OBJECTIVE: To investigate a novel intermuscular surgical approach for posterior upper cervical spine fixation. METHODS: Twenty-three healthy volunteers underwent magnetic resonance imaging. By using the magnetic resonance imaging scans in transverse view at the level of lower edge of atlas, the distances from the posterior midline to lateral margin of trapezius, to the medial margin of splenius capitis, and to middle line of semispinalis capitis were recorded. The angle between posterior middle line and the line crossing the lateral margin of trapezius and middle point of ipsilateral pedicles. From October 2009 to May 2013, 12 patients with upper cervical spine injuries were operated via the bilateral intermuscular approach. The time required for surgery, blood loss, and pre-and postoperative visual analogue scale scores were analyzed. RESULTS: The average distance of 0-Twas 39.2 +/- 7.5 mm, the angle between the approach and posterior middle line was 33.2 +/- 8.4 degrees. The surgical time was 78.3 +/- 22.5 minutes (45-140 minutes), and the mean intraoperative blood loss was 87.5 +/- 44.2 mL (30-200 mL). Preoperative and postoperative visual analogue scale scores were 6.4 +/- 0.8 and 1.8 +/- 0.7, respectively. The average follow-up time was 19.7 +/- 11.5 months (9-48 months). CONCLUSIONS: The posterior bilateral intermuscular approach for upper cervical spine injuries is a valid alternative for Hangmans' fractures type I, type II, and type Ia according to Levine and Edwards classification as well as atlantoaxial subluxation caused by upper cervical spine trauma.