Osteology Flashcards
(87 cards)
How do the bones of the calvaria, of the neurocranium, develop?
Intramembranous Ossification
How do the bones of the base of the skull, of the neurocranium, develop?
Endochondral Ossification
From what does the viscerocranium develop?
From Pharyngeal arches
What is the cartilaginous structure, from the 1st pharyngeal arch, that developes into the template for the developing mandible?
Meckel’s Cartilage
What is significant about the superior and inferior temporal lines of the squamus portion of the temporal bone?
They mark the attachment of the temporalis fascia and temporalis muscle respectively. These lines also demarcate the superior limit of the temporal fossa.
What is the nasion?
The intersection of the frontal bone with the two nasal bones. Located b/t the eyes.
What is the significance of the frontal crest?
The frontal crest is a vertical feature of the internal midline of the frontal bone that serves as an attachment for the anterior end of the faulx cerebri, a reflection of the dura mater, the outermost layer of the meninges, which separates the eft and right cerebral hemispheres.
What is the importance of the sagittal sulcus and its contents?
The sagittal sulcus is an internal, midline feature that houses the superior sagittal (dural venous) sinus. The superior sagittal sinus, found b/t the periosteal and meningeal layers of the dura, carries blood along the superior margin of the falx cerebri.
What are the fossae of the orbital portion of the frontal bone that house the lacrimal glands during life?
Lacrimal fossae
What is found within the ethmoid notch of the orbital portion of the frontal bone?
Cribriform plate of the ethmoid bone
In what portion of the frontal bone are the frontal sinuses found?
Orbital portion
Where is the foramen caecum found and what is its significance?
Forament caecum is found inferior to the frontal crest at the midpoint of the frontoethmoidal articulation (just abouve the cribriform plate). It transmits an emissary vein from the frontal (paranasal) sinus to the superior sagittal (venous dural) sinus.
What is transmitted through the supraorbital foramen?
The supraorbital neurovascular bundle. The supraorbital nerve is a branch of the frontal nerve of the opthalmic division of the trigeminal nerve (V1). The supraorbital nerve provides sensory innervation to the skin of the forehead.
The parietal bones articulate at the midline along what suture?
Sagittal suture
What is the point of intersection of the coronal and sagittal sutures called? Significance?
Bregma. Marks the site of the anterior (bregmatic) fontanelle in the neonate.
What is point of intersection of the lambdoidal and sagittal sutures called? Significance?
Lambda. Marks the site of the posterior fontanelle in the neonate.
A skull fracture in the viscinity of pterion may impact what middle meningeal vessels found in the grooves for the middle meningeal vessels of the parietal bone. What is a possible consequence?
The pterion is the intersection of the parietal, frontal, temporal and sphenoid bones and is known as the weakest portion of the skull. A fracture here could damage the anterior division of the middle meningeal vessels causing an epidural hematoma where blood builds up b/t the dura mater and the skull.
The middle meningeal artery is a branch of what artery? Be specific. What foramen allows middle meningeal vessels to enter the skull?
Middle meningeal artery is the 3rd branch of the first portion of the maxillary artery (one of the two terminal branches of the external carotid), the retromandibular portion.
The middle meningeal artery is intimately associated with what nerve, which wraps around the artery, making both easily identifiable in a cadaver?
The auriculotemporal nerve is a branch of the mandibular nerve, V3. It arises as two roots that wrap around the middle meningeal vessels before joining to form a single auriculotemporal nerve.
What is found within the arachnoid fovea that are concentrated along the sagittal sulcus? Importance?
Arachnoid granulations that are responsible for resorption and filtration of the cerebrospinal fluid, CSF, which fills the subarachnoid space during life.
What foramina, located posteriorly, adjacent to the sagittal sinus in the parietal bone, transmit emissary veins b/t the scalp and the superior sagittal sinus?
Parietal foramina
The Superior Nuchal lines, bilateral ridges extending to the right and left from the external occipital protuberance, mark the origin of what two muscles and insertion of what two muscles?
Origin: Occipitalis & Trapezius
Insertion: SCM & splenius capitis
The nuchal ligament attaches to what bony element of the occipital bone?
The median nuchal line
What is the significance of the nuchal ligament?
The nuchal ligament is a band of fibroelastic tissue that limits forward flexion of the head and provides surface area for the attachment of deep muscle of the posterior neck that are critical for both maintaining head position against gravity and moving the head quickly in response to visual and acoustic stimuli.