Osteology Flashcards
What exits the skull through the superior orbital fissure?
CN 3, 4 and 6
Lacrimal, frontal and nasociliary branches of opthalmic nerve (V1 of CN 5)
Opthalmic veins and vessels
What exits the skull through the supraorbital foramen?
Supraorbital nerve, vein and artery (branch of V1 of trigeminal)
What exits the skull through the infraorbital foramen?
Infraorbital nerve, artery and vein (branch of V2 of trigeminal)
What exits the skull through the inferior orbital fissure?
Maxillary nerve (V2 of CN 5)
What is the pterion and what is its clinical significance?
Pterion is the point where the greater wing of the sphenoid bone, the frontal bone, the parietal bone and the temporal bone all join together. It is a site of weakness in the skull so it is prone to injury in head trauma. Its internal surface is also traversed by the middle meningeal artery, so the pterion is the most common site of damage to the MMA.
What exits the skull through the foramen magnum?
What enters the skull through the foramen magnum?
Exits:
- Medulla
- Spinal cord
- Vertebral arteries
Enters:
- Spinal roots of CN 11
What exits the skull through the jugular foramen?
CN 9
CN 10
CN 11
What exits the skull through the optic canal?
Optic nerve
Opthalmic artery
What exits the skull through the foramen rotundum?
Maxillary nerve (V2 of CN 5)
What exits the skull through foramen ovale?
Mandibular nerve (V3 of CN 5)
Lesser petrosal nerve (branch of CN 9)
What exits the skull through foramen spinosum?
Middle meningeal artery and vein
Meningeal branch of mandibular nerve (V3 of CN 5)
What exits the skull through foramen lacerum?
Greater petrosal nerve
What exits/enters the skull through the carotid canal?
Internal carotid artery
Internal carotid nerve plexus
What exits the skull through the internal acoustic meatus?
CN 7 and CN 8
What exits the skull through the hypoglossal canal?
CN 12
What is the function of the skull in general? (3)
- Bony foundation for special sense organs (sight, sound, smell, taste)
- Houses and protects the brain
- Connects to the vertebral column
- What is the piriform aperture?
- What are the inferior, middle, and superior nasal concha?
- What is their purpose?
- Pear-shaped; anterior nasal opening in the cranium
- Curved bony plates in the nasal septum
- Increase surface area so that air can be warmed and humidified before reaching the lungs
What exits the skull through the mental foramen?
Mental nerve (branch of mandibular nerve, V3 of CN 5)
Which bones form the orbit?
Frontal
Zygomatic
Sphenoid
Lacrimal
Ethmoid
Palatine
The size of the orbit is large relative to the size of an eyeball. Why is there such a size discrepancy?
- Shape helps to stabilize eye in socket
- Needs to allow space for 6 EOMs, optic nerve, lacrimal apparatus, fascia, adipose tissue, and the neurovascular structures which supply these tissues
What type of joint joins the bones of the calvaria?
- Serrated immovable sutures
- separated by a thin layer of fibrous connective tissue that is continuous with the periosteum
- become less distinct with age
Name one structure that attaches to the external occipital protuberance?
Ligamentum Nuchae
How is the mandible attached to the skull?
TMJ – synovial joint head of the mandible with mandibular fossa of temporal bone
What is the lambda and the bregma?
Point where the saggital suture meets the lambdoid and coronal sutures, respectively
What is the asterion?
Junction of parietomastoid, occipitomastoid and lambdoid sutures
What parts of the brain are situated in each cranial fossa? (anterior, middle, posterior)
Anterior - inferior and anterior parts of the frontal lobes of the brain
Middle – temporal lobes and pituitary
Posterior - cerebellum, pons, and medulla oblongata
Describe the separation between the anterior and middle cranial fossae.
- The middle cranial fossa is behind and below the anterior cranial fossa
- Separated by the lesser wings of the sphenoid bones laterally and two sharp bony projections, the anterior clinoid processes, medially
What is the purpose of the frontal sinus?
The frontal sinus is an air cavity in the frontal bone that is presumably to decrease the bone’s weight. The total volume of the air spaces in bones with these air cavities increases with age.
- What is the sella turcica?
- What structure is situated in the sella turcica?
- The sella turcica (Turkish saddle) is the saddle-like bony formation on the upper surface of the body of the sphenoid, which is surrounded by the anterior and posterior clinoid processes.
- The pituitary gland - clinoid means “bedpost,” and the four processes (two anterior and two posterior) surround the hypophysial fossa, making the “bed” of the pituitary gland, like the posts of a four-poster bed.
For the atlanto-occipital joint:
- Type of joint?
- Points of articulation?
- Movements permitted?
- Synovial joint with no articulating disc
- Articulations are between the superior articular surfaces of the lateral masses of the atlas and the occipital condyles
- Primarily flexion (nodding of the head) but also permit a little lateral flexion and rotation
Where is the tectorial membrane located?
The tectorial membrane is the strong superior continuation of the posterior longitudinal ligament that broadens and passes posteriorly over the median atlanto-axial joint and its ligaments. It runs superiorly from the body of C2 through the foramen magnum to attach to the central part of the floor of the cranial cavity, formed by the internal surface of the occipital bone.
