title: Innervation of the triangular fibrocartilage complex of the human wrist: quantitative immunohistochemical study.
abstract: The distribution of neural elements in the triangular fibrocartilage complex (TFCC) of the human wrists was studied via immunohistochemical staining of protein gene product (PGP) 9.5 and calcitonin gene-related peptide (CGRP). Articular branches projecting to the TFCC arose from the dorsal branch of the ulnar nerve in all wrists examined. The TFCC is subdivided into the following six regions: the articular disc proper (ADP), meniscus homolog (MH), radio-ulnar ligament (RUL), loose part of ulnar collateral ligament (lUCL), dense part of ulnar collateral ligament (dUCL), and internal portion (IP). The IP consists of a mixture of dense and loose connective tissues enclosed by the ADP, MH, RUL, and UCL, and resides deep in the prestyloid recess, which is a pit in the MH. The densities of PGP 9.5-positive neural elements, including free nerve endings, single nerve fibers, nerve fascicles, and perivascular neural nets, were significantly higher in the IP than in other regions. Some of the neural elements except for the perivascular neural nets were positive for CGRP. The high density of neural elements in the IP suggests that sensory nerves projecting to the TFCC enter into the IP and from there distribute to adjacent regions such as the MH and RUL. Free nerve endings are responsible for pain transmission. The high density of free nerve endings in the IP suggests that the IP is a source of ulnar side wrist pain.
authors.affiliation: Department of Second Orthopedic Surgery, Toho University School of Medicine, Tokyo, Japan. fwga8140@nifty.com
authors.forename: Toshio
authors.initials: T
authors.lastname: Shigemitsu
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tobe
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Mizutani
authors.forename: Kunio
authors.initials: K
authors.lastname: Murakami
authors.forename: Youichi
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Fumi
authors.initials: F
authors.lastname: Sato
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009411:Nerve Endings / Q000033:anatomy & histology / Q000737:chemistry; D010146:Pain / Q000503:physiopathology; D051478:Triangular Fibrocartilage / Q000294:innervation*; D043222:Ubiquitin Thiolesterase / Q000032:analysis*; D014459:Ulnar Nerve / Q000033:anatomy & histology* / Q000737:chemistry; D014953:Wrist / Q000294:innervation*; D014954:Wrist Injuries / Q000503:physiopathology
chemical_list: C482860:UCHL1 protein, human; D043222:Ubiquitin Thiolesterase; D015740:Calcitonin Gene-Related Peptide