Skull Holes & Contents
The single, large hole in the base of the skull that the brainstem and the two vertebral arteries pass through.
What is the Foramen Magnum?
The most anterior and shallowest of the three cranial fossae, largely formed by the frontal bone.
What is the Anterior Cranial Fossa?
This large, unpaired bone makes up the forehead and the upper borders of the orbits.
What is the Frontal Bone?
The major blood supply to the brain that enters the cranial cavity through the carotid canal.
What is the Internal Carotid Artery?
The deepest layer of the SCALP, which is the periosteum of the cranial bones.
What is the P (Periosteum/Pericranium) layer?
The thin, sieve-like plate in the ethmoid bone that serves as the "bed" for the olfactory bulbs.
What is the Cribriform Plate?
This bony process in the Anterior Cranial Fossa serves as the attachment site for the falx cerebri.
What is the Crista Galli?
The single, unpaired bone that is shaped like a trapezoid and forms the back of the skull.
What is the Occipital Bone?
The sinus located in the "s"-shaped groove that eventually drains into the Internal Jugular Vein.
What is the Sigmoid Sinus?
This part of the SCALP contains the arteries, veins, and nerves, and connects the top layers with the aponeurosis.
What is the C (Connective Tissue) layer?
This hole allows passage for the largest sensory nerve in the face, the Trigeminal Nerve branch V3 (Mandibular nerve).
What is the Foramen Ovale?
The deep depression in the sphenoid bone within the Middle Cranial Fossa that holds the pituitary gland.
What is the Sella Turcica?
This projection of the temporal bone is located posteroinferiorly and contains air pockets, making it an important clinical landmark.
What is the Mastoid Process?
The space where injury to the cerebral veins (bridging veins) leads to a Subdural Hematoma.
What is the Subdural Space?
The aponeurosis layer that is pulled apart when the scalp is cut, causing profuse bleeding.
What is the Galea Aponeurotica (or Aponeurosis)?
This large, irregularly shaped opening is formed between the temporal and occipital bones and transmits the Jugular Vein and three Cranial Nerves (IX, X, XI)
What is the Jugular Foramen?
The ridge that separates the Middle Cranial Fossa from the Posterior Cranial Fossa, formed by the superior portion of the temporal bone.
What is the Petrous Ridge (or Petrous part of the Temporal Bone)?
The process of the temporal bone that projects anteriorly to form the posterior half of the Zygomatic Arch.
What is the Zygomatic Process?
The structure located in the Cavernous Sinus that makes it unique because it is the only place in the body where a major artery runs within a vein.
What is the Internal Carotid Artery?
The layer of the SCALP where the spreading of fluid or bleeding causes "Raccoon Eyes," indicating a deeper injury.
What is the L (Loose Connective Tissue) layer?
If a patient has a complete loss of sensation over their maxilla and the upper teeth, the nerve affected most likely exited the skull through this opening.
What is the Foramen Rotundum (V2, Maxillary Nerve)?
A fracture affecting the dorsum sellae and the petrous ridge would involve the boundaries of which two cranial fossae?
What are the Middle and Posterior Cranial Fossae?
In a newborn, a persistence of the line where the two sides of the frontal bone fused during development is called this type of suture.
What is the Frontal or Metopic Suture?
A severe infection in the area of the face called the "danger triangle" could potentially spread to this clinically important dural venous sinus, as noted in your notes.
What is the Cavernous Sinus?
In Bell's Palsy, a patient loses the ability to close their eye and move their lips. This condition involves paralysis of all muscles supplied by this cranial nerve.
What is the Facial Nerve (CN VII)?