Arthroscopic approach and intra-articular anatomy of the equine discomandibular joint compartment of the temporomandibular joint.
Authors: Carmalt James L, Tucker Michelle L
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Arthroscopic Access to the Equine Discomandibular Joint Carmalt and Tucker developed the first systematic arthroscopic approach to the discomandibular joint (DMJ)—the ventral compartment of the temporomandibular joint—using nine cadaveric heads and two live horses to establish safe portal placement and anatomical landmarks. Employing a 2.5-mm 30° arthroscope with joint distension, they created a caudal portal first, then positioned a rostral portal under direct visualisation; nasotracheal intubation in live horses permitted mandibular manipulation, which proved essential for complete joint exploration. The technique achieved consistent arthrocentesis, allowed thorough debridement of the DMJ, and revealed anatomical variations between individuals including one case of mandibular condylar cyst; notably, no communication existed between the DMJ and the dorsal compartment. Parotid gland trauma occurred in three cadavers, highlighting the importance of precise portal placement, though this complication risk can be minimised in clinical practice through careful anatomical awareness. Since the DMJ harbours the vast majority of TMJ pathology in horses (excluding septic cases), this arthroscopic approach offers a valuable diagnostic and therapeutic tool for conditions that have previously been challenging to access and treat directly.
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Practical Takeaways
- •This arthroscopic technique enables direct visualization and treatment of discomandibular joint pathology, which represents the majority of non-septic TMJ problems in horses.
- •Portal placement must be precise and mandibular manipulation is essential during the procedure—nasotracheal intubation facilitates this in standing or sedated horses.
- •The independence of TMJ compartments means pathology can be localized to the discomandibular joint, allowing targeted treatment without assuming bilateral or multi-compartmental involvement.
Key Findings
- •A novel arthroscopic approach to the equine discomandibular joint was successfully developed using caudal and rostral portals with mandibular manipulation for complete visualization.
- •The discomandibular and temporomandibular joint compartments are independent with no communication between them, having significant diagnostic and treatment implications.
- •Anatomical variations in the medial joint capsule were observed between individual horses, requiring tailored surgical approaches.
- •Parotid salivary gland damage occurred in 3 of 9 cadaver specimens, indicating risk during portal placement that should be mitigated in live cases.