Os basihyoideum
The basihyoid is the single, unpaired bone that forms the transverse body (corpus) of the hyoid apparatus. It lies at the root of the tongue in the intermandibular space and carries a prominent rostral lingual process that projects into the tongue. Laterally it articulates or fuses with the thyrohyoids (which connect toward the thyroid cartilage) and connects via the ceratohyoids to the rest of the suspensory apparatus that attaches to the skull. It provides the central bony anchor for the tongue and larynx, enabling coordinated movements required for swallowing, vocalization, and airway stability. Muscles such as the geniohyoideus, mylohyoideus, and sternohyoideus attach to it. Clinically, the hyoid apparatus is evaluated by external palpation and guttural pouch endoscopy. Temporohyoid osteoarthropathy (THO) can involve adjacent joints and may lead to ceratohyoidectomy as treatment. The basihyoid and lingual process are used as suture anchors in the laryngeal tie-forward procedure for dorsal displacement of the soft palate.
Palpate the basihyoid and lingual process. Endoscopy of the guttural pouches evaluates the stylohyoid and temporohyoid joint. CT is preferred for THO. Laryngeal tie-forward uses the basihyoid as an anchor point.
## Overview Difficulty swallowing (dysphagia) occurs when the nerves or muscles that coordinate the swallow are damaged. Food or water may return through the nostrils, and there is risk of aspiration
## Overview Fracture of the hyoid apparatus (the bony support of the tongue and larynx) is uncommon and usually traumatic. It can cause difficulty swallowing, throatlatch swelling, pain on manipulati
Difficulty swallowing, nasal discharge, or head-shaking may involve the hyoid region; have a veterinarian examine the throat. Do not force the mouth open or pull the tongue if the horse shows pain in this area.
## Overview Difficulty swallowing (dysphagia) occurs when the nerves or muscles that coordinate the swallow are damaged. Food or water may return through the nostrils, and there is risk of aspiration pneumonia. Common causes include guttural pouch disease, retropharyngeal abscess, or neurologic injury. ## Causes Damage to cranial nerves IX, X, or XII, or to the pharyngeal muscles themselves. ## Diagnosis Observation of eating and drinking, endoscopic examination of the pharynx and guttural pouches, and neurologic assessment. ## Treatment Address the underlying cause (for example, treatment of guttural pouch mycosis or abscess drainage). Supportive care includes feeding modifications and management of aspiration. ## Recovery and Prognosis Variable. Some nerve injuries improve; others are permanent. Aspiration pneumonia worsens the outlook. ## Prevention Prompt treatment of guttural pouch or upper-airway infections. Signs include: food or water returning from the nostrils; coughing while eating; weight loss; risk of aspiration pneumonia
## Overview Fracture of the hyoid apparatus (the bony support of the tongue and larynx) is uncommon and usually traumatic. It can cause difficulty swallowing, throatlatch swelling, pain on manipulation, abnormal respiratory noise, and sometimes epistaxis. Resistance to poll flexion may be noted. ## Causes Trauma to the throat or tongue region, or excessive traction. ## Diagnosis Radiographs or computed tomography of the hyoid bones, endoscopy, and clinical signs of dysphagia or local pain. ## Treatment Conservative management with soft feeds and anti-inflammatories for stable fractures. Surgical repair is rarely required. Supportive care for dysphagia. ## Recovery and Prognosis Generally good for uncomplicated fractures. Persistent dysphagia worsens the outlook. ## Prevention Avoidance of throat trauma. Signs include: difficulty swallowing; swelling under the jaw or throat; pain on throat manipulation; abnormal respiratory noise; possible epistaxis
Palpate the basihyoid and lingual process. Endoscopy of the guttural pouches evaluates the stylohyoid and temporohyoid joint. CT is preferred for THO. Laryngeal tie-forward uses the basihyoid as an anchor point.
Difficulty swallowing, nasal discharge, or head-shaking may involve the hyoid region; have a veterinarian examine the throat. Do not force the mouth open or pull the tongue if the horse shows pain in this area.
See the Basihyoid Bone on our interactive 3D horse model. Open 3D Model