Purpose: Traumatic and degenerative disc lesions cause ulnar-sided wrist pain. To date, anatomical investigations of cadaver triangular fibrocartilage discs examining the innervation of the triangular fibrocartilage complex have found no evidence of nerve fibers in the healthy disc. In this study, we immunohistologically investigated biopsies from patients with either central traumatic or degenerative disc lesions, to determine the existence of nerve fibers. We hypothesized that an ingrowth of nerve fibers causes ulnar-sided wrist pain associated with traumatic and degenerative disc lesions. Methods: We included 32 patients with a traumatic Palmer 1A lesion and 17 patients with a degenerative Palmer 2C lesion in the study. We obtained a biopsy of each patient and stained the specimen with protein gene product 9.5 for nerve fiber detection. Results: There were no nerve fibers in either traumatic or degenerative disc lesions. In addition, the marginal areas of the biopsies showed no evidence of nerve fibers. Conclusions: Traumatic and degenerative disc lesions show no ingrowth of nerve fibers. Clinical relevance: The ulnar-sided pain associated with traumatic and degenerative disc lesions must have other, currently unknown causes.