Musculus sternohyoideus
The sternohyoideus is a paired strap muscle running the full length of the ventral neck. It originates from the manubrium of the sternum and inserts on the basihyoid bone. Its actions are to depress the hyoid apparatus and assist in swallowing and opening the mouth. It is innervated by ventral branches of C1-C2 via the ansa cervicalis. It is critical for laryngeal positioning during exercise and swallowing.
Origin: Manubrium of the sternum
Insertion: Basihyoid bone (hyoid apparatus)
Action: Depresses the hyoid apparatus; assists in swallowing and opening the mouth
Innervation: Ventral branches of C1-C2 via the ansa cervicalis
Relevant in evaluations of hyoid and laryngeal function. Dysfunction can contribute to airway positioning issues. Isolated injury is uncommon.
## Overview Problems related to the guttural pouch (empyema, tympany, or mycosis) can affect surrounding structures, producing difficulty swallowing, nasal return of feed, or visible swelling in the
## Overview Sternohyoideus myectomy or myotomy is a surgical procedure used to treat dorsal displacement of the soft palate (DDSP). A portion of the sternohyoideus (and often sternothyroideus) muscle
Difficulty swallowing or abnormal neck posture after trauma should be evaluated.
## Overview Problems related to the guttural pouch (empyema, tympany, or mycosis) can affect surrounding structures, producing difficulty swallowing, nasal return of feed, or visible swelling in the throatlatch. The pouch lies close to cranial nerves and major vessels, so disease there readily causes secondary signs. ## Causes Distension or inflammation of the pouch compressing nerves or the pharynx. ## Diagnosis Endoscopy and imaging of the guttural pouches, plus neurologic assessment. ## Treatment Directed at the underlying pouch disease (lavage, surgery for tympany, antifungal and vascular occlusion for mycosis). ## Recovery and Prognosis Depends on the primary condition and whether nerve damage is reversible. ## Prevention Early treatment of guttural pouch infections. Signs include: difficulty swallowing; nasal discharge of food; throatlatch swelling; may accompany empyema or tympany
## Overview Sternohyoideus myectomy or myotomy is a surgical procedure used to treat dorsal displacement of the soft palate (DDSP). A portion of the sternohyoideus (and often sternothyroideus) muscle is transected or removed to reduce caudal pull on the larynx, theoretically stabilizing it and decreasing the likelihood of palatal displacement. ## Causes N/A (this is a surgical treatment). The underlying DDSP is often related to upper-airway instability during exercise. ## Diagnosis Pre-operative diagnosis of DDSP is made by exercising endoscopy. The procedure itself is chosen based on case selection and surgeon preference. ## Treatment The surgery is performed under standing sedation or general anesthesia. Reported success rates are moderate (around 60 percent in some series). Many surgeons now prefer the laryngeal tie-forward procedure, which has higher published success. ## Recovery and Prognosis Most horses resume training within weeks. Noise and performance may improve, but recurrence of DDSP occurs in a substantial proportion of cases. ## Prevention N/A. Signs include: Pre-surgery: intermittent gurgling at speed, exercise intolerance. Post-surgery: reduced frequency of displacement in successful cases
Relevant in evaluations of hyoid and laryngeal function. Dysfunction can contribute to airway positioning issues. Isolated injury is uncommon.
Difficulty swallowing or abnormal neck posture after trauma should be evaluated.
See the Sternohyoideus on our interactive 3D horse model. Open 3D Model