Key Insights
  • Dorsal Displacement of the Soft Palate causes upper airway obstruction during intense exercise
  • This condition occurs when the soft palate moves above the epiglottis, blocking nasal airflow
  • Contributing factors include weak epiglottis, muscle fatigue, inflammation and poor conditioning
  • Clinical signs include noisy breathing, exercise intolerance, coughing and reduced performance
  • Diagnosis relies on endoscopy and dynamic endoscopy performed during active exercise
  • Treatment options range from conditioning and tack changes to surgical correction procedures
  • Prognosis varies with severity and management, with many cases responding to tie-forward surgery

Dorsal Displacement of the Soft Palate (DDSP), commonly known as “flipping the palate,” is a respiratory condition that significantly affects a horse’s performance, especially during intense exercise. It is one of the most common causes of upper airway obstruction in racehorses. [1][2]

DDSP occurs when the soft palate, located at the back of the horse’s mouth, is displaced upward during exertion, causing partial or complete airway obstruction. This can lead to difficulty breathing, noisy respiration, and a decline in athletic ability.

While the condition is most commonly observed in racehorses and high-performance athletes, it can affect horses across various disciplines. Understanding the causes, symptoms, and management of DDSP is essential for maintaining horse health and optimizing performance in competition.

Flipping the Palate in Horses

Dorsal Displacement of the Soft Palate (DDSP) is an intermittent equine condition where the soft palate moves upward, above the epiglottis, during high-intensity exercise. Normally, the soft palate rests below the epiglottis, allowing air to flow freely from the nasal passages to the lungs. When DDSP occurs, the soft palate temporarily obstructs the airway. [2][3][4]

This disruption of airflow makes it difficult for the horse to breathe, reducing oxygen delivery to the muscles and impairing performance. DDSP typically occurs during intense exercise at high speeds, especially in racehorses, with episodes varying in frequency and severity.

Soft Palate Anatomy

Horses are obligate nasal breathers, meaning they are anatomically adapted to breathe exclusively through their nostrils. Due to the unique structure of their upper respiratory tract, they cannot effectively breathe through their mouths. [5]

Proper function of the upper respiratory tract is vital for a horse’s overall health and performance. The upper region of the tract is responsible for intake and temperature conditioning of air before it reaches the lungs. It includes several structures that work together to ensure efficient respiration by filtering, warming, and humidifying the air.

The soft palate is located at the back of the horse’s mouth and plays a key role in breathing and swallowing. This long structure extends backward into the throat, partially obstructing oral breathing.

The soft palate spans the back of the horse’s oral cavity, extending from the roof of the mouth to the back of the throat. It usually sits just below the epiglottis – a cartilage flap that helps close the airways during swallowing. The epiglottis is a component of the larynx (voice box). [5][6]

The soft palate is located behind the hard palate, the bony section of the roof of the mouth. Unlike the rigid hard palate, the soft palate is a muscular and flexible structure made primarily of soft tissue.

The soft palate serves the crucial function of separating the nasal passages from the oral cavity. During swallowing, it moves upward to seal off the nasal passages, preventing food or liquid from entering the nose. During normal breathing, the soft palate remains underneath the epiglottis, allowing air to pass freely through the airway. [5][6]

Causes of DDSP in Horses

The causes of Dorsal Displacement of the Soft Palate (DDSP) are multifactorial and not fully understood. However, several anatomical, neurological, physiological, and environmental factors are believed to contribute to its occurrence in horses. [3][7]

DDSP often results from a combination of these factors rather than a single cause. This highlights the importance of identifying and addressing specific contributors in each case to develop an effective management strategy.

Anatomical Issues

Historically, it was thought that an excessively long soft palate was a contributing factor to DDSP, but more recent evidence suggests that is not the case.  [8]

Rather, irregularities in epiglottis morphology increase the risk of flipping the palate. The epiglottis is a cartilage flap that sits just above the soft palate. During swallowing, it flips upward to cover the windpipe opening, acting as a barrier to prevent food or liquid from entering.

A weak, floppy epiglottis can compromise the stability of the soft palate, increasing the likelihood of displacement. A small or underdeveloped epiglottis may also fail to keep the soft palate in its normal position during intense exercise. [2][3]

Muscular Dysfunction

Maintaining airway patency, or keeping the airway open, is a complex process that depends on the coordinated action of several muscles in the horse’s upper respiratory tract. Damage or weakness in the nerves or muscles controlling the soft palate can disrupt this coordination. [5]

Additionally, pharyngeal muscle fatigue during intense exercise can destabilize the soft palate, increasing the risk of displacement. [5]

Environmental & Physiological Triggers

Factors like head and neck positioning during performance, respiratory inflammation from infections or allergies, and high-intensity exercise can exacerbate the risk of DDSP. [9]

The presence of masses, granulomas, or cysts below the epiglottis and along the free edge of the soft palate can also lead to displacement. [2]

Other Factors

Poor conditioning, muscle fatigue, stress, cardiovascular and pulmonary diseases, and foreign bodies in the throat may indirectly contribute to DDSP by altering the horse’s breathing mechanics or airway alignment. [3]

Symptoms of DDSP

The clinical signs of Dorsal Displacement of the Soft Palate (DDSP) vary in severity but generally include: [2][3][5]

  • Noisy Breathing: A distinctive, often loud noise during breathing, such as gurgling, snorting, or a sound resembling airway obstruction, occurs when the soft palate disrupts normal airflow.
  • Exercise Intolerance: Horses with DDSP may struggle with high-intensity exercise, showing reduced endurance and quick fatigue, making it harder to maintain speed or performance.
  • Coughing or Gagging: The displaced soft palate can trigger coughing or gagging as the horse attempts to clear its airway.
  • Poor Performance: Overall athletic performance may decline, with slower times, decreased agility, and difficulty completing work the horse could handle previously.

Signs of DDSP typically occur sporadically, especially during intense exercise. The condition may be more noticeable in racing or competitive events. In severe cases, repeated episodes of displaced soft palate during exercise can lead to a noticeable reduction in the horse’s athletic capabilities.

Diagnosis of DDSP

Diagnosing Dorsal Displacement of the Soft Palate (DDSP) involves a combination of clinical evaluation, observational findings during exercise, and diagnostic imaging.

Endoscopy allows the veterinarian to directly examine the horse’s upper airway by inserting a flexible endoscope (camera) through the nostrils. This procedure helps visualize the soft palate, epiglottis, and larynx while the horse is at rest. [3]

Typically, the airway appears normal at rest. However, persistent DDSP at rest or difficulty repositioning the soft palate during swallowing may indicate more serious issues. These concerns are often more apparent during high-speed exercise, providing further insight into the condition. [3]

Dynamic endoscopy is a crucial diagnostic tool for assessing DDSP during exercise. This technique uses a flexible endoscope while the horse is exercising, typically on a high-speed treadmill or during a controlled exercise session. [10][11][12]

The dynamic nature of this procedure allows the veterinarian to observe the soft palate’s movements in real-time, identifying any displacement during intense physical exertion. This method is vital for diagnosing DDSP, as it replicates the conditions under which the soft palate is most likely to displace.

By combining clinical signs, endoscopic findings, and exercise testing, a veterinarian can accurately diagnose DDSP and differentiate it from other upper respiratory conditions that may cause similar symptoms.

Differential Diagnosis

When diagnosing Dorsal Displacement of the Soft Palate (DDSP), it is important to rule out other conditions with similar clinical signs. Key differential diagnoses include: [3][13] [14][15]

  • Idiopathic Laryngeal Hemiplegia: Paralysis of one side of the larynx causes airway obstruction and noisy breathing (‘roars‘), resembling DDSP
  • Aryepiglottic Fold Deviation: Deviation of the aryepiglottic folds can partially obstruct the airway, leading to abnormal respiratory sounds and exercise intolerance
  • Epiglottic Entrapment: The epiglottis becomes trapped under the aryepiglottic folds, restricting airflow and causing respiratory noise, particularly during exercise
  • Nasopharyngeal Collapse: The nasopharynx may collapse during exercise, restricting airflow and causing poor performance and noisy breathing, similar to DDSP
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Treatment & Prognosis of DDSP

The treatment of DDSP depends on the severity of the condition, its underlying causes, and the horse’s intended use. Options typically fall into two categories: conservative management and surgical intervention. Prognosis also depends on severity and complexity of the medical intervention.

Conservative Management

Conservative management of Dorsal Displacement of the Soft Palate (DDSP) focuses on addressing underlying factors and making non-invasive adjustments to improve the horse’s condition. These methods can be highly effective, particularly in mild cases or when surgical intervention is not immediately warranted. [3][16]

Conservative strategies include: [2][3][17][18][19]

  • Eliminating Predisposing Factors: Identifying and addressing contributing conditions, such as respiratory infections, inflammation, or poor fitness, is critical. Ensuring the horse is in optimal health reduces strain on the upper airway and minimizes the risk of displacement.
  • Improving Fitness: Poor conditioning can exacerbate DDSP. A structured fitness program helps strengthen the horse’s respiratory and pharyngeal muscles, improving stability and reducing the likelihood of displacement during exercise.
  • Tack Modifications: Using specialized tack, such as a dropped noseband, Australian noseband, or tongue bits, can help stabilize the tongue and soft palate, reducing the risk of DDSP by preventing excessive movement during exercise.
  • Tongue Ties: A tongue tie is a leather or fabric loop secured around the horse’s tongue and fastened under the lower jaw. It holds the tongue in a forward (rostral) position, helping stabilize the soft palate and reduce the risk of displacement. While this method can be effective for some horses, individual responses may vary.
If your horse is showing signs of DDSP, it’s important to get a veterinary assessment before attempting to manage the condition on your own.

 

Surgical Interventions

Surgical options for managing Dorsal Displacement of the Soft Palate (DDSP) focus on addressing the anatomical and functional issues contributing to the condition. The choice of surgery depends on the severity of DDSP, the horse’s clinical signs, and its intended use.

Tie-Forward Surgery (Laryngeal Advancement Surgery)

Tie-forward surgery repositions the larynx closer to the basihyoid bone, reducing the likelihood of the soft palate displacing. Sutures are used to advance the larynx and secure it in place, improving the contact between the epiglottis and the soft palate, thereby minimizing the risk of airway obstruction. [1][16]

The procedure is minimally invasive and has a high success rate, with approximately 80% of horses having full resolution of intermittent DDSP. It is also favored for its relatively short recovery time, allowing horses to return to training more rapidly. [1][3]

Staphylectomy

Staphylectomy involves the partial removal of the caudal free edge of the soft palate to reduce its thickness and bulk. This improves flexibility and minimizes interference with the epiglottis, reducing the risk of displacement. The procedure is performed on horses with a mass at the back edge of the soft palate, and only a small portion should be removed to avoid difficulty swallowing. [2][3][20]

Staphylectomy is particularly useful for horses with an excessively thick or flaccid soft palate. However, excessive resection can impair soft palate function, potentially leading to greater airway instability or swallowing difficulties. [3][20]

Myectomy

Myectomy involves the surgical removal of specific muscles in the throat that contribute to the caudal pull on the larynx, such as the sternohyoideus, sternothyroideus, or omohyoideus muscles. By removing these muscles, the tension on the larynx is reduced, helping stabilize the soft palate. [2][21]

This procedure is often combined with other surgical interventions, such as tie-forward surgery, to improve overall outcomes. Approximately 60% of horses that undergo myectomy for DDSP show improvement. [3]

Sclerotherapy

Sclerotherapy is a treatment option for DDSP that involves injecting a sclerosing agent into the submucosal layer of the soft palate. A sclerosing agent induces inflammation and scarring (fibrosis) in the tissue. This process increases the stiffness of the soft palate, reducing its flexibility and helping to stabilize it. [22]

While sclerotherapy offers a potential solution for horses with DDSP, its effectiveness has been questioned. Reported success rates for this treatment range from 25% to 50%, indicating that it may not always provide the desired improvement in palatal stability. [2]

Tension Palatoplasty

Tension palatoplasty is a procedure designed to restructure and tighten the soft palate to increase its rigidity. By reducing the soft palate’s flexibility, the surgery helps minimize the risk of displacement during exercise. [2][3][23]

This method is especially useful for horses with a long or excessively flaccid soft palate. However, careful evaluation is essential, as over-tightening may impair the normal function of the soft palate or interfere with swallowing.

Frequently Asked Questions

Here are some frequently asked questions about DDSP or flipping the palate in horses:

Summary

DDSP (Dorsal Displacement of the Soft Palate), or "flipping the palate," occurs when a horse's soft palate shifts upward during intense exercise, blocking airflow, which causes breathing difficulty and reduced performance.

  • The exact cause is not fully understood but may involve anatomical issues, muscular dysfunction, environmental factors, and airway masses or growths
  • Clinical signs include noisy breathing, exercise intolerance, coughing, gagging, and poor performance, particularly during intense exercise
  • DDSP is diagnosed with endoscopy and dynamic endoscopy during exercise. Conditions like laryngeal hemiplegia and epiglottic entrapment can have similar symptoms
  • Treatment options include conservative management (improving fitness, specialized tack) and surgical interventions (tie-forward surgery, staphylectomy, myectomy, sclerotherapy, tension palatoplasty)
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References

  1. Lean N.E. et al., Laryngeal Tie‐forward in Standing Sedated Horses. Vet Surg. 2023.
  2. Boone L., Dorsal Displacement of the Soft Palate in Horses - Respiratory System. Merck Veterinary Manual. 2023.
  3. Archer D. et al., Soft palate: dorsal displacement in Horses. VetLexicon.
  4. Franklin S.H. et al., Effect of Dorsal Displacement of the Soft Palate on Ventilation and Airflow during High-Intensity Exercise. Equine Vet J Suppl. 2002. View Summary
  5. Allen K., Soft Palate Displacement in Horses. In Practice. 2015.
  6. Dorsal Displacement of the Soft Palate. American College of Veterinary Surgeons. 2025.
  7. Allen K.J. et al., A Systematic Review of the Efficacy of Interventions for Dynamic Intermittent Dorsal Displacement of the Soft Palate. Equine Vet J. 2012. View Summary
  8. Holcombe S.J. et al., Pathophysiology of Dorsal Displacement of the Soft Palate in Horses. Equine Vet J Suppl. 1999. View Summary
  9. Joó K. et al., Asthmatic Disease as an Underlying Cause of Dorsal Displacement of the Soft Palate in Horses. Journal of Equine Veterinary Science. 2021. View Summary
  10. Allen K. and Franklin S., Characteristics of Palatal Instability in Thoroughbred Racehorses and Their Association with the Development of Dorsal Displacement of the Soft Palate. Equine Vet J. 2013.
  11. Davidson E., Dorsal Displacement of the Soft Palate: Standing and Dynamic Endoscopic Examination. In: Advances in Equine Upper Respiratory Surgery. John Wiley & Sons, Ltd. 2015.
  12. Pollock P.J. et al., Dynamic Respiratory Endoscopy in 67 Thoroughbred Racehorses Training under Normal Ridden Exercise Conditions. Equine Vet J. 2009. View Summary
  13. Boone L., Laryngeal Hemiplegia in Horses. Merck Veterinary Manual. 2023.
  14. King D.S. et al., Clinical Experiences with Axial Deviation of the Aryepiglottic Folds in 52 Racehorses. Vet Surg. 2001. View Summary
  15. Ahern T.J., A Review of the Anatomical Components, and the Process of Entrapment of the Epiglottis in the Horse, with a Comparative Synopsis of Surgical Treatments. Journal of Equine Veterinary Science. 1996.
  16. Woodie J.B. et al., Surgical Advancement of the Larynx (Laryngeal Tie-Forward) as a Treatment for Dorsal Displacement of the Soft Palate in Horses: A Prospective Study 2001-2004. Equine Vet J. 2005.
  17. Barakzai S.Z. and Dixon P.M., Conservative Treatment for Thoroughbred Racehorses with Intermittent Dorsal Displacement of the Soft Palate. Veterinary Record. 2005. View Summary
  18. Franklin S.H. et al., The Effect of a Tongue-Tie in Horses with Dorsal Displacement of the Soft Palate. Equine Vet J Suppl. 2002. View Summary
  19. Weller D. et al., The Reported Use of Tongue-Ties and Nosebands in Thoroughbred and Standardbred Horse Racing—A Pilot Study. Animals (Basel). 2021. View Summary
  20. Carmalt J.L. et al., Comparisons Between Staphylectomy and Tie-Forward Procedures in Combination with a Sternothyroideus Myotenectomy for the Treatment of Intermittent Dorsal Displacement of the Soft Palate: An Observational Study. Vet Surg. 2016.
  21. Munroe G. et al., Soft palate: sternothyrohyoid / omohyoid - myectomy in Horses. VetLexicon.
  22. Fiske-Jackson A. and Williams J., Soft palate: sclerotherapy in Horses. VetLexicon.
  23. Ahern T., (PDF) The Modified Oral Palatopharyngoplasty or Modified Ahern Procedure. ResearchGate. 2024.