Sphenoid Flashcards
1. Identify select features of the sphenoid bone 2. Identify the location and significance of the pterion 3. Identify the foramina of the sphenoid bone 4. Identify which bones the sphenoid articulates with 5. Identify the sutures of the sphenoid bone
The functions of this bone are:
- large contribution to the floor of the cranium
- United the neurocranium and viscerocranium (bridging bones)
- Strengthens side of the skull
Sphenoid bone
Overlies the sphenoid sinus and houses the pituitary gland
Sella turcica of the sphenoid bone
Part of the lesser wing of the sphenoid, serves as an attachment site for the dural covering of the brain and allows for dura to form a tent over the pituitary gland
Anterior Clinoid Process of sphenoid bone
Attachments sit for the dural covering of the brain - allows dura to form a tent over the pituitary gland
Posterior clinoid process
Air-filled within the body of the sphenoid bone; deepest sinus in the head; lined with a mucus membrane
Sphenoid sinus
Attachment sites for muscles of mastication (medial & lateral)
pterygoid process
What is located directly below the sella turcica
sphenoid sinus
Sphenoid bone makes up a large proportion of the posterior ___ wall. It is mainly composed of the (greater/lesser) wing of the sphenoid.
orbital, greater
T/F: The lesser and greater wings of the sphenoid are present in the posterior wall of the orbit
True
Located between greater and lesser wings; transmits the following soft tissue structures:
CN III, IV, V, VI, V1, Superior opthalmic vein
Superior orbital fissure
The superior orbital fissure allows for the passage of which nerves?
CN III - Oculomotor Nerve
CN IV - Trochlear Nerve
CN V - Trigeminal Nerve
CN VI - Abducens Nerve
CN V1 (Opthalmic nerve) Superior opthalmic vein
The superior orbital fissure allows for the passage of what vein?
Superior opthalmic vein
Located between greater wing of sphenoid and orbital plate of maxilla.
Inferior orbital fissure
Exit for V2 (infraorbital nerve), inferior opthalmic vein
Inferior orbital fissure
Most medial foramen on either side of the sphenoid
Foramen rotundum
Transmits CN V2
Foramen rotundum
Ovoid in shape, transmits CN V3 (mandibular nerve)
Foramen Ovale
Transmits CN V3
Foramen Ovale
Serves as an entrance foramen. Allows middle meningeal artery into the skull
Foramen Spinosum
Foramen Spinosum allows for the passage of this artery into the skull.
Middle meningeal artery
Appears as an actual hole in skeletal form, but is actually partially covered in cartilage
Foramen lacerum
Formed by the sphenoid, the apex of the petrous portion of the temporal bone, and the basilar part of the occipital bone
Foramen Lacerum
The part that is patent allows exit of the artery and nerve to the pterygoid canal and the greater petrosal nerve
Foramen Lacerum
Some emissary veins pass through here and because of their connection to the pterygoid plexus, they can carry infections intracranially to the cavernous sinus
Foramen Lacerum
Optic canal, Superior orbital fissure, and inferior orbital fissure are located in the ____ but are part of the _____ bone
Orbit, sphenoid
Looking inferiorly into the skull, which foramens can be seen?
Foramen ovale, foramen spinosum and foramen lacerum
T/F: Foramen rotundum can only be seen from the superior aspect of the skull
True
Pterior is an H shaped connection located at the intersection of these 4 bones
Temporal, frontal, parietal, and sphenoid
Middle meningeal artery passes immediately deep to it
Pterion
A blow to this region can quickly result in an extradural bleed and death if medical attention is not sought immediately
Pterion
There are _ bones the sphenoid articulates with
9
There are _ suture of the sphenoid bone
8
The sphenoid bone articulates with these bones
Frontal Parietals Temporals Occipital Ethmoid Palatines Zygomatics Maxillae Vomer
Sutures of the sphenoid bone
Sphenofrontal Sphenoparietal Sphenosquamosal Sphenoethmoid Sphenopalatine Sphenozygomatic Sphenomaxillary Sphenovomer
The opthalmic nerve (CN V1) exits the cranial cavity through this opening
Superior orbital fissure
CN V1
Opthalmic nerve
CN V3
Mandibular nerve
The abducens nerve (CN VI) exits the cranial cavity through this opening
Superior orbital fissure
The oculomotor nerve (CN III) exits the cranial cavity through this opening
Superior orbital fissure
The maxillary nerve (CN V2) exits the cranial cavity through this opening
Foramen Rotundum
CN V2
Maxillary nerve but also have infraorbital nerve that branches off of it
The middle meningeal artery enters the cranial cavity through this opening
Foramen Spinosum
Infraorbital nerve (CN V2) exits out of which fissure
Inferior orbital fissure
What nerve does CN V2 (infraorbital nerve) branch off of?
Maxillary nerve (CN V2)
