Week 7 Flashcards
1
Q
What does the mandible consist of
A
the body and the ramus
2
Q
What does the body of the mandible consist of
A
external and internal surface
3
Q
Where is the mental symphysis
A
secondary cartilaginous joint that joins the two halves of the mandible together in a fetus
4
Q
Wha tis the mental protuberance
A
forward projection of the chin and it is a feature seen only in humans
5
Q
What is the mental tubercle
A
feature seen near the mental protuberance and those who have a cleft mandible will see it in this area
6
Q
What is the mental foramen
A
is where the mental nerve and the blood vessels emerge from the bone
7
Q
How is the mental foramen orientated
A
such that the nerve tends to pass backwards and outwards as it emerges from the foramen
8
Q
What is the base of the mandible
A
is what the underside of the mandible is and what it lies on
9
Q
What is the digastric fossa
A
an oval depression for the attachment for the anterior belly of digastric
10
Q
What is the alveolar process
A
bone that bears the teeth
11
Q
What happens to the alveolar process without the presence of teeth
A
§ It will atrophy if teeth are not present
If the mandible becomes very atrophic then a denture can end up sitting on the mental foramen which can be painful
12
Q
Where is the mylohyoid line seen
A
on the medial side of the mandible
13
Q
What is the mylohyoid line
A
It is the place of attachment for the mylohyoid muscle and the two mylohyoid muscles meet at the midline
14
Q
Why is the mylohyoid line significant in pros
A
§ A denture should stop short of this line otherwise when speaking or eating the mylohyoid will lift the denture
15
Q
What is the submandibular fossa
A
where the submandibular gland sits
§ It is a smooth area
§ Below the mylohyoid line
16
Q
What is the sublingual fossa
A
sublingual fossa is where the sublingual salivary gland sits
§ Smooth area
§ Above mylohyoid line
17
Q
What is the mental spine/genial tubercle
A
§ There are 4 mental spines and collectively they rare known as genial tubercles
§ They give attachment to the geniohyoid (below) and the genioglossus (above)
18
Q
What is the mylohyoid groove
A
a distinct groove
§ The nerve to mylohyoid lies in this groove
19
Q
Describe the ramus
A
○ It has a lateral and medial surface
○ It has an anterior, posterior, inferior and superior border
20
Q
What is the mandibular foramen
A
is seen on the ramus in which the inferior alveolar nerve and vessels pass through
21
Q
What is the mandibular canal
A
what the foramen leads to
22
Q
What is the lingula
A
little projection that creates the shadow of the canal. It varies in shape from patient to patient. You do not want to hit the lingula when drawing back as you will deposit the LA too far
23
Q
What is the rough surface on the angle of the mandible for (medial side)
A
has a rough surface and this rough surface is where the medial pterygoid muscle attaches
24
Q
What is the mandibular notch
A
Where the nerves and vessels to the masseter coming from the mandibular nerve enter through
25
What is the coronoid process
where the temporalis attaches
26
What is the condylar process
what makes up the head and neck of the mandible
27
What is the pterygoid fovea
seen at the front of the neck of the mandible and there is a little depression and it is the place of insertion for the inferior belly of the lateral pterygoid muscle
28
What is the pterygoid hamulus
○ The pterygoid hamulus is part of the sphenoid bone
○ It is the medial pterygoid plate that ends in this small hook-shaped process called the pterygoid hamulus which projects behind the posterior border of the hard palate
29
What is the pterygomandibular Raphe
thin band consisting of interlacing tendinous fibres from the buccinator anterior and the pterygopharyngeal part of the superior constrictor posteriorly
30
Where does the raphe descend from
○ The raphe descends from the hamulus of the medial pterygoid plate to the posterior end of the mylohyoid line of the mandible
31
Where is the superior constrictor seen
Runs back from the pterygomandibular raphe
It is made of skeletal muscle
Its action is to constrict the upper part of the pharynx
32
What is the middle constrictor
○ The middle constrictor comes from the side of the hyoid bone and it overlaps the superior constrictor
○ Its action is to carry out general sphincteric and peristaltic action in swallowing
33
What is the inferior constrictor
○ Overlaps the middle one
○ Two parts to it - upper part acts as a propulsive force and the lower part acts as a sphincter for the oesophagus / larynx
34
What is the pharyngeal raphe
○ All the constrictors insert with their opposing partners into a median fibrous band known as the median pharyngeal raphe
Inferiorly it blends with the circular muscular fibres of the oesophagus and superiorly it is attached to the pharyngeal tubercle of the occipital bone
35
Where does the stylopharyngess arise and insert into
○ Arises from the styloid process of the temporal bone
○ It passes down into the pharynx between the superior and middle constrictor muscles
○ Some fibres merge with the constrictor muscles while others insert into the thyroid cartilage of the larynx
36
What is the function of the stylopharyngess
○ It elevates the pharynx and larynx
37
What is the mucosa of the oro and naso pharynx supplied by
○ The mucosa of the oro and nasopharynx are supplied by the glossopharyngeal nerve as well which comes around the stylopharyngeus to supply it
38
What are the constrictors supplied by
• The constrictors are supplied by the vagus nerve via the pharyngeal pelxus
39
Where does the tensor veil palatini come from
○ Comes from the base of the skull and originates from the medial pterygoid plate and the auditory tube
40
Where does the tensor veil palatini descend between
the medial pterygoid plate and medial pterygoid muscle to end in a tendon that winds around the pterygoid hamulus
41
What is the palatal aponeurosis
○ The two tendons spread out to form a flattened sheet that forms the skeleton of the soft palate - this is the tendon of the tensor veli palatini
○ When the muscles contract the tendon is pulled and it is winded around the hamulus and the palate becomes tense
42
What is tensor veil palatini supplied by
mandibular nerve
43
Where does levator veil palatini originate from and insert into
the base of the skull at the petrous part of the temporal bone and from the auditory tube
○ It inserts into the palatine aponeurosis
44
What do the levator muscles of the palate form
a U shaped muscular sling
45
When the palatine aponeurosis is stiffened by the tensor muscles what happens
contraction of the levator muscles produces an upwards and backwards movement of the soft palate so that the nasopharynx is shut off from the oropharynx by the positioning of the soft palate onto the posterior wall of the pharynx
46
What is levator veli palatini supplied by
vagus
47
Where does the palatoglossus muscle come from
○ Goes from the tongue to the soft palate
○ Arises from the aponeurosis
○ Extends downwards and forwards and laterally in front of the palatine tonsil to the side of the tongue
○ Innervates by glossopharyngeal / pharyngeal plexus
48
What is the palatopharyngeus muscle attached to
○ Attached to the palatal aponeurosis
○ The muscle passes laterally and downwards behind the tonsils and it then it travels in close contact to the stylopharyngeus
○ It inserts with the stylopharyngeus muscle to the posterior border of the thyroid cartilage and some fibres blend with the constrictor muscles
49
What is the uvular muscle
○ Inserts into mucosa of the uvula
○ Moves the uvula upwards and laterally
○ Uvula is there to improve seal of the soft palate when swallowing fluids
50
What is the maxillary tuberosity
○ Is a rounded eminence located posterior to the third maxillary molar
○ Occasionally in extraction it can come off and open the maxillary sinus
51
What is the TMJ
○ Consists of the mandibular fossa, articular tubercle and head of the mandible
52
Why do the articular surfaces of the TMJ not come into contact with each other
they are separated by an articular disc which splits the joint into two synovial joint cavities lined by a synovial membrane
53
What are the articular surfaces covered with
○ The articular surfaces of the bones are covered by fibrocartilage not hyaline cartilage
54
What head of the lateral pterygoid is largest
lower head
55
What does the lower head arise from
§ It arises from the lateral surface of lateral pterygoid plate of the sphenoid bone
56
Where does the smaller head originate from
takes origin from the infratemporal surface of the greater wing of the sphenoid in the roof of the fossa
57
What do the fibres of the upper head insert primarily into
the capsule and articular disc of the TMJ
58
What do the fibres of the lower head insert primarily into
The fibres from the lower head insert into the pterygoid fovea on the mandibular condyle
59
What is the action of the lateral pterygoid
○ Because the tendinous fibres join the capsule, when the lateral pterygoid contracts, it pulls on the neck of the TMJ bringing the head out of the fossa and into the eminence in front
60
Where does the buccal nerve come out from
○ Coming out through the lateral pterygoid is the buccal nerve, a branch of the mandibular nerve that is sensory to the cheek and gives little twigs to the gums (buccal side)
61
What is the maxillary artery
○ One of the terminal branches of the external carotid
| ○ Has 3 parts to it - the mandibular, pterygoid and pterygopalatine parts
62
Where does the maxillary artery come out of
Comes out at the same area as the buccal nerve
○ Sometimes it runs deep and sometimes it runs superficial to the lateral pterygoid - in the above picture it runs superficial
63
What does the maxillary artery supply
○ Supplies tissues in the infratemporal fossa and gives supply to the lower jaw and to structures in the upper jaw
64
Where is the pterygoid plexus
it is situated around and within the lateral pterygoid muscle and temporalis
○ Surrounds maxillary artery
65
How does the pterygoid venus plexus communicate with the cavernous sinus
via emissary veins passing through foramen ovale, foramen lacerum and where present, the emissary sphenoidal foramen
66
Why is the pterygoid venus plexus significant to dentists
○ Need to aspirate during IBD administration to ensure you havent gone into one of these veins
67
What is the superficial temporal artery
○ 1 of the terminal branches of the external carotid artery within the parotid gland
68
What does the superficial temporal artery supply
○ Supplies the frontal and parietal parts of the scalp, temporalis muscle, the external lower part of the ear and the orbicularis oculi muscle
69
What is the inferior alveolar artery
○ Branch of the maxillary
○ Enters mandibular foramen, prior to this it gives off a branch to mylohyoid
○ Splits into mental and incisor branches near the first premolar
○ Mental branch leaves mental foramen
70
What are the heads of the medial pterygoid called
○ Also has 2 heads (superficial and deep NOT superior and inferior)
○ It is the deepest of the four muscles of mastication
71
What is the origin of the deep head
§ Deep head is the bulk of the muscle and arises from the medial surface of the lateral pterygoid plate
72
What is the origin of the smaller superficial head
originates from maxillary tuberosity and the neighbouring part of the palatine bone, the pyramidal process
73
Where does the medial pterygoid insert
§ The fibres pass downwards and backwards to insert into the roughened surface of the angle of the mandible on its medial aspect
74
What is the action of the medial pterygoid
§ If the two medial pterygoids contract together the muscle fibres come downwards from the origin to the angle of the mandible so they are going to elevate the mandible and protract it
§ The fibres also come towards us (laterally) as well as downwards and backwards so that if two sides work alternately, the MP will pull the angle of the mandible to the opposite side
75
Where does the inferior alveolar nerve
○ Comes from the undercover of the lateral pterygoid
○ Sinks into the mandibular foramen to go into the jaw in the bone to supply the teeth
○ Before it enters it gives off nerve to mylohyoid which supplies the mylohyoid and the anterior belly of the digastric
LA is coming at where the pencil is pointing at
76
Where is the lingual nerve
○ Makes its way near the area of the mandible
○ Similar size to the inferior alveolar nerve
○ Infront of the inferior alveolar nerve
77
What comes off the main trunk of the mandibular nerve
○ Nerve to the medial pterygoid comes off of this main trunk
○ Further along the nerve splits into 2 - an anterior and posterior division
78
What comes off the anterior division of the mandibular nerve
nerve to masseter
deep temporal nerves
nerve to lateral pterygoid
79
Where does the anterior division run
high up in the infra temporal fossa and gives off several branches
80
When does the anterior division change its name
§ It is after it goes through the two heads of the lateral pterygoid (after supplying it) that its name changes to the buccal nerve which is the continuation of the anterior division
81
What comes off the posterior division
lingual nerve
inferior alveolar
auriculotemporal
82
What is the lingual nerve
§ Goes downwards and forwards to supply sensation to the mucosa of the anterior 2/3 of the tongue and to the floor of the mouth and the lingual gingiva in the lower jaw
§ It is purely sensory
§ It is at risk of being pressed by forceps due to the close proximity to the roots of the third molar
83
What is the inferior alveolar nerve?
§ Runs 2-3mm behind the lingual nerve is the inferior alveolar nerve and it enters the jaw
84
What does the inferior alveolar nerve give off before entering the mandibular foramen
§ where it enters the jaw, it gives a branch to the mylohyoid called the Nerve to mylohyoid and it supplies the mylohyoid and anterior belly of digastric
§ The nerve to mylohyoid is the only motor fibre of the posterior division
85
What does the inferior alveolar nerve give off anteriorly
§ At the area of the root of the premolars it gives off the mental nerve which turns laterally and comes out through the mental foramen to supply the skin of the lip and chin
§ The incisive branch is the continuation of the IAN
86
What is the function of the auriculotemporal never
§ The auriculotemporal nerve is the sensory nerve to supply sensation to the TMJ and supplies the skin anterior to the ear
87
What is the course of chorda tympani
§ The facial nerve is in the posterior cranial fossa and goes into the acoustic internal meatus, into temporal bone close to the middle ear and then turns down to come out at the stylomastoid foramen at the base of the skull and it branches in the parotid
§ A few mm from the stylomastoid foramen the chorda tympani nerve branches from the facial nerve as it passes downwards behind the tympanic cavity
§ It then runs upward and forward in a canal and enters the tympanic cavity and it crosses the tympanic membrane
§ After emerging from it, It then joins the lingual nerve
88
What does the chorda tympani supply
§ It provides taste to the anterior 2/3 of the tongue
§ It also carries preganglionic parasympathetic fibres that make the salivary gland secrete
The sublingual and submandibular gland get their parasympathetic supply from the facial nerve. These fibres follow the same route as the fibres concerned with taste through the chorda tympani branch joining the lingual nerve which helps carry these preganglionic parasympathetic fibre
89
What is the palatine bone
• The palatine bone is a small bone, shaped like a square and the two narrow plates of bone meet at right angles.
90
What does the palatine bone make up
○ Part of the palatine bone makes up the posterior part of the palate and the other extends up into the side of the wall of the nasal cavity but that cannot be seen clearly
○ The piece of palatine bone that contributes to the bony palate is called the horizontal plate of the palatine bone
91
What is the rough thick bone of the maxilla called
we call it the palatine process of the maxilla where it is a bony shelf.
92
what is the incisive foramen for
incisive fossa which is the site where the incisive papilla would be and inside it there would be 4 little holes and 2 of these carry branches of the nasopalatine nerve which supplies sensation to the anterior 1/4 of the hard palate and also supplies the nasal septum as it runs through it. The ant parts of the greater palatine artery make its way to the incisive foramen and it goes to supply the most anterior parts of the nasal cavity and front parts of the nasal septum
93
What is the curved edge of the palatine bone called
palatine crest (green) and it is the attachment for the palatine aponeurosis
94
What is the elevation next to the greater palatine nerve called
pyramidal process of the palatine bone
95
Where does the greater palatine foramen run
• The greater palatine artery runs in the groove outlined in pink and it is a branch of the maxillary artery. It goes through the incisive foramen to give blood to the nasal septum and cavity
96
What happens if the maxillary tuberosity is pulled off
• The maxillary tuberosity outlined in orange can be pulled off in extraction opening the maxillary sinus
97
Where does the hauler notch lie
• The hamular notch lies between the pterygoid hamulus and maxillary tuberosity and it is this area that is covered by mucosa that gives the hamular notch and it is an important landmark in the making of upper dentures
98
What does the massaterattach to
* It attaches at the lower border of the zygomatic arch on its deep surface but it extends forward onto the zygomatic bone
* Its other attachment is the lateral surface of the ramus of the mandible and attaches to most of it
99
What direction do the fibres of master run
attaches to most of it
• Its fibres run downwards but slightly backwards as well (superficial fibres)
• In dissection, you would see the deeper fibres the fibres are more vertical in their orientation (i.e downwards)
100
What happens if the two masseters contract
• If the two masseter contract together the action produced is the elevation of the mandible but the superficial fibres run backwards so there will be another vector for the force which will mean that it will also pull it slightly forward as well so also aids in protraction (forward movement) of the mandible
101
Why is masseter so strong
* Masseter has a lot of tendon in it, the power of the muscle is related to the absolute number of muscle fibres within it not so much the size of the fibres
* A muscle fibre under the microscope is wide whereas a tendinous fibres which is continuous is narrower so it is possible by having fleshy fibres running into tendinous fibres which are narrower, that allows the masseter to have a bigger absolute number of individual contracting units. The fleshy fibres can fit around the narrower tendinous fibres.
102
What is the masseter supplied by
mandibular nerve (trigeminal) - nerve to Masseter and it along with blood vessels come through mandibular notch and comes through deep surface of the masseter
103
Where is temporalis
• Muscle is fan shaped and can see the superior and inferior lines for the fascia
• Behind the zygomatic arch and in front of the temporalis muscle
The posterior part is very thin but the anterior fibres is much thicker, lots of muscle behind the zygomatic arch
104
What direction do anterior fibres run
vertically and attach to edge of coronoid process to anterior border of ramus to part where lower tooth is
105
What happens if two temporalis contract together
it will produce elevation of the mandible because of the big bulk of the muscle and gives a powerful elevation
106
What happens if the posterior fibres contract independently
retract the mandible
107
What is the function of the buccinator
• Used in mastication
It pushes food between molar teeth so doesn’t collect in vestibule of the mouth and orbicularis oris is important in pushing the food between incisor teeth
108
Where do upper fibres of the buccinator come from
the maxilla above the vestibule of the mouth
109
Where do lower fibres of the masseter come from
from the oblique line
110
What is the arrangement of the middle friers
• The middle fibres there is a criss crossing arrangement, the upper middle fibres run and pass into the lower lip and blend with orbicularis oris and the lower of the middle fibres pass to the upper lip and blend with orbicularis oris
CALLED MODIOLUS
111
What pierces the buccinator
• Parotid duct has to pierce buccinator to get into oral cavity
