Myography in horses involves the study and recording of muscle function and activity through various techniques, such as electromyography (EMG). This area of study focuses on assessing muscle physiology, including contraction patterns, electrical activity, and overall muscular health. Myography can provide insights into muscle disorders, performance issues, and rehabilitation outcomes in equine subjects. Common applications include evaluating muscle function in performance horses, diagnosing neuromuscular conditions, and monitoring recovery from injury. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, applications, and findings related to myography in equine research.
Lamar CH, Masty J, Adams SB, Tacker WA.Myoelectrical and myomechanical activities of the distal portion of the jejunum and pelvic flexure were studied in 7 ponies, using permanently implanted monopolar and bipolar stainless steel electrodes. Dental acrylic embedded recording electrodes were surgically sutured to the serosal surface of the distal portion of the jejunum and pelvic flexure. Myoelectrically, regular spike bursts and irregular spike bursts were observed in the jejunum. Short spike bursts and long spike bursts were recorded and associated with spike potentials, using impedance recording techniques. Electrical and mechani...
Adams SB, Lamar CH, Masty J.Bipolar stainless steel electrodes were surgically implanted in 4 ponies to record myoelectrical and mechanical activity of the distal portion of the jejunum and pelvic flexure. After determining normal activity, the effects of neostigmine, xylazine, flunixin meglumine, dipyrone, panthenol, and atropine sulfate were determined. Flunixin meglumine, dipyrone, and panthenol had no effect on the motility of the jejunum or pelvic flexure. Xylazine and atropine sulfate decreased motility of the distal portion of the jejunum and pelvic flexure, with atropine sulfate having a greater effect and lastin...
Blythe LL, Kitchell RL, Holliday TA, Johnson RD.Normal nerve conduction velocity values in 10 ponies were determined for sensory nerve fibers in the median and ulnar nerves. A percutaneous signal-averaging technique was developed and used. Medial and lateral palmar digital nerves on the abaxial surface of the proximal sesamoid bones were used as the sites for percutaneous stimulation, whereas recording sites included the medial and lateral palmar nerves just distal to the carpus and the median and ulnar nerves in the middle of the radius. Sensory nerve conduction velocities can be evaluated simply and clinically in the limbs of horses, usin...
Blythe LL, Kitchell RL.The cutaneous innervation of the thoracic limb was investigated in 18 barbiturate-anesthetized horses, using electrophysiologic techniques. The cutaneous area (CA) innervated by each cutaneous nerve was delineated in at least 4 horses by stroking the hairs with a small watercolor brush while recording from the nerve. Mapping of adjacent CA revealed areas of considerable overlap. The part of a CA of a given nerve supplied only by that nerve is referred to as its autonomous zone (AZ). In contrast to the standard textbook illustrations cutaneous branches of the axillary, radial, musculocutaneous,...
Quinlan TJ, Goulden BE, Barnes GR, Anderson LJ, Cahill JI.The nerve supply to the intrinsic laryngeal muscles of the horse was studied by gross dissection and by electromyography which was carried out before, during and after section of various intralaryngeal nerve branches. The anatomical relationships and passage of the laryngeal nerves throughout the larynx were defined. Unlike the dog and man there was no evidence of the passage of motor nerve fibres from one side of the larynx to the other.
Beech J.An 18-month-old male Quarter Horse was referred for evaluation of a tic that had started after injury to the right forelimb 4 weeks earlier. The right forelimb appeared paretic and had constant regular twitches of variable intensity that were usually sufficiently forceful to move the trunk, neck, and head. The horse frequently threw the limb forward. The twitch persisted during sleep but disappeared during general anesthesia and following sedation with xylazine. It was unaffected by acetylpromazine, diphenylhydantoin, diazepam, carbamazepine, trimethadione, procainamide, quinidine, propranolol...
Henry RW, Diesem CD.Radial and median motor nerve conduction velocities were determined on 10 clinically healthy 1- to 11-year-old ponies. These velocities were obtained by stimulation at the brachial plexus directly through a surgical incision and later in the ambulatory pony via implanted Formvar-coated wire electrodes. Percutaneous stimulation was used at the cubital region in both anesthetized and ambulatory ponies. The values for radial motor nerve fibers ranged from 96.4 to 100 m/s. These were 15.3% faster than previously reported distal values. Median motor nerve fiber values ranged from 86.8 to 90.2 m/s, ...
Henry RW, Diesem CD, Wiechers DO.Eleven ponies and 13 horses were used to develop a technique for determining conduction velocity for the radial and median nerves and establishing normal limits for these values. One pony was euthanatized to determine the course of the radial and the median nerves. From this dissection, both proximal and distal stimulation sites for the radial and the median nerves were selected, as well as areas for recording muscle evoked responses from the abductor digiti I longus (extensor carpi obliquus) and the radial head of the deep digital flexor muscles. The other ten ponies and the horses were used ...
Taverne MA, van der Weyden GC, Fontijne P, Dieleman SJ, Pashen RL, Allen WR.Uterine electromyography was performed by means of chronically implanted surface electrodes in 3 Pony mares during spontaneous oestrous cycles and following luteolysis induced by a prostaglandin analogue (fluprostenol). Three distinct patterns were recognized during the oestrous cycle. (1) During oestrus well defined phases of activity with closely grouped high-amplitude spikes were separated by long periods (10-45 min) of complete inactivity. (2) During dioestrus more diffuse phases of activity with low-amplitude spikes were separated by variable periods of relative inactivity. (3) During lut...
Wentink GH.The locomotor pattern of the hind limb of seven horses has been studied in intact animals and after transection of the following structures: the peroneus tertius tendon, the cranial tibial muscle, both cranial tibial muscle and peroneus tertius tendon, and the superficial digital flexor tendon. The investigation was carried out by high speed cinematography and electromyography. It is concluded that (1) the muscles and tendons over the cranial aspect of the tibia play an important role during the support phase; (2) the movements of the hind limb may be performed without the action of the crania...
Wentink GH.The movements of the right hind limb of horses with normal locomotion were studied using cinephotography and electromyography. A model of the cycle of a stride in the walk and the trot was constructed and the kinetic parameters of the segments of the limb were calculated. A good correlation was obtained between the kinetics and the periods of the cycle of a stride during which individual muscles display activity. The results of this study demonstrate that: at placing and lifting, i.e., when a change occurs in the direction of the movement of the limb; b) At the walk, the greatest forces operan...
Rieger C.The article surveys some of the scientific fundamentals of hippo- and riding therapy, and its methods using the characteristic horseback three dimensional rhythmic movement impulses for its therapeutic values, particularly in cerebral palsy. The influence of riding on posture and balance reactions, position of the pelvic, postures of head and trunk as well as rotatory movements was demonstrated in film studies using the cerebral palsied with different syndromes as an example. Electromyographic examinations of antagonistic muscle groups, kinesiologic analyses with the help of a video-recorder, ...
Beckett SD, Walker DF, Hudson RS, Reynolds TM, Purohit RC.A needle-tipped catheter or subminiature pressure transducer was implanted in the corpus spongiosum penis (CSP) of Shetland Pony stallions to determine pressure during coitus. Electrodes for monitoring the electromyographic (EMG) activity were implanted in the ischiocavernosus (IC) and bulbospongiosus (BS) muscles. The mean peak CSP pressure recorded with the catheter was 762 mm of Hg, and with the subminiature pressure transducer, it was 994 mm of Hg. The simultaneous occurrence of the CSP pressure peaks and bursts of BS muscle activity indicated that these muscles were the likely source of e...
Phaneuf LP, Grivel ML, Ruckebusch Y.The electrical potentials were recorded from the antrum, the duodenum, the ileum and the first part of the colon of ponies under (a) normal resting conditions, (b) during nonpainful colic and (c) after intravenous morphine administration. The normal pony, at rest, had five contractions of the antrum per minute. On the small intestine, the basal electrical activity decreased from the duodenum (14-15/min) to the ileum (10-11/min). The small bowel also had three types of motility: peristaltic waves, rhythmic segmentations and random contractions. On the colon, bursts of potentials indicating inte...
To evaluate the effect of hippotherapy (physical therapy utilizing the movement of a horse) on muscle activity in children with spastic cerebral palsy. Methods: Pretest/post-test control group. Methods: Therapeutic Riding of Tucson (TROT), Tucson, AZ. Methods: Fifteen (15) children ranging from 4 to 12 years of age diagnosed with spastic cerebral palsy. Methods: Children meeting inclusion criteria were randomized to either 8 minutes of hippotherapy or 8 minutes astride a stationary barrel. Methods: Remote surface electromyography (EMG) was used to measure muscle activity of the trunk and upper...
Brown DR, Forster HV, Lowry TF, Forster MA, Forster AL, Gutting SM, Erickson BK, Pan LG.Breathing, diaphragmatic and transversus abdominis electromyograms (EMGdi and EMGta, respectively), and arterial blood gases were studied during normoxia (arterial PO2 = 95 Torr) and 48 h of hypoxia (arterial PO2 = 40-50 Torr) in intact (n = 11) and carotid body-denervated (CBD, n = 9) awake ponies. In intact ponies, arterial PCO2 was 7, 5, 9, and 11 Torr below control (P less than 0.01) at 1 and 10 min and 5 and 24-48 h of hypoxia, respectively. In CBD ponies, arterial PCO2 was 3-4 Torr below control (P less than 0.01) at 4, 5, 6, and 24 h of hypoxia. In intact ponies, pulmonary ventilation, ...
Lin YL, Moolenaar H, van Weeren PR, van de Lest CH.To determine the relationship between the output of an electrical treatment device and the effective field strength in the superficial digital flexor tendon of horses. Methods: Cadaver horse forelimbs without visible defects (n = 8) and 1 live pony. Methods: Microcurrents were generated by a microcurrent electrical therapy device and applied in proximodistal, dorsopalmar, and mediolateral directions in the entire forelimbs, dissected tendons, and the pony with various output settings. Corresponding field strengths in the tendons were measured. Results: A linear relationship was detected betwee...
Rankins EM, Manso Filho HC, Malinowski K, McKeever KH.Horses' muscular tension during acute stress remains unexplored. Our aim was to assess muscular, behavioral, cortisol, and hematocrit responses to social isolation (ISO), novel object exposure (NOV), and sham clipping (CLIP). Altered stress responses were expected. Eight mature Standardbred horses (four mares and four geldings) were exposed to acute stressors and a control period (CON) in a balanced, replicated 4×4 Latin Square experimental design with 3 min treatment periods and 10 min washout periods. Surface electromyography collected from the masseter, brachiocephalas, cervical trapeziu...
Brice AG, Forster HV, Pan LG, Lowry TF, Murphy CL, Mead J.We studied the changes in breathing and respiratory muscle electromyograms (EMG) during passively induced increases in end-expiratory lung volume (EELV) in awake normal (N), hilar nerve-denervated (HND), carotid body-denervated (CBD), and HND + CBD ponies. EELV was increased by applying continuous negative pressure (-10 and -20 cmH2O) around the torso of the standing pony. In all groups, negative pressure produced sustained increases in EELV that were linearly related to the degree of negative pressure. Elevated EELV decreased breathing frequency (f) in N and CBD ponies but increased f in HND ...
Beech J, Fletcher JE, Tripolitis L, Lindborgh S.The effects of phenytoin treatment were evaluated in 2 myotonic horses with hyperkalemic periodic paralysis (HPP). Phenytoin treatment abolished the clinical signs of muscle fasciculations following oral potassium challenge and decreased or abolished repetitive firing and myotonic discharges found on electromyographic examination. In both horses, an abnormally low threshold for calcium-induced calcium release was measured in heavy sarcoplasmic reticulum fractions from skeletal muscle, and this threshold increased with phenytoin treatment. Results suggest phenytoin is useful in modifying disord...
Legg K, Cochrane D, Gee E, Macdermid P, Rogers C.Physiological parameters and muscle activity of jockeys may affect their fall and injury risk, performance, and career longevity, as well as the performance and welfare of the horses they ride. Therefore, this study aimed to quantify the physiological demands, body displacement, and electromyographic (EMG) activity of twelve jockeys riding 52 trials and 16 professional races. The jockeys were instrumented with heart rate (HR) monitors, accelerometers, and integrated EMG clothing (recording eight muscle groups: quadriceps, hamstrings, gluteal, erector spinae/lower back, abdominal external obliq...
Ducharme NG, Horney FD, Partlow GD, Hulland TJ.The purpose of this project was to adapt a surgical technique from humans and dogs to horses in which a portion of an accessory muscle of respiration and its nerve supply is transplanted to a denervated dorsal cricoarytenoid muscle. Anatomical dissections in seven horses revealed two possible donor nerve-pedicle grafts: the omohyoid and the sternothyrohyoid, both innervated by a branch of the first and second cervical nerves. Histochemical evaluations in two ponies of the dorsal cricoarytenoid, omohyoid and sternothyrohyoid muscles revealed similar proportions of fiber types 1 and 2 in all thr...
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...
Tokuriki M, Aoki O, Niki Y, Kurakawa Y, Hataya M, Kita T.Electromyographic (EMG) activity of 4 muscles of the cubital joint and the strain of forelimb hooves were recorded telemetrically in 4 Thoroughbreds (with and without a rider) standing, walking, trotting, and cantering. Bipolar fine wire electrodes were inserted into the muscles, and strain gauges were attached to the hoof wall. Motion pictures (16 mm), synchronized with EMG tracings, were taken to obtain kinematic data. When horses were standing, the biceps brachii had tonic activity, but the brachialis and the caput longum and the caput laterale of the triceps brachii had no EMG activity. Th...
Peham C, Licka TF, Scheidl M.To evaluate an adaptive-filter method for use in analysis of periodic electromyography (EMG) signals in which the transfer function of the filter is matched to characteristics of the signal. Methods: 15 adult horses without clinical signs of back pain. Methods: Electromyography signals of the left and right longissimus dorsi muscles, middle gluteal muscles, and triceps brachii muscle were recorded from horses walking on a treadmill, using bilaterally placed surface electrodes. A reflective marker was placed on the hoof of the left hind limb for simultaneous kinematic measurement of motion cycl...
Tokuriki M, Ohtsuki R, Kai M, Hiraga A, Oki H, Miyahara Y, Aoki O.We recorded the electromyographic (EMG) activity of 7 skeletal muscles in the forequarters and 1 in the hindquarters of 6 Thoroughbred horses during overground walking, swimming in a circular pool, and walking and trotting in a water treadmill. Bipolar fine wire electrodes were inserted into the muscles and the EMG signals were recorded using a telemetric system. The splenius exhibited tonic EMG activity during swimming. The brachiocephalicus showed its highest intensity during swimming followed by the walk and trot in the water treadmill and then walking overground. The triceps brachii caput ...
Kruluc P, Nemec A.Clinically, the use of detomidine and butorphanol is suitable for sedation and deepening of analgosedation. The aim of our study was to establish the influence of detomidine used alone and a butorphanol-detomidine combination on brain activity and to evaluate and compare brain responses (using electroencephalography, EEG) by recording SEF90 (spectral edge frequency 90%), individual brain wave fractions (beta, alpha, theta and delta) and electromyographic (EMG) changes in the left temporal muscle in standing horses. Ten clinically healthy cold-blooded horses were divided into two groups of five...
King MR, Seabaugh KA, Frisbie DD.Back pain and inflammation of the epaxial musculature is a significant problem in all equine athletes. Treatment of back pain can be challenging and often requires a multimodal approach. In humans, bio-electromagnetic energy regulation therapy (BEMER) has been reported to be effective in pain modulation. With its increased use in people comes a similar robust application in veterinary medicine unfortunately, there is unsubstantiated evidence for this type of therapy in horses. Objectives of this study were to assess analgesic responses and biomechanical outcome variables using a bio-electromag...
Rieger C.The article surveys some of the scientific fundamentals of hippo- and riding therapy, and its methods using the characteristic horseback three dimensional rhythmic movement impulses for its therapeutic values, particularly in cerebral palsy. The influence of riding on posture and balance reactions, position of the pelvic, postures of head and trunk as well as rotatory movements was demonstrated in film studies using the cerebral palsied with different syndromes as an example. Electromyographic examinations of antagonistic muscle groups, kinesiologic analyses with the help of a video-recorder, ...
Gamucci F, Pallante M, Molle S, Merlo E, Bertuglia A.Superficial skeletal muscle activation is associated with an electric activity. Bidimensional High-Density Surface Electromyography (HD-sEMG) is a non-invasive technique that uses a grid of equally spaced electrodes applied on the skin surface to detect and portray superficial skeletal muscle activation. The goal of the study was to evaluate the feasibility of HD-sEMG to detect electrical activation of skeletal muscle and its application during rehabilitation exercises in horses. To fulfil this aim, activation of the superficial descending pectoral and external abdominal oblique core muscles w...
Traub-Dargatz JL, Schlipf JW, Granstrom DE, Ingram JT, Shelton GD, Getzy DM, Lappin MR, Baker DC.Multifocal myositis was diagnosed in a 7-year-old Quarter Horse gelding on the basis of history and findings on physical examination, serum biochemical analysis, electromyography, and microscopic examination of frozen sections of muscle biopsy specimens. Histologic examination of the muscle specimen revealed multifocal accumulations of histiocytes, lymphocytes, and plasma cells, with attendant myofiber degeneration and necrosis. Parasitic cysts with morphologic characteristics of Sarcocystis sp were found in regions of myocyte degeneration and necrosis, and in regions of normal muscle. Based o...
Adams SB, Lamar CH, Masty J.Bipolar stainless steel electrodes were surgically implanted in 4 ponies to record myoelectrical and mechanical activity of the distal portion of the jejunum and pelvic flexure. After determining normal activity, the effects of neostigmine, xylazine, flunixin meglumine, dipyrone, panthenol, and atropine sulfate were determined. Flunixin meglumine, dipyrone, and panthenol had no effect on the motility of the jejunum or pelvic flexure. Xylazine and atropine sulfate decreased motility of the distal portion of the jejunum and pelvic flexure, with atropine sulfate having a greater effect and lastin...
Dutton DM, Honnas CM, Watkins JP.To determine the outcome of horses with suprascapular nerve injury treated with stall rest alone. Methods: Retrospective case series. Methods: 8 horses. Methods: Information on signalment, history, limbs affected, severity of lameness, degree of muscle atrophy, gait abnormalities, and results of radiography and electromyography was obtained from medical records. All horses were treated with stall rest. Follow-up information on severity of lameness, gait abnormalities, degree of muscle atrophy, time between injury and resolution of gait abnormalities, and outcome was obtained during reexaminati...
Lester GD, Bolton JR, Cullen LK, Thurgate SM.Myoelectric activity was monitored from the terminal ileum, cecum, and colonic pelvic flexure by use of AgpAgCl bipolar electrodes in 4 adult horses before, during, and after general anesthesia. Horses were anesthetized by way of 3 commonly used regimens, including xylazine (1.1 mg/kg of body weight) and ketamine hydrochloride (2.2 mg/kg); thiopental sodium (7.7 mg/kg), followed by halothane vaporized in oxygen; and thiopental sodium (2.5 g) in guaifenesin (100 mg/ml) solution given to effect, followed by halothane in oxygen. All 3 anesthetic regimens decreased intestinal spike-burst activity ...
Keen JA, Hillier C, McGorum BC, Nally JE.Endothelin-1 (ET-1) may be a key mediator in the pathogenesis of laminitis, but endothelin-mediated responses in the venous microcirculation of the equine foot have yet to be fully characterised. Objective: To characterise the response of equine laminar veins to ET-1 and evaluate the ET-1 receptor subtypes that mediate this response. Methods: Small veins (150-500 microns) draining the equine digital laminae from healthy horses and ponies subjected to euthanasia at an abattoir were investigated using wire myography. Concentration response curves were constructed for ET-1 in the presence of ETA ...
