Anatomy and Ultrasound-Guided Injection of the Medial Branch of the Dorsal Ramus of the Cervical Spinal Nerves in the Horse: A Cadaveric Study.

The research delves into understanding the anatomy of nerves that supply the cervical articular process joint in horses and proposes methods to guide injections to these nerves. The aim is to use this knowledge and technique for managing pain in cervical articular process joint arthropathy in horses.

Anatomy and Methodology

• The study was conducted on twelve cadaveric equine necks to map the anatomy of the medial branch of the dorsal ramus of the cervical spinal nerves 3 to 7.
• Five out of these necks were dissected to understand the anatomical details. The information collected through these dissections was combined with ultrasonographic images collected from another neck.

Injection Process

• The remaining six necks were used to verify the precision of ultrasound-guided injections to the medial branch. These injections were carried out using blue dye.
• Out of the 55 nerves injected under ultrasonographic guidance, 51 were confirmed to have been successfully stained with the dye, indicating the success of the guided injection process.

Findings

• The study revealed that each cervical articular process joint, except for C2 to C3, received dual nerve supply.
• The articular process joints were discovered to be in close anatomical relationship with the medial branch of the dorsal ramus of the cervical spinal nerve. This relation was prominent both where the cervical spinal nerve came out from the intervertebral foramen at the same level and one level cranial to the articular process joint of interest.

Conclusions

• The research provides vital insights into the innervation of the cervical articular process joint in horses.
• The successful administration of guided injections onto the medial branches of the dorsal rami of the cervical spinal nerves suggests clinical applicability.
• This foundational work can be used to devise new diagnostic and treatment methods for managing pain in horses suffering from cervical articular process joint arthropathy.