The pharynx in horses is a muscular tube that serves as a passageway for both the respiratory and digestive systems. It connects the nasal and oral cavities to the larynx and esophagus, facilitating the movement of air to the lungs and food to the stomach. The equine pharynx plays a role in breathing, swallowing, and vocalization. Anatomically, it is divided into the nasopharynx, oropharynx, and laryngopharynx, each with distinct functions. This section provides access to peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and clinical relevance of the pharynx in equine health, including its involvement in respiratory and swallowing disorders.
Gehlen H, Ohnesorge B.To describe removal of guttural pouch chondroids through a laser fenestrated mesial septum in a pony with an obstructed pharyngeal ostium of the left guttural pouch. Methods: Case report. Methods: Pony. Methods: Transendoscopic laser neodymium:yttrium aluminum garnet (Nd:YAG) fenestration of the mesial guttural pouch septum was made by contact method (bare fiber, 15-25 W, exposure time 4 seconds). Dissected tissue was removed by transendoscopic monopolar electrosurgery (loop electrode, cutting blade) and multiple chondroids of varying size were removed from the left guttural pouch through the ...
Brown JA, Hinchcliff KW, Jackson MA, Dredge AF, O'Callaghan RA, McCaffrey JR, Slocombe RF, Clarke AF.Little information is available regarding the prevalence of abnormalities of the upper airway and their association with performance in the general population of Thoroughbred racehorses. Objective: To describe the prevalence of selected abnormalities of the upper airway and their association with performance in Thoroughbred racehorses in Australia. Objective: That abnormalities of the upper airway of Thoroughbred racehorses are associated with poor race performance. Methods: Rhinolaryngoscopy was performed after racing and presence and characteristics of abnormalities of the larynx and pharynx...
Woodie JB, Ducharme NG, Hackett RP, Erb HN, Mitchell LM, Soderholm LV.Dorsal displacement of the soft palate (DDSP) is a common condition in racehorses for which various surgical treatments are often performed. In light of recent findings that suggested the position of the larynx may influence the occurrence of DDSP, we investigated whether a noninvasive mean of affecting the position of the larynx could be effective in the management of DDSP. Objective: An external device (laryngohyoid support; LHS) positioning the larynx in a more rostral and dorsal location and preventing caudal displacement of the basihyoid bone would be effective in preventing DDSP during s...
Kumar P, Timoney JF.The tubal tonsil of the horse surrounds the pharyngeal opening of the eustachian tube and is lined by pseudostratified columnar ciliated epithelium interspersed with areas of follicle-associated epithelium (FAE) heavily infiltrated by lymphocytes but devoid of goblet and ciliated cells. Scanning and transmission electron microscopy revealed microvillous cells and cells with features characteristic of M cells such as reduced microvilli or depressed bare surface, more numerous mitochondria, small vesicles and lysosomes, as well as vimentin filaments and epitopes specific for GS 1-B4 as previousl...
Tessier C, Holcombe SJ, Stick JA, Derksen FJ, Boruta D.There is a need to understand the process which leads to failure of recruitment of the stylopharyngeus muscle in clinical cases of nasopharygeal collapse. We therefore studied the timing and intensity of stylopharyngeus muscle activity during exercise in horses. Objective: To measure the electromyographic (EMG) activity of the stylopharyngeus muscle in exercising horses and correlate it with the breathing pattern. Methods: Five horses were equipped with a bipolar fine wire electrode placed on the stylopharyngeus muscle and a pharyngeal catheter. The horses exercised on a treadmill at speeds co...
Klebe EA, Holcombe SJ, Rosenstein D, Boruta D, Bartner LR, Tessier C.Dysfunction of the glossopharyngeal nerve has been implicated as a cause of dysphagia in horses. However, recent studies have indicated that this is not the case. Objective: To determine whether bilateral glossopharyngeal nerve anaesthesia would cause dysphagia in horses or result in measurable alterations in the timing, function, or sequence of swallowing. Methods: Swallowing was evaluated in 6 normal horses with and without bilateral glossopharyngeal nerve anaesthesia. Swallowing dynamics were assessed subjectively and objectively based on time from prehension of food until swallowing, numbe...
Tessier C, Holcombe SJ, Derksen FJ, Berney C, Boruta D.Nasopharyngeal collapse has been observed in horses as a potential cause of exercise intolerance and upper respiratory noise. No treatment is currently available and affected horses are often retired from performance. Objective: To determine the effect of bilateral glossopharyngeal nerve block and stylopharyngeus muscle dysfunction on nasopharyngeal function and airway pressures in exercising horses. Methods: Endoscopic examinations were performed on horses at rest and while running on a treadmill at speeds corresponding to HRmax50, HRmax75 and HRmax, with upper airway pressures measured with ...
Blikslager AT, Tate LP.There are clearly a number of applications for which flexible endoscopic laser surgery has become the state of the art in equine surgery, and the Nd:YAG laser seems to be the most versatile instrument for this type of surgery. Nevertheless, it is critical to understand the advantages and disadvantages of each laser technique. For example, the Nd:YAG laser used in a noncontact fashion seems to be superior when ablation of tissue is required such as treatment of upper airway masses. Conversely, contact Nd:YAG laser techniques have proven themselves to be superior when more precise cutting is adv...
McCue ME, Davis EG, Rush BR, Cox JH, Wilkerson MJ.A 4-year-old Paint mare was examined because of respiratory tract infection, dermatitis, and weight loss of 2 months' duration. Initial examination revealed generalized pruritic dermatitis, ocular and nasal discharges, and stranguria. Laboratory abnormalities included leukopenia and hypoalbuminemia. Further examination of the respiratory tract revealed grade III of IV pharyngitis and pyogranulomatous pneumonia. Endoscopic examination of the bladder revealed a prolific mass at the junction of the bladder and urethra. Hypoproteinemia was suspected to be caused by protein-losing enteropathy. On h...
Judy CE, Chaffin MK, Cohen ND.To identify features of guttural pouch (auditory tube diverticulum) empyema in horses and compare findings of uncomplicated guttural pouch empyema with guttural pouch empyema complicated by chondroids. Methods: Retrospective study. Methods: 91 horses with guttural pouch empyema. Methods: Medical records of horses with guttural pouch empyema were reviewed. Results: The most common owner complaint and abnormal finding was persistent nasal discharge. Chondroids were detected in 21% (19/91) of affected horses. Streptococcus equi was isolated from the guttural pouch in 14 of 44 horses; for Streptoc...
Ducharme NG, Hackett RP, Woodie JB, Dykes N, Erb HN, Mitchell LM, Soderholm LV.Contributes to the understanding of the pathogenesis of dorsal displacement of the soft palate during exercise so that management of this condition could be enhanced. Objective: That the thyrohyoid muscles play an important role in the stability of the laryngo-palatal relationship and that dysfunction of these muscles leads to dorsal displacement of the soft palate (DDSP) during exercise. Methods: Ten horses were exercised on a high-speed treadmill under 4 different treatment conditions: control conditions (n = 10), after resection of thyrohyoid muscles (TH, n = 10), after sham-treatment (n = ...
Sullivan EK, Parente EJ.Pharyngeal disorders are complex and difficult to treat. Disorders that lead to anatomic derangement, such as trauma and neoplasia, can significantly affect the function of this organ. Pharyngeal dysfunction can manifest as dysphagia, persistent palatal displacement, or exercise intolerance. Secondary complications are serious and life threatening and include aspiration pneumonia, weight loss, and death. Pharyngeal disorders that are only recognizable during strenuous exercise are difficult to diagnose and are treated with limited success, even though they are responsible for significant econo...
Durando MM, Martin BB, Hammer EJ, Langsam SP, Birks EK.The primary goal was to investigate the relationship between dynamic upper airway abnormalities and arterial blood gas tensions during exercise. Horses that completed a high-speed treadmill examination consisting of upper-airway videoendoscopy, blood gas evaluation and electrocardiogams and, postexercise, echocardiograms and tracheal washes, were included. An age-matched group of fit, healthy Thoroughbreds, trained to run on a high-speed treadmill, served as controls for blood gas values at specific exercise speeds. One hundred and nineteen horses completed the treadmill examination. Sixty (50...
Kirkham LE, Vasey JR.An Anglo-Arab foal with bilateral postprandial nasal discharge was diagnosed as having a full-length defect of the soft palate. Surgical repair was attempted using a combination of two surgical approaches. Initially a mandibular symphysiotomy approach was used. The posterior portion of the defect did not heal adequately, so a ventral laryngotomy, bisecting the body of the thyroid cartilage and extending to a pharyngotomy approach, was performed 5 months later. The foal has since matured fully despite a slight unilateral nasal discharge. This case report demonstrates that these two surgical app...
Cornelisse CJ, Rosenstein DS, Derksen FJ, Holcombe SJ.To determine the effect of manual tongue protrusion on the dimensions of the hyoid apparatus, nasopharynx, and oropharynx in anesthetized horses. tongue protrusion on the dimensions of the hyoid. Methods: 5 adult horses. Methods: Horses were anesthetized and positioned in sternal recumbency for 2 sequential computed tomographic (CT) scans. Images were acquired with the tongue in a natural position inside the mouth. Then, the tongue was pulled rostrally and secured, and a second CT scan was performed. Dorsoventral length of the hyoid apparatus and angles of the basisphenoid, basihyoid, and cera...
Kumar P, Timoney JF, Sheoran AS.The aim of this study was to characterise the morphological and histochemical features of equine nasopharyngeal tonsillar tissue. Nasal and oropharyngeal tonsillar tissue has been described as the gatekeeper to mucosal immunity because of its strategic location at the entrance to the respiratory and alimentary tracts. A combination of light, scanning and transmission electron microscopy has revealed the presence of follicle-associated epithelium (FAE) overlying lymphoid tissue of the equine nasopharyngeal tonsil caudal to the pharyngeal opening of the guttural pouch. Membranous microvillus (M)...
Cornelisse CJ, Holcombe SJ, Derksen FJ, Berney C, Jackson CA.To determine the effect of a tongue-tie on upper airway mechanics in exercising horses. Methods: 5 Standardbreds. Methods: Peak inspiratory and expiratory tracheal and pharyngeal pressures and airflow were measured while horses exercised on a treadmill with and without a tongue-tie. Respiratory rate was also measured. Horses ran at speeds that corresponded to 50 (HR50), 75, 90 (HR90), and 100% of maximal heart rate. The tongue-tie was applied by pulling the tongue forward out of the mouth as far as possible and tying it at the level of the base of the frenulum to the mandible with an elastic g...
Beard WL, Holcombe SJ, Hinchcliff KW.To determine the effect of a tongue-tie on upper airway mechanics in clinically normal horses exercising on a treadmill following sternothyrohyoid myectomy. Methods: 6 Standardbreds. Methods: Upper airway mechanics were measured with horses exercising on a treadmill at 5, 8, and 10 m/s 4 weeks after a sternothyrohyoid myectomy was performed. Pharyngeal and tracheal inspiratory and expiratory pressures were measured by use of transnasal pharyngeal and tracheal catheters connected to differential pressure transducers. Horses were fitted with a facemask and airflow was measured by use of a pneumo...
Blikslager AT, Tate LP, Tudor R.To document the use and clinical outcome of transendoscopic laser techniques for treatment of rostral displacement of the palatopharyngeal arch (RDPA) in horses. Background: Rostral displacement of the palatopharyngeal arch is a rare cause of upper respiratory noise and exercise intolerance in horses, and may be associated with abnormal laryngeal anatomy. There are few reports of successful treatment of this condition, and no reports of the treatment of RDPA using laser techniques. Methods: The diagnosis of RDPA was based on the presence of palatal tissue covering the dorsal aspect of the aryt...
Martin BB, Reef VB, Parente EJ, Sage AD.To determine results for horses undergoing a high-speed treadmill examination, including videoendoscopy of the pharynx and larynx before and during exercise, echocardiography before and after exercise, and electrocardiography before, during, and after exercise, because of poor performance. Methods: Retrospective study. Methods: 348 horses. Results: A definitive diagnosis was obtained for 256 (73.5%) horses. One hundred forty-eight horses had dynamic obstruction of the airway during exercise, 33 had clinically important cardiac arrhythmias alone, 22 had a combination of dynamic airway obstructi...
Yarbrough TB, Voss E, Herrgesell EJ, Shaw M.To report the clinical signs and management of 4 foals with persistent frenulum of the epiglottis. Methods: Case report. Methods: Four newborn foals. Methods: Foals were admitted with a complaint of oronasal reflux after nursing. Variable systemic signs of aspiration pneumonia were evident. Nasal endoscopy confirmed persistent dorsal displacement of the soft palate. Persistent frenulum of the epiglottis, confirmed by oral endoscopic examination, was transected. Results: After surgery, all foals had the epiglottis positioned normally, dorsal to the soft palate. Clinical signs of oronasal reflux...
Scarratt WK, Crisman MV.Tumors of the equine respiratory tract occur infrequently. An accurate diagnosis of neoplasia of the respiratory tract is critical because the prognosis is usually grave. The clinical signs and diagnostic procedures are discussed for tumors of the nasal and paranasal sinuses, nasopharynx/larynx, guttural pouch and thorax including lung, pleura, and thymus.
Butt TD, MacDonald DG, Crawford WH, Dechant JE.A 14-month-old filly with chronic pharyngitis was diagnosed with incomplete esophageal constriction and megaesophagus due to a persistent right aortic arch. This report is unusual because clinical signs of respiratory dysfunction secondary to chronic regurgitation occurred prior to the recognition of dysphagia.
Ramirez O, Jorgensen JS, Thrall DE.Due to the complex nature of the anatomy of the equine head, superimposition of numerous structures, and poor soft tissue differentiation, radiography may be of limited value in the diagnosis of basilar skull fractures. However, in many horses radiographic changes such as soft tissue opacification of the guttural pouch region, irregular bone margination at the sphenooccipital line, attenuation of the nasopharynx, ventral displacement of the dorsal pharyngeal wall and the presence of irregularly shaped bone fragments in the region of the guttural pouches are suggestive of a fracture of the skul...
Baptiste KE.The equine guttural pouch is a large, air-filled diverticulum of the auditory tube whose function is not clear. Since the horse does not possess a known, well-developed brain-cooling mechanism that could satisfy cerebral thermoregulatory demands, an hypothesis is proposed that respiratory air enters the guttural pouches, when needed, to ventilate and cool the internal carotid arteries (ICA). Experiments were initially carried out on nine cadavers, where blood flow was mimicked with warmed saline propelled by peristaltic pumps. Subsequent experiments were conducted on an anaesthetized horse whe...
O'Brien RT, Biller DS.This article addresses the current status and clinical opportunities for portable radiography and ultrasonography. Radiology is indicated for imaging the nasal cavity, larynx, pharynx and thin portions of the neck. In young foals, adequate radiographs of the entire respiratory tract may be possible. Ultrasonography is indicated in superficial parts of the head and neck, the pleural space and diseased parts of the lungfields.
Lacourt M, Marcoux M.To report use of a shielded hook bistoury developed for correction of epiglottic fold entrapment in standing sedated horses. Methods: Prospective clinical study. Methods: Standardbreds (n=8), 3-19 years of age. Methods: Epiglottic fold entrapment was corrected during standing sedation using a shielded hook bistoury passed nasally into the pharynx. Owners, trainers, and referring veterinarians were contacted by telephone to establish outcome. Results: Axial division of the entrapping epiglottic fold was successful in all horses. No short- or long-term complications occurred. Axial transection o...
Kumar P, Timoney JF, Sheoran AS.The aim of this study was to characterise the morphological and histochemical features of equine nasopharyngeal tonsillar tissue. Nasal and oropharyngeal tonsillar tissue has been described as the gatekeeper to mucosal immunity because of its strategic location at the entrance to the respiratory and alimentary tracts. A combination of light, scanning and transmission electron microscopy has revealed the presence of follicle-associated epithelium (FAE) overlying lymphoid tissue of the equine nasopharyngeal tonsil caudal to the pharyngeal opening of the guttural pouch. Membranous microvillus (M)...
Saied AA, Bryan LK, Bolin DC. infection in horses is common and is characterized by pyogranulomatous pneumonia and ulcerative enterocolitis. clinical disease in cattle, however, is rare and typically manifests as granulomatous lymphadenitis discovered in the abattoir. A 19-mo-old female Santa Gertrudis had a history of intermittent inappetence and weight loss for a 3-mo period before euthanasia. Gross and histologic examination revealed severe, chronic, ulcerative, and granulomatous inflammation in the tongue, pharynx, and small intestine. Also, the heifer had severe, granulomatous pharyngeal and mesenteric lymphadenitis...
Speirs VC, van Veenendaal JC, Harrison IW, Smyth GB, Anderson GA, Wilson DV, Gilbo B.Endoscopic examinations of the upper respiratory tract were done on 92 of 314 Standardbred horses that raced one or more times at 4 consecutive, weekly race meetings. Although participation was voluntary, the characteristics of the population of horses examined were not statistically different from those of all horses that raced. No horse showed epistaxis, but 34 (32.4%) examinations of the trachea revealed blood that ranged from a trace in the tracheal mucus to large amounts scattered over the tracheal walls. Forty-four horses exhibited minor degrees of pharyngeal lymphoid hyperplasia, 2 had ...
Holcombe SJ, Hurcombe SD, Barr BS, Schott HC.Dysphagia due to pharyngeal dysfunction occurs in human neonates and is associated with prematurity and hypoxic episodes. This syndrome probably occurs in neonatal foals but has not been reported. Objective: The objectives of this study were to describe 1) a series of neonatal foals with dysphagia due to pharyngeal dysfunction; 2) the progression, treatment and resolution of the dysphagia; 3) the comorbidities; and 4) the prognosis for life and athleticism for affected foals. Methods: Records from 3 referral equine hospitals were reviewed from neonatal foals with dysphagia of pharyngeal origin...
Jones S, Franklin S, Martin C, Steel C.There is limited knowledge of the breathing strategy and impact on the patency of the upper respiratory tract (URT) in swimming horses. Objective: To describe the respiratory responses and endoscopic appearance of the URT during tethered swimming in horses. Methods: Prospective descriptive study. Methods: Ten race-fit horses, with no history of URT obstruction, were examined during tethered swimming. Endoscopic examination, heart rate, sound recordings and above and below water video recordings were obtained. Plasma lactate concentration was measured before and 5 min after swimming and trache...
Holcombe SJ, Derksen FJ, Robinson NE.Determining the respiratory related activity of the palatinus and palatopharyngeus muscles in exercising horses is relevant because dysfunction of these muscles has been implicated in the pathogenesis of dorsal displacement of the soft palate. Objective: To determine if the palatinus and palatopharyngeus muscles have respiratory activity that increases with intensity in exercising horses. Methods: Electromyographic activity was measured in the palatinus and palatopharyngeus muscles using bipolar fine-wire electrodes while the horses completed an incremental exercise treadmill protocol. Results...
Gehlen H, Ohnesorge B.To describe removal of guttural pouch chondroids through a laser fenestrated mesial septum in a pony with an obstructed pharyngeal ostium of the left guttural pouch. Methods: Case report. Methods: Pony. Methods: Transendoscopic laser neodymium:yttrium aluminum garnet (Nd:YAG) fenestration of the mesial guttural pouch septum was made by contact method (bare fiber, 15-25 W, exposure time 4 seconds). Dissected tissue was removed by transendoscopic monopolar electrosurgery (loop electrode, cutting blade) and multiple chondroids of varying size were removed from the left guttural pouch through the ...
Greet TR, Baker GJ, Lee R.Using fluoroscopic techniques and videotape recordings, a study of normal deglutition was made in 2 ponies. Paryngeal function was studied at intervals after laryngoplasty on 1 animal and after a sham technique on the other. Two clinical cases of laryngeal paralysis, which had been treated by laryngoplasty, were also examined. In the 2 experimental ponies, liquid food passed into the lower respiratory tract post-operatively. One of the clinical cases appeared to swallow solid food normally, but some food material entered the larynx of the other horse. It is suggested that pharyngeal dysfunctio...
Pringle J, Aspán A, Riihimäki M.The value of repeated nasopharyngeal lavage (NPL) to detect silent carriers of Streptococcus equi has not been investigated. Objective: Determine if results of serial testing for S. equi by NPL predicts subsequent true carrier status as determined by both NPL and guttural pouch lavage. Methods: An outbreak of strangles with 100% morbidity in 41 mature Icelandic horses was followed prospectively to investigate development of silent carriers. All were initially positive to S. equi on NPL. The farm was closed to horse movement during the entire study. Methods: Prospective observational study. Tes...
Parente EJ.Many abnormalities of the upper airway that can inhibit performance are determined on a critical resting endoscopic evaluation. Some dynamic abnormalities can only be seen during an exercising endoscopic evaluation, which should be performed whenever the history of abnormal noise or performance limitations is not completely consistent with the resting endoscopic findings. Head and neck position may play a critical role in the evaluation process and the exact position during performance should be reproduced during the clinical examination to definitively define the abnormality. Treatments and p...
Jones DL.Medical records were reviewed for 11 horses with squamous cell carcinoma of the larynx and/or pharynx. The average age at presentation was 15.3 years. No breed or sex predilection was present. At presentation, 6 of 11 horses were dyspneic and 4 horses had inspiratory stridor. Endoscopy was performed in all cases and was more useful in demonstrating a mass in the laryngopharyngeal region than laryngeal or guttural pouch radiography. Surgical excision was attempted in 3 horses and in 1 horse alleviated clinical signs for 4 months. Ten horses were euthanatized and 1 horse died. Results of this st...
Scarratt WK, Crisman MV.Tumors of the equine respiratory tract occur infrequently. An accurate diagnosis of neoplasia of the respiratory tract is critical because the prognosis is usually grave. The clinical signs and diagnostic procedures are discussed for tumors of the nasal and paranasal sinuses, nasopharynx/larynx, guttural pouch and thorax including lung, pleura, and thymus.
Kirkham LE, Vasey JR.An Anglo-Arab foal with bilateral postprandial nasal discharge was diagnosed as having a full-length defect of the soft palate. Surgical repair was attempted using a combination of two surgical approaches. Initially a mandibular symphysiotomy approach was used. The posterior portion of the defect did not heal adequately, so a ventral laryngotomy, bisecting the body of the thyroid cartilage and extending to a pharyngotomy approach, was performed 5 months later. The foal has since matured fully despite a slight unilateral nasal discharge. This case report demonstrates that these two surgical app...
Tomasic M, Mann LS, Soma LR.To determine the effects of endotracheal intubation on respiratory mechanics during xylazine sedation and xylazine-diazepam-ketamine anesthesia in adult horses. Methods: 5 healthy adult horses. Methods: Measurements were derived from recordings of respiratory gas flow, and transpulmonary and transtracheal pressures. Total pulmonary resistance (RT) was partitioned into upper airway resistance (extrathoracic portion of trachea, larynx, pharynx, nasal cavity, nares; RUA) and lower airway resistance (intrathoracic portion of trachea, bronchi, bronchioles). Baseline measurements were obtained in un...
Butt TD, MacDonald DG, Crawford WH, Dechant JE.A 14-month-old filly with chronic pharyngitis was diagnosed with incomplete esophageal constriction and megaesophagus due to a persistent right aortic arch. This report is unusual because clinical signs of respiratory dysfunction secondary to chronic regurgitation occurred prior to the recognition of dysphagia.
Mirazo JE, Page P, Rubio-Martinez L, Marais HJ, Lyle C.Upper airway endoscopy at rest has been the diagnostic method of choice for equine upper respiratory tract (URT) conditions. Development of high-speed treadmill endoscopy improved the sensitivity of URT endoscopy by allowing observation of the horse's nasopharynx and larynx during exercise. However, treadmill exercise may not always accurately represent the horse's normal exercise as track surface, rider, tack and environmental variables are altered. Recently, the development of dynamic overground endoscopy (DOE) has addressed some of these shortcomings. A retrospective study was undertaken to...
Dougherty SS, Palmer JL.A 4-year-old horse was evaluated for chronic coughing, mucopurulent nasal discharge, and failure to thrive. Results: Endoscopy was performed on the larynx, pharynx, and trachea and revealed an approximately 2-cm fluctuant subepiglottic cyst. Results: The subepiglottic cyst was treated with intralesional formalin administration. Following 2 injections, 2 weeks apart, the cyst was completely resolved with no evidence of scarring or epiglottic deformity. Conclusions: Findings suggest that intralesional formalin administration for treatment of subepiglottic cysts may be a minimally invasive, econo...
Hance SR, Bertone AL.Equine tumors are rather uncommon; however, of the body regions, the head is a relatively common location for neoplasia, including sarcoids and squamous cell carcinomas of the skin, tumors of the sinus/nasal cavity, and bony tumors of the head. Tumors discussed in the article include odontogenic and bony tumors; sarcoids; tumors of the guttural pouch and pharyngeal and oral mucosa; tumors of the larynx; and tumors of the paranasal sinuses and nasal passages. In general, tumors involving deeper structures of the head carry a poor prognosis; however, some tumors such as sarcoids, ossifying fibro...
Diab S, Pascoe J, Shahriar M, Read D, Kinde H, Moore J, Odani J, Uzal F.There is increasing anecdotal evidence among horse owners, trainers and equine clinicians of a high prevalence of subepiglottic ulcers, suggested to have a negative effect on racing performance. Objective: To provide a prevalence study and pathological characterisation of laryngopharyngeal lesions with emphasis in the subepiglottic area and, in particular, subepiglottic ulcers. Methods: The study was carried out on 91 Thoroughbred racehorses received for post mortem examination from 4 major Southern California racetracks. The most common reason for submission was catastrophic musculoskeletal i...
Kumar P, Timoney JF.The tubal tonsil of the horse surrounds the pharyngeal opening of the eustachian tube and is lined by pseudostratified columnar ciliated epithelium interspersed with areas of follicle-associated epithelium (FAE) heavily infiltrated by lymphocytes but devoid of goblet and ciliated cells. Scanning and transmission electron microscopy revealed microvillous cells and cells with features characteristic of M cells such as reduced microvilli or depressed bare surface, more numerous mitochondria, small vesicles and lysosomes, as well as vimentin filaments and epitopes specific for GS 1-B4 as previousl...
Barton AK, Troppenz A, Klaus D, Lindenberg I, Merle R, Gehlen H.There is contradictory evidence on the potential benefits of tongue ties on upper airway function and their efficacy in inhibiting intermittent dorsal displacement of the soft palate (DDSP) in racehorses. Objective: To test the hypothesis that tongue ties increase the pharyngeal diameter and decrease the occurrence of dynamic airway obstruction in racehorses. Methods: Prospective, crossover blinded clinical study. Methods: Data of 22 Thoroughbred and 8 Standardbred racehorses examined using overground endoscopy under full-intensity exercise on training racetracks with and without fixation of t...
Dean PW.Abnormalities of the nasal cavity, pharynx, larynx, and trachea result in respiratory noise and exercise intolerance. Clinical features of common upper respiratory conditions of performance horses are reviewed with emphasis on diagnosis, treatment, and risk factors that affect the outcome of surgical treatment.
Holcombe SJ, Beard WL, Hinchcliff KW.To investigate the effect of a mask and pneumotachograph on ventilation, respiratory frequency, and tracheal and nasopharyngeal pressures in horses running on a treadmill. Methods: Six horses ran at 50, 75, and 100% of the speed that resulted in maximum oxygen consumption, with and without a mask and pneumotachograph. Tracheal and pharyngeal inspiratory and expiratory pressures, respiratory frequency, and arterial blood gases were measured. Methods: Six Standardbred horses. Methods: Oxygen consumption was measured during an incremental exercise test to determine the speed that resulted in maxi...
Virgin JE, Holcombe SJ, Caron JP, Cheetham J, Kurtz KA, Roessner HA, Ducharme NG, Hauptman JG, Nelson NC.Pharyngeal dysphagia is a debilitating, sometimes fatal condition in horses, with multiple aetiologies. The pathophysiology is complex and not fully understood. Treatment is largely supportive. Laryngeal advancement surgery may diminish symptoms of dysphagia and improve swallowing in affected horses. Objective: 1) to induce reversible moderate and marked pharyngeal dysphagia by regional anaesthesia of branches of the glossopharyngeal (IX), vagus (X) and hypoglossal (XII) nerves; 2) to characterise the dysphagia produced by each model; and 3) to determine whether laryngeal advancement surgery i...
Tulleners E, Mann P, Raker CW.Epiglottic augmentation with injectable bovine collagen or an autogenous or allogenous auricular cartilage graft was performed in 12 horses with endoscopically and radiographically normal epiglottises. The grafting procedures were easy to perform and did not cause apparent discomfort. Cartilage graft extrusion or resorption may have occurred, but was not seen by endoscopy and lateral laryngeal radiography. Only collagen implants remained evident endoscopically, as smooth round submucosal bulges ventral to the epiglottic cartilage. Two horses with collagen implants, and all horses with cartilag...
