ons114 | VOLUME 65 | OPERATIVE NEUROSURGERY 1 | DECEMBER 2009 www.neurosurgery-online.com GENERAL Surgical Anatomy Daniel D. Cavalcanti, M.D. Division of Neurological Surgery, Neurosurgery Research Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona Cassius Vinicius C. Reis, M.D. Departamento de Neurocirurgia, Hospital das Clini-nicas da Universidade Federal de Minas Gerais, Belo Horizonte, Brasil Ricardo Hanel, M.D. (Current Address) Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona Sam Safavi-Abbasi, M.D. (Current Address) Division of Neurological Surgery, Neurosurgery Research Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona Pushpa Deshmukh, Ph.D. Division of Neurological Surgery, Neurosurgery Research Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona Robert F. Spetzler, M.D. Division of Neurological Surgery, Neurosurgery Research Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona Mark C. Preul, M.D. Division of Neurological Surgery, Neurosurgery Research Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona Reprint requests: Mark C. Preul, M.D., c/o Neuroscience Publications, Barrow Neurological Institute, 350 West Thomas Road, Phoenix, AZ 85013. Email: neuropub@chw.edu Received, March 3, 2008. Accepted, October 14, 2008. Copyright © 2009 by the Congress of Neurological Surgeons T he ascending pharyngeal artery (APA), a branch of the external carotid artery (ECA), has important implications for endovascular and skull base surgery. The artery, which supplies the lower cranial nerves and superior cervical ganglion, is part of an anastomotic vascular network to the supraten- torial and infratentorial circulations. If the APA is damaged or occluded, paralysis of Cranial Nerves IX, X, XI, and XII can occur. The APA has been described in neuroradio- logical studies (8, 15, 17), but no surgical or anatomic studies specific to the APA have been published in the English-language medical lit- erature. This study describes the anatomy of the APA on the basis of the dissection of 20 cadaveric craniocervical sides. Two clinical cases are presented to illustrate the clinical rel- evance of the APA. MATERIALS AND METHODS The vascular trees of 10 human cadaveric speci- mens (20 sides) were injected with colored silicone and lightly fixed in a formalin solution. The mean age of the specimens was 74.4 years, and the sex dis- tribution was equal. An anterior midline neck incision was combined with an incision above the margin of the mandible, ABBREVIATIONS: APA, ascending pharyngeal artery; CCA, common carotid artery; ECA, exter- nal carotid artery; ICA, internal carotid artery THE ASCENDING PHARYNGEAL ARTERY AND ITS RELEVANCE FOR NEUROSURGICAL AND ENDOVASCULAR PROCEDURES OBJECTIVE: The ascending pharyngeal artery (APA), a branch of the external carotid artery (ECA), supplies the lower cranial nerves, superior cervical ganglion, and nasopharyngeal structures. The APA can also supply blood to various intracranial lesions. We studied the anatomy of the APA in the context of its neurosurgical and endovascular relevance. METHODS: The cervical origin, branching pattern, and course of the APA were stud- ied in 20 human cadaveric craniocervical sides. The diameter of the APA, the exten- sion of its main trunk, and the distance of its origin from the common carotid artery bifurcation were measured. The relationships between the APA and surrounding struc- tures were also observed. RESULTS: In 80% of the specimens, the APA originated from the ECA. It originated from its medial wall in 56% and from the posterior wall in 44%. The APA originated from the internal carotid artery, common carotid artery bifurcation, occipital artery, and a trunk common to the lingual and facial arteries in 5% each. The APA was usually the third branch of the ECA (40%). The mean distance from the origin of the APA to the common carotid artery bifurcation was 15.3 mm (range, 0–32; standard deviation,  8.3 mm). The APA was frequently the second smallest branch of the ECA (caliber, 1.54 mm; range, 1.1–2.1; standard deviation,  0.25 mm). CONCLUSION: The APA is an important channel for supplying neural structures of the posterior fossa. Knowledge of its anatomy, variants, and anastomotic channels is essen- tial in the treatment of lesions supplied by its branches and to avoid complications related to its inadvertent injury. KEY WORDS: Anatomic study, Ascending pharyngeal artery, Cranial base surgery, Dural arteriovenous fis- tula, Endovascular treatment, Paraganglioma, Skull base surgery Neurosurgery 65[ONS Suppl 1]:ons114–ons120, 2009 DOI: 10.1227/01.NEU.0000339172.78949.5B