H&N anatomy wk 3 (special senses) Flashcards
7 bones that form the orbit
Ethmoid (lamina papyracea of) Frontal Sphenoid (lesser & greater wings, and body) Maxilla (orbital surface of) Zygomatic (orbital process of) Lacrimal Palatine (orbital process of)
Name the 3 foramina at the apex of the orbit
Optic foramen
Superior orbital fissure
Inferior orbital fissure
What 2 things pass through optic foramen
Optic nerve
Ophthalmic artery
What 5 things pass through the superior orbital fissure
CN III CN IV CN VI (abducens) CN V1 (ophthalmic division) Ophthalmic veins
What 1 thing passes through the inferior orbital fissure
CN V2 (maxillary division)
Name the 3 paranasal air sinuses that lie adjacent to the orbit
Frontal
Maxillary
Ethmoidal
Name the 7 contents of the orbit
Eyeball Extrinsic ocular muscles Intrinsic ocular muscles Ligaments supporting the eye CN II Ophthalmic artery (branch of ICA) and its branches Lacrimal apparatus Orbital fat - cushions globe
What is the ophthalmic artery a branch of
ICA
Clinical significance of paranasal air sinuses lying close to the orbit
Can spread infection into the orbit such as orbital cellulitis
Name the 3 layers of the eyeball
Outer fibrous layer
Middle vascular layer (urea)
Inner sensory layer
What 2 things makes up the outer fibrous layer of the eyeball + is this layer complete 360
Sclera (posterior 5/6)
Cornea (anterior 1/6)
Complete layer
What 3 things makes up the middle vascular layer of the eyeball + is this layer complete 360
Choroid
Ciliary body
Iris
Incompletely anteriorly due to aperture in the iris = pupil
What makes up the inner sensory layer of the eyeball + is this layer complete 360
Retina
Present posteriorly and stops just in front of equator of the eye at the ORA SERRATA
The crystalline lens divides the eyeball into what 2 things
Anterior and posterior segment
Anterior segment anterior to the lens
Anterior segment contains what
AH (watery fluid)
Posterior segment contains what
VH (gel-like substance)
Function of vitreous humor
Cushions the retina
Anterior segment further subdivided into what 2 things
Anterior and posterior chamber
- anterior chamber in front of iris
- posterior chamber behind iris but in front of lens
2 functions of ciliary body
Suspends the lens via zones
Secretes AH
What is the ora serrata - google this
Anterior end of retina?
What chamber is AH secreted into first
Posterior chamber
Name the 3 intrinsic muscles of the eye
Ciliaris
Constrictor/sphincter pupillae
Dilator pupillae
Location of the ciliaris muscle
In the ciliary body
Location of the constrictor/sphincter pupillae
Pupillary border of iris (the circular edge of the iris)
Location of the dilator pupillae
Radially arranged in the iris (like the spokes of a wheel radiating from the pupil)
Function of the ciliaris
Accommodation (changes the shape of the lens to allow us to focus on near objects from far objects)
Function of constrictor pupillae
Decrease pupil diameter
Function of dilator pupillae
Increase pupil diameter
Innervation of ciliaris
Parasympathetic fibres of CN III
Innervation of constrictor pupillae
Parasympathetic fibres of CN III
Innervation of dilator pupillae
Sympathetic fibres from sympathetic plexuses running along blood vessels
General function of intrinsic muscles v extrinsic ocular (extra-ocular) muscles
Intrinsic - change size of pupil and shape of lens
Extrinsic - eye movements, i.e. moving the eyeball
Name the 6 UNIOCULAR eye movements
Elevation Depression Abduction Adduction Intorsion Extorsion
Name the extrinsic muscles of the eye
Superior rectus Inferior rectus Lateral rectus Medial rectus Superior oblique Inferior oblique
Additional muscle of the eye sometimes considered as an extrinsic muscle but not technically because it doesn’t move the eyeball+ its function
Levator palpebrae superioris (LPS)
Elevates upper eyelid
Innervation of extrinsic muscles of the eye
SO - CN IV
LR - CN VI
Everything else CN III
Where do the recti muscles insert onto
Anterior sclera
Where do the oblique muscles of the eye insert onto
Posterior sclera
What is intorsion + extorsion
+ when does it occur
Intorsion - when the eye rotates towards (medially)
Extorsion - when the eye rotates away (laterally) from the nose
Only occurs when you tilt your head
Primary/secondary/tertiary actions of the superior rectus
Primary - elevation
Secondary - adduction
Tertiary - intorsion
Primary/secondary/tertiary actions of the inferior rectus
Primary - depression
Secondary - adduction
Tertiary - extorsion
Name the 6 BINOCULAR eye movements (moving as a pair)
Dextroelevation - up and right
Dextrodepression - down and right
Dextroversion - both to the right (so abduction of right eye and adduction of left)
Levoelevation - up and left
Levodepression - down and left
Levoversion
Primary action of medial rectus (no secondary or tertiary actions)
Adduction
Primary action of lateral rectus (no secondary or tertiary actions)
Abduction
Primary/secondary/tertiary actions of the superior oblique
Primary - intorsion
Secondary - depression
Tertiary - abduction
Primary/secondary/tertiary actions of the inferior oblique
Primary - extorsion
Secondary - elevation
Tertiary - abduction
Common action of superior and inferior obliques
Abduction
Common action of superior and inferior recti
Adduction
Origin of the recti muscles of the eye
Common tendinous ring at the apex of the orbit
Origin of the superior oblique muscle
From roof of orbit posteriorly
Origin of inferior oblique muscle
From medial floor of orbit anteriorly
Which is the only extrinsic eye muscle that doesn’t arise posteriorly
Inferior oblique
What ligaments prevent over-adduction/abduction of the eye
Medial and lateral check ligaments - attached to lacrimal and zygomatic bones respectively
Function of suspensory ligament of eye
Connects the ciliary body to the lens
Arterial supply of the orbit and eye
Ophthalmic artery (branch of ICA) and its branches
Are there lymphatic vessels in the orbit
No
Function of lacrimal gland
Secretes lacrimal fluid (tears)
Innervation of lacrimal gland
Parasympathetic fibres of CN VII
Position of lacrimal gland
Lateral roof of orbit
External ear consists of (2)
Pinna and EAC
Middle ear consists of (4)
Tympanic membrane
Tympanic cavity containing:
Ossicle - malleus, incus & stapes
Epitympanic recess
Inner ear consists of what 2 chambers + what are these chambers made up of
Bony labyrinth - bone lined chambers:
- consists of the cochlea, vestibule and 3 semi-circular canals
Membranous labyrinth (lies within bony labyrinth): -consists of the cochlear duct, semi-circular ducts, utricle and saccule
What joints are found between the components of the ossicle
Synovial
Which part of the ossicle is in contact with tympanic membrane
Malleus - head of the malleus
Which part of the ossicle is in contact with the oval window of the inner ear
Stapes - footplate of the staples
2 muscles associated with the ossicles (muscles of the middle ear)
Tensor tympani
Stapedius (smallest muscle in the body, not visible)
Name the parts of the pinna (auricle) (5)
Helix Antihelix Lobule Tragus Antitragus
Function of tensor tympani
Tenses the tympanic membrane by pulling the malleus medially, to reduce vibration of the ossicles and therefore dampen sound
Function of Stapedius
Reduces vibration of the ossicles and therefore dampen sound by stabilising the stapes bone so it doesn’t move around excessively
Function of tympanic membrane
When sound waves enter ear, they hit the tympanic membrane which vibrates it, it transmits these vibrations to the ossicle attached to it
Sensory innervation of the pinna and EAC
CN VII
2 areas that the tympanic cavity of the middle ear communicates with
Nasopharynx Mastoid antrum (cavity in mastoid process)
Which bone (be specific) does the middle and inner ear lie in
Petrous part of temporal
What fluid lies in the bony labyrinth
Perilymph
What fluid lies in the membranous labyrinth
Endolymph
Function of the cochlea + semi-circular canals (inner ear)
Hearing + balance respectively
Describe the intracranial course of the facial nerve
Emerges from pontomedullary junction then exits posterior cranial fossa from the internal auditory meatus –> passes into the facial canal in the petrous temporal bone –> extends inferiorly and laterally to exit at the stylomastoid foramen
What foramen does CN VII exit in the cranial fossa + what other CN exits at this fossa
Internal acoustic meatus
CN VII
Where is the facial canal located into the tympanic cavity
Medial wall
What branch does CN VII give off in the middle ear + what fibres does this branch contain
Chorda tympani
Parasympathetic efferent fibres to the submandibular and sublingual salivary glands
Special sensory fibres to the anterior 2/3 of tongue for TASTE
Damage to facial nerve in middle ear can cause hyperacusis because
Hyperacusis - increased sensitivity to everyday sounds that are not usually a problem
Chorda tympani branch innervates stapedius so loss of stapedius function –> less dampening of sound –> normal sounds perceived louder
Innervation of tensor tympani
CN V3
Innervation of Stapedius
Chorda tympani
Innervation of inner ear
CN VIII
Cochlear branch of CN VIII innervates cochlea
Vestibular branch of CN VIII innervates semi-circular canals
Small lymphatic capillaries in the head & neck first drain into …… then from these, lymph drains into ……, then from these ultimately into the …
Regional lymph nodes
- -> Deep cervical lymph nodes
- -> IJV
Deep cervical lymph nodes are a linked chain of nodes found where (2)
Around the IJV and within the fascia of the carotid sheath
Where are the jugular lymph trunks + what joins to make these trunks
At the inferior end of the deep cervical chain nodes
Efferent lymphatic vessels joining together
Where do efferent lymphatics from the right jugular lymph trunk drain into
Right lymphatic duct –> Right brachiocephalic
Where do efferent lymphatics from the left jugular lymph trunk drain into
Thoracic duct –> L brachiocephalic
Name the regional groups of lymph nodes in the FACE + SCALP (6)
Parotid Buccal Submental Submandibular Mastoid - overlie mastoid process Occipital - overlie occipital process
Areas that the parotid lymph nodes drain (3)
- just think of what’s around parotid gland
Around parotid gland
Lateral parts of eyelid
Middle ear
Area that the buccal lymph nodes (over the buccinator) drain (1)
Cheek region
Areas that the submental lymph nodes (under mandible) drain (2)
- just think of what’s around submental lymph nodes
Anterior tip of tongue
Central part of floor of mouth + chin
Areas that the submandibular lymph nodes drain (9)
- just think of what’s around submandibular lymph nodes
Front of scalp Nose, lips Air sinuses - ethmoidal, frontal, maxillary Teeth, gums Anterior tongue Floor of mouth Lymph from submittal nodes
Areas that mastoid lymph nodes drain (2)
Middle region of scalp
EAC
Area that the occipital lymph nodes drain (1)
Back of scalp
Name the groups of lymph nodes in the NECK (5)
Anterior cervical Superficial cervical Retropharyngeal Laryngeal Tracheal
Location of the anterior cervical lymph nodes
Along the anterior jugular VEINS
Location of the superficial cervical lymph nodes
Along the external jugular vein
Location of the retropharyngeal lymph nodes
Between the pharynx and the vertebral bodies
Location of the laryngeal lymph nodes
Around the cricothyroid ligament in the larynx
What do the anterior cervical lymph nodes drain
Superficial structures of the anterior neck
What do the superficial cervical lymph nodes drain (3)
Parotid lymph nodes
Angle of mandible
Structures that lie at the junction between neck, face and scalp
What do the retropharyngeal lymph nodes drain (3)
Nasopharynx
Eustachian tube
Upper cervical vertebral column
What do the laryngeal lymph nodes drain (2)
Larynx and adjacent structures
What do the tracheal lymph nodes drain (2)
Trachea
Thyroid gland
Name the lymph node that lies at the junction of the internal jugular and common facial veins + what level lymph node is this
Jugulodigastric (tonsillar) node
Level II
What lymph node enlarges in tonsillitis (commonest lymph node to enlarge in neck)
Jugulodigastric (tonsillar) node - level II
Block dissection of the neck for tumours requires removal of lymph nodes in what regions
Lymph nodes of the anterior and posterior triangles and their associated lymph channels
Name the 3 cranial fossa
Anterior, middle, posterior
What bone forms posterior boundary of anterior cranial fossa
Sphenoid (greater wing)
Which bones form the floor of the middle cranial fossa
Sphenoid and temporal (Squamous AND petrous parts)
Which bone forms the posterior border of the middle cranial fossa
Temporal
Which 4 bones come together to form the pterion
Frontal
Parietal
Temporal
Sphenoid (Greater wing)
Which bones forms the anterior and posterior border of the posterior cranial fossa
Anterior - petrous temporal bone + dorsum sellae of sphenoid
Posterior - occipital
Foramen in the anterior cranial fossa (1)
Foramina of cribriform plate
Foramina in the middle cranial fossa (7)
Optic foramen Superior orbital fissure Foramen rotundum Foramen ovale Foramen spinosum Foramen lacerum Carotid canal
Foramina in the posterior cranial fossa (4)
Internal acoustic foramen
Jugular foramen
Hypoglossal foramen
Foramen magnum
Structure passing through foramina of cribriform plate
Olfactory nerve
Structures passing through optic foramen (2)
Optic nerve
Ophthalmic artery
Structures passing through superior orbital fissure (5)
Ophthalmic veins
CN III, IV, VI
CN V1
Structure passing though foramen rotundum (1)
CN V2
Structures passing through foramen ovale (2)
CN V3
Accessory meningeal artery
Structures passing through foramen spinosum (3)
Middle meningeal artery + vein
Meningeal branch of CN V3
Structures passing through foramen lacerum (3)
ICA (lies on top of it, doesn’t actually traverse it)
Sympathetic and venous plexuses accompanying the ICA
Structures passing through carotid canal (2)
ICA
Sympathetic plexus
Structures passing through internal acoustic foramen (2)
CN VII
CN VIII
Structures passing through jugular foramen (6)
CN IX CN X CN XI IJV Inferior petrosal + sigmoid sinuses?
Structure passing through hypoglossal foramen (1)
CN XII
Structures passing through foramen magnum (3)
Medulla + meninges
2 Vertebral arteries
Spinal part of accessory nerve
What are the intra-cranial venous blood sinuses found between
Inner (dura proper) and outer layer (periosteum of inside face of skull bone) of dura mater
What 2 things lie in the grooves in the floor of the skull
Arteries or
Intra-cranial venous blood sinuses
What artery lies in the groove lateral to the foramen spinosum
Middle meningeal artery
What artery supplying the brain is commonly damaged in injuries such as a blow to the head + why
Middle meningeal artery
What prevents extradural haemorrhages (between periosteum of skull and dura mater) from spreading over a wider area/being restricted to a lens shaped area
The attachment of dura at the sutures of the skull
What runs in the grooves lateral to the internal occipital protuberance
Transverse sinus
What does the transverse sinus continue on as
S- shaped sigmoid sinus
Transverse sinus –> sigmoid sinus –> what foramen
Jugular foramen
What is the sella turcica
Deep depression in the midline of the middle cranial fossa housing the pituitary gland
Which bone is the sella turcica part of
Sphenoid
Sella turcica is anteriorly, inferiorly and posteriorly composed of
Anterior - Tuberculum sellae
Inferior - Pituitary (hypophyseal) fossa
Posterior - Dorsum sellae
Name the 4 processes on anterior and posterior of the sella turcica
2 Anterior and 2 posterior clinoid processes
Which fold of dura attaches to the clinoid processes
Tentorium cerebelli
What lies in the grooves lateral to the sella turcica
Cavernous sinus
Which foramen lies immediately anterior to the groove for the cavernous sinus
Superior orbital fissure
Most structures that pass through the superior orbital fissure (i.e. CN III/IV/VI etc) actually pass within what sinus
Cavernous sinus
What sinus lies in the groove in the midline of the inner surface of the skull cap
Superior saggital
Bones that make up the base of the skull
Palatine process of maxilla Palatine bone Vomer Parts of temporal bone Parts of occipital bone Parts of sphenoid bone - medial and lateral pterygoid plates, pterygoid hamulus
What is the pterygoid hamulus
Most inferior part of the medial pterygoid plate, forming a hook like process
Muscle that attaches to the medial pterygoid plate
Superior pharyngeal constrictor
Muscles that attach to the lateral pterygoid plate
Medial pterygoid muscle attaches to medial surface of lateral pterygoid plate
Lateral pterygoid muscle attaches to the lateral surface of the lateral pterygoid plate
2 advantages of neonate having flexible skull
Allows for compression of skull during childbirth
Allows brain to grow + expand during infancy
Disadvantage of neonate having flexible skull
Brain could get damaged through breakage of the fontanelles if you fall
Type of ossification that occurs in flat bones of the skull
Membranous
Type of ossification that occurs in irregular bones of the base of the skull
Endochondrial
How many teeth do adults v child have
32
20
Name differences between adult and foetal skulls (3)
Babies have fontanelles
32 teeth in adults, 20 in children
Babies don’t have styloid or mastoid process yet
What age range does the anterior fontanelle fuse
18-24 months
What age range does the posterior fontanelle fuse
2-3 months
Another name for C1
Atlas
What epithelium lines dorsal surface of tongue
Stratified squamous keratinised
What type of muscle fibres lie under epithelium of tongue
Skeletal
Name the 3 paired salivary glands
Parotid
Sublingual
Submandibular
What is the rounded secretory component of a gland called, not just salivary gland
Acinus
Serous acini secrete what type of secretion + describe the stain
Protein rich secretion so strain strongly with H&E stain
Mucous acini secrete what type of secretion + describe the stain
Glycoprotein mucous so stain poorly (pale) with H&E stain
What cells line the acinus of salivary glands + function of these cells
Myoepithelial cells
To help squeeze the contents of the salivary duct out
What type of secretion does parotid gland secrete + describe its stain
Predominantly serous so strongly stained
What type of secretion does submandibular gland secrete + describe its stain
Mixed serous and mucous so both dark + pale staining seen
What type of secretion does sublingual gland secrete + describe its stain
Predominantly mucous so pale staining
Name 4 conditions where a clinical sign can be seen at the anterior fontanelle in an infant
Hydrocephalus
Raised intracranial pressure
Meningitis
Dehydration