Morphological Analysis of the Saphenous Nerve in the Dog

Owners spend millions of US dollars to alleviate pain from stifle osteoarthritis (OA) pain in pet dogs each year. Neurectomy of the saphenous nerve has been shown to effectively alleviate symptoms of knee OA in humans. In order to translate this therapy to the dog, saphenous nerve branches and innervation must be identified. The hind limbs of seven fixed canine cadavers, male and female, were dissected to trace the course of the saphenous nerve. After skin removal, the femoral nerve was traced distally to the branching of the saphenous nerve at the proximal border of the femoral triangle. The saphenous nerve was then traced distally between the caudal head of the sartorius muscle and the cranial head of the gracilis muscle to the level of the stifle (knee). The femoral artery was traced distally to the branch of the saphenous artery, which was then traced to the level of the stifle. The saphenous nerve was identified in all limbs and remained superficial until the level of the medial femoral epicondyle, in close proximity to the saphenous artery. A consistent branch left the saphenous nerve and coursed cranially to the stifle, where it appeared to innervate the medial aspect of the stifle joint capsule. In addition, other minor branches supply surrounding musculature were observed and documented. This study determined that the saphenous n. appears to provide substantial innervation to the medial side of the stifle joint in the dog. Future work would need to be done to confirm the joint structures these branches innervate and whether ablation would result in OA symptom relief. Financial support provided by NIH Bridges to the Baccalaureate Program.