Cartilagines nasi (Cartilago nasi lateralis dorsalis, Cartilago alaris)
The equine nasal cartilages support the nasal passages. Major components include the dorsal lateral nasal cartilage, the ventral lateral nasal cartilage, the alar cartilage (with its lamina and cornu that form the framework of the nostril), and the nasal septum cartilage that divides the nasal cavity into left and right sides. The alar cartilage is especially important because active muscular dilation of the nostril increases the aperture during exercise and reduces airway resistance. At rest the equine nostril is comma-shaped; during exercise it becomes more circular. The false nostril (diverticulum nasi) is a blind-ended pouch on the dorsolateral aspect of the nostril. Horses cannot breathe through their mouths because of the long soft palate overlapping the epiglottis, so any restriction of nasal airflow directly affects performance and can become life-threatening.
Any condition that reduces nasal airflow impacts performance. Evaluation of the nasal passages is indicated in horses with abnormal respiratory noise, nasal discharge, or poor performance. Epistaxis (nosebleed) after exercise is most often exercise-induced pulmonary hemorrhage until proven otherwise, but unilateral resting epistaxis suggests local nasal or guttural pouch disease. Deviation of the nasal septum or septal hematoma can cause unilateral obstruction. Dynamic endoscopy is useful for exercise-related noise.
## Overview Epistaxis is bleeding from the nostrils. Common causes in horses include exercise-induced pulmonary hemorrhage (EIPH), guttural pouch mycosis, ethmoid hematoma, and trauma. The pattern (d
The character, laterality, timing, and volume of nasal discharge provide important diagnostic information. Serous (clear): normal, allergic, viral. Mucopurulent (thick, yellow-green): bacterial infect
## Overview False nostril (alar fold) entrapment or redundancy produces a loud fluttering or snoring noise during exercise, especially at speed. The noise originates at the nostril and can often be e
Nasal polyps are benign pedunculated masses arising from the nasal mucosa that can obstruct airflow. Progressive ethmoid hematoma (PEH) is an expanding, encapsulated mass of hemorrhagic granulation ti
## Overview Dynamic nasal collapse is inward collapse of the nasal structures (alar folds or related tissues) during high-speed inspiration. It produces a fluttering noise at the nostrils and can lim
A small amount of clear nasal discharge after exercise or in dusty conditions is normal. Call the veterinarian for thick yellow or green discharge (especially from one side), blood from the nostrils at rest, food material at the nostrils, foul-smelling discharge, or any discharge with fever or swollen lymph nodes. Abnormal respiratory noise during exercise warrants evaluation. Both nostrils should dilate equally.
## Overview Epistaxis is bleeding from the nostrils. Common causes in horses include exercise-induced pulmonary hemorrhage (EIPH), guttural pouch mycosis, ethmoid hematoma, and trauma. The pattern (during exercise versus at rest, unilateral versus bilateral) helps narrow the source. ## Causes EIPH from pulmonary capillary rupture during intense exercise; fungal erosion of vessels in guttural pouch mycosis; progressive ethmoid hematoma; or trauma. ## Diagnosis History and endoscopy. EIPH is confirmed by post-exercise airway examination. Guttural pouch mycosis and ethmoid hematoma are seen on endoscopy at rest. ## Treatment Depends on cause: furosemide and management for EIPH; antifungal and vascular occlusion for guttural pouch mycosis; surgical or laser treatment for ethmoid hematoma. ## Recovery and Prognosis Variable by cause. EIPH is manageable; guttural pouch mycosis can be fatal if untreated. ## Prevention For EIPH, management of racing intensity and medication. No prevention for other causes. Signs include: blood from one or both nostrils; may occur during/after exercise (EIPH) or at rest (guttural pouch mycosis, ethmoid hematoma); possible dysphagia with mycosis
The character, laterality, timing, and volume of nasal discharge provide important diagnostic information. Serous (clear): normal, allergic, viral. Mucopurulent (thick, yellow-green): bacterial infection (sinusitis, strangles, pneumonia). Unilateral purulent: dental sinusitis (tooth root abscess draining into the maxillary sinus), sinus cyst, or nasal foreign body. Bilateral purulent: lower respiratory infection. Hemorrhagic: see epistaxis causes. Food material: dysphagia (choke, guttural pouch disease, cleft palate in foals). Signs include: Clear/serous: may be normal or early viral infection; bilateral suggests systemic cause. Yellow-green unilateral: think sinusitis or dental disease. Foul-smelling unilateral: strongly suggests tooth root abscess or necrotic mass. Bilateral purulent with fever and cough: lower airway disease. Food at nostrils: choke (esophageal obstruction) or dysphagia. Blood: see epistaxis. Frothy bilateral: pulmonary edema (emergency)
## Overview False nostril (alar fold) entrapment or redundancy produces a loud fluttering or snoring noise during exercise, especially at speed. The noise originates at the nostril and can often be eliminated by manually holding the nostril open. It may limit performance. ## Causes Redundant or flaccid alar folds. Some breeds (Standardbreds, Saddlebreds) appear predisposed. Pathogenesis is not fully understood. ## Diagnosis Clinical noise that disappears when the nostril is supported, confirmed by exercising endoscopy showing alar fold collapse or vibration. ## Treatment Alar fold resection is effective in many cases when no other airway abnormalities are present. Nasal strips may help temporarily. ## Recovery and Prognosis Good after successful resection. Concurrent airway problems reduce success. ## Prevention None specific. Signs include: fluttering or snoring noise at exercise; noise loudest at the nostril; reduced performance; noise eliminated by holding the nostril open
Nasal polyps are benign pedunculated masses arising from the nasal mucosa that can obstruct airflow. Progressive ethmoid hematoma (PEH) is an expanding, encapsulated mass of hemorrhagic granulation tissue originating from the ethmoid labyrinth that progressively fills the nasal cavity and/or paranasal sinuses. PEH is not a true neoplasm. Cause is unknown. Tends to recur after treatment. Most common in horses >6 years old. Signs include: Nasal polyp: unilateral nasal obstruction; stertor (snoring); serous to mucopurulent discharge; visible on endoscopy as smooth, pedunculated mass. PEH: intermittent unilateral epistaxis (hallmark); progressive unilateral nasal obstruction; may see bulging of facial bones in advanced cases; greenish to hemorrhagic, encapsulated mass on endoscopy; facial deformity in severe cases
## Overview Dynamic nasal collapse is inward collapse of the nasal structures (alar folds or related tissues) during high-speed inspiration. It produces a fluttering noise at the nostrils and can limit performance. External nasal dilator strips may provide temporary relief. Diagnosis requires exercising endoscopy. ## Causes Insufficient rigidity of the alar cartilages or fatigue of the dilator muscles under high negative pressure. ## Diagnosis Exercising endoscopy demonstrating collapse at the nostril level. Resting examination is often normal. ## Treatment Nasal strips (for example, FLAIR strips) can help some horses. Surgical options are limited. Management of concurrent airway inflammation is supportive. ## Recovery and Prognosis Variable. Some horses perform adequately with strips; others remain limited. ## Prevention None specific. Signs include: fluttering noise from the nostrils at gallop; exercise intolerance; nostril collapse on inhalation; improvement with nasal strips
Any condition that reduces nasal airflow impacts performance. Evaluation of the nasal passages is indicated in horses with abnormal respiratory noise, nasal discharge, or poor performance. Epistaxis (nosebleed) after exercise is most often exercise-induced pulmonary hemorrhage until proven otherwise, but unilateral resting epistaxis suggests local nasal or guttural pouch disease. Deviation of the nasal septum or septal hematoma can cause unilateral obstruction. Dynamic endoscopy is useful for exercise-related noise.
A small amount of clear nasal discharge after exercise or in dusty conditions is normal. Call the veterinarian for thick yellow or green discharge (especially from one side), blood from the nostrils at rest, food material at the nostrils, foul-smelling discharge, or any discharge with fever or swollen lymph nodes. Abnormal respiratory noise during exercise warrants evaluation. Both nostrils should dilate equally.
See the Nasal Cartilages on our interactive 3D horse model. Open 3D Model