The posterior cranial fossa is the most posterior and deepest portion of the cranial cavity. The posterior cranial fossa is the most posterior aspect of the skull base housing the brainstem and cerebellum. The foramen magnum is located centrally and inferiorly in the posterior fossa. The posterior cranial fossa is the rearmost hollow or depressed area in the base of the cranium, which constitutes the upper part of the human skull. It contains the cerebellum, pons, and medulla oblongata. BRAIN STEM AND POSTERIOR FOSSA. The posterior fossa dura is innervated by the upper three cervical spinal nerves that give off ascending meningeal branches, entering via the foramen magnum (C3), hypoglossal canal, and jugular foramen (C2 and C3). These can be either acquired or congenital disorders. The posterior fossa is a small space in the skull, found near the brainstem and cerebellum. Within this fossa are two critical brain areas: the brain stem and the cerebellum. The posterior cranial fossa is formed from the posterior surface of the body of the sphenoid bone (the dorsum sella), the posterior surfaces of the petrous and mastoid portions of the temporal bones, and the inner surfaces of the occipital bones. It is also the largest and deepest area of the skull. The posterior fossa is bounded anteriorly by the petrous ridges, while the occipital bone forms the floor and posterior wall. To treat this difficult problem a posterior cranial fossa box expansion was devised and studied. Traditional approaches to the posterior cranial fossa do not permit direct access to complex lesions of the lateral skull base, cerebellopontine angle (CPA), or clivus. These areas of the brain control the autonomic nervous system, coordination and movement. The cerebellum is the part of the brain responsible for balance and coordinated movements. It contains the cerebellum of the brain. The posterior cranial fossa is one of the three cranial fossae, the others being the anterior cranial fossa and the middle cranial fossa. If the posterior fossa craniectomy during corrective surgery leads to excessive enlargement of the foramen magnum, the complication of cerebellar ptosis may result. Related pathophysiology. The brainstem contains all the cranial nerve nuclei and many efferent and afferent fiber tracts that connect the brain with the rest of the body. The brainstem is responsible for controlling vital body functions, such as breathing. The posterior cranial fossa is formed in the endocranium, and holds the most basal parts of the brain. a: the posterior one that is the largest and deepest of the three and lodges the cerebellum, pons, and medulla oblongata — called also posterior cranial fossa, posterior fossa The posterior fossa is the largest and deepest of the 3 fossae. The posterior fossa, or posterior cranial fossa, is the deepest and largest and is defined by the occipital bone of the skull. The occipital bone is the main contributor to the fossa and the temporal bone forms the antero-lateral boundaries (Figure 4). The posterior fossa is surrounded by deep grooves containing the transverse sinuses and sigmoid sinuses. There are 4 foramina found in the posterior cranial fossa: John R. Hesselink, MD, FACR and John F. Healy, MD, FACR The posterior fossa houses the brainstem and cerebellum. The posterior cranial fossa is the deepest and most capacious of the 3 cranial fossae. 39–41 The nerves originating from C3 supply the dura mater in the anterior part of the posterior cranial fossa. An underdeveloped posterior cranial fossa can cause Arnold–Chiari malformation. The posterior third of the floor of the cranial cavity; it is larger and deeper than the anterior and middle cranial fossae.