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BIBIBI Biomedicine International 2011; 2: 39-42.

ORIGINAL ARTICLE

Use of the Triangle of Farabeuf for Neurovascular Procedures of the

R. Shane Tubbs,1 Mark Rasmussen, 1 Marios Loukas,2 Mohammadali Shoja,3,4 Martin Mortazavi,3 Aaron A. Cohen-Gadol 5 1Pediatric Neurosurgery, Children’s Hospital, Birmingham, AL, USA 2 Department of Anatomical Sciences, St. George’s University, Grenada, West Indies 3Division of Neurological Surgery, Department of Surgery, University of Alabama at Birmingha, Birmingham, AL, USA 4Medical Philosophy and History Research Center, Tabriz University of Medical Sciences, Tabriz, Iran 5Clarian Neuroscience Institute, Indianapolis Neurosurgical Group and Indiana University Department of Neurosurgery - Indianapolis, IN, USA

ABSTRACT Surgical landmarks for application during surgery of the neck may be useful to the neurosurgeon. The present study was performed to explore the utility of a nearly forgotten anatomical triangle of the neck, the triangle of Farabeuf (TF) formed by the common facial and internal jugular veins and the as its base directly superiorly. This study was carried out on 12 (24 sides) formaldehyde-fixed adult human cadavers (5 males and 7 female. The presence of TF was documented and measurements made of its sides. Additionally, structures found within the triangle were observed. TF was present on 15 sides and absent on 5 sides. The TF, when present, contained at least the proximal internal or in 14 of the 15 sides (93.3%), and both in 6 of the sides (40%). The carotid bifurcation was present in the triangle on 2 sides (13.3%) and was located inferior to the TF in the other cases. A jugulodigastric node was found in the TF on 8 sides (33%). The mean length of the TF for inferior, superior and posterior legs of the triangle was 1.05 cm, 1.58 cm, and 1.92 cm, respectively. We found that the proximal was up to 2 cm superior to or 1.5 cm inferior to the bifurcation. Knowledge of the TF may be of use to the surgeon during procedures of the neck such as placement of ventriculoatrial shunts into the common facial vein or neurotization procedures utilizing the hypoglossal nerve. Carotid endarterectomy may be performed by traversing the TF to access the proximal . Biomed . Int . 2011; 2: 39-42. ©2011 Biomedicine International, Inc. Key words : Anatomy, artery, neck, nerve, surgery, vein

INTRODUCTION The neck not only serves to connect the head with the rest of the body, it also houses structures within it that act as conduits for blood and nerve impulses traveling both to and from the brain. Many localizing have been described and some are well known 1, however, some have been nearly forgotten such as the triangle of Farabeauf (TF) ( Figure 1). On either side of the neck, the sternocleidomastoid muscle can be used as a guide to divide the neck into an anterior and a posterior triangle. The anterior border of the anterior cervical triangle is the midline and the posterior border is the anterior margin

Address correspondence to R. Shane Tubbs, PhD, Pediatric Neurosurgery, Children’s Hospital, 1600 7th Avenue South ACC 400, Birmingham, Alabama 35233, USA. Phone: 001-205-939-9914. Fax: 001-205-939-9972. E-mail: [email protected] Submitted August 22, 2010; accepted in revised form November 24, 2010. Advance Access Publication 1 July 2011 (see www.bmijournal.org)

Tubbs et al. / Biomed Int (2011) 2:2:39393939----42424242 of the sternocleidomastoid. The base is directed superiorly and is formed by the inferior border of the . 2 The roof of both the anterior and posterior cervical triangles, and all of their further subdivisions, is a deep investing layer of cervical fascia and the platysma. 3

Figure 1 : Photograph of cadaveric left side TF. The inferior leg formed by the common facial vein, the superior leg by the hypoglossal nerve and the posterior leg by the . A jugulodigastric node was identified in the TF of this specimen and has been removed for clarity.

The anterior cervical triangle can be subdivided into three bilateral and one unpaired triangles. The three paired triangles include the carotid (superior carotid), the muscular (inferior carotid), and the submandibular (submaxillary or digastric) triangles. 4 The anterior border of the is the superior surface of the superior belly of the omohyoid. The inferior surface of the posterior belly of the makes up the superior border of this triangle, while the anterior margin of the sternocleidomastoid makes up the posterior border. The TF is found within the carotid triangle and is named for the French surgeon Louis-Hubert Farabeuf (1841–1910), is made up of the internal jugular vein and the common facial vein serving as the posterior and inferior sides, respectively, and the hypoglossal nerve creating the base superiorly. 5 The purpose of this study was to measure and document the occurrence of this triangle and the structures found within it, and to discuss its surgical significance.

MATERIALS AND METHODS This study was carried out on 12 (24 sides) formaldehyde-fixed adult human cadavers (5 males and 7 female) with a mean age of 80-years-old (range 59 to 94-years-old). The presence or absence, size, anatomical relationships and accompanying structures contained within the TF was measured with calipers and documented. All measurements were made twice and the average taken. Statistical analysis was performed using Student’s T-test (Microsoft Excel, Redmond, WA) and statistical significance was set at P < 0.05.

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RESULTS When present, the TF was always found within the carotid triangle of the anterior cervical triangle. TF was present on 15 sides ( Figures 1 and 2) and absent on 5 sides (75%). The TF, when present, contained at least one of the branches of the common carotid artery in 14 of the 15 sides (93.3%), and both in 6 of the sides (40%). The carotid bifurcation was present only on 2 of the sides (13.3%) and was located inferior to the TF in the other cases. Moreover, we found that the proximal common facial vein was up to 2 cm superior to or 1.5 cm inferior to the common carotid artery bifurcation ( Figure 2). A jugulodigastric node was found within the TF on 8 sides (33%). The size of the TF ranged from 0.5 to 2.0 cm (mean 1.05 cm; SD 0.46) for the inferior leg, 1.0 to 3.5 cm (mean 1.58 cm; SD 0.63) for the superior leg, and 1.0 to 4.0 cm (mean 1.92 cm; SD 0.83) for the posterior leg. The smallest triangle measured 0.5 x 1.0 x 1.0 cm and contained just the internal carotid artery. The largest triangle measured 2.0 x 3.5 x 4.0 cm and contained the carotid bifurcation, external and internal carotid arteries and the superior root of the . No statistically significant differences were found between the measurements of each leg of TF and gender, or between the measurement of each leg of TF and right versus left sides.

Figure 2 : Right side cadaveric neck dissection illustration posterior half of the TF housing the proximal internal carotid artery (outlined). A facial vein tributary (Common Facial Vein) is seen uniting to form the common facial vein proper and thus dividing TF into two parts. Note the carotid bifurcation is medial to the TF in this specimen.

DISCUSSION Both Deaver 6 and Henry 4 have discussed the importance of using the TF during dissections of the neck. Campbell made reference to TF and its importance in locating the internal

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Tubbs et al. / Biomed Int (2011) 2:2:39393939----42424242 jugular vein (one of the legs) and the external carotid artery, which was mentioned as being found within the triangle. 7 Deaver stated that TF “is another useful and neglected feature of carotid anatomy which forms an admirable rallying point of the neck.” 6 Based on our study, the majority of specimens were found to have a TF and the jugulodigastric node was found in roughly one third of these. Although TF has been stated as being a good landmark for identifying the common carotid artery bifurcation, this was found within TF on 13.3% sides and on 40%, the proximal internal and external carotid arteries were found here that is the bifurcation was located more inferiorly. Therefore, the bifurcation of the common carotid artery was not well correlated to the common facial vein. Others have also found that the common facial vein’s entrance into the internal jugular vein is variable and does not correlate well with the carotid artery bifurcation. 8 In the current study, we found that the proximal common facial vein was up to 2 cm superior to or 1.5 cm inferior to the common carotid artery bifurcation. Anecdotally and surgically, we have found good success in identifying the common facial vein approximately two finger breadths inferior to the angle of the mandible and just anterior to the anterior edge of the sterno- cleidomastoid muscle. Campbell has stated that the external carotid bisects the TF but this was not always the case as found in our study. 7 Campbell also stated that “this triangle is a helpful landmark in extensive dissections of the neck, especially in locating the internal jugular vein, the safety of which is best conserved by promptly exposing it.” 3 Cévese et al. have also stated that many branchial sinus tracts can be followed and found to traverse the TF. 9

CONCLUSIONS Additional surgical landmarks may be of use to the surgeon during procedures of the neck. The TF may be of utility when localizing the hypoglossal nerve for neurotization procedures for example to the facial nerve following transection, for identifying the common facial vein for use in surgical placement of intravenous catheters or ventriculoatrial shunts, and for identifying branches of the common carotid artery within its confines. Carotid endarterectomy may be performed by traversing the TF to access the proximal internal carotid artery.

REFERENCES 1. Bademci G, Ya şargil MG. Microsurgical anatomy of the hypoglossal nerve. J Clin Neurosci 2006; 13: 841- 847. 2. Hiatt JL, Gartner LP. Textbook of Head and Neck Anatomy. 3 rd edition. Philadelphia, Lippincott Williams and Wilkins, 2001. 3. Moore KL, Agur AMR. Essential Clinical Anatomy. 3 rd edition. Baltimore, Lippincott Williams and Wilkins, 2007. 4. Breisch EA, Greenway, Jr., HT. Cutaneous Surgical Anatomy of the Head and Neck. New York, Churchill Livingstone, 1992. 5. Henry AK. Extensile Exposure, 2nd ed. Edinburgh, Churchill Livingstone, 1973. 6. Deaver JB. Surgical Anatomy of the Human Body. Philadelphia, Blakiston’s, 1926. 7. Campbell WF. A Text-Book of Surgical Anatomy, 3rd edition. Brooklyn, WB Saunders Company, 1922. 8. Lo A, Oehley M, Bartlett A, Adams D, Blyth P, Al-Ali S. Anatomical variations of the common carotid artery bifurcation. ANZ J Surg 2006; 76: 970-972. 9. Cévese PG, D’Amico D, Favia G. Surgery of the Neck. Padua, Piccin, 1988.

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