Bony Anatomy Flashcards
Nasion
The suture between frontal and nasal bones

Bregma
Located at the vertex of the skull.
The point at which the sagittal suture meets the coronal suture

Pterion
Lateral skull
The point at which the greater wing of the sphenoid, squamous temporal, frontal and parietal bones meet.

Asterion
Located posterolaterally
The point at which the parietomastoid, occipitomastoid and lamboid sutures meet.

Opisthion
The name given to the posterior of the foramen magnum in the midline

Inion
AKA occipital protuberance
Corresponds to the confluence of the venous sinuses on the internal surface



What are the 8 bones of the cranium
Medial:
Frontal, ethmoid, sphenoid, occipital
Bilateral:
Temporal, parietal
Division of the cranium
Vault and base


Kocher’s point
11cm posterior to the nasion, 3cm lateral to the midline

Frazier’s point
6cm above inion, 3cm lateral to the midline

Surface markings of the transverse sinus?
Horizontal line drawn from the inion

Surface marking of the sigmoid sinus
Vertical line from the tip of the mastoid and passing through the mastoid (digastric) groove

Six standard segments for vertebra
Body
Pedicles
Lamina
Spinous process
Facet/articular process
Transverse process
Features of vertebral pedicles
2 pedicles extending from the vertebral body
Serve as attachments for articular facets, transverse processes, laminae
The superior and inferior borders of the pedicles serve as the margins for the intervertebral foramina
What makes up the posterior arch of the SC?
Laminae
Special features of C1
Lacks a vertebral body
Possesses two lateral masses which articulate with the occipital condyles superiorly and C2 inferiorly
Anterior arch and two posterior arches enclose the spinal canal.
The anterior arch of C1 articulates with the odontoid process of C2 in the midline
What is found on the anterior surface of the anterior arch?
Possesses an anterior tubercle which serves as a point of attachment for the longus colli muscle
What is found on the posterior surface of the posterior arch?
Posterior tubercle which serves as a point of attachment for the rectus capitis posterior minor
Special features of C2
Characterised by the odontoid process
What is unique about the C6 vertebra?
Possesses a tubercle at the anterior aspect of its transverse process called the carotid tubercle which denotes the entry of the vertebral artery

Transverse foramen of C7
Smaller or absent
Contains the vertebral vein
Transverse ligament
Short ligament attached laterally to the transverse tubercle of C1
Runs posterior to the dens and thus has a concave trajectory

What are the two bands of ligaments at the level of C1?
Superior and inferior longitudinal bands which along with the transverse ligament make up the cruciate ligament

Attachment of superior band of cruciate ligament?
Anterior edge of foramen magnum
Attachment of the inferior band of cruciate ligament
Extends to C2
Alar ligaments
Two strong ligaments (left and right) connecting the superolateral segments of the dens to the axis an to the medial segment of the occipital condyles

Apical ligament
The short ligament attaching the vertex of the dens to the anterior edge of the foramen magnum
Features of the tectorial membrane
Posterior to alar and apical ligaments divided into a medial and two lateral segments
The medial segment runs from the anterior edge of the body of C2 to the foramen magnum
Lateral segments run connect C2 with the occipital condyles.

Components of the atlanto-occipital membrane
Anterior
Posterior

Anterior segment of the atlantooccipital membrane
Connects the anterior arch of C1 with the anterior edge of the foramen magnum
Considered an extension of the anterior longitudinal ligament of the spine
Posterior segment of the atlantooccipital membrane
Connects the posterior arch of C1 to the posterior edge of the foramen magnum
it is traversed by the vertebral arteries as they exit the transverse foramina to enter the cranium.
It is the equivalent of the ligamentum flavum
Attachments of the anterior longitudinal ligament of the spine?
Basilar portion of the occipital bone
To the anterior segment of S2
Attachments of the posterior longitudinal ligament
From the internal aspect of the basilar segment of the occipital bone to the coccyx

Sphenoid ostia

Sphenopalatine foramen
Connects the nasal cavity and the pterygopalatine fossa
Transmitting the nasopalatine nerve, posterior superior nasal nerves, and sphenopalatine artery and vein.


Vidian nerves
Run along the floor of the sphenoid sinus
Can lead back to terminal portion of petrous carotid

Sphenopalatine artery
Branch of maxillary

Medial canthal ligament
If divided should be reapproximated as there is a risk of lateral globe drift

Eustachian tubes
Lateral limit of transnasal approach
Eustachian tubes

Inferior turbinate in yellow
Nasolacrimal duct in green

