The Nerve Supply to the Lumbar Region of the Dog With Special Reference to Cutaneous Innervation

Detailed anatomical information on the innervation of the skin by spinal nerve branches is fundamental for numerous integrative therapies, such as acupuncture or manual treatments. In recent years, interest in these therapies has grown, and they have gained increasing importance. Many musculoskeletal disorders in dogs are located in the region of the trunk, but knowledge about the course and branching of the cutaneous branches remains limited. This study presents a morphological analysis of the innervation pattern of the first cutaneous branch of the spinal dorsal nerve branches in 14 dogs. The dissection was performed in four layers to trace the cutaneous branches from the intervertebral foramen to their target area. The distances covered in each layer were measured and described using the Caudal Shift Index (CSI_n). For this purpose, the 'back region' was defined as a dimensional unit, representing the distance between the spinous processes of two consecutive vertebrae within the examination area from the ninth thoracic (Th9) to the seventh lumbar (L7) vertebra. The results showed that the cutaneous branches innervating the lumbar region originated, on average, between Th11 and L4. The mean CSI_n-S was three back regions, indicating a distance equivalent to the length of three vertebral bodies between the nerve's origin at the foramen and the skin entry. In conclusion, these findings demonstrate consistency in the caudal shift of the cutaneous branches between Th9 and L4, with a high degree of symmetry between both sides of the body. These findings should be considered in therapeutic treatments.