Head anatomy Flashcards
What is a Blow Out fracture
‘Blowout’ fracture – This refers to partial herniation of the orbital contents through one of its walls. This usually occurs via blunt force trauma to the eye. The medial and inferior walls are the weakest, with the contents herniating into the ethmoid and maxillary sinuses respectively.
The oculomotor nerve receives branches from the internal carotid plexus as it travels through the cavernous sinus.
Which modality are these nerve fibres?
The internal carotid plexus is formed by sympathetic nerve fibres.
What bone does the cribriform plate belong to
The cribriform plate is part of the ethmoid bone.
Where does the vagus nerve pass through in the Skull
The vagus nerve passes through the jugular foramen to leave the cranial cavity.
In a scalp laceration, the resting tone of which muscle inhibits closure of the bleeding vessel and surrounding skin?
Occipitofrontalis
Where does the facial nerve divide into the five terminal motor branches?
Parotid gland
The mastoid fossa is an anatomical landmark for which structure during middle ear surgery?
Mastoid antrum
Which bones contribute to the calvarium of the skull
The calvarium forms the roof of the skull and is comprised of the frontal, occipital and two parietal bones.
Which is the nerve that is most likely to be damaged during a cortical mastoidectomy
The facial nerve travels in close proximity to the middle ear and is most likely to be damaged during a cortical mastoidectomy
Which part of the occipital bone contains the hypoglossal canal?
Condylar part
TM anatomy
Which embryological structure do the muscles of mastication develop from?
The muscles of mastication are derived from the 1st pharyngeal arch.
Where do the post-ganglionic fibres to the lacrimal gland originate?
The post-ganglionic fibres to the lacrimal gland originate from the pterygopalatine ganglion.
Which muscle aids in pulling the cheeks inwards against the teeth and thereby prevents accumulation of food that area?
Buccinator - This is supplied by the buccal bracnh of the facial nerve
The tensor tympani muscle of the middle ear is responsible for the afferent arm of the acoustic reflex.
Which nerve innervates the tensor tympani muscle?
The tensor tympani originates from the auditory tube and attaches to the handle of malleus, pulling it medially when contracting. It is innervated by the tensor tympani nerve, a branch of the mandibular nerve
Fibres from which spinal nerve root(s) accompany the hypoglossal nerve after exiting the cranial cavity?
C1C2
Through which foramina does the trochlear nerve enter the bony orbit?
Superior orbital fissure
Which nerve provides sensory innervation to the lacrimal gland?
The lacrimal nerve and this is a branch of the ophthalmic nerve
Which nerve innervates the buccinator muscle?
Buccal branch of the facial nerve
WHat are the paired and unpaired bones of the nasal septum
The ethmoid and vomer bones are the unpaired bones of the nasal septum. The paired bones are the nasal, maxillary and palatine.
Which nerve innervates the masseter muscle
The masseter muscle is innervated by the mandibular nerve, a branch of the trigeminal nerve
Which nerve innervates the inferior oblique muscle?
Oculomotor
What are the spinal roots of the accessory nerve
The spinal accessory nerve innervates the trapezius and sternocleidomastoid muscles. It arises from cervical nerve roots C1-5.
What is the name given to the thin, tendon-like structure that connects the occipitalis and frontalis muscles?
Epicranial aponeurosis
Describe the movements of the TMJ joint
The lateral pterygoid muscle is responsible for protrusion (assisted by the medial pterygoid), and the posterior fibres of the temporalis perform retraction. Elevation is very strong movement, caused by the contraction of the temporalis, masseter, and medial pterygoid muscles. Depression is mostly through gravity
What is the neurovascular supply of the TMJ
External carotid, principally the superficial temporal branch. Other contributing branches include the deep auricular, ascending pharyngeal and maxillary arteries.
The TMJ is innervated by the auriculotemporal and masseteric branches of the mandibular nerve (CN V3).
What nerves are at risk in the event of anterior dislocation of the TMJ
The patient becomes unable to close their mouth. The facial and auriculotemporal nerves run close to the joint and can be damaged if the injury is high-energy.
Temporal bone fracture
The facial nerve passes through the temporal bone and hence motor function is likely to be compromised as a result of fracture
What surrounds the optic nerve?
Cranial meninges
What is the sagittal sulcus
Sagittal sulcus – vertical groove in the midline of the frontal bone. It contains the superior sagittal sinus.
Which facial fractures are the most common
Nasal
Greater wing of the sphenoid process
There are three foramina present in the greater wing – the foramen rotundum, foramen ovale and foramen spinosum. They conduct the maxillary nerve, mandibular nerve and middle meningeal vessels respectively.
The TMJ joint has which type of cartilage
Fibrocartilage
Abducens nerve path
It then enters the subarachnoid space and pierces the dura mater to travel in an area known as Dorello’s canal.
At the tip of petrous temporal bone, the abducens nerve leaves Dorello’s canal and enters the cavernous sinus (a dural venous sinus). It travels through the cavernous sinus and enters the bony orbit via the superior orbital fissure.
How would you distinguish between a stye and a chalazion
A chalazion is a painless granuloma of the Meibomian glands. It can be distinguished from a stye by the absence of pain in a chalazion, whereas styes are normally painful.
Cranial nerves leaving the brainstem
1,2 - cerebrum
4 - midbrain
3 - midbraine and pons junction
5-8 pons (lateral pons is 5,7,8 and medial is 6)
9-12 medulla
In a TMJ joint dislocation, which nerve is at the greatest risk
Auriculotemporal
Submandibular gland and relationship with nerves
Relationship with Nerves
Both the submandibular gland and duct share an intimate anatomical relationship with three principal nerves; the lingual nerve, hypoglossal nerve and facial nerve (marginal mandibular branch). The courses of these nerves are briefly outlined:
Lingual nerve: Beginning lateral to the submandibular duct, this nerve courses anteromedially by looping beneath the duct and then terminating as several medial branches. The terminal branches ascend on the external and superior surface of hypoglossus to provide general somatic afferent innervation to the mucus membrane of the anterior two-thirds of the tongue.
Hypoglossal nerve: Lies deep to the submandibular gland and runs superficial to the hyoglossus and deep to the digastric muscle.
The facial nerve (marginal mandibular branch): Exits the anterior-inferior portion of the parotid gland at the angle of the jaw and traverses the margin of the mandible in the plane between platysma and the investing layer of deep cervical fascia curving down inferior to the submandibular gland.
How is the superior oblique muscle attached to the frontal bone
The superior oblique muscle itself does not attach to the frontal bone – instead, it passes through a cartilaginous pulley (trochlea) which diverts the direction of pull for this muscle. This trochlea is what is attached to the frontal bone.
The cartilage of the external nose and nasal septum
hyaline cartilage.
site of origin of the medial and lateral pterygoid muscles
Lateral pterygoid plate
Lacrimal gland supply
The main arterial supply to the lacrimal gland is from the lacrimal artery, which is derived from the ophthalmic artery – a branch of the internal carotid.
Venous drainage is via the superior ophthalmic vein, and ultimately empties into the cavernous sinus.
Lymphatic drainage is to the SUPERFICIAL PAROTID lymph nodes. They empty into the superior deep cervical nodes
The spinal part of the accessory nerve arises from which spinal segments?
C1 - C5/C6
It descends through the jugular foramen and the ascending is through foramen magnum
Which nerve does not arise from the brain itself
Accessory nerve
Where does the nasolacrimal duct drain
Inferior meatus, the ET also drains here
What drains into the middle meatus of the nose
The paranasal sinuses drain into the nasal cavity. The frontal, maxillary and anterior and middle ethmoidal sinuses open into the middle meatus.
It also contains bullae ethimoidalis
What happens to the ET when swallowing
Opens thanks to tensor and salphinogophyrangeus muscles
What drains into the superior meatus of the nose
Post ethmoidal air cells
TM anatomy, fascial nerve relations
Outer layer of stratified squamous epithelium.
Middle layer of fibrous tissue.
Inner layer of mucous membrane continuous with the middle ear.
The tympanic membrane is approximately 1cm in diameter.
The chorda tympani nerve passes on the medial side of the pars flaccida.
The middle ear is innervated by the glossopharyngeal nerve and pain may radiate to the middle ear following tonsillectomy.
Paediatric fractures
Paediatric fracture types
Complete fracture Both sides of cortex are breached
Toddlers fracture Oblique tibial fracture in infants (AS INFANTS CRAWL)
Plastic deformity Stress on bone resulting in deformity without cortical disruption
Greenstick fracture Unilateral cortical breach only (Unilateral)
Buckle fracture Incomplete cortical disruption resulting in periosteal haematoma only (HAEMATOMA ONLY)
Which structure attaches the inferior aspect of the tongue to the oral mucosa?
Frenulum
Orbital emphysema is caused by fracture of the ethmoid bone at which site?
Labrynth
Which structure is the embryonic precusor to the muscles of facial expression?
2nd phyrangeal arch
The spinal part of the accessory nerve arises from which spinal segments?
C1 - C5/C6
Which of the following types of facial fracture would be most likely to damage the infraorbital nerve?
Zygomatic arch
The olfactory mucosa is lined by which type of epithelium?
Pseudostratified columnar
Which nodes receive the majority of lymphatic drainage from the lacrimal gland?
Superficial parotid
Which type of tooth is only present in the permanent dentition?
Pre-molar
The tensor tympani muscle of the middle ear is responsible for the afferent arm of the acoustic reflex.
Which nerve innervates the tensor tympani muscle?
Tensor tympani nerve that is a branch of the mandibular nerve
Which part of the mandible characteristically fractures obliquely?
The angle of the mandible
How many sensory nuclei does the trigeminal nerve arise from?
Three
Which type of cartilage lines the articular surfaces of the temporomandibular joint?
Fibrocartilage
Fibres from which spinal nerve root(s) accompany the hypoglossal nerve after exiting the cranial cavity?
C1 and C2
Which structure lies between the vestibule of the inner ear and the middle ear?
The oval window lies between the middle ear and the vestibule, whilst the round window separates the middle ear from the scala tympani.
OVALLEE - VESTIBJULAAAE
ROUND - SCALA
Which muscle attaches to the coronoid process of the mandible?
Temporalis
Which sympathetic cervical ganglion is associated with the cardiac plexus?
The superior, middle and inferior cervical ganglia each contribute a branch to the cardiac plexus.
Which nerve provides general sensory innervation to the parotid gland?
The auriculotemporal nerve also contributes to the parasympathetic supply to the parotid gland.
The pre-ganglionic parasympathetic fibres that supply the sublingual gland originate from which nucleus?
Superior salivatory nucleus
Which nerve provides innervation to the area of scalp behind the pinna?
The lesser occipital nerve is derived from the anterior rami (division) of C2 and supplies the skin behind the pinna. The auriculotemporal nerve innervates the skin anterosuperior to the pinna.
Which type of tooth is most at risk from traumatic dental injury?
Incisors
Where in the eyelid do the Meibomian glands lie?
Tarsal plate
What is the epithelial covering of the superior aspect of the hard palate?
Pseudostratified ciliated columnar
What type of cartilage is the cartilage of the nose and nasal septum?
Hyaline cartilage
Where do the vestibulocochlear nuclei originate?
The vestibular component arises from the nuclei in the pons and medulla and the cochlear nuclei are in the inferior cerebellar peduncle
What are the unpaired bones of the nasal septum
Unpaired bones: Ethmoid and vomer bones.
Hard palate cells
The hard palate is covered superiorly by respiratory mucosa (ciliated pseudostratified columnar epithelium) and inferiorly by oral mucosa (stratified squamous epithelium).
Which cervical ganglion is associated with the innervation of the superior tarsal muscle?
Superior cervical ganglion
Which cervical ganglion is associated with the sympathetic innervation of the trachea?
Middle cervical ganglion
What is the parasympathetic innervation of the parotid gland
The glossopharyngeal nerve provides parasympathetic innervation to the parotid gland. These fibres originate in the inferior salivatory nucleus of CN IX. These fibres travel with the tympanic nerve to the middle ear. From the ear, the fibres continue as the lesser petrosal nerve, before synapsing at the otic ganglion.
The fibres then hitchhike on the auriculotemporal nerve to the parotid gland, where they have a secretomotor effect.
What is the difference between the superior and inferior salivatory nucleus
Superior - Supplies pterygopalatine ganglion and submandibular ganglion hence CN7 stuff such as submandibular glands, lacrimal glands and palate
Inferior - Supplies otic and hence CN9 stuff and hence parotid
What is a ranula
Ranulas can be caused by trauma to the delicate sublingual gland ducts causing them to rupture, with mucin then collecting within the connective tissues to form a cyst.
Which of the middle ear bones is the largest
The malleus is the largest
What is the cochlea held in place by
The cochlear duct is located within the bony scaffolding of the cochlea. It is held in place by the spiral lamina.
Where is the organo of corti
The basilar membrane houses the epithelial cells of hearing – the Organ of Corti
Through which bone does the ICA enter the intracranial cavity
ICA
Why does cleft lip occur
Incomplete closure of the maxillary and/or frontonasal processes. Cleft palate occurs when there is a fusion of the primary and secondary palate. It can be associated with cleft lip
What is thyroid tissue in the foramen cecum known as
Lingual thyroid
Which muscle can be palpated in the jaw when the teeth are clenched?
Masseter
Which muscle elevated the eyebrows in a look of surprise
Occipitofrontalis
What is bregma
Anterior fontanelle
What is Glabella
the smooth part of the forehead above and between the eyebrows.
Where does the nasolacrimal duct pass-through
The nasolacrimal canal
How is aqueous humour reabsorbed
Ciliary veins via canal of schlemm
What are the layers of the tympanic membrane
Outer strat squam
middle fibrous
Inner mucus
Why do tongue cancers spread B/L
Extensive communication between the 2 sides
Submandibular gland excision pointers
Superficial
Platysma
Cervical branch of FN
MMN
facial VEIN
Deep
Hypoglossal and lingual nerve
The lingual nerve double-crosses the duct, it passes lateral, below and then medial to it. (basically what the median nerve does to the brachial artery)
To avoid the MMN, make an incision 2.5cm deep to the angle of the mandible.
What is the lymphatic drainage of the auricle?
Superficial cervical nodes
Which nerve is most affected in a parotidectomy
Greater auricular nerve
What is the supply to the angle of the jaw
Greater auricular nerve
Which artery liest posterolaterally to the external carotid at the point of it’s origin
Internal carotid
FACT
The middle meningeal artery is a branch of the maxillary artery
Which are the branches of the external carotid artery and how do they lie
3 from the anterior surface: Thyroid, lingual and facial
1 medial: Phyrangeal
2 posterior: Posterior auricular and occipital
Which muscle is penetrated by the parotid gland
Buccinator
What is the lymph node drainage of the lacrimal gland?
Superficial parotid lymph nodes
Orbital emphysema is caused by fracture of the ethmoid bone at which site?
The labyrinth
In a minor whiplash injury, which ligament of the spine is affected?
Ant long
Which artery comes off medially from the external carotid
Ascending pharyngeal
Which artery comes off and sits near the angle of the mandible
Facial artery
The middle meningeal artery and the auriculotemporal nerve
The middle meningeal artery is intimately associated with the auriculotemporal nerve which wraps around the artery making the two easily identifiable in the dissection of human cadavers and also easily damaged in surgery.
Which vessel lies in close proximity to the auditory opening of the Eustachian tube?
ICA
