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Thyrohyoideus muscle innervation in the horse
Author(s) -
Genton Martin,
Robert Celine,
Jerbi Hassen,
Huet Hélène,
Cordonnier Nathalie,
VitteRossignol Amelie,
Perkins Justin D.,
Rossignol Fabrice
Publication year - 2021
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/vsu.13536
Subject(s) - medicine , anatomy , accessory nerve , anastomosis , dissection (medical) , cervical nerve , surgery , nerve root
Abstract Objective To describe the innervation of the thyrohyoideus (TH) muscle and to confirm our findings with stimulation of first cervical (C1) nerve branches. Study design Ex vivo phase 1 and clinical phase 2. Animals Fourteen head and neck specimens and 17 client‐owned horses. Methods In phase 1, the cranial nerve (CN) XII and the C1 nerve were dissected with their branches in 20 dissections were performed on 14 specimens (6 left and right side and 8 only left or right) Anatomy was noted. Samples of nerve bifurcations were collected for histological confirmation of anatomical findings. First cervical nerve branches were stimulated in horses undergoing cervical nerve graft to treat laryngeal hemiplegia. Results The nerve innervating the TH muscle arose directly from the C1 nerve in 17 of 20 dissections, from an anastomotic branch between CN XII and the C1 nerve in two of 20 dissections, and from the C1 nerve and the anastomotic branch in one of 20 dissections. No direct connection between the TH muscle and CN XII was found. Histological examination revealed that the anastomosis was composed of C1 nerve fibers passing over to CN XII. First cervical stimulation resulted in TH muscle contraction in 16 of 17 horses. Conclusions The innervation of the TH muscle originated from the C1 nerve according to dissection, histological, and conduction studies, with variation in the branching pattern. Clinical significance Care should be taken to preserve the C1 nerve during prosthetic laryngoplasty. The surgical technique for C1 nerve grafts should be reconsidered in light of these findings, along with new options to treat dorsal displacement of the soft palate..