Dysphagia resulting from unilateral rupture of the rectus capitis ventralis muscles in a horse.

This research discusses a case where a 2-year-old Quarter Horse experienced difficulty swallowing (dysphagia) after falling backward and straining the neck muscles, leading to serious muscle rupture. This muscle damage indirectly harmed certain cranial nerves, causing more complications including a temporary nosebleed, laryngeal paralysis, pharyngeal paralysis and continued dysphagia, ultimately resulting in gangrenous pneumonia, which led to euthanasia.

Incident Background

• The case study revolves around a 2-year-old Quarter Horse filly which was exercising on a mechanical horse walker. During the exercise, the horse fell backwards, hyper-extending its neck.

Consequences of the Incident

• The horse’s fall and neck strain resulted in a unilateral rupture of two vital neck muscles. This forced position led to muscle rupture at their insertion point.
• There was also the presence of a prefabricated mycotic lesion on the horse. This lesion was located on the dorsomedial wall of the left guttural pouch and it might have contributed to weakening the region where the injured muscles were inserted.

Complications Developed

• The rupture of these muscles resulted in damage to the IX, X, and XI cranial nerves. This damage led to several health problems including laryngeal hemiplegia, pharyngeal paralysis, a temporary nosebleed (epistaxis), and continued difficulty swallowing (dysphagia).
• The horse’s swallowing difficulty had serious repercussions, as it resulted in the inhalation of food (ingesta), which led to the development of a severe lung infection known as gangrenous pneumonia.

End Result

• Following the development of gangrenous pneumonia, the horse’s condition was deemed to be untenable. Consequently, the decision was made to euthanize the 2-year-old filly.