Cervical spinous process bifurcation is not useful as a landmark in posterior cervical spine approach.

Background: In the posterior cervical spine approach, the form of the cervical spinous process tip is one important landmark for level determination. However, it is still controversial whether the most caudal level of the bifurcated spinous process is C5 or C6 in previous reports.
Methods: The study samples consisted of 47 bleached bones and 3 fixed bodies for anatomical practice. According to the classification of Okuwa, patients who showed remarkable bifurcation of the spinous process tip were regarded to have "remarkable bifurcation", those who showed unclear indentation in the spinous process tip to have "slight bifurcation", and those who showed no bifurcation and no indentation to have "lack of bifurcation".
Results: The spinous process tips from C2 to C5 bifurcated in 26 out of 50 cervical spines (52%), and those from C2 to C6 in 20 (40%). There was no significant difference in the frequency of bifurcation of the spinous process tip between males and females.
Conclusion: The results of the present study indicate that it does not seem useful to use bifurcation of the cervical spinous processes for anatomical landmarks.