Lecture 4 = Skull, Face, and Scalp Lecture Flashcards
1
Q
What’s the neurocranium and what bones does it have?
A
Cranial bones to protect the brain. Bony case of brain and meninges, it contains the proximal portions of the cranial nerves and the vasculature of the brain. It consists o the calvaria (skull cap) and cranial base.
It has 8 bones:
- 4 singular midline bones - frontal (development of a right and left half of the frontal bone results in a midline suture anterior to bregma = metopic suture), ethmoidal, sphenoidal and occipital bones
- 2 paired bones - temporal and parietal bones united by sutures (developmentally these are synchrondroses joints filled with hyaline cartilage)
2
Q
What’s the viscerocranium and what bones does it have?
A
facial bones to protect airway and alimentary canal. Facial bones that develop from mesenchyme from the pharyngeal arches, supports anterior cranium and defines, mouth, nose, and most of the orbits.
15 bones comprise the cranial base:
- 3 singular midline bones - ethmoid, vomer, and mandible
- 6 paired bones - maxilla, inferior nasal concha (turbinate), zygomatic, palatine, nasal, and lacrimal - there are responsible for the bilateral symmetry of the face
3
Q
What is the mandible not a bone of the face?
A
it’s the lower jaw bone and articulate with the face at the TMJ - b/c of this the bone is with the oral cavity and is not a bone of the face.
4
Q
What is the pterion and why can it be bad if you are hit here?
A
is a point where the bones can be broken readily since 4 sutures come together at this point. And there is a major vessel, the middle meningeal artery, that runs right behind it so if you get hit at this point, that artery can break and there can be a massive internal bleeding.
5
Q
What is vertical orientation?
A
this defines the three different branches of trigeminal nerves - V1, V2, and V3.
6
Q
What are the features of the Maxilla and mandible?
A
- both have alveolar process = sockets for teeth
- mandible has mental foramen
- maxilla has infraorbital formamina
- coronoid process
- condyloid (condylar) process (TMJ)
- head, neck, and ramus, body and angle
- mandibular notch, foramen
- mylohyoid groove
- mental spines or genial tubercles (superior and inferior)
*frontal bones have supraorbital foramina/notches and all 3 foramina line up
7
Q
What are the boundaries of the orbit?
A
- frontal bone = roof
- zygomatic bone = lateral wall
- maxilla bone = floor and part of the medial wall
- lacrimal and ethmoid bones = rest of medial wall
- sphenoid bone = posterior wall
8
Q
What are the features of the orbit?
A
- supraorbital foramen/notch: in superciliary arch
- optic cana (foramen): in medial wall
- superior orbital fissure: in medial wall
- inferior orbital fissure: in floor
- lacrimal groove (nasolacrimal canal) - communicates with nasal cavity
9
Q
What are the boundaries of the nasal cavity?
A
- nasal bones, frontal sinus, ethmoid, sphenoid sinus: roof
- maxillary bones: floor and lateral wall
- palatine horizontal plate: floor
- vomer and perpendicular plate of ethmoid bones: medial wall
- nasal septum: medial wall
10
Q
What are the features of the nasal cavity?
A
-nasal conchae: projections from lateral wall
-superior nasal conchae: ethmoid bone
-middle nasal conchae: ethmoid bone
-inferior nasal conchae: separate bones
-conchae = turbinates
The nasal cavity is line by a nasal mucosal membrane (respiratory epithelium).
Most bony features have a mucosal covering on them.
Oral mucosa vs. respiratory mucosa
11
Q
What does the anterior cranial fossa hold?
A
holds the frontal lobes
12
Q
What does the middle cranial fossa hold?
A
holds the temporal lobe
13
Q
What does the posterior cranial fossa hold?
A
holds the cerebellum and brainstem
14
Q
What are the features of the paranasal sinuses?
A
- are air spaces within the skull bones
- we have 4 pairs of theses
- these are internal bony features that are apparent on CT, MRI, etc
- make bones lighter
- add resonance to voice
- all lines by mucosal membranes
- all continuous with nasal cavity
15
Q
What are the paranasal sinuses?
A
frontal sinuses - in frontal bones (2) ethmoid air cells - in ethmoid bone (3-13 cells) - on both sides of the face sphenoid sinuses - in sphenoid bone (2-5 cells) maxillary sinuses - in maxilla (2)
16
Q
Where are the foramen of the skull?
A
- there are 13 foramen of the skull
- allow vessels and cranial nn. to exit cranial vault
- a nerve might enter one foramen on the skull and exit through a completely different foramen on the skull
17
Q
What does the cribriform plate transmit?
A
olfactory nerve (CN I)
18
Q
What does the optic canal transmit?
A
optic nerve (CN II) and the ophthalmic a.
19
Q
what does the superior orbital fissure transmit?
A
CN III (Oculomotor), IV (Trochlear), VI (Abducens), and ophthalmic (CN V1)
20
Q
What does the foramen rotundum transmit?
A
Maxillary nerve (CN V2)
21
Q
What does the foramen ovale transmit?
A
Mandibular nerve (CN V3)
22
Q
What does the foramen spinosum transmit?
A
middle meningeal artery
23
Q
What does the foramen lacerum transmit?
A
internal carotid artery, travels superiorly over it and greater petrosal never association.
-this is a major hole but nothing really passes through it because it’s filled by a fibro-cartilage and is part of the floor of the carotid artery pathway in the carotid canal.
24
Q
What does the jugular foramen transmit?
A
internal jugular vein, CN IX (glossopharyngeal), CN X (vagus) and CN XI (accessory)
25
What does the internal acoustic foramen transmit?
CN VII (facial) and CN VIII (vestibulocochlear)
26
What does the stylomastoid foramen transmit?
CN VII (facial)
27
What does the hypoglossal canal transmit?
CN XII (hypoglossal)
28
What does the foramen magnum transmit?
vertebral arteries, spinal cord, and CN XI (accessory)
29
What does the carotid canal transmit?
internal carotid artery (this enters the skull through here)
30
What are the layers of the scalp?
```
From superficial to deep:
-skin
-connective tissue (dense)
-aponeurotic layer
-loose connective tissue
-pericranium
SCALP
```
31
Describe the skin layer on the scalp
it is thin except in the occipital regions. It contains many sweat and sebaceous glands and hair follicles. It has abundant arterial supply, good venous and lymphatic drainage.
32
Describe the connective tissue layer on the scalp
it forms the thick, dense, richly vascularized subcutaneous layer with many cutaneous nerves (where the vessels and nerves reside). This layer tend to "hold" cut vessels open - allowing profuse bleeding.
33
Describe the aponeurosis layer on the scalp
aka epicranial aponeurosis. is the strong tendinous sheet that covers the calvaria, serves as the attachment for the frontal and occipital bellies of the occipitofrontalis muscles and the superior auricular muscle. Together, this is called the musculoaponeurotic epicranius.
34
Describe the loose connective tissue layer on the scalp
it is the sponge-like later. It has potential spaces that may distend with fluid as a result of injury or infection. This layer allows the free movement of the scalp proper (the first 3 layers) over the underlying calvaria.
35
Describe the pericranium layer on the scalp
a dense layer of CT, forms the external periosteum of the neurocranium and is firmly attached. Parts of the pericranium are continuous with the fibrous tissue in the cranial sutures.
36
What are scalp lacerations?
superficial wounds into the connective tissue layer tend to bleed profusely. This is due to vascular anastomoses - vascular connections. if unconscious, may bleed to death from a minor injury because the lacerations are held open by the dense CT.
deep wounds into the aponeurosis layer gape widely - deep woulds gape because of the muscles attached to the aponeurotic layer : the frontal and occipitalis mm. The muscles will pull the wound even wider because the muscles are pulling this apart - gaping wound.
37
What is loose areolar tissue?
is called the danger space of the scalp.
Infections spread easily in this layer b/c travels into the cranial cavity through emissary veins (pass through the calvaria - drains venous blood of the scalp down to the superior sagittal sinus) to meninges (gets into the epidural space) and fluid can move anteriorly into eyelids and root of nose
Loose Ct means potential space for bleeds, edemas and infections.
38
What are the muscles of the scalp and ears?
occipotofrontalis muscle and
| 3 auricularis muscles
39
What is the action of the occipitofrontalis muscle?
moves scalp back and forward
| this muscle is a combo of occipitals m. + galea aponeurotica (aponeurosis aka cranial epineurosis) + frontalis m.
40
What is the action of the auricularis mm?
anterior: protract ear
superior: elevate ear
posterior: retract ears
There 3 are very superficial muscles
41
What are the muscles of the face?
mm of facial expression:
- all attach to bone or fascia and act by pulling the skin (insert into skin) - literally pull on the skin when they are acting
- also surround the orifices of the face (mouth, eyes, nose) acting as sphincters and dilators
mm of mastication (4 pairs)
the face is the anterior aspect of the head from the forehand to the chin and ear to ear
no deep fascia of the face because of all the muscle attachments of the muscles of facial expression - loose connective tissue
42
What CN innervates the muscles of facial expression?
CN VII - facial nerve
43
What are the muscles of the eye region?
frontalis m
corrugator supercilii m - deep muscle, hard to find
orbicularis occuli m - wide band around the eye, has a smaller portion over the upper and lower eyelids and these come in contact when the eye closes
44
What is the action of frontalis m?
raises eyebrow (surprised)
45
What is the action of the corrugator supercilii m?
draws eyebrow in (frowning)
46
What is he action of the orbicularis oculi m?
closes eye (winking)
47
What are the origin and insertion of eye region muscles on the face?
origin: either bone or CT
insertion: skin
48
What are the muscles of the nasal region?
- procerus m.
- nasalis m.
- levator labii superioris alaeque nasi m,
49
What is the action of the procerus m?
wrinkles bridge of nose. Has vertically oriented muscles.
50
What is the action of the nasalis m?
compresses and dilates nostrils. both parts have procedures done for gummy smiles. There 2 parts are directly related to the shape of the nose.
51
What is the action of elevator labii superioris alaeque nasi m.
dilates nostril (not on practical)
52
What are the superficial muscles of the mouth region?
- orbicularis oris
- levator labii superioris
- zygomaticus major/minor
- depressor anguli oris
- depressor labii inferioris
- risourius
- mentalis
53
What is the action of the orbicularis oris m.?
closes mouth
54
What is the action of the levator labii superioris m.?
elevates upper lip
55
What is the action of the zygomaticus major/minor m. ?
draws mouth up. minor over major and major is broader and has a more lateral attachment.
56
What is the action of the depressor anguli oris m. ?
depresses angle of mouth
57
What is the action of the depressor labii inferioris m.?
depresses lower lip. is deeper than depressor anguli oris m.
58
What is the action of the risourius m.?
retracts the corner of the mouth. comes off of the commissure and goes laterally.
59
What is the action of the mentalis m.?
protrudes lower lip. comes off from the chin and goes straight out into the skin
60
What are the deep muscles of the mouth region?
- buccinator m.
- levator anguli oris m.
- depressor labii inferioris m.
61
What is the action of the buccinator m.?
compresses check and assists with mastication. this is deep to the buccal fat pad and below the infraorbital foramen.
62
What is the action of the levator anguli oris m.?
elevates angle of mouth
63
What is the action of the depresses labii inferioris m.?
depresses lower lip
64
What are the muscles of mastication?
-temporalis m.
-masseter m.
-medial pterygoid m.
-lateral pterygoid m.
All of them have 2 heads and a deep and superficial component.
65
What is the action of the temporalis m.?
elevates and retracts mandible
66
What is the action of the masseter m.?
elevates and clenches mandible
67
What is the action of the medial pterygoid m.?
elevates, protracts, and rotates mandible
68
What is the action of the lateral pterygoid m.?
protrudes and rotates mandible ; opens mouth
69
What are the innervations of the face and scalp?
- trigeminal (CN V) n.
- cervical (C2, 3) n.
- facial (CN VII) n.
- mandibular (CN V3) n
70
What does the trigeminal n. innervate?
sensory to the face and anterior scalp
71
What does the cervical n. innervate?
sensory to the back of head (posterior scalp), ears, and jaw
72
What does the facial n. innervate?
motor to mm. of facial expression
73
What does the mandibular n. (CN V3) innervate?
motor to mm of mastication
74
What are the divisions of the trigeminal nerve?
V1 - ophthalmic division
V2- maxillary division
V3 - mandibular division
75
What are the branches of the ophthalmic division (V1) and what area does this division supply?
```
suborbital n.
supratrochlear n.
infratrochlear. .
external nasal n.
lacrimal n,
supplies the forehead till the tip of the nose and till the upper eyelid (in a T shape)
```
76
What does the supraorbital n. innervate?
the central forehead
77
What does the supratrochlear n. innervate?
medial forehead
78
What does the infratrochlear n. innervate?
upper nose
79
What does the external nasal n. innervate?
lower nose
80
What does the lacrimal n. innervate?
lateral brow
81
What are the branches of the Maxillary division and what region does it supply?
zygomaticotemporal n.
zygomaticofacial n.
infraorbital n.
Supplies from the lower eyelid to the upper lip and the zygomatic region (temple region)
82
What does the area where V1 and V2 meet is called?
palpebral fissures
83
What does the area where V2 and V3 meet called?
oral fissure
84
What does the zygomaticotemporal n. innervate?
temple
85
What does the zygomaticofacial n. innervate?
upper cheek
86
What does the infraorbital n. innervate?
maxilla and upper lip
87
What are the branches of the mandibular division and what region does it supply too?
auriculotemporal n.
buccal n.
mental n.
Supplies the lower lip, chin, external acoustic meatus and anterior half of ear.
88
What does the auriculotemporal n. innervate?
ear and temple
89
What does the buccal n. innervate?
lower cheep
90
What does the mental n. innervate?
chin and lower lip
91
What is the parotid (stensen's) duct?
transmits saliva from gland
crosses masseter 1-2 cm below zygomatic arch
turns 90 deg to pierce buccinator m.
opens into oral cavity opposite 2nd molar - marked by elevated parotid papilla
outer surface is irregular
inner surface is wedge-shaped
92
What is the parotid gland?
enclosed in a parotid sheath of deep cervical fascia
is anterior and inferior to the ear
will vary in size
has a superficial and deep lobe
93
What are some problems associated with the parotid gland?
- calculus formation (stones): associated with chronic parotiditis (happens in all 3 salivary glands but most common in submandibular). Stone can get caught in duct if it's large enough
- salivary fistulas (communication to the outside: usually is a product of an outside procedure) - most close spontaneous but can do a duct ligation
- neoplasms: 85-90% of mixed tumors involved with parotid
- frey's syndrome: gustatory sweating. Salivary production is parasympathetic. This happens after a surgery when the parasympathetic ends up on the sweat glands and vice versa. When you are hungry, you don't salivate but sweat heavily from the face.
- facial n. (CN VII): passes thru gland. Nerve in danger during parotidectomy. Must ID branches prior to excision of any tumor tissue. Damage results in paralysis of facial mm on affected side.
94
What are the branches of the facial n?
temporofacial n.
cervicofacial n.
These 2 give off multiple branches
There is also another branch that goes to innervate the posterior belly of the digastric and stylohyoid muscles - these are the pharyngeal arch 2 derivatives which also innervate the muscles of facial expression.
95
What nerves do the superior temporofacial and inferior cervicofacial nn. of the facial nerve give rise too?
```
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Posterior auricular n.
temporal n
zygomatic n.
buccal n.
marginal mandibular n.
cervical n.
```
96
What does the temporal n. innervate?
travels superior to temples
97
What does the zygomatic n. innervate
travels inferior to arch
98
What does the buccal n. innervate?
medially to buccinator m.
99
What does the marginal mandibular n innervate?
along inferior mandible
100
What does the cervical n. innervate?
inferiority to platysma m.
101
What does the posterior auricular n. innervate?
posteriorly to lower ear
102
What are some problems that can arise with the facial n
-injury to CN VII produces muscle paralysis on affected side
-nerve may be inflamed at stylomastoid
-edema and compression of nerve in facial canal
Bell's palsy- most common, unilateral, non-traumatic sudden on set of facial paralysis
103
What's the buccal fat pad?
- fat pad is located anterior to masseter m.
- covers up buccinator m. located medially
- provides protection for parotid duct and CN VII (buccal branch)
- helps give cheek fuller appearance is a direct result of the buccal fat pad
104
What are the nerves of the buccinator m.?
-There are two buccal nn. related to the buccinator m.
1) buccal branch of facial nerve - lateral to masseter m.
- CN VII: motor to buccinator m. - facial expression
2) buccal branch of trigeminal nerve
- CN V3: sensory to buccal mucosa and skin of cheek
Note: V3 only pieces buccinator m. - it doesn't supply it
105
What does the superficial temporal artery and vein supply and are branches of?
Artery: branch of external carotid a.
vein: drains to retromandibular v.
- Both run anterior to ear to temporal region
- travel with auriculotemporal n.
106
What does the transverse facial artery and vein supply and are branches of?
- branches of superficial temporal vessels
- cross masseter m. between zygomatic arch and parotid duct
- supply blood to upper cheek region
* parotid gland, duct and masseter m.
107
What does the facial artery and vein supply and are branches of?
artery is tortuous and anterior to vein
- both cross mandible at anterior border of masseter m.
- facial artery pulse can be palpated here
at angle of mouth: inferior and superior labial branches (to lips)
at angle of mouth: inferior and superior labial branches (to lips)
continue to medial angle of eye to angular a. and v.
** this is superior to the lingual artery
108
What veins drain into the EJV?
```
anterior jugular v.
superficial temporal v.
maxillary v.
occipital v.
posterior auricular v.
external jugular v.
retromandibular v.
pterygoid plexus (deep temporal vv.)
```
109
What veins drain into the internal jugular vein?
```
pterygoid plexus (deep temporal vv.)
angular v.
facial v.
retromandibular v.
superior thyroid v.
internal jugular v.
```
110
What is the lymphatic drainage of the head and neck?
remains (drains) ipsilateral
- very few nodes cross the midline
- submental MIGHT cross the midline
- pre-laryngeal and pre-tracheal are areas where some crossing might occur
drains medial to lateral neck
drains inferiority and generally superficial to deep because looking at the collection of lymphatics at the venous angle
ultimately go to the right lymphatic duct or thoracic duct
111
Where are the submental nodes located and what do they drain?
located inferior and posterior to the chin and drain from the medial lower lip to the chin ipsilaterally
112
Where are the submandibular nodes located and what do they drain?
are superficial to the gland and inferior to the body of the mandible and drain from the medial corner of the orbit, most of the external nose, the medial part of the cheek, super lip, and lateral lower lip that follows the course of the facial artery.
113
Where are the pre-auricular and parotid nodes located and what do they drain?
are anterior to the ear and drain most of the eyelids, part of the external nose, and the lateral cheek
114
What does the jugulodigastric node drain?
it drains the preauricular and parotid nose, mastoid nose, and occipital node
this can be palpated easily
115
What does the deep cervical node drain?
drains the submandibular nodes
116
What does the jugulo-omohyoid node drain?
drains the jugulodigastric node, deep cervical node and submental nodes
- it's an inferior and anterior coalescence.
