Lab 10 - Cranial Nerve Nuclei and Brain Stem Circulation

Points of Attachments on the Gross Specimen

Use the gross brainstem to review the attachments of the cranial nerves. The glossopharyngeal (IX), vagus (X), spinal accessory (XI), and hypoglossal (XII) are associated with the medulla, and the vestibulocochlear (VIII), facial (VII),abducens (VI), and trigeminal (V) nerves are associated with the pons.

On the tectum or roof of the midbrain, find the superior and inferior colliculi, which are important for orienting to visual and acoustic stimuli and for the processing of acoustic information, respectively. Notice the trochlear nerve (IV) caudal to the inferior colliculus. This is the only cranial nerve to exit the brainstem on its posterior surface. On the anterior surface of the midbrain, locate the cerebral peduncles with the interpeduncular fossa between them. Notice that the oculomotor (III) nerve exits the midbrain in the interpeduncular fossa.

Points of Attachment on the Gross Specimen