Anatomy pearls Flashcards
What is the distinguishing difference between CNIII and horners
- Pupil:
- CNIII - dilated, unopposed sympathetic (CNIII parasympathetic supply is lost)
- Horner’s - constricted, unopposed parasympathetic,
- CNIII: eye is down and out - unopposed superior oblique (trochlear) and lateral rectus (abducence)
- Horner’s: ptosis, enophthalmus, anhydrosis, small pupil (miosis)
Which nerve supplies sensation to the tongue?
- Tase:
- Glossopharyngeal IX - posterior 1/3rd
- Corda tympani, branch of VII - anterior 2/3
- Somatic sensation:
- glossopharyngeal IX
- Lingual nerve, branch of mandibular division of trigeminal Viii
Which nerve supplies motor sensation to the tongue?
XII, pharyngeal plexus of IX, X
What is the course of CN VII
VII (facial nerve) originated at junction between pons and medulla, crosses posterior cranial fossa, passing into temporal bone in the facial canal and exiting via the stylomastoid foramen
Tell me about the trigeminal nerve?
3 branches: ophthalmic, maxillary, mandibular
sensation to the face + motor supply to muscles of mastication
What do you know about the cranial sutues?
Usually ossify 18-24mo
Before this time the fontanelles are open, they can be seen to bulge in times of increased ICP
when they fuse at birth = craniosyntosis
What is the pterion?
junction of 4 bontes; frontal, parietal, temporal, sphenoidal
Middle meningeal artery runs behind the pterion - injury may damage this and result in extradural H’gge
What are the base of skull foramina?
- Anterior cranial fossa:
- cribriform plate - olfactory n, emissary veins and arteries
- middle cranial fossa:
- optic canal - optic nerve, 3 layers of dura, opthalmic artery and sympathetic
- Superior orbital fissure - CN III, IV, VI, ophthalmic division of CNV, ophthalmic veins; sympathetic; br of middle meningeal & lacrimal arteries
- Foramen rotundum; maxillary division of CN V
- Foramen ovale - mandibular br of CN V, petrosal n, accesory meningeal art
- F Spinosum - middle memningeal artery, meningeal br of mandibular n
- F lacerum - artery and nerve of pterygoid canal, (via carotid canal - internal carotid art and n
- posterior cranial fossa
- F magnum - medulla oblongata surrounded by meninges, spinal roots of accessory n, vertebral arteries with surrounding sympathetic plexus, anterior and posterior spinal arteries, apical ligament of dens, tectoral membrane
- Jugular F - IJV, CN IX, X, XI, inferior petrosal sinus
- Hypoglossal canal - CN XII, meningeal br of ascending pharyngeal artery
- Internal auditory meatus - CN VII, VIII, labyrinthine artery
What passes through the foramen lacerum?
artery and nerve of pterygoid canal
The internal carotid artery passes from the carotid canal in the base of the skull, emerging and coursing superior to foramen lacerum as it exits the carotid canal. The internal carotid artery does not travel through foramen lacerum. The segment of the internal carotid artery that travels above foramen lacerum is called the lacerum segment.
What are the boundaries of the middle cranial fossa?
Anterior = posterior margin of lesser wing, anterior clinoid process and anterior margin of chiasmatic groove of sphenoid
Posterior = crest of petrous temporal bone and dorsum sellae of sphenoid bone, squamous temportal bone, greater wings of sphenoid
Temporal lobe lies inside the middle cranial fossa
Where can the pituitary gland be found?
Sella turcica
What passes through the foramen magnum?
Blood vessles - vertebral arteries, anterior and posterior splinal arteries
Nerves - spinal roots of accessory nerve, sympathetic plexus around the vertebral artery
Tissues - medulla, meninges, tectorial membrane, apical ligament of dens
What runs through the optic canal?
optic nerve, 3 laters of dural, opthalmic artery, sympathetics
What are the contents of the jugular foramen?
IVJ, IX, X, XI, inferior petrosal sinus
What are the branches of the ICA?
no branches in the neck, intracranial -> middle cerebral and posterior communicating arteries
What is the cavernous sinus?
2 cavernous sinuses in the skull- each lying laterally on either side of the sella turcica
contain venous blood
draining the superficial middle cerebral, superior and inferior opthalmic veins & sphenoparietal sinuses
joined by the intercavernous sinuses and themselves drain into the superior and inferior petrosal sinuses
What are the contents of the cavernous sinus?
- ICA (with sympathetic plexus)
- venous blood
- CN VI
- within the lateral wall: CNIII, CNIV, Va, Vb
how does cav sinus thrombosis occur?
- infections of the danger area of the face i.e. those drained via the facial and opthalmic veins - may spread into the cavernous sinus as the draining veins are valveles -> thrombosis
- Sx: painful swelling of the eye, gradual loss of vision, CNIII, IV, V, VI palsies
- infection spreads rapidly due to the intercavernous sinuses
- DDx= CVA
What are the 4 layers of deep cervical fascia?
carotid sheath
prevertebral fascia
pre-tracheal fascia
investing layer of deep cervical fascia - outer layer, deep to platysma
What are the carotid sheath contents?
common carotid artery, IJV, with vagus in between
+ LN
embeded in the wall = ansa cervicalis
What are the contents of pretracheal fascia?
thyroid gland, trachea, oesophagus
what level does common carotid artery bifurfacte?
C4 -> internal and external carotid
surface marking - superior thyroid notch
What are the branches of external carotid artery?
superior thyroid, ascending pharyngeal, lingual, fascial, occipital, posterior auricular, maxillary, superficial temporal
what muscles are contained within the pre-vertebral fascia?
Scalenus anterior, medius, posterior
levator scapulae
splenius capitis
