Chapter 8 pt1: Head and Neck Flashcards
- cranial cavity
- 2 ears
- 2 orbits
- 2 nasal cavities
- oral cavity
- air filled paranasal sinuses
- hard and soft palates
head and neck
continuous with the nasal cavity
air filled paranasal sinuses
separate the nasal and oral cavities
hard and soft palates
- posterior to upper jaw
- acts as a conduit for the mandibular nerve between cranial and oral cavities
infratemporal fossa
- just posterior to upper jaw
- communicates with: cranial cavity, infratemporal fossa, the orbit, nasal and oral cavities
Pterygopalatine fossa
passes through the pterygopalatine fossa
maxillary nerve
contains unique muscles that move the skin relative to underlying bone
the face
also open and close openings to orbits and oral cavities
face muscles
covers the superior, posterior, and lateral regions of the head
scalp
extends between the head and thorax
neck
extends higher than the anterior neck
posterior neck
is made up by the top of the sternum, clavicle, and acromion
inferior border of the neck
what are the 4 major compartments of the neck?
- vertebral
- visceral
- two vascular
houses musculoskeletal elements
vertebral compartment of neck
houses glands and structures associated with the respiratory and digestive systems
visceral compartment of the neck
house major blood vessels and vagus nerve
two vascular compartments of the neck
- are specialized structures associated with the respiratory and digestive tracts
- are joined by the laryngeal inlet
larynx and pharynx
connects the esophagus to the oral and nasal cavities
pharynx
joins the trachea to the pharynx
larynx
connected by sutures
most bones of the skull
fibrous immovable joints
sutures
found on each side of the head
3 pairs of synovial joints
synovial joints on each side of the head
The temporomandibular joint and 2 between the 3 inner ear bones
- are large unossified gaps between bones
- fetuses and newborns have them
fontanelles
are modified for moving the head
CI and CII
form the boney framework of the neck
the 7 cervical vertebrae
have posterior and anterior tubercles on their transverse processes
cervical vertebrae
- is small and U-shaped bone, found just superior to the larynx
- free floating and attaches the floor of the mouth, larynx, and pharynx
hyoid
forms the base of the U of hyoid bone
the body
form the arms of the hyoid bone
the greater horns
is a soft tissue flap-like structure that hangs off the hard palate
soft palate
opens directly into the base of the neck
The superior thoracic aperture (thoracic inlet)
opens into the base of the neck
axillary inlet
what are the two important vertebrae
CIII-CIV and CV-CVI
bracket the larynx and mark the bifurcation of the common carotid artery
CIII-CIV and CV-CVI
anterior to the digestive tract
larynx and trachea
how can the larynx and trachea be assessed in cases of emergency?
cricothyrotomy (through the cricothyroid ligament) and a tracheostomy
- 12 pairs
- innervate structures in the head
cranial nerves
also innervates viscera
vagus (CN X) nerve
leave the brain in CN III, VII, IX, X
Parasympathetic fibers
leave these nerves and join CN V
Parasympathetic fibers from CN III, VII, IX
leaves head and neck
CN X
how many cervical nerves?
8 (C1-C8)
form the cervical plexus
Anterior rami of C1-C4
form the brachial plexus
Anterior rami of C5-C8
innervates: strap muscles, skin on anterior and lateral neck, skin on upper thoracic wall, skin on inferior parts of head
cervical plexus
innervates upper limb
brachial plexus
pass through the oropharynx
food and air
what can food NOT enter?
trachea
seal the mouth when food or liquid are in the mouth
oropharyngeal isthmus and tongue
- can pass through the nose and mouth
- can pass just through the nose with food in the mouth
air
closes the laryngeal inlet when swallowing
epiglottis
raised superiorly which allows suckling and nasal breathing
Larynx of infants
divide the neck into anterior and posterior triangles
trapezius and sternocleidomastoid
between the thorax and head
anterior triangle
between the thorax and the arm
posterior triangle
how many bones are in the skull?
22 bones
- covers cranial cavity that houses the brain
- upper dome
calvaria
the facial skeleton or viscerocranium
lower part of skull
provide passage ways for blood vessels and nerves
foramen of skull
- shows many of the face bones
- shows maxilla, sphenoid, vomer, zygomatic, and occipital bones
anterior view of skull
shows many of the sutures between skull bones
lateral view of skull
what are the structures seen on the lateral side of skull?
- zygomatic arch
- temporomandibular joint -mastoid and styloid processes
- external acoustic meatus
shows the parietal, temporal, and occipital bones
posterior view of skull
what are the structures of skull in the posterior view?
- external occipital protuberance
- superior and inferior nuchal lines
- external occipital crest
sometimes exist within the sutures
sutural bones
shows the top of the calvaria- frontal, parietal and occipital bones and sutures between cranial bones
superior view of skull
- Consists of layers of dense internal and external compact bone
- Middle layer is made up of spongy bone- diploe
bone of calvaria
what are the structures of the skull in the anterior view?
- hard palate
- pterygoid process
- zygomatic arch
- mandibular fossa
- foramen magnum
- occipital condyles
what are the external foramina of the anterior view of the skull?
- supra orbital foramen
- infra orbital foramen
- mental foramen
passes through the supra-orbital foramen
Supra-orbital nerve and vessels
passes through Infra-orbital foramen
infra-orbital nerve and vessel
passes through mental foramen
mental nerve and vessel
what is the external foramina of the skull in the lateral view?
Zygomaticofacial foramen
passes through Zygomaticofacial foramen
Zygomaticofacial nerve
what is the external foramina of the skull in the superior view?
Parietal foramen
passes through the Parietal foramen
emissary vein
what are the external foramina of the skull in the interior view?
- incisive foramen
- greater palatine foramen
- less palatine foramen
- pterygoid canal
- foramen ovale
- foramen lacerum
- carotid canal
- foramen magnum
- condylar canal
- hypoglossal canal
- jugular foramen
- stylomastoid foramen
passes through incisive foramen
Nasopalantine nerve; sphenopalatine vessels
passes through greater palatine foramen
Greater palatine nerve and vessel
passes through lesser palatine foramen
Lesser palatine nerve and vessel
passes through pterygoid canal
pterygoid nerve and vessel
passes through foramen ovale
Mandibular nerve (V3); lesser petrosal nerve
passes through foramen lacerum
filed with cartilage
passes through carotid canal
Internal carotid artery and nerve plexus
passes through foramen magnum
Continuation of brainstem and spinal cord, vertebral arteries and nerve plexuses, anterior spinal artery, posterior spinal arteries, roots of accessory nerve (XI), meninges
passes through condylar canal
emissary
passes through hypoglossal canal
Hypoglossal nerve (XII), vessels
passes through jugular foramen
Internal jugular vein, inferior petrosal sinus, glossopharyngeal nerve (IX), vagus nerve (X), accessory nerve (XI)
passes through stylomastoid foramen
facial nerve (VIII)
has: frontal crest, groove for sagittal sinus, and granular foveolae
inner surface of the calvaria roof
- divided into anterior, middle, posterior fossa
- above the nasal cavity and orbits and houses the frontal lobes
Floor of Calvaria (Anterior Cranial Fossa)
elevated in the midline and lateral to this the greater wing of sphenoid form depressions
middle cranial fossa
housed in the sella turcica
pituitary gland
- Formed largely by the occipital bone
- Obvious structures include: the foramen magnum, internal occipital crest, and internal occipital protuberance
Posterior Cranial Fossa of Calvaria
pass into the posterior cranial fossa
formina
surrounded by 3 meninges (dura, arachnoid, pia)
brain
has 2 layers (periosteal and meningeal layer)
cranial dura mater
has 1 layer (meningeal)
spinal dura mater
separates to form 2 unique structures- dural partitions, intracranial venous structure
cranial dura
project into the cranial cavity
dural partitions
what are the dural partitions of the cranial cavity?
- falx cerebri (between cerebral hemispheres)
- tentorium cerebelli (between cerebellum and cerebrum)
- falx cerebelli (between cerebellar hemispheres)
- diaphragm sella (covers hyophyseal fossa of sella turcica)
travels in the outer periosteal layer of dura
Arterial supply of dura mater
consists of anterior, middle, accessory, and posterior meningeal arteries
outer periosteal layer of dura mater
the largest and supplies the greatest part of the dura
middle meningeal artery
give rise to anterior, middle, and posterior meningeal arteries respectively
ethmoid, maxillary, and occipital arteries
what is the innervation of the dura mater by?
small meningeal branches from: CN V1, 2, 3 , X, and the 1st, 2nd, and sometimes 3rd cervical nerves
innervated by branches of CN V1, 2, 3
Dura mater of the anterior and middle cranial fossae
innervated by the 1st, 2nd, and 3rd, cervical nerves
Dura mater of the posterior cranial fossa
thin membranes that are found deep to the dura
Arachnoid and pia mater
the only naturally occurring space and is filed with CSF
subarachnoid space
returns to the venous system via arachnoid granulations which project into the superior sagittal sinus
CSF
divided up based on development and adult structures
the brain
becomes the cerebral hemispheres
telencephalon
becomes the thalamus and hypothalamus
Diencephalon
becomes the midbrain
Mesencephalon
becomes the cerebellum
Metencephalon
becomes medulla oblongata
Myelencephalon
receives blood from the internal carotid and vertebral arteries
brain
meet in the cranial cavity to form the cerebral arterial circle
internal carotid and vertebral arteries
enter the cranial cavity through the foramen magnum
2 vertebral arteries
enter the cranial cavity through the carotid canals
internal carotids
join to form the basilar artery
vertebral arteries
gives off: anterior inferior cerebellar, pontine, superior cerebellar, and posterior cerebral arteries
basilar artery
give off: ophthalmic, posterior communicating, middle and anterior cerebral arteries
internal carotids
begins as small venous channels that lead to cerebral and cerebellar veins
Venous drainage of the brain
drain into the dural venous sinus
Cerebral, cerebellar, emmissary, and diploic veins
eventually drains into the internal jugular vein
dural venous sinus
what are the dural sinuses?
- superior sagittal
- inferior sagittal
- straight
- transverse
- sigmoid
- occipital sinuses
- confluence of sinuses
- the cavernous
- sphenopariteal
- superior and inferior petrosal
- basilar sinuses
found on either side of the sphenoid bones
paired cavernous sinuses
pass through the cavernous sinus
Internal carotid and abducent nerve
pass through walls of the cavernous sinuses
Occulomotor, trochlear, ophthalmic, and maxillary nerves
pass through foramina or fissures of the skull
12 pairs of cranial nerves
All pairs of cranial nerves except for the…………extend off the brain
hypoglossal nerve
what are the components of the cranial nerves?
- somatic component
- visceral component
- sensory component
- special motor component
numbered I-XII, starting anteriorly with the olfactory nerve and moving posteriorly ending with the hypoglossal
cranial nerves
conveys emotional information and is an important cue for a physician
face
- develop from the 2nd pharyngeal arch and are innervated by the facial nerve (CN VII)
- They are in superficial fascia, with origins from either bone or fascia and insert into skin
muscles of face
orbital and palpebral parts for eye closure
Orbicularis oculi
functions in frowning
Corrugator supercillii
what does the orbital group of facial muscles consist of?
- Orbicularis oculi
- Corrugator supercillii
what does the nasal group of facial muscles consist of?
- nasalis
- procerus
- depressor septi nasi
- largest and best developed muscle of the nasal group
- consists of a transverse and alar parts
nasalis
compresses the nares
transverse part of nasalis
draws the alar cartilages downward and laterally and opens the nares
alar part of nasalis
superficial to the nasal bones- draws medial border of eyebrows downward
procerus
widens the nares
depressor septi nasi
muscles of this group move the lips and cheek
oral group
what is the oral group divided into?
- upper group
- lower group
- orbicularis oris
- buccinator
- forms muscular part of cheek
- arises from posterior part of mandible and maxilla opposite the molar teeth and pterygomandibular raphe
buccinators
- pushes cheeks against teeth
- helps in mastication and suckling
contraction of buccinators
help move the ear
auricular muscles
what are the 3 auricular muscles?
- superior auricular
- anterior auricular
- posterior auricular
elevates ear
superior auricular
pulls ear upward and forward
anterior auricular
retracts and elevates ear
posterior auricular
closes eyelids
orbicularis oculi
origin: Medial palpebral ligament
Palpebral part of orbicularis oculi
insertion: Fibers form an uninterrupted ellipse around orbit
Palpebral part of orbicularis oculi
innervation: Facial nerve (VII)
ALL muscles of face
function: Closes eyelids gently
Palpebral part of orbicularis oculi
origin: Nasal part of frontal bone; frontal process of maxilla; medial palpebral ligament
orbital part of orbicularis oculi
insertion: Fibers form an uninterrupted ellipse around orbit
orbital part of orbicularis oculi
function: Closes eyelids forcefully
orbital part of orbicularis oculi
origin: Medial end of the superciliary arch
Corrugator supercilii
insertion: Skin of the medial half of eyebrow
Corrugator supercilii
function: Draws the eyebrow medially and downward
Corrugator supercilii
origin: Maxilla just lateral to nose
transverse part of nasalis
insertion: Aponeurosis across dorsum of nose with the muscle fibers from the other side
transverse part of nasalis
function: Compresses nasal aperture
transverse part of nasalis
origin: Maxilla over lateral incisor
alar part of nasalis
insertion: Alar cartilage of nose
alar part of nasalis
function: Draws cartilage downward and laterally, opening nostrils
alar part of nasalis
origin: Nasal bone and upper part of lateral nasal cartilage
Procerus
insertion: Skin of lower forehead between eyebrows
Procerus
function: Draws down medial angle of eyebrows, producing transverse wrinkles over bridge of nose
Procerus
origin: Maxilla above medial incisor
Depressor septi
insertion: Mobile part of the nasal septum
Depressor septi
function: Pulls nose inferiorly
Depressor septi
origin: Oblique line of mandible below canine, premolar, and first molar teeth
Depressor anguli oris
insertion: Skin at the corner of the mouth and blending with orbicularis oris
Depressor anguli oris
function: Draws corner of mouth downward and laterally
Depressor anguli oris
origin: Anterior part of oblique line of mandible
Depressor labii inferioris
insertion: Lower lip at midline; blends with muscle from opposite side
Depressor labii inferioris
function: Draws lower lip downward and laterally
Depressor labii inferioris
origin: Mandible inferior to incisor teeth
mentalis
Insertion: Skin of chin
mentalis
function: Raises and protrudes lower lip as it wrinkles skin on chin
mentalis
origin: Fascia over masseter
Risorious
insertion: Skin at the corner of the mouth
Risorious
Function: Retracts corner of mouth
Risorious
origin: Posterior part of lateral surface of zygomatic bone
Zygomaticus major
insertion: Skin at the corner of the mouth
Zygomaticus major
function: Draws the corner of the mouth upward and laterally
Zygomaticus major
origin: Anterior part of lateral surface of zygomatic bone
Zygomaticus minor
insertion: Upper lip just medial to corner of mouth
Zygomaticus minor
function: Draws the upper lip upward
Zygomaticus minor
origin: Infra-orbital margin of maxilla
Levator labii superioris
insertion: Skin of upper lateral half of upper lip
Levator labii superioris
function: Raises upper lip; helps for nasolabial furrow
Levator labii superioris
origin: Frontal process of maxilla
Levator labii superioris alaeque nasi
insertion: Alar cartilage of nose and upper lip
Levator labii superioris alaeque nasi
function: Raises upper lip and raises nostrils
Levator labii superioris alaeque nasi
origin: Maxilla below infra-orbital foramen
Levator anguli oris
insertion: Skin at the corner of mouth
Levator anguli oris
function: Raises corner of mouth; helps with nasolabial furrow
Levator anguli oris
origin: From muscles in area; maxilla and mandible midline
Orbicularis oris
insertion: Forms ellipse around mouth
Orbicularis oris
function: Closes lips; protrudes lips
Orbicularis oris
origin: Posterior parts of maxilla and mandible; pterygomandibular raphe
Buccinator
insertion: Blends with orbicularis oris into lips
Buccinator
function: Presses cheeks against teeth; compresses distended cheeks
Buccinator
origin: Anterior part of temporal fascia
Anterior auricular
insertion: Into helix of ear
Anterior auricular
function: Draws ear upward and forward
Anterior auricular
origin: Epicranial aponeurosis on side of head
Superior auricular
insertion: Upper part of auricle
Superior auricular
function: Elevates ear
Superior auricular
origin: Mastoid process of temporal bone
Posterior auricular
insertion: Convexity of concha of ear
Posterior auricular
function: Draws ear upward and backwards
Posterior auricular
origin: Skin of eyebrows
frontal belly of Occipitofrontalis
insertion: Into galea aponeurotica
frontal belly of Occipitofrontalis
function: Wrinkles forehead; raises eyebrows
frontal belly of Occipitofrontalis
origin: Lateral part of superior nuchal line of occipital bone and mastoid process of temporal bone
occipital belly of Occipitofrontalis
insertion: Into galea aponeurotica
occipital belly of Occipitofrontalis
function: Draws scalp backward
occipital belly of Occipitofrontalis
the largest of the 3 pairs of salivary glands
parotid gland
carries saliva into the oral cavity
parotid duct
passes through the parotid and provides motor inputs for muscles of the face
facial nerve (VII)
is formed in the parotid gland by superficial temporal and maxillary veins
Retromandibular vein
divides into: posterior auricular, maxillary, transverse facial, and superficial temporal arteries
External carotid
provides sensory inputs for the skin of the face
trigeminal nerve (V)
what are the 3 major branches of the trigeminal nerve?
- ophthalmic (V1)
- maxillary (V2)
- mandibular (V3)
branches into : supra-orbital, supra-trochlear, infra-trochlear, lacrimal, and external nasal nerves
ophthalmic nerve
branches into: zygomaticotemporal branch, zygomaticofacial branch, infra-orbital nerve
maxillary nerve
branches into: auriculotemporal, buccal, and mental nerves
mandibulalr nerve
originate from the second branchial arch, embryonically, and are therefore innervated by CN VII
muscles of the face
exits via stylomastoid foramen
CN VII
what are the branches of CN VII?
- temporal
- zygomatic
- buccal
- marginal mandibular
- cervical
give rise to inferior and superior labial, angular, and lateral nasal vessels
facial vessels
branch off superficial temporal vessels
Transverse facial vessels
branch from ophthalmic vessels
Zygomatico- facial and temoral and dorsal nasal artery
branches into infra-orbital, buccal, and mental arteries
maxillary artery
major draining vessel of the face that also receives blood from deep regions of the head
facial vein
interconnected with the intracranial cavernous sinus through emissary veins
venous channels of the face
why can infections move from the mouth into the intracranial region?
because there are no valves between the systems
what groups of lymph nodes does lymphatic drainage move towards?
- submental
- submandibular
- pre-auricular
- parotid
- Extends from the superciliary arch (anteriorly) to the external occipital protuberance and superior nuchal lines (posteriorly)
- And laterally to the zygomatic arches
scalp
what are the layers of the scalp?
S-skin C-connective tissue (dense) A-aponeurotic layer L- loose connective tissue P-pericranium
anchors skin to the aponeurotic layer
Dense connective tissue layer
- separates the aponeurotic layer from the pericranium
- facilitates movement of scalp over calvaria
loose connective layer
the periosteum of the outer surface of the calvaria
pericranium
consists of the occipitofrontalis muscle and the epicranial aponeurosis (galea aponeurotica)
aponeurotic layer
made up of the frontal and occipital bellies
occipitofrontalis muscle
nerves anterior to the ears and vertex
- branches of CN V
- supratrochlear
- supra-orbital
- zygomaticotemporal
- auriculotemporal
nerves posterior to the ears and vertex
C1 and C2 spinal nerves form greater auricular, lesser and greater occipital, and 3rd occipital nerves
arise from external and internal carotid/ophthalamic
Arteries that supply the scalp
where does venous drainage go?
the jugulars
what are the scalp vessels?
- supra- trochlear
- orbital
- posterior auricular
- occipital
- superficial temporal arteries
drains into the occipital nodes which drain into upper deep cervical nodes
occipital region
drainage is into the mastoid nodes that also drain into the upper deep cervical nodes
posterior to the vertex of the head
the scalp drains into pre-auricular and parotid nodes`
anterior to the vertex
formed by: maxilla, zygomatic, frontal, ethmoid, lacrimal, sphenoid, and palatine bones
the orbits
includes, possibly the trochlear fovea (for muscle attachment) and the lacrimal fossa
superior wall of orbits
contains: the anterior and posterior ethmoidal foramina, lacrimal groove, and part of the optic canal
medial wall of orbits
has part of the inferior orbital fissure
floor of the orbit
where the superior orbital fissure is found
lateral wall of orbit
what are the layers of the eyelids?
- skin
- subcutaneous tissue
- voluntary muscle
- orbital septum
- tarsus
- conjunctiva
2 additional muscles of the upper eyelid
-levator palebrae superioris -superior tarsal muscles
voluntary muscle of the eyelid
orbicularis oculi
made up of 3 parts: the orbital, palpebral, and lacrimal parts
orbicularis oculi
is anchored medially and laterally via the medial and lateral palpebral ligaments
palpebral part of orbicularis oculi
passes deep and medially, attaching to the lacrimal crest and may drain tears
lacrimal part of orbicularis oculi
an extension of the periosteum that extends into the upper and lower lid
orbital septum
attaches to the tendon of the levator palpebrae superioris
orbital septum of the upper lid
attaches to the tarsus
orbital septum of the lower lid
covers the full extent of the inner surface of the eyelid and reflects onto the outer surface of the eye (sclera)
conjunctiva
formed when the eyelids are closed
- conjunctiva sac
- with upper and lower extensions of sac formed by super and inferior conjunctiva fornices
provides major support for each eyelid
tarsus
plates of dense connective tissue that attach laterally and medially via the lateral and medial palpebral ligaments
inferior and superior tarsus
attaches to the levator palpebrae superioris muscle via a tendon, which raises the upper eyelid
superior tarsus
bloody supply of eyelid
- supratrochlear
- supraorbital
- lacrimal
- dorsal nasal arteries
- veins from the ophthalmic vessels
come from the facial vessels
angular artery and vein
come from the temporal artery
transverse facial artery
drain mostly into parotid and submandibular nodes
lymphatics of eyelids
innervated with both motor and sensory components
eyelids
are all branches of the trigeminal (V)
sensory components of eyelid innervation
where do palpebral branches arise from?
- Supraorbital
- supratrochlear
- infratrochlear
- lacrimal branches of the ophthalmic nerve (V1)
what are the motor components of eyelid innervation supplied by?
- facial (VII) (innervates orbicularis oculi)
- oculomotor (III) (innervates levator palpebrae superioris)
- sympathetic fibers that innervate superior tarsal
Makes, moves, and drains fluid of the eyeball
Lacrimal Apparatus
made up of the: lacrimal gland, lacrimal canaliculi, lacrimal sac, and naso-lacrimal duct
Lacrimal Apparatus
what is the lacrimal gland divided by and what are the two parts?
-divided by tendon of levator palpebrae
-divided into:
~orbital part
~palpebral part
Fluid leaves the gland and passes medially over the eye into the lacrimal sac via….?
the puncta and canaliculi
Superiolateral to the eye and divided into orbital and palpebral parts by the tendon of the levator palpebrae superioris
lacrimal gland
enter the lacrimal sac by passing medially
canaliculi
drains into the nose
nasolacrimal duct
what happens when the orbicularis oculi muscle contracts during blinking?
the small lacrimal part of the muscle may dilate the lacrimal sac and draw tears through the canaliculi
what are the 3 components of innervation of the lacrimal apparatus?
- sensory
- secretomotor (parasympathetic)
- postganglionic sympathetic fibers
from lacrimal nerve that return to CNS through ophthalamic (V1)
sensory innervation of lacrimal apparatus
preganglionic fibers from CNVII enter petrosal nerve and meet postganglonic fibers in pterygopalantine ganglion; postganglionic fibers innervate gland via CN V2, zygomatic, zygomaticotemporal nerves
secretomotor (parasympathetic) innervation of lacrimal apparatus
follow parasympathetic pathway
postganglionic sympathetic fibers innervation of lacrimal apparatus
optic nerve, ophthalamic artery pass through this
optic canal
CN III, IV, V1 branches (lacrimal, frontal, nasociliary), VI, and superior ophthalamic vein pass through thi…..
superior orbital fissure
CN V2, infraorbital vessels pass through this…
inferior orbital fissure
nasolacrimal duct passes through this….
nasolacrimal canal
ethmoid nerves and vessels pass through this….
anterior and posterior ethmoidal openings
- The periosteum lining the bones of the bones of the orbit
- continuous with the dural periosteum
periorbital
thickens into the common tendinous ring
the periorbital in the posterior part of the orbit
the origin for the 4 rectus muscles
common tendinous ring
encloses the major part of the eyeball
fascial sheath
what is the fascial sheath attached to posteriorly?
to the sclera at the point the optic nerve enters
what is the fascial sheath attached to anteriorly?
is firmly attached to the sclera at the edge of the cornea
restrict the medial and lateral rectus muscles
check ligaments of lateral and medial rectus
what are the groups of rectus muscles?
- intrinsic (control pupil size and lens shape)
- extrinsic (control eye movement and eyelid raising)
origin: Lesser wing of sphenoid anterior to optic canal
Levator palpebrae superioris
insertion: Anterior surface of tarsal plate
Levator palpebrae superioris
innervation: oculomotor
Levator palpebrae superioris
function: Elevation of upper lid
Levator palpebrae superioris
origin: Superior part of common tendinous ring
Superior rectus
insertion: Anterior half of eyeball superiorly
Superior rectus
innervation: oculomotor
Superior rectus
function: Elevation, adduction, medial rotation of eyeball
Superior rectus
origin: Inferior part of common tendinous ring
Inferior rectus
insertion: Anterior half of eyeball inferiorly
Inferior rectus
innervation: oculomotor
Inferior rectus
function: Depression, adduction, lateral rotation of eyeball
Inferior rectus
origin: Medial part of common tendinous ring
medial rectus
insertion: Anterior half of eyeball medially
medial rectus
innervation: oculomotor
medial rectus
function: Adduction of eyeball
medial rectus
origin: Lateral part of common tendinous ring
lateral rectus
insertion: Anterior half of eyeball laterally
lateral rectus
innervation: abducent
lateral rectus
fucntion: Abduction of eyeball
lateral rectus
origin: Body of sphenoid, superior and medial to optic canal
superior oblique
insertion: Outer posterior quadrant of eyeball (superior surface)
superior oblique
innervation: trochlearr
superior oblique
function: Depression, abduction, medial rotation of eyeball
superior oblique
origin: Medial floor of orbit posterior to rim; maxilla lateral to nasolacrimal groove
inferior oblique
insertion: Outer posterior quadrant of eyeball (inferior surface)
inferior oblique
innervation: oculomotor
inferior oblique
function: Elevation, abduction, lateral rotation of eyeball
inferior oblique
moves the pupil superiorly
elevation
moves pupil inferiorly
depression
moves pupil laterrally
abduction
moves pupil medially
adduction
rotating the upper part of pupil medially
Internal rotation (intorsion)
rotating upper part of pupil laterally
External rotation (extorsion)
slightly lateral
axis of each orbital
directed anteriorly
each eyeball axis
raises upper eyelid
Levator palpebrae superioris
have complicated actions due to apex of orbit being medial to insertion
Rectus muscles- 4 muscles (medial ,lateral, superior, inferior)
both insert posterolaterally on the eyeball
oblique muscles
arises from body of sphenoid and passes along medial border, through trochlear notch
superior oblique
crosses floor of orbit from medial side
inferior oblique
originate from the common tendinous ring
4 rectus muscles
originate from the sphenoid bone
Superior oblique and levator palpebrae
have a downward (superior) and upward (inferior) action on the eye due to inserting laterally and posteriorly
obliques
what is the arterial supply to the orbit and eyeball?
the ophthalmic which is a branch off the internal carotid
passes into the orbit, through the optic canal with the optic nerve
Ophthalmic artery
branches into: lacrimal, central retinal, long and short posterior ciliary, muscular, supra-orbital, posterior ethmoidal, and anterior ethmoidal
ophthalmic artery
venous drainage of the eyeball
2 venous channels in the orbit- superior and inferior ophthalmic veins
forms from the supraorbital and angular veins
superior ophthalmic vein
can either leave the orbit on its own, join the inferior ophthalmic or connect to the pterygoid plexus
infraorbital
innervates many of the extrinsic eye muscles
oculomotor
innervates the superior rectus and levator palpebrae superioris
superior branch of oculomotor
innervates medial and inferior rectus and inferior oblique
inferior branch of oculomotor
innervates the superior oblique
trochlear nerve (IV)
passes through the trochlear notch before turning laterally toward the eye
superior oblique
gives rise to the nasociliary, frontal, lacrimal nerves
ophthalmic nerve (V1)
innervates the lacrimal gland
lacrimal nerve
innervates the conjunctiva, skin of upper eyelid, parts of the forehead, and middle of scalp
frontal nerve
innervates the pupil, ethmoidal cells, sphenoid sinus, upper and lower lids, lacrimal sac, skin of nose, anterior cranial fossa, nasal cavity, skin of nose
nasociliary nerve
