ORIGINAL ARTICLE T. Shimokawa Æ S.-Q. Yi Æ A. Izumi Æ F. Ru K. Akita Æ T. Sato Æ S. Tanaka An anatomical study of the levator veli palatini and superior constrictor with special reference to their nerve supply Received: 30 September 2002 / Accepted: 2 June 2003 / Published online: 28 October 2003 Ó Springer-Verlag 2003 Abstract We dissected 50 head halves of 25 Japanese cadavers (10 males, 15 females) to investigate the inn- ervations of the levator veli palatini (LVP) and superior constrictor pharyngis. The branches supplying the LVP were classified into the following three types according to their origins: supplying branches that originated from the pharyngeal branch of the glossopharyngeal nerve (type I, four sides, 8%), branches that originated from a communicating branch between the pharyngeal bran- ches of the glossopharyngeal and vagus nerves (type II, 36 sides, 72%), and those that originated from the pharyngeal branch of the vagus nerve (type III, 10 sides, 20%). In previous studies, supplying branches of type I were seldom described. Regarding the innervation of the superior constrictor, some variations were observed, and we consider it likely that there is a close relationship between these variations and the type of innervation of the LVP. Keywords Levator veli palatini Æ Superior constrictor Æ Glossopharyngeal nerve Æ Vagus nerve Æ Innervation Introduction The levator veli palatini (LVP) is closely associated with the movement of the soft palate, and plays a key role in normal velopharyngeal movements during speech, swallowing and respiration [1, 16, 17]. Thus, a knowl- edge of its anatomy and physiology is essential for pal- atoplasty. Abnormal muscle function frequently results in hypernasal speech, conductive hearing loss and seri- ous otitis media, especially in patients with cleft palate [27]. Previous studies on the innervation of the LVP have yielded very controversial findings. The LVP is gener- ally considered to be innervated by branches of the pharyngeal plexus, which is composed of pharyngeal branches of the glossopharyngeal (IX) and vagus (X) nerves [4, 6, 29], and the motor fibers to the LVP have been considered to leave the medulla in the cranial part of the accessory nerve [3, 4, 5, 25, 28, 30]. Based on studies of the juxtabulbar sections of the cranial nerves in dogs, Vernet [28] noted that isolated sections of IX and X did not cause paralysis of the velum, whereas the isolated section of the cranial root of XI caused paralysis of the corresponding hemivelum. On the other hand, numerous investigators have suggested that the facial nerve (VII), in addition to the supplying branches of the pharyngeal plexus, innervates the LVP [10, 12, 13, 18, 19, 21, 22, 24, 26]. According to these authors, the main part of the levator muscle is inner- vated by a branch of VII, and the rest of the muscle by X, and also frequently by IX [10, 18]. Based on electromyographic techniques, Nishio et al. [22] sug- gested that the levator veli palatini, uvula and superior constrictor pharyngis muscles might be regarded as being doubly innervated by the branch of VII and branches of the pharyngeal plexus derived from the IX and X. Furthermore, Nishio et al. [22] mentioned that the accessory nerve might have no relation with the innervation of these muscles. In contrast, however, Keller et al. [14], using the neuroanatomical tracing technique of retrograde axonal transport of horserad- ish peroxidase (HRP) in cats, determined the location of the motoneurons of the levator veli palatini in the rostral portions of the nucleus ambiguus, and ruled out the involvement of VII in the innervation of the Surg Radiol Anat (2004) 26: 100–105 DOI 10.1007/s00276-003-0183-1 T. Shimokawa (&) Æ S.-Q. Yi Æ A. Izumi Æ F. Ru Æ S. Tanaka Department of Anatomy and Neuroembryology, Kanazawa University, 13-1 Takaramachi, 920-8640 Kanazawa, Japan E-mail: simoort1@med.kanazawa-u.ac.jp Tel.: +81-76-2652157 Fax: +81-76-2344221 K. Akita Æ T. Sato Unit of Functional Anatomy, Graduate School, Tokyo Medical and Dental University, 113-8519 Tokyo, Japan