A 38-year-old woman underwent a 4-hour operation in the prone position for a laminectomy at C4-7 and posterior cervical decompressive fusion at C7-T1 under general anesthesia. After undraping at the end of surgery, considerable swelling with many blisters of the left forearm and hand was observed. The chest roll at the left side had moved cephalad into the axilla and compressed the axillary structures. An emergency fasciotomy to decompress the compartments of the forearm and dorsal surface of the hand was performed. In the post anesthesia care unit, the radial pulse of the left hand was palpable and the level of oxygen saturation was normal. Forearm and hand edema subsided gradually over several days and the patient was discharged with full function of her left arm. This compartment syndrome suggests careful attention should be paid to the position of the chest roll when the prone position is established for a long duration.