Musculus pterygoideus
The pterygoid muscles are deep jaw muscles on the medial side of the mandible. They originate from the pterygoid bone and palatine bone of the skull and insert on the medial surface of the mandible (angle and ramus). The medial pterygoid assists in closing the jaw. The lateral pterygoid protrudes and laterally deviates the mandible, which is essential for the side-to-side grinding motion unique to herbivore mastication. They are innervated by the mandibular branch of the trigeminal nerve (CN V3).
Origin: Pterygoid bone and palatine bone of the skull
Insertion: Medial surface of the mandible (angle and ramus)
Action: Medial: closes the jaw. Lateral: protrudes and laterally deviates the mandible for grinding
Innervation: Mandibular branch of the trigeminal nerve (CN V3)
Isolated injury is uncommon. Relevant in evaluations of mastication problems, dental disease, or trigeminal nerve dysfunction. Difficulty grinding or unilateral jaw deviation may involve these muscles.
## Overview Temporomandibular joint (TMJ) dysfunction is inflammation or misalignment of the jaw joint. It causes reluctance to chew, quidding, head tossing, resistance to the bit, tenderness over th
Difficulty chewing, dropping feed, or jaw asymmetry should be evaluated by a veterinarian, often with a dental examination.
## Overview Temporomandibular joint (TMJ) dysfunction is inflammation or misalignment of the jaw joint. It causes reluctance to chew, quidding, head tossing, resistance to the bit, tenderness over the temporal fossa, and visible muscle wasting above the eye. Dental problems or poor bitting often contribute. ## Causes Dental disease, trauma, or bit-related pressure. ## Diagnosis Palpation, dental examination, and sometimes radiographs or computed tomography of the TMJ. ## Treatment Correct dental issues, adjust bitting, anti-inflammatories, and physiotherapy. Injections are used in some cases. ## Recovery and Prognosis Good when the underlying cause is addressed. ## Prevention Regular dental care and appropriate bit fit. Signs include: reluctance to chew; quidding; head tossing; resistance to the bit; tenderness over the temporal fossa; muscle wasting above the eye
Isolated injury is uncommon. Relevant in evaluations of mastication problems, dental disease, or trigeminal nerve dysfunction. Difficulty grinding or unilateral jaw deviation may involve these muscles.
Difficulty chewing, dropping feed, or jaw asymmetry should be evaluated by a veterinarian, often with a dental examination.
See the Pterygoideus on our interactive 3D horse model. Open 3D Model