ORIGINAL COMMUNICATION Analysis of the Relationship between the Double Transverse Foramen and the Possibility of Developing Clinical Symptoms after Whiplash JUAN A. SANCHIS-GIMENO , 1 * MARCELINO PEREZ-BERMEJO, 1,2 LUIS RIOS, 1,3 SUSANNA LLIDO, 1 MARKUS BASTIR, 3 ESTHER BLANCO-PEREZ, 1,4 AND FEDERICO MATA-ESCOLANO 2,5,6 1 Department of Anatomy and Human Embryology, University of Valencia. Faculty of Medicine, Avda. Blasco Ibanez 15, Valencia, Spain 2 University San Vicente Martir, C/Espartero 7. Valencia, Valencia, Spain 3 National Museum of Natural Sciences - Spanish National Research Council, C/Jose Gutierrez Abascal 2, Madrid, Spain 4 Department of Radiology, University Hospital de La Ribera, Carretera Corbera km 1, Alzira, Valencia, Spain 5 Department of Radiology, General University Hospital, Avda. Tres Cruces 2, Valencia, Spain 6 CT and MRI Unit, ERESA Clinic Research Foundation, Calle Marques de San Juan 6, Valencia, Spain Currently, there is no information about the possibility of developing clinical symptoms after whiplash in double transverse foramen subjects. Our aim was to test whether subjects with double transverse foramen have an increased risk of presenting with an acute headache, dizziness, vertebral artery dissec- tion, and vomiting after whiplash. We recorded the absence/presence of double transverse foramen, and the absence/presence of neck pain, acute headache, dizziness, vertebral artery dissec- tion, and vomiting in 85 patients who had suffered whiplash injuries in car rear-end impacts in road traffic accidents. We used the odds ratio test to determine whether double transverse foramen subjects are at a higher risk of developing an acute headache, dizziness, and vomiting than non-double transverse foramen subjects. Although double transverse foramen subjects presented with more clinical symp- toms after whiplash, the odds ratio test revealed that their risks of developing acute headache (P 5 0.30), dizziness (P 5 0.09), or vomiting (P 5 0.18) were not signifi- cantly greater than in the control group. Double transverse foramen subjects are not at a higher risk of presenting acute headache, dizziness, vertebral artery dissection, and vomiting after whiplash. Clin. Anat. 00:000–000, 2017. V C 2017 Wiley Periodicals, Inc. Key words: cervical vertebrae; dizziness; pain; post-traumatic headache; risk factors; spine; vomiting; vertebral artery; vertebrobasilar insuffi- ciency; whiplash injuries INTRODUCTION The double transverse foramen (DTF) from C3 to C7 (Fig. 1 and 2) is a well-known anatomical variant (Rios et al., 2014) that could be related to variations in the course and development of the vertebral artery (VA) (Das et al., 2005). The DTF has been studied in relation to the VA because the V2 segment of the VA *Correspondence to: Juan A. Sanchis-Gimeno, Department of Anatomy and Human Embryology. University of Valencia. Fac- ulty of Medicine. Avda. Blasco Ibanez, 15, Valencia E46010, Spain. E-mail: juan.sanchis@uv.es Received 13 March 2017; Revised 25 April 2017; Accepted 5 May 2017 Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/ca.22897 V V C 2017 Wiley Periodicals, Inc. Clinical Anatomy 00:00–00 (2017)