The Inferior Alveolar Nerve of the Horse: Course and Anatomical Relationship with Mandibular Cheek Teeth.

The research article discusses the path and relationship between the inferior alveolar nerve (IAN) and the roots of the lower cheek teeth in horses. Information was obtained through CT scans and anatomical dissection of 40 horses’ mandibles, showing the equine IAN’s course and its proximity to the roots of certain teeth, crucial for planning surgical procedures on the horse’s mandible to avoid potential complications.

Introduction

• The inferior alveolar nerve (IAN) is a crucial anatomical aspect in horses, particularly in surgical procedures involving the mandible or lower jaw.
• Unlike in other animals, the horse’s IAN enters the mandibular canal from the inner side and innervates all the lower teeth.
• For successful surgical procedures in the area, understanding these complicated anatomical pathways is paramount, though previously they were not described in detail.

Methodology

• To examine the IAN’s exact path and relationship to the roots of the horse’s lower cheek teeth, researchers conducted CT scans and anatomical dissection on the mandibles of 40 horses.
• The mandibles used for research provided bilateral, detailed anatomical information about the IAN’s course.

Results

• Researchers discovered that the IAN in horses is located towards the front (ventral side) of the tips (apices) of the molar teeth, listed as 311/411, 310/410, and 309/409 according to the Triadan numerical system.
• The IAN was found to sit on the inside (lingual side) of the tooth roots and above (coronally) the tips of the tooth roots at the level of PM(4) (coded as 308/408 in the Triadan system).
• Further along, at PM(3) or 307/407 level, the IAN is still on the lingual side but near the tips of the roots.
• The study also revealed that in 5% of examined horses, the IAN veers towards the lingual side, moving between the forward (mesial) and the rear (distal) root of PM(4).

Conclusion

• This anatomical insight implies that surgeons should plan any approach to the ventral side of the horse’s mandible with caution, thereby avoiding potential post-operative complications caused by accidental damage to the IAN.
• The study’s results provide valuable data for veterinary surgeons and can inform surgical techniques and approaches to preserving the equine IAN during procedures.