Home › Body Atlas › Bones › Posterior Clinoid Process

Posterior Clinoid Process

processus clinoideus posterior

The posterior clinoid processes are paired bony projections at the superior angles of the dorsum sellae, forming the posterior boundary of the sella turcica. The dura of the tentorial incisura (free edge of the tentorium cerebelli) attaches to the posterior clinoid process. The trochlear nerve (CN IV) passes below the posterior clinoid process as it pierces the dura of the tentorial edge.

Region: Head & Skull

Clinical Relevance

Clinical Notes

The posterior clinoid process is removed in posterior clinoidectomy during the transpetrosal approach to the petroclival region, widening access to the basilar trunk and posterior fossa. The trochlear nerve runs immediately below the posterior clinoid process as it emerges from the brainstem and enters the tentorial edge, placing it at high risk during posterior clinoidectomy. Posterior clinoid meningiomas produce CN III and IV palsies from local compression.

Pathology

Common Injuries & Conditions

Trochlear Nerve Injury at Posterior Clinoid in Skull Base Surgery

The trochlear nerve running below the posterior clinoid process as it pierces the tentorial dura is the nerve most at risk during posterior clinoidectomy in petroclival approaches, producing post-operative vertical diplopia; careful identification of the nerve before any drilling preserves this small but functionally critical cranial nerve.