Head and Neck (SEM 2) Flashcards
how many bones in the skull and how many teeth
22 bones
32 teeth
cranial fractures
The convexity of the cranial vault distributes and there by minimizes the effects of a blow to it.
Linear cranial fractures, the most frequent type,
(usually occur at the point of impact, but other fracture lines often radiate away from it)
mandible fractures
usually involves two fractures that occur on opposite sides (butterfly fracture).
gomphosis joint
teeth and mandible
fibrous joint
temporomandibular joint type
synovial joint (modified-hinge type)
masseter
lateral and medial pterygoid
all innervated by mandibular nerve (3rd branch of trigeminal)
masseter(superficial and deep)
- elevation
- zygomatic arch–>angle of mandible ramus
- masseteric nerve
lateral pterygoid(superior and inferior head)
- depression(opening jaw)
- protusion and side to side with medial
- inserts: condyle of mandible/TMJ
medial
- elevation and protrusion(forward)
- inserts: medial(inner) surface of angle of ramus
where does temporalis muscle insert and innervation
coronoid process of mandible
temporal nerve of facial
excessive contraction of the lateral pterygoid muscles
may cause the heads of the mandibles to dislocate anteriorly, by passing anterior to the articular tubercles.
In this position, the mandible remains depressed and the person may not be able to close their mouth
TMJ degenerative arthritis
joint may lead to abnormal function and result instructural problems such as dental occlusion, and joint clicking (crepitus).
Orbicularis oculi
2 parts
orbital obicularis
palpebral orbicularis
- action: closes eyelids
- temporal/zygomatic branches of facial
list the facial muscles (muscles for facial expressions)
- frontal belly of occiptovfrontalis
- orbicularis oculi (orbital+palpebral parts)
- procerus
- buccinator
- nasalis (transverse + alar)
- orbicularis oris
- levator labii superioris
- Levator labii superioris alaque nasi
- Zygomaticus minor
- Risorius
- Zygomaticus major
- Depressor labii inferioris
- Depressor anguli oris
what does the facial artery branch from and where does the facial vein empty into
artery from external carotid
vein into internal jugular
what vein joins the facial vein to the cavernous sinus
superior ophthalmic vein
clinical: spread of infection and danger triangle
facial vein - superior ophthalmic vein - cavernous sinus
inferior opthalmic vein - pterygoid venous plexus - deep facial veins
no valves between them so blood from face may enter the sinus
can use sinus thrombosis/meningitis/ brain abscess
maxillary artery
branch of external carotid
divided into 3 parts by lateral pterygoid muscle
5 branches in each part
2nd part - supplies muscles
1st part -middle meningeal artery
what cranial fossa does the middle meningeal artery enter the skull
foramen spinosum
what artery from maxillary artery enters the mandibular foramen to supply teeth
and what branch does it give off before it enters the foramen
inferior alveolar artery (from 1st part)
mylohyoid artery
what can damage to the middle meningeal artery cause
extradural haematoma
what nerve in the floor of the mouth could be damaged during dental surgery
lingual nerve (branch of mandibular nerve)
supplies tongue
what nerve do dentists anaesthetise before removing mandibular teeth
inferior alveolar nerve
Because the mental and incisive nerves are its terminal braches, the chin and lower lip of the affected side also lose sensation
what is weakness/paralysis of facial nerve called
what is the most common non-traumatic cause of facial paralysis
Bell’s palsy
inflammation of the facial nerve near the stylomastoid foramen
causes facial asymmetry, an inability to whistle, blow a wind instrument, or chew effectively.
what can higher lesions of cn vii cause
lead to loss of taste over anterior 2/3 tongue
nerve that exits stylomastoid foramen
facial nerve
what fossa does the facial nerve exit the cranial fossa
internal auditory meatus —> facial canal
Viral infection related to parotid gland that children receive vaccination
Mumps
pain is often worse during chewing
what pierces through parotid gland
all branches of facial nerve
external carotid artery
retromandibular vein
4 extrinsic muscles of tongue
which one is not supplied by the hypoglossal nerve
genioglossus
-protusion and depression
hyoglossus
-retraction and depression of sides
styloglossus
-retraction and elevation
palatoglossus(innervated by pharyngeal branch of vagus)
-elevation of posterior part
adenoidectomy
enlargement of adenoids –> removal (usually children)
adenoids = pharyngeal tonsils
in nasopharynx
Quinsy
inflammation of throat
especially abscess in region of palatine tonsils
Little’s Area (Kiesselbach’s triangle)
An area on nasal septum where branches of facial, maxillary and ophthalmic arteries anastomose
Common site for nose bleeds (Kiesselbach’s plexus)
which branch of the internal carotid artery enters the optic canal and what does it supply
ophthalmic artery
eye/extraocular muscles/eyelids/optic nerve
nose and forehead
function of sinuses
resonant voice
Reduce weight of skull
Help humidify and warm inspired air
Infection of ethmoid air cells and what can be caused if severe
due to blocked drainage of the sinuses
blindness as some posterior ethmoidal cells lie close to the optic nerve/artery
what surgery can be performed through the nose (Trans-sphenoidal surgery)
to remove tumours of the hypophysis gland
how could you fracture laryngeal skeleton and what outcomes are likely to arise
sports eg. hockey/kickboxing
car accident eg. seatbelts
SUBMUCOUS haemorrhage
respiratory obstruction, hoarsenes, and sometimes a temporary inability to speak
why are maxillary sinuses commonly infected
because of the high location of the opening of maxillary sinus, when the head is erect, it is impossible for the sinuses to drain until they are full
Their position on the medial side of the sinus allows only the upper sinus to drain
Ie. The right sinus drains if lying on left side
Oro-antral fistula
abnormal communication between maxillary sinus and oral cavity (hole in roof of mouth)
what connects the thyroid to cricoid cartilage
conus elasticus
= anterior part of Cricothyroid ligament
suprahyoid muscles (extrinsic laryngeal muscles)
elevates hyoid
anterior and posterior bellies of diagastric
mylohyoid
stylohyoid
geniohyoid
infra hyoid muscles (depress hyoid)
omohyoid (superior and inferior belly)
sternothyroid
sternohyoid
thryohyoid
what nerve are the intrinsic laryngeal muscles innervated by (except what)
inferior laryngeal nerve (branch of RECURRENT laryngeal nerve/vagus)
except cricothyroid (branch of SUPERIOR laryngeal nerve)
Intrinsic laryngeal Muscles
transverse arytenoid (not paired)
- Cricothyroid = stretches/ tenses vocal ligament
- Thyroarytenoid = relaxes vocal ligament
- Posterior cricoarytenoid = abducts vocal folds (only muscle capable of widening rima glottidis)
- Lateral cricoarytenoid = adducts vocal folds (close)
- Transverse & oblique arytenoids = adducts arytenoid cartilages
arteries supplying thyroid
superior first branch of external carotid
inferior from thyrocervical trunk of subclavian
thryoid ima artery (only in 10% of people)
venous drainage of thyroid
superior and middle thyroid veins drain into internal jugular veins
both inferior thyroid veins drain into LEFT brachiocephalic vein
may be a ima thyroid vein
what does the internal branch of the superior laryngeal nerve (of vagus) innervate
epiglottis
laryngeal mucosa
base of tongue
SENSATION
Damage of recurrent laryngeal nerves
smoking/chewing tabacco
but also DUE TO CANCER - more common from a left nerve cancer
present with persistent hoarseness, earache, dysphagia
indication:Enlarged pretracheal or paratracheal lymph nodes
injured superior laryngeal nerve
results in a voice that is monotonous in character because the paralysed cricothryoid muscle
(its unable to vary the length and tension of the vocal fold)
Surgical procedure that recurrent laryngeal nerve most at risk
thyroidectomy
and surgical operations in the anterior triangles of the neck.
Lingual thyroid
rare embryological anomaly due to failure of thyroid gland to descend from the foramen caecum to its normal site
where do superior and inferior parathyroid glands originate from
INFERIOR - 3rd
SUPERIOR - 4th pharyngeal pouch
4th pouch also gives rise to the ‘ultimo-branchial body’ which is incorporated into the thyroid gland and forms the C cells which secret calcitonin
carotid sinus + role
dilated region at base of internal carotid artery (superior to the bifurcation from common carotid)
contains baroreceptors - sensitive to BP
- sends impulses to medulla oblongata via the glossopharyngeal nerve (so does carotid body)
what does absence of carotid pulse indicate
cardiac arrest
what might external pressure on carotid artery in people with carotid sinus hypersensitivity cause
slowing of the heart rate, a fall in blood pressure, and cardiac ischemia with fainting (syncope)
branches of external carotid
superior thyroid ascending pharyngeal lingual facial posterior auricular occipital maxillary superficial temporal
5 branches of subclavian and what muscle divides it into 3 parts
anterior scalene
- vertebral
- internal thoracic
- thyrocervical
- costocervical
- dorsal scapula
what 2 veins—> external jugular vein
retromandibular + posterior auricular vein
