Abstract
Introduction
A variant of the innervation of the infrahyoid neck musculature is reported in which the typical looped ansa cervicalis structure is absent. In this variant, the infrahyoid muscles (sternohyoid, sternothyroid omohyoid and thyrohyoid) were innervated by a presumptive superior root of “ansa cervicalis” traveling with vagus nerve (CN X) and not branching from hypoglossal nerve (CN XII). The omohyoid muscle, typically innervated by the inferior root of ansa cervicalis, is instead innervated by nerve fibers branching from the accessory nerve (CN XI). This formation created a non-looping variant of ansa cervicalis. Furthermore, the omohyoid muscle did not attach to the hyoid bone but instead attached to the mastoid process of the temporal bone by merging its fibers superiorly and posteriorly with the clavicular portion of the sternocleidomastoid muscle, creating a “sternocleidoomomastoid” muscle innervated by a branch of accessory nerve.
Materials and methods
This variation was found in one black male cadaver from a cohort of 25 male and female cadavers.
Results
Only one variation of ansa cervicalis was observed.
Conclusions
As neck dissections and surgical procedures of this region are performed for a variety of conditions—including coronary artery bypass grafting and metastatic neck disease—variations of this type are of broad clinical surgical importance.
References
Banneheka S (2008) Morphological study of the ansa cervicalis and the phrenic nerve. Anat Sci Int 83:31–44. https://doi.org/10.1111/j.1447-073X.2007.00201.x
Brennan PA, Alam P, Ammar M, Tsiroyannis C, Zagkou E, Standring S (2017) Sternocleidomastoid innervation from an aberrant nerve arising from the hypoglossal nerve: a prospective study of 160 neck dissections. Surg Radiol Anat 39:205–209. https://doi.org/10.1007/s00276-016-1723-9
Caliot P, Dumont D, Bousquet V, Midy D (1986) A note on the anastomoses between the hypoglossal nerve and the cervical plexus. Surg Radiol Anat 8:75–79
Jelev L (2013) Some unusual types of formation of the ansa cervicalis in humans and proposal of a new morphological classification. Clin Anat 26:961–965. https://doi.org/10.1002/ca.22265
Khaki AA, Shokouhi G, Shoja MM, Farahani RM, Zarrintan S, Khaki A, Montazam H, Tanoomand A, Tubbs RS (2006) Ansa cervicalis as a variant of spinal accessory nerve plexus: a case report. Clin Anat 19:540–543. https://doi.org/10.1002/ca.20299
Loukas M, Thorsell A, Tubbs RS, Kapos T, Louis RG Jr, Vulis M, Hage R, Jordan R (2007) The ansa cervicalis revisited. Folia Morphol (Warsz) 66:120–125
Manjunath KY (2000) Vagal origin of the ANSA cervicalis nerve—report of two cases. Indian J Otolaryngol Head Neck Surg 52:257–258. https://doi.org/10.1007/BF03006195
Natsugoe S, Okumura H, Matsumoto M, Ishigami S, Owaki T, Nakano S, Aikou T (2005) Reconstruction of recurrent laryngeal nerve with involvement by metastatic node in esophageal cancer. Ann Thorac Surg 79:1886–1889. https://doi.org/10.1016/j.athoracsur.2004.11.055
Smith ME (2012) Pediatric ansa cervicalis to recurrent laryngeal nerve anastomosis. Adv Otorhinolaryngol 73:80–85. https://doi.org/10.1159/000334443
Sonne J, Lopez-Ojeda W (2018) Neuroanatomy, cranial nerve. StatPearls Publishing, Treasure Island, FL
Author information
Authors and Affiliations
Contributions
Sonne performed all work described in this manuscript, including the dissections and structure identification, research, writing, photography, and illustrations.
Corresponding author
Ethics declarations
Conflict of interest
Sonne reports no conflicts of interest.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Sonne, J.W.H. Report of a non-looped variant of ansa cervicalis with omohyoid innervation from accessory nerve branch and omohyoid attachment to mastoid process. Eur Arch Otorhinolaryngol 276, 2105–2108 (2019). https://doi.org/10.1007/s00405-019-05436-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00405-019-05436-2