Overview
The dog mandible is made of two hemimandibles joined rostrally by the mandibular symphysis, a fibrocartilaginous joint that never fully ossifies. Each half has a horizontal body, holding the teeth, and a vertical ramus, where the masticatory muscles insert and which articulates with the skull.
Key features
- Body (corpus mandibulae): with the alveoli of the lower incisors, canine, four premolars and three molars (adult dental formula: 3/3 I, 1/1 C, 4/4 PM, 2/3 M). The first lower molar is the lower carnassial tooth.
- Mental foramina: on the lateral surface of the body, exit of the inferior alveolar nerve (mental nerve block).
- Mandibular foramen: on the medial surface of the ramus, entry of the inferior alveolar nerve (mandibular nerve block).
- Coronoid process: tall and wide, insertion of the temporalis muscle.
- Condylar process: articulates with the mandibular fossa of the temporal bone (temporomandibular joint).
- Angular process: caudal projection, insertion of the masseter and pterygoid muscles.
Clinical relevance
Mandibular fractures are common after trauma and in small dogs with advanced periodontal disease (pathological fractures of the body at the first molar). Symphyseal separation is frequent in cats and in dogs after falls. Temporomandibular luxation and open-mouth jaw locking by the coronoid process are other conditions to recognise.