HNS 1 Flashcards
What are the 3 layers of the meninges
Dura, arachnoid and pia mater
What is held within the anterior cranial fossa?
frontal lobe
What is held within the middle cranial fossa?
temporal lobe
What is held within the posterior cranial fossa?
cerebellum and brainstem
What is the point where the frontal, parietal, temporal and greater wing of sphenoid bone meet called?
Pterion
Suture between 2 parietal bones and occipital bone called?
Lambdoid suture
What is the point where the sagittal and coronal suture meet called?
Bregma
What is the point where the sagittal suture and lambdoid suture meet called?
Lambda
What is the unfused bone in the anterior
and posterior portion of the neonatal skull called?
Anterior fontanelle and posterior frontanelle
What are fontanelles
Soft part of a fetus skull which allows flexibility when exiting the birth canal
Describe the dura mater
thick inelastic with 2 layers (periosteal and meningeal)
Describe the arachnoid mater?
elastic with spiderlike projections
Describe pia mater
innermost, thin, delicate layer
What is the relationship of the dural venous sinuses to the brain?
the dural venous sinuses drains deoxygenated blood and CSF from the brain and surrounding structures
What is the blood supply to the meninges
anterior, middle (maxillary artery) + accessory and posterior meningeal artery
Explain the difference between extra-dural and sub-dural hemorrhages of the dura
extra-dural: damage to middle MA causing pooling of blood between dura and skull
sub-dural: damagae associated w/ venous sinuses causing pooling of blood between dura and arachnoid space
Blow to pterion can cause what?
intercranial bleed due to middle meningeal artery located here
What is the anatomy of the scalp?
SCALP: skin, connective tissue(dense), aponeurotic layer, loose connective tissue, pericranium
Why is it so important to avoid infection of lacerations (cut) to the scalp?
highly vascularised (including occipital artery) therefore could be rapid spread of infection to brain
difference between meninges arrangment between cranial cavity and vertebral canal?
dura is closely adherent to the skull whereas there is space (epidural space) between the dura and bone of the vertebral canal (allowing anaesthetics ie epidural)
What is in the subarachnoid space?
CSF
What is the largest dural venous sinus?
Superior sagittal sinus.
function of CSF
protection, buoyancy and chemical stability
what are the ventricles lined with?
ependymal cells forming the choroid plexus
CSF eventually drains where?
into the dura sinuses via arachnoid villi (granulations)
What is the spinal cord?
- cylindrical shape continuous with the medulla oblongata through the foramen magnum at the base of the skull
- it occupies the vertebral canal of the vertebral column to the L1 and L2 lumbar vertebral level
What is the spinal cord composed of?
segments that give rise to a pair of mixed spinal nerves
What are the spinal nerves of the spinal cord and their frequency?
- 8 cervical spinal nerves (pair of mixed)
- 12 thoracic spinal nerves
- 5 lumbar spinal nerves
- 5 sacral spinal nerves
- 1 coccygeal spinal nerve
What nerves emerge above, and what nerves emerge below vertebrae?
Above: C1-C7
Below: C8-Co1
Terminal end of spinal cord
conus medullaris
Reasons for the impingement of spinal nerve roots
nerve root compression such as in pregnancy or herniated disc
What does the middle meningeal artery supply?
the dura mater
What does the cribiform plate contain?
Olfactory nervs [I]
What foramina is in the anterior cranial fossa?
cribiform plate
What foramina is in the posterior cranial fossa?
-internal acoustic meautus
-jugular foramina
-hypoglossal canal
-foramen magnum
What does the cribiform plate contain?
Olfactory nervs [I]
What foramina is in the anterior cranial fossa
cribiform plate
What foramina is in the middle cranial fossa
-superior orbital fissure
-foramen rotundum
-foramen ovale
-foramen spinosum
-Carotid canal
What does the cribiform plate contain?
Olfactory nerves [I]
What does the optic cancal contain?
-optic nerve [II]
-opthalmic artery
Superior orbital fissue contain?
-oculomotor nerve [III]
-trochlear nerve [IV]
-opthalmic division of the trigeminal nerve [V1]
-abducen nerve [VI]
-opthalmic veins
foramen rotundem contains?
-maxillary division of the trigeminal nerve [V2]
foramen ovale contains?
-mandibular division of the trigeminal nerve [V3]
-lesser petrosal nerve
foramen spinosum contains?
middle meningeal artery
internal acoustic meatus contains?
-facial nerve
-vestibulocochlear nerve
jugular foramen contains
-glossopharyngeal nerve [IX]
-vagus nerve [X]
-accessory nerve [XI]
-inferior pertrosal sinus
-sigmoid sinus (forming internal jugular vein)
hypoglossal canal contains
-hypoglossal nerve [XII]
-meningeal branch of the ascending pharyngeal artery
foramen magnum contains
-end of brainstem/beginning of spinal cord
-vertebral arteries
-spinal roots of the accesory nerve
-meninges
describe epidural injections
-injected into epidural space (between dura and vertebral wall)
epidural injections uses
labour + during and after surgery
describe spinal injections
are injected to dural sac that contains CSF for immediate relief
dural sac-surrounds the spinal cord inside the vertebral column. It separates the epidural space from the subarachnoid space
what are spinal injections used for
diagnostically and therapeutically
describe caudal epidural
inserting a needle through the sacral hiatus to gain entrane into sacral epidural space
what are the two spinotransversales muscles?
-splenius capitis
-splenius cervicis (colli
origin of splenius capitis
Lower aspect of the ligamentum nuchae, and the spinous processes of C7 – T3/4 vertebrae
what are the three erector spinae muscles?
-iliocostalis
-longissimus
-spinalis
insertion of splenius capitis
Mastoid process and the occipital bone
action of splenius capitis
Rotate head to the same side
innervation of splenius capitis
Posterior rami of spinal nerves C3 and C4
function of Splenius cervicis (colli)
Rotate head to the same side
innervation of Splenius cervicis (colli)
Posterior rami of the lower cervical spinal nerves
origin and insertion of Splenius cervicis (colli)
o: Spinous processes of T3-T6 vertebae
i: Transverse processes of C1-3/4
iliocsotalis function
Unilaterally laterally flex the vertebral column Bilaterally extend the vertebral column and head
iliocostalis innervation
Posterior rami of the spinal nerves
iliocostalis attachments
o: Common tendinous origin of the erector spinae
i: Costal angle of the ribs and the cervical transverse processes
what are the three erector spinae muscles?
-iliocostalis
-longissimus
-spinalis
longissimus action
Unilaterally laterally flex the vertebral column. Bilaterally extend the vertebral column and head
longissimus innervation
Posterior rami of the spinal nerves
longissimus attachments
o: Common tendinous origin of the erector spinae
i: Lower ribs, the transverse processes of C2 – T12, and the mastoid process of the skull
spinalis function
Unilaterally laterally flex the vertebral column. Bilaterally extend the vertebral column and head
spinalis innervation
Posterior rami of the spinal nerves
spinalis attachments
o:Common tendinous origin of the erector spinae
i: Spinous processes of C2, T1-T8 and the occipital bone of the skull
