of the pharynx. At present, little is known about the neuromuscular specializations of the GG in any mammal. This study examined the specializations of these compartments in the canine tongue using a variety of anatomical and histochemical techniques. Six canine GG muscles were sectioned and stained for myofibrillar ATPase to study muscle fiber types; five whole-mount GG muscles were stained for acetylcholinesterase (AChE) to study the distribution of motor endplates; and eight whole mount GG muscles were processed with Sihler's stain to study the entire nerve supply pattern. In addition, the arrangement of muscle fibers of the GG within the tongue was also determined (N = 3). The most notable difference between the compartments of the GG was their proportions of fast and slow twitch muscle fibers: the horizontal compartment contained 64% slow twitch muscle fibers compared to 41% in the oblique compartment. In addition, although the oblique compartment appeared to be grossly homogeneous, it could be divided into thirds by significant differences in the percentages of slow twitch fibers: posterior (23%), middle (15%), and anterior (56%; P < 0.05). The muscle fibers of the oblique GG within the tongue were found to be divided into medial and lateral layers that run vertically and transversely, respectively. The nerve supply to each third of the oblique GG formed a plexus with the anterior third being the densest. The innervation pattern of the oblique GG was also notable as terminal nerve branches coursing parallel to the muscle fascicles gave off perpendicular secondary branches along each motor endplate band. These secondary nerve branches connected the primary nerves and formed a regularly spaced grid throughout the compartment. Evidently, the two compartments of the GG exhibited different anatomical specializations. The horizontal had a slow muscle fiber profile and simple innervation pattern; these qualities are possibly related to its single force vector and respiratory related activity. The oblique compartment had a relatively fast muscle fiber profile with evidence for three separate functional subdivisions. The most anterior part was noticeably different, and was presumably specialized for fine motor control of the tip of the tongue. The vertically oriented fibers of the oblique GG within the tongue body may function as a midline depressor of the tongue, whereas its transversely oriented fibers could play a role in narrowing the tongue during other motor tasks.
Collapse
Affiliation(s)
- L Mu
- Grabscheid Voice Center, Department of Otolaryngology, The Mount Sinai Medical Center, New York, New York 10029, USA
| | | |
Collapse
|
13
|
Cox KA, Alipour F, Titze IR. Geometric structure of the human and canine cricothyroid and thyroarytenoid muscles for biomechanical applications. Ann Otol Rhinol Laryngol 1999; 108:1151-8. [PMID: 10605920 DOI: 10.1177/000348949910801210] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The geometric structure of the cricothyroid (CT) muscle and thyroarytenoid (TA) muscle was quantified in 6 human and 3 canine larynges. Each muscle was divided into a series of fiber bundles. With a 3-dimensional micrometer probe, the coordinates of the origin and insertion of each bundle were measured before dissection. It was found that the mass of the CT muscle in the dog was 1.463+/-0.280 g, which was significantly greater than the 0.9423+/-0.123 g found in the human. This was a result of the cross-sectional area of the canine CT muscle being 105.3+/-11.6 mm2 instead of the 73.8+/-7.4 mm2 found for the human. However, the ratios of CT/TA mass and cross-sectional area between the two groups were not significantly different, suggesting that the two muscles grow proportionally.
Collapse
Affiliation(s)
- K A Cox
- National Center for Voice and Speech and the Department of Speech Pathology and Audiology, The University of Iowa, Iowa City 52242-1012, USA
| | | | | |
Collapse
|
14
|
Abstract
The tongue manipulates food while chewing and swallowing, dilates the airway during inspiration, and shapes the sounds of speech in humans. While performing these functions the tongue morphs through many complex shapes. At present it is not known how the muscles of the tongue perform these complex shape changes. The difficulty in understanding tongue biomechanics is partly due to gaps in our knowledge regarding the complex neuromuscular anatomy of the tongue. In this study the motor and sensory nerve anatomy of four canine tongues was studied with Sihler's stain, a technique that renders most of the tongue tissue translucent while counterstaining nerves. An additional tongue specimen was serially sectioned to provide a reference for the muscle structure of the tongue. The hypoglossal nerve (XII) has approximately 50 primary nerve branches that innervate all intrinsic and extrinsic tongue muscles. Two extrinsic muscles, the styloglossus and hyoglossus, are innervated by about three to four branches from the lateral division of the XII. The third extrinsic muscle, the genioglossus, is composed of oblique and horizontal compartments, which receive about ten nerve branches from the medial division of the XII. The intrinsic muscles are composed of many neuromuscular compartments. On each side, the superior longitudinal muscle had an average of 40 distinct muscle fascicles that spanned the length of the tongue. Each of the fascicles is supplied by a nerve branch. The inferior longitudinal muscle had a similar organization. Each of the transverse and vertical muscles is composed of over 140 separate muscle sheets, and every sheet is innervated by a separate terminal nerve. The muscle sheets from the vertical and transverse alternate their orientation 90 degrees throughout the length of the tongue. It is concluded that the intrinsic canine tongue muscles are actually composed of groups of neuromuscular compartments that are arranged in parallel (longitudinal muscles) or in a precise alternating sequence (transverse and vertical muscles). This arrangement suggests that the compartments from the different tongue muscles could cooperate to control the three-dimensional contractile state of their local area. This hypothesis could explain how many different tongue shapes are formed, and is supported by physiologic evidence.
Collapse
Affiliation(s)
- L Mu
- Grabscheid Voice Center, Department of Otolaryngology, The Mount Sinai Medical Center, New York, New York 10029-6574, USA
| | | |
Collapse
|
15
|
Abstract
Active and passive characteristics of the canine cricothyroid muscle were investigated through a series of experiments conducted in vitro and compared with their counterparts in the thyroarytenoid muscle. Samples from separate portions of canine cricothyroid muscle, namely, the pars recta and pars obliqua, were dissected from dog larynges excised a few minutes before death and kept in Krebs-Ringer solution at a temperature of 37 degrees C +/- 1 degrees C and a pH of 7.4+/-0.05. Active tetanic stress was obtained in isometric and isotonic conditions by applying field stimulation to the muscle samples through a pair of parallel-plate platinum electrodes and using a train of square pulses of 0.1-ms duration and 85-V amplitude. Force and elongation of the samples were obtained electronically with a dual-servo system (ergometer). The results indicate that the dynamic response of the canine cricothyroid muscle is almost twice as slow as that of the thyroarytenoid muscle. The average 50% tetanic contraction times for pars recta and pars obliqua were 84 ms and 109 ms, respectively, in comparison to 50 ms for thyroarytenoid. The examination of force-velocity response of this muscle indicates a maximum shortening velocity of 2 to 3 times its length per second, which is about half of the thyroarytenoid shortening speed. The passive properties of the pars recta and pars obliqua portions are similar to those of thyroarytenoid muscle.
Collapse
Affiliation(s)
- F Alipour
- Department of Speech Pathology and Audiology, National Center for Voice and Speech, The University of Iowa, Iowa City 52242-1012, USA.
| | | |
Collapse
|
16
|
Hong KH, Ye M, Kim YM, Kevorkian KF, Kreiman J, Berke GS. Functional differences between the two bellies of the cricothyroid muscle. Otolaryngol Head Neck Surg 1998; 118:714-22. [PMID: 9591880 DOI: 10.1177/019459989811800530] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The contraction of the cricothyroid (CT) muscle, which results in a decrease in the distance between the thyroid and cricoid cartilages, is considered to be the main factor in lengthening the vocal folds. This is achieved by rotation of the CT joint. The CT muscle is composed of two distinct bellies, the pars recta and the pars obliqua. The function of each subunit is not clearly understood, although it is believed that they act differently because their fibers run in different directions. To clarify the function of the two bellies in phonation, the fundamental frequency (F0), vocal intensity, subglottic pressure, vocal fold length, and CT distance were measured using an in vivo canine laryngeal model. On the basis of these measurements, we demonstrated that the two bellies are varied in their effect on raising the pitch, rotation, and forward translation of the CT joint. The stimulation of the pars recta nerve resulted in a greater increase in the F0 value compared with that of pars obliqua. The combined activity of the pars recta and pars obliqua is important in adjustment of the vocal fold length. The CT approximations directed parallel to the pars recta and pars obliqua simultaneously were more effective in elevation of the pitch than the approximation placed parallel to the pars recta only. This finding may be clinically significant with regard to CT approximation thyroplasty in human trails.
Collapse
Affiliation(s)
- K H Hong
- Department of Otolaryngology-Head and Neck Surgery, Chonbuk National University Medical School, Republic of Korea
| | | | | | | | | | | |
Collapse
|
17
|
Wu YZ, Baker MJ, Crumley RL, Blanks RH, Caiozzo VJ. A new concept in laryngeal muscle: multiple myosin isoform types in single muscle fibers of the lateral cricoarytenoid. Otolaryngol Head Neck Surg 1998; 118:86-94. [PMID: 9450834 DOI: 10.1016/s0194-5998(98)70380-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This report describes the first known investigation of canine laryngeal muscle in which single fibers were dissected and their myosin heavy chain (MHC) isoform content was analyzed. Both SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and western blot techniques were used. The data from single fiber SDS-PAGE indicate that the lateral cricoarytenoid (LCA) is predominantly a fast muscle composed of the following MHC isoforms: Type I, 16.3%; Type IIA, 71.3%; Type IIX, 10.4%; and Type IIB, 2.0%. The results reveal a phenomenon that, to our knowledge, has not been previously described for laryngeal muscle: the presence of two or more MHC isoforms in a single canine LCA muscle fiber. A large number (41%) of muscle fibers coexpressed two or more MHC isoforms. The three most common patterns of coexpression were Type IIA/IIX (72%), Type IIA/I (16%), and Type IIA/IIX/I (8%). Interestingly, the fast Type IIX MHC isoform was typically present with other isoforms and rarely found by itself in individual fibers. Additional experiments are underway to determine whether other laryngeal muscles exhibit such an unusually high ratio of MHC isoform polymorphism.
Collapse
Affiliation(s)
- Y Z Wu
- Department of Otolaryngology-Head and Neck Surgery, College of Medicine, University of California, Irvine 92717, USA
| | | | | | | | | |
Collapse
|
18
|
McHenry MA, Kuna ST, Minton JT, Vanoye CR, Calhoun K. Differential activity of the pars recta and pars oblique in fundamental frequency control. J Voice 1997; 11:48-58. [PMID: 9075176 DOI: 10.1016/s0892-1997(97)80023-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This study was designed to determine if differences exist in pars recta and pars oblique muscle activity during speech and singing. Hooked wire electrodes were implanted in the muscle bundles under direct vision during thyroid surgery in two men and three women. It was found that the pars recta and pars oblique do not function in a similar manner across fundamental frequencies (fo's), tasks, or subjects. Large inter- and intrasubject variability was evident in the contribution of the cricothyroid bundles to fundamental frequency (fo) control. It is speculated that the effect of pars recta and pars oblique contraction may be a function of individual anatomic variations.
Collapse
Affiliation(s)
- M A McHenry
- Galveston Institute of Human Communication, TX 77550, USA
| | | | | | | | | |
Collapse
|
19
|
Sanders I, Jacobs I, Wu BL, Biller HF. The three bellies of the canine posterior cricoarytenoid muscle: implications for understanding laryngeal function. Laryngoscope 1993; 103:171-7. [PMID: 8426508 DOI: 10.1002/lary.5541030209] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The posterior cricoarytenoid (PCA) muscle is known to be active during phonation and respiration. The presence of muscle compartments (bellies) that might subserve these functions was investigated in the canine PCA by anatomical dissection and muscle fiber histochemistry. Five PCA muscles were microdissected and the origins and insertions of all muscle bundles were recorded. An additional six PCA muscles were frozen, sectioned, and stained for adenosine triphosphatase (ATPase) activity. The total number of fast- and slow-twitch fibers were counted and their proportion was determined for each region of the muscle. The PCA muscle was found to contain three distinct neuromuscular compartments. The vertical compartment is oriented at 24 degrees from true vertical, inserts on the lateral aspect of the muscular process of the arytenoid, and is composed of 65% type 2 (fast) muscle fibers. The oblique is oriented at 44 degrees from vertical, inserts on the top of the muscular process of the arytenoid, and is composed of 77% type 2 muscle fibers. The horizontal is oriented at 63 degrees from vertical, inserts on the medial aspect of the muscular process of the arytenoid, and is composed of 59% type 2 muscle fibers. The cricoarytenoid joint is capable of three arcs of motion and the physical arrangement of each compartment appears to correspond to each of these motions. Moreover, the histochemical profiles show that the activity of the three bellies is quite different. These results suggest that the different compartments of the PCA perform distinctive motions during phonation and inspiration.
Collapse
Affiliation(s)
- I Sanders
- Department of Otolaryngology, Mount Sinai Medical Center, New York, NY 10029-6574
| | | | | | | |
Collapse
|