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The head of the condylar process of the mandibular ramus articulates with the base of the zygomatic process of the squamous part of the temporal bone (mandibular fossa) at the TMJ: a transversely elongated (cigar‐shaped) synovial joint (Figure 1.17). The retroarticular process is a caudoventral extension of the mandibular fossa which helps prevent caudal luxation of the mandible (Figure 1.18).

Figure 1.15 (a) Lower jaw. (b) Right mandible buccal aspect: 1. Mandibular body; 2. Mandibular ramus; 3. Masseteric fossa; 4. Coronoid process; 5. Condylar process; 6. Angular process; 7. Middle mental foramen; 8. Caudal mental foramen. (c) Right mandible lingual aspect: 1. Mandibular symphysis articular surface; 2. Mandibular foramen.

The articular cartilage of the TMJ is fibrocartilaginous tissue, with a fibrocartilaginous disc separating the joint into two non‐communicating compartments.

The insertion of the masseter muscle reaches the ventral and rostral aspect of the joint capsule. There is a thin, cartilaginous intra‐articular disc dividing the joint into dorsal and ventral compartments. This disc reduces friction by providing a double synovial film.

Figure 1.16 (a) Mandibular symphysis dorsal view. (b) Mandibular symphysis rostral view showing the mental foramina (arrows). (c) Mental foramina.

Figure 1.17 Temporomandibular joints ventral view: 1. Retroarticular process; 2. Mandibular fossa; 3. Condylar process; 4. Angular process.

Figure 1.18 Lateral aspect of the left temporomandibular joint: 1. Coronoid process; 2. Zygomatic arch; 3. Zygomatic process of the temporal bone; 4. Mandibular ramus; 5. Condylar process; 6. Articular eminence; 7. Tympanic bulla; 8. Mandibular fossa; 9. Retroarticular process; 10. Angular process.