Os thyrohyoideum
The thyrohyoid bone is the most caudal paired element of the hyoid apparatus, connecting the ceratohyoid to the thyroid cartilage of the larynx. The hyoid apparatus suspends the tongue and larynx from the skull base and is critical for swallowing and vocalization.
The hyoid apparatus is assessed via throat palpation and guttural pouch endoscopy. THO is a serious condition; CT is the gold standard for diagnosis.
Progressive fusion and thickening of the temporohyoid joint (where the stylohyoid articulates with the temporal bone). Can lead to fracture of the petrous temporal bone, damaging cranial nerves VII an
Fractures of the hyoid bones from trauma (kicks to the throat, rearing and falling backward, or iatrogenic during dental work). Can compromise the airway.
Progressive fusion and thickening of the temporohyoid joint (where the stylohyoid articulates with the temporal bone). Can lead to fracture of the petrous temporal bone, damaging cranial nerves VII and VIII. A serious, potentially life-threatening condition. Signs include: Sudden onset facial nerve paralysis (drooping ear, lip, eyelid); head tilt; difficulty swallowing; loss of balance (vestibular signs); may have history of ear discharge or previous mild episodes; can cause sudden death from basilar skull fracture; diagnosed on endoscopy of the guttural pouches or CT.
Fractures of the hyoid bones from trauma (kicks to the throat, rearing and falling backward, or iatrogenic during dental work). Can compromise the airway. Signs include: Difficulty swallowing; swelling under the jaw or throat; pain when manipulating the throat area; abnormal respiratory noise; resistance to poll flexion; may see blood at the nostrils.; Consult veterinarian for specific symptoms.
The hyoid apparatus is assessed via throat palpation and guttural pouch endoscopy. THO is a serious condition; CT is the gold standard for diagnosis.
See the Thyrohyoid Bone (Left) on our interactive 3D horse model. Open 3D Model