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
