Cricothyroid muscle function and vocal fold stability in exercising horses.
Abstract: To determine (1) if the cricothyroid muscle had respiratory-related electromyographic (EMG) activity that increased with respiratory effort and (2) if bilateral cricothyroid myotomy resulted in vocal fold instability and collapse in exercising horses. Methods: Experimental. Methods: Seven (3 EMG; 4 cricothyroid myotomy) Standardbred horses. Methods: Three horses exercised on a treadmill at speeds corresponding to the speed that produced maximum heart rate (HR(max)), 75% of maximum heart rate (HR(75%max)), and 50% of maximum heart rate (HR(50%max)) for 60 seconds at each speed while EMG activity of the cricothyroid muscle and nasopharyngeal pressures were measured. Another 4 normal horses were exercised on the treadmill at HR(max) and HR(75%max) for 60 seconds at each speed before and after bilateral cricothyroid myotomy. Upper airway pressures were measured and videoendoscopic examinations were performed and videotaped at each speed. Results: Peak phasic EMBG activity of the cricothyroid muscle was coincident with inspiration and increased with treadmill speed. Bilateral cricothyroid myotomy resulted in vocal fold collapse in all horses. Mean peak inspiratory pressures were significantly more negative compared with control values at both HR(max) and HR(75%max). Conclusions: Cricothyroid muscle dysfunction may be implicated in vocal fold collapse and likely causes inspiratory airway obstruction in exercising horses. Conclusions: Conditions compromising cricothyroid muscle function or motor innervation could result in vocal fold collapse.
Publication Date: 2006-08-17 PubMed ID: 16911149DOI: 10.1111/j.1532-950X.2006.00182.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
- Anatomy
- Clinical Findings
- Clinical Study
- Diagnosis
- Disease Diagnosis
- Disease Etiology
- Equine Health
- Exercise
- Experimental Methods
- Heart Rate
- Horses
- Laryngeal Dysfunction
- Musculoskeletal System
- Myography
- Pathophysiology
- Physiology
- Respiratory Health
- Standardbred Horses
- Treadmill Exercise
- Veterinary Medicine
- Veterinary Research
Summary
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This research work investigates the function of the cricothyroid muscle in horses during physical exertion, its impact on respiratory activity, and its link to vocal fold instability that can affect a horse’s breathing. Specifically, it assesses the effect of a surgical technique (bilateral cricothyroid myotomy) on the vocal folds’ stability.
Research Methodology
- The study involved seven Standardbred horses, divided into two test groups: three for electromyographic (EMG) analysis and four for cricothyroid myotomy.
- The horses in the EMG group were put to exercise on a treadmill at varying speeds (max heart rate, 75% max heart rate, and 50% of max heart rate) with each speed sustained for 60 seconds.
- During exercise, the EMG activity in the cricothyroid muscle and the nasopharyngeal pressures were measured.
- The remaining four horses underwent a bilateral cricothyroid myotomy – a surgical procedure that involves cutting or severing the cricothyroid muscle.
- Post-surgery, these horses were similarly exercised on a treadmill at different heart rates and their upper airway pressures were measured. Videoendoscopic examinations were done and recorded at each speed.
Research Findings
- The EMG activity in the cricothyroid muscle of the horses correlated with their breathing patterns and increased with the speed of the treadmill.
- In all horses that underwent the bilateral cricothyroid myotomy, a collapse of the vocal folds was observed.
- After the myotomy procedure, mean peak inspiratory pressures were significantly more negative compared to pre-surgery measurements at both maximum and 75% of maximum heart rates.
Research Conclusions
- The study concluded that cricothyroid muscle dysfunction might lead to vocal fold collapse and is likely to trigger inspiratory airway obstruction in exercising horses.
- Any conditions that might compromise the functionality of cricothyroid muscle or its motor innervation could result in the collapse of vocal folds, affecting the respiratory efficiency of the horse in demanding physical activities.
Cite This Article
APA
Holcombe SJ, Rodriguez K, Lane J, Caron JP.
(2006).
Cricothyroid muscle function and vocal fold stability in exercising horses.
Vet Surg, 35(6), 495-500.
https://doi.org/10.1111/j.1532-950X.2006.00182.x Publication
Researcher Affiliations
- Department of Large Animal Clinical Sciences, Michigan State University, College of Veterinary Medicine, East Lansing, 48824, USA. Holcombe@cvm.msu.edu
MeSH Terms
- Airway Obstruction / etiology
- Airway Obstruction / physiopathology
- Airway Obstruction / veterinary
- Animals
- Electromyography / methods
- Electromyography / veterinary
- Endoscopy / veterinary
- Esophageal Sphincter, Upper / physiology
- Esophageal Sphincter, Upper / physiopathology
- Esophageal Sphincter, Upper / surgery
- Exercise Test / veterinary
- Female
- Heart Rate
- Horse Diseases / etiology
- Horse Diseases / physiopathology
- Horses
- Male
- Oxygen Consumption
- Pharyngeal Muscles / physiology
- Pharyngeal Muscles / physiopathology
- Pharyngeal Muscles / surgery
- Physical Conditioning, Animal / physiology
- Pressure
- Respiration
- Running
- Video Recording
Citations
This article has been cited 3 times.- Fitzharris LE, Hezzell MJ, McConnell AK, Allen KJ. Training the equine respiratory muscles: Ultrasonographic measurement of muscle size. Equine Vet J 2023 Mar;55(2):295-305.
- Fretheim-Kelly ZL, Halvorsen T, Clemm H, Roksund O, Heimdal JH, Vollsæter M, Fintl C, Strand E. Exercise Induced Laryngeal Obstruction in Humans and Equines. A Comparative Review. Front Physiol 2019;10:1333.
- Grevemeyer B, Bogdanovic L, Canton S, St Jean G, Cercone M, Ducharme NG, Brown BN. Regenerative medicine approach to reconstruction of the equine upper airway. Tissue Eng Part A 2014 Apr;20(7-8):1213-21.
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