The central canal of the spinal cord: ultrasonic identification.

An intramedullary linear echo is frequently visible on real-time intraoperative ultrasound images of the spinal cord. An ultrasonographic-anatomic correlative study of the normal spinal cord of a cadaver demonstrated that these intramedullary reflections correspond to the central canal. Twenty-one cases of spinal surgery employing ultrasound in an adjunctive role are reviewed. In cases of intramedullary lesions this echo is absent or disrupted in the scanning plane of the mass, but it is preserved when the process is extramedullary.