ANA 301 Osteology & Scalp Flashcards
1
Q
What is the cranium?
A
The cranium (skull) is the skeleton of the head
•The many bones of the head collectively form the skull
• Most of these bones are interconnected by sutures which are immovable fibrous joints
2
Q
Parts of the cranium
A
the neurocranium /cranial vault
the viscerocranium/ facial skeleton
3
Q
What is the neurocranium?
A
is the bony covering (case) of the brain and its membranous coverings, the cranial meninges
•It also contains proximal parts of the cranial nerves and the vasculature of the brain
4
Q
What are the parts of the neurocranium?
A
A dome-like roof called the calvaria (skullcap)
and a floor or cranial base (basicranium)
5
Q
What are the 4 singular bones of the neurocranium?
A
frontal
occipital
ethmoidal
sphenoidal
6
Q
What are the 2 sets of paired bones of the neurocranium?
A
Temporal
Parietal
7
Q
What is unique about the ethmoid bone?
A
The ethmoid bone is an irregular bone that makes a relatively minor midline contribution to the neurocranium but is primarily part of the viscerocranium
8
Q
Briefly describe the viscerocranium (facial skeleton)
A
comprises the facial bones
•forms the anterior part of the cranium
• consists of the bones surrounding the mouth (upper and lower jaws), nose/nasal cavity, and most of the orbits (eye sockets or orbital cavities)
9
Q
What are the bones that make up the viscerocranium?
A
consists of 15 irregular bones:
*3 are singular bones
*6 bones occur as bilateral pairs
●The three singuar bones are:
➢Mandible
➢Ethmoid
➢Vomer
●The 6 bilateral paired bones are:
➢Maxillae
➢inferior nasal conchae
➢zygomatic
➢palatine
➢nasal
➢lacrimal bones
10
Q
Briefly describe the maxilla
A
contribute the greatest part of the upper facial skeleton,
•form the skeleton of the upper jaw
•It is fixed to the cranial base
11
Q
Briefly describe the mandible and what makes it movable
A
*forms the skeleton of the lower jaw,
*It is movable because it articulates with the cranial base at the temporomandibular joints (TMJs)
is a U-shaped bone
Its alveolar process supports the mandibular teeth.
12
Q
Features of the Anterior / Facial (Frontal) Aspect Of The Cranium
A
the frontal bone
zygomatic bones
orbits
nasal region
maxillae
mandible
13
Q
What is the frontal bone?
A
• it is a squamous (flat) part
•forms the skeleton of the forehead
14
Q
The frontal bone articulates inferiorly with__________
A
the nasal and zygomatic bones.
15
Q
The supraorbital margin of the frontal bone has_______________
A
a supraorbital foramen (notch) for the passage of the supraorbital vessels and nerves
16
Q
Just superior to the supraorbital margin is a ridge called the____________
A
superciliary arch
17
Q
Between these arches is a smooth, slightly depressed area called the______________
A
GLABELLA
18
Q
Describe the glabella and ophryon
A
The Glabella is the anterior-most projecting part of the forehead
Just above the glabella is a point on the midline of the forehead called the Ophyron
19
Q
On the midline of the mandible is the the most anterior point on the mandible which is the most prominent part of the chin called the____________
A
pogonion
20
Q
The intersection of the frontal and nasal bones is called the ___________
A
NASION, a depressed area (bridge of the nose)
21
Q
The frontal bone also articulates with the___________
A
lacrimal, ethmoid, and sphenoids bones
22
Q
Describe the nasal region
A
it’s made up of a pair of nasal bones which are joined together at midline by the nasal septum
Inferior to these nasal bones is a pear-shaped pyriform aperture
the bony nasal septum can be observed through this aperture dividing the nasal cavity into the right and left parts
On the lateral wall of each nasal cavity are curved bony plates called nasal conchae
23
Q
The two maxillae are united at the___________
A
intermaxillary suture in the median plane
24
Q
Describe the alveoli processes
A
their alveolar processes include the tooth sockets (alveoli) and house the maxillary teeth
25
The maxilla articulate with______the anteriorly and________laterally
frontal bone
zygomatic bones
26
On the body of the maxilla is the infraorbital foramen for passage of the
infraorbital nerve and vessels
27
Parts of the mandible
of a horizontal part (the body)
and a vertical part (the ramus )
28
Inferior to the second premolar teeth are the___________________
mental foramina for the passage of the mental nerves and vessels
29
Describe the base of the mandible
The base of the mandible has a midline swelling called the mental protuberance
Lateral to the mental protuberance on either side is a slightly more pronounced bumps called the mental tubercles
30
What is the zygomatic bone?
Also known as cheek bone, malar bones
31
On the lateral aspect of the zygomatic bone is a foramen called the______________
zygomaticofacial foramen
this foramen allows for the passage of the zygomaticofacial nerve
32
The zygomatic bone articulates with the_________
frontal, sphenoidal, maxillae and temporal bones
33
Describe an injury to the superciliary arches
The superciliary arches are relatively sharp bony ridges; consequently, a blow to them (e.g., during boxing) may lacerate the skin and cause bleeding. Bruising of the skin surrounding the orbit causes tissue fluid and blood to accumulate in the surrounding connective tissue, which gravitates into the superior (upper) eyelid and around the eye
34
Describe Malar Flush
The zygomatic bone was once called the malar bone.
Clinically the term malar flush refers to redness of the skin covering the zygomatic prominence (malar eminence), which is associated with a rise in temperature in various fevers occurring with certain diseases, such as tuberculosis
35
The Superior aspect of the skull is also called the___________
calvaria or skull cap
36
Bones that make up the calvaria include
Frontal bone (unpaired)
Paired parietal bones
Occipital bone (unpaired)
36
Landmarks of the outer surface of the skull include
The frontal bone articulates with the paired parietal bones at the coronal suture
The two parietal bones articulate with each other at the sagittal suture
The paired parietal bones articulate with the occipital bones at the lambdoid suture
The junction(intersection) between the coronal and sagittal sutures is called the bregma
The junction (intersection) between the sagittal suture and lambdoid sutures is called the lambda
The vertex is the most superior point of the skull near the midpoint of the sagittal suture
The parietal foramen on the parietal bone is variable, and it allows for the passage of emissary veins
Obelion: The region of the skull between the two parietal foramina where the closure of the sagittal suture usually begins
37
Describe linear calvarial fractures
the most frequent type
usually occur at the point of impact; but fracture lines often radiate away from it in two or more directions
37
Describe the depressed fractures of the calvaria
this can results from hard blows in thin areas of the calvaria in which a bone fragment is depressed inward, compressing and/or injuring the brain
38
Describe comminuted fractures
the bone is broken into several pieces
If the area of the calvaria is thick at the site of impact, the bone may bend inward without fracturing; however, a fracture may occur some distance from the site of direct trauma where the calvaria is thinner
39
Describe contrecoup (counterblow) fracture
no fracture occurs at the point of impact, but one occurs on the opposite side of the cranium
40
Describe the obliteration of the Cranial Sutures
The obliteration of sutures between the bones of the calvaria usually begins between the ages of 30 and 40 years on the internal surface and approximately 10 years later on the external surface
Obliteration of sutures usually begins at the bregma and continues sequentially in the sagittal, coronal, and lambdoid sutures
41
The halves of the frontal bone in the newborn are separated by the______________
frontal suture
42
the frontal and parietal bones in newborns are separated by the_____________
coronal suture
43
the maxillae in newborns are separated by the_______________
intermaxillary suture
44
a newborn's mandible consists of two halves united in the median plane by the_______________
mandibular symphysis
45
the union of the mandible begins during_____________
the 1st year and the halves are fused by the end of the 2nd year
46
What parts of the skull are not present at birth in a newborn? When do they develop?
No mastoid process at birth
No styloid process
The mastoid processes form gradually during the 1st year
47
The bones of the calvaria of a neonate are separated by membranous intervals called___________
fontanelles
48
Fontanelles of a newborn include
anterior fontanelle
posterior fontanelle
paired sphenoidal fontanelle
Paired mastoid fontanelles
49
Describe the size shape, boundary, location and closure of the anterior fontanelle
intro: the largest fontanelle
shape: diamond or star-shaped
boundary: bounded by the halves of the frontal bone anteriorly and the parietal bones posteriorly.
Location: at the junction of the sagittal, coronal, and frontal sutures, the future site of the bregma
closure: By the 18 months of age, the surrounding bones have fused and the anterior fontanelle is no longer clinically palpable
50
Describe the future of the frontal bone of a newborn
Union of the halves of the frontal bone begins in the 2nd year
In most cases, the frontal suture is obliterated by the 8th year
in approximately 8% of people
51
a remnant of the frontal suture persists called the
metopic suture
52
Describe the shape, boundary, location and closure of the posterior fontanelle
Shape: is triangular
boundary: bounded by the parietal bones anteriorly and the occipital bone posteriorly
location: at the junction of the lambdoid and sagittal sutures, the future site of lambda
Closure: begins to close during the first few months after birth and by the end of the 1st year, it is small and no longer clinically palpable
53
Discuss the sphenoidal and mastoid fontanelles in newborns
Sphenoidal and mastoid fontanelles
overlain by the temporal muscle,
fuse during infancy and are less important clinically than the midline fontanelles
54
Briefly describe the closure of the maxilla and mandible
The halves of the mandible fuse early in the 2nd year
The two maxillae and nasal bones usually do not fuse
55
During the passage of the fetus through the birth canal what typically occurs to the calvaria of a newborn?
the halves of the frontal bone become flat, the occipital bone is drawn out, and one parietal bone slightly overrides the other
56
Describe the enlargement of the calvaria in the stages of human development
The fibrous sutures of the calvaria also permit the cranium to enlarge during infancy and childhood
The increase in the size of the calvaria is greatest during the first 2 years, the period of most rapid brain development
The calvaria normally increases in capacity for 15-16 years
After this, the calvaria usually increases slightly in size for 3-4 years as a result of bone thickening
57
Premature closure of the cranial sutures is called________________
craniosynostosis results in several cranial malformations
58
Describe the premature closure of the sagittal suture
the anterior fontanelle is small or absent, results in a long, narrow, wedge-shaped cranium, a condition called scaphocephaly
59
What is plagiocephaly?
When premature closure of the coronal or the lambdoid suture occurs on one side only,
60
What is oxycephaly or turricephaly>
Premature closure of the coronal suture results in a high, tower-like cranium
61
The lateral aspect of the skull includes
lateral part of the neurocranium
Lateral part of the viscerocranium (facial skeleton)
62
bones forming the lateral portion of the neurocranium include
the frontal, parietal, occipital, sphenoid, and temporal bones
63
bones forming the visible part of the facial skeleton include
the nasal, maxilla, and zygomatic bones and the mandible
64
The main features of the neurocranial part (of the lateral aspect of the skull) are the_________
temporal fossa, the external acoustic opening, and the mastoid process of the temporal bone
65
The main features of the viscerocranial part (of the lateral part of the cranium) are the______________
infratemporal fossa, zygomatic arch, and lateral aspects of the maxilla and mandible
66
What is the pterion and it's notable feature?
The junction where the frontal, parietal, sphenoid(greater wing) and temporal bone meet is called the pterion
It is usually indicated by an H-shaped formation of sutures
67
Importance and clinical significance of the pterion
The pterion is an important area because it overlies the middle meningeal artery
Fracture to the pterion can rupture the anterior branch of this artery resulting in hematoma which exerts pressure on the underlying cerebral cortex
An untreated meningeal artery can cause hemorrhage which can lead to death in a few hours
68
Describe the standard craniometric reference/ plane called the orbitomeatal plane (Frankfort horizontal plane)
In the anatomical position, the cranium is oriented in such a way that the inferior margin of the orbit and the superior margin of the external acoustic meatus opening of both sides lie in the same horizontal plane
69
Describe the parts of the temporal bone of the lateral aspect of the skull
1. a squamous part which articulates with the greater wing of the sphenoid at the sphenosquamous suture
2. a zygomatic process which articulates with the zygomatic bone to form the zygomatic arch
3. a tympanic part which has the external acoustic meatus
4. a petromastoid part which is usually separated into the petrous and mastoid part
5. A large bony prominence projects from the inferior border of the mastoid part of the temporal bone called the mastoid process
6. Medial to the mastoid process is the styloid process which projects from the lower border of the temporal bone
70
The point where the superior temporal line cuts the coronal suture is called the __________
stephanion
71
At the junction of which sutures is the asterion?
it is located at the junction of three sutures: parietomastoid, occipitomastoid, and lambdoid
72
Bones of the posterior aspect of the skull include
Occipital bone
Parts of the parietal bones
Temporal bones (mastoid part)
73
The occipital bone is separated from the paired parietal bone by the_____________
lambdoid suture
74
Along the lambdoid suture are small bones called____________
sutural or wormian bones
75
there is a midline projection on the occipital bone called the_____________
external occipital protuberance
76
Curved lines extend laterally from the external occipital protuberance called the_______________
superior nuchal lines
77
The most prominent part of the external occipital protuberance is the____________
inion
78
About 1 inch (2.5cm) below the nuchal lines are additional 2 lines called the_______________
inferior nuchal lines which curves laterally
79
Extending downwards from the external occipital protuberance is the______________
external occipital crest
80
In between the mastoid and the occipital in is the_________________
occipitomastoid suture
81
Obliteration of sutures usually begins at____________
bregma and continues sequentially in the sagittal, coronal, and lambdoid sutures
82
The region of the skull between the 2 parietal foramina where the closure of the sagittal suture begins is called the________
OBELION
83
The Internal surface of the cranial base (cranial cavity/fossae)
has three large depressions that lie at 3 different levels:
anterior crania fossa
middle cranial fossa
posterior cranial fossa
84
What form the bowl-shaped floor of the cranial cavity
anterior crania fossa
middle cranial fossa
posterior cranial fossa
85
______________ is at the highest level(shallowest)
while the_____________ is at the lowest level(deepest)
The anterior cranial fossa
posterior cranial fossa
86
Sitting on the floor of the anterior cranial fossa is the
frontal lobes of the cerebral hemispheres
87
Sitting on the floor of the lateral portion of the middle cranial fossa is the_____________
temporal lobe, and in the midline of the middle crania fossa is the pituitary gland
88
the occipital lobe do not sit on the floor of the posterior cranial fossa, it is the_______________
cerebellum that sit of the floor of the posterior cranial fossa
88
Sitting on the anterior portion of the floor of the posterior cranial fossa is the____________
brainstem (midbrain, pons and medulla oblongata) and occupying the rest of the posterior cranial fossa are the cerebellar hemispheres
89
Description and formation of Anterior cranial fossa
Introduction:
Shallowest of the 3 cranial fossae
Lodges the frontal lobe of the brain
Bony formation:
Formed by 3 bones, namely:
Frontal bone in the anterior and lateral directions
Ethmoid bone in the middle portion
2 parts of the sphenoid bone in the posterior portion
90
The part of the frontal bone in the anterior cranial fossa is the______________
orbital part/orbital surface
91
The ethmoid bone of the anterior cranial fossa is made up of :
A ridge which projects superiorly called the crista galli
And a sieve-like cribriform plate of ethmoid which lies on each side of this ridge
92
The 2 parts of the sphenoid bone in the anterior cranial fossa are:
The jugum
The lesser wing of sphenoid
93
Foramen
The cribriform plate of ethmoid has numerous tiny foramina that transmit___________ from the______________to the_______________
olfactory nerves (CN 1)
olfactory area of the nasal cavity
olfactory bulb of the brain
94
The frontal bone also has a bony median extension called the________, at the base of it is the_____________
frontal crest
foramen cecum
95
Clinical significance of the foramen cecum
varies in size in different individuals, and is frequently impervious; when open, it transmits the emissary vein from the nose to the superior sagittal sinus
This has clinical importance in that infections of the nose and nearby areas can be transmitted to the meninges and brain
96
Each lesser wing widens, curves__________, and ends as a__________
posteriorly, rounded anterior clinoid process
97
The optic canal allows for the passage of
ophthalmic artery and
optic nerve [CN II] to pass through as they exit the cranial cavity to enter the orbit
98
The optic canals are usually included in the
middle cranial fossa
99
separating the anterior and middle cranial fossae laterally and centrally are the_____________
sharp sphenoidal crests laterally and the sphenoid limbus centrally
100
The sphenoid limbus forms the posterior and anterior boundary of what?
posterior boundary of the jugum and the anterior boundary of the prechiasmatic sulcus
101
the prechiasmatic sulcus is bounded posteriorly by the__________
tuberculum sellae
102
What is the prechiasmatic sulcus?
is a smooth groove stretching between the optic canals across the body of the sphenoid
103
Parts of the middle crania fossa
Formed mainly by the:
Parts of the sphenoid bone
Parts of the temporal bone
104
The parts of sphenoid involved in the middle crania fossa:
-Sella turcica which is part of the body of sphenoid
-greater wings of sphenoid laterally
105
Parts of the sella turcica
an anterior wall called the turberculum sella
a posterior wall called the dorsum sella
a deep central part lying in between the turberculum sella and dorsum sella
106
This central part is called the hypophyseal fossa, which houses the______________
pituitary gland
107
On each side of the body of the sphenoid are four foramina perforating the roots of the greater wings of the sphenoid, these include :
i Superior orbital fissure
ii foramen rotundum
iii foramen ovale
iv foramen spinosum
108
The superior orbital fissure allows for the passage of the
Cranial nerves III, IV and VI (occuomotor, trochlear and abducens nerves)
Ophthalmic division of trigerminal nerve (CN V1) ophthalmic vein
109
foramen rotundum: allows for the passage of the___________
maxillary division of the trigeminal nerve (CN V2)
110
foramen ovale: allows for the passage of the___________
mandibular division of the trigeminal nerve (CN V3)
111
foramen spinosum: allows for the passage of______________
the middle meningeal artery and the meningeal branch of mandibular nerve
112
Superior orbital fissure: a diagonal gap that______________
separates the greater wing from the lesser wing of the sphenoid
113
Parts of the temporal bone include:
squamous part of the temporal bones laterally
and the petrous part of the temporal bones posteriorly
On the petrous part are grooves for both the greater and lesser petrosal nerves
Posterolateral to the hypophyseal fossa is the foramen lacerum,
In life, it is closed by a cartilage plate
Only some meningeal arterial branches and small veins are transmitted vertically through the cartilage
The lateral parts of the middle cranial fossa support the temporal lobes of the brain
The boundary between the middle and the posterior cranial fossae is the:
the superior border of the petrous part of the temporal bone laterally
and a flat plate of bone, the dorsum sellae of the sphenoid, medially
114
Posterior cranial fossa
Largest and deepest of the 3 cranial fossa
Lodges the brainstem (medulla oblongata, pons and midbrain) and the cerebellum
Formed mainly by the occipital bone and the temporal bone
There is a slope that extend down from the dorsum sellae leading to the foramen magnum called the clivus
posterior to the foramen magnum are cerebellar fossae which accommodate the cerebellar hemispheres
The cerebellar fossae are partly divided by the internal occipital crest into bilateral concave impression
The internal occipital crest ends superiorly in a bony prominence called the internal occipital protuberance
115
internal acoustic meatus allows the passage of
passage of facial nerve (CN VII) and vestibulochear nerve (CN VIII)
116
Jugular foramen: allows the passage of:
3 cranial nerves pass through it, which are cranial nerves IX, X and XI {glossopharyngeal,vagus and accessory nerve}
2 important venous structures, the dura venous sinuses, coming in from the posterior side is the sigmoid sinus and from the anterior side is the inferior petrosal sinus
117
Formation of the internal jugular vein
these two sinuses enter the jugular foramen and when they emerge from the other side, they fuse together and once fused together, they are called the internal jugular vein
118
Describe the hypoglossal canal
located superior to the anterolateral margin of the foramen magnum and allows for the passage of the hypoglossal nerve {CN XII}
119
Foramen magnum: allows for the passage of;
The spinal cord which is continuous with the medullar obongata
The two vertebral arteries
The spinal contribution of accessory nerve, the spinal accessory nerve
120
The base of the skull is seen in the inferior view and extends ________________
anteriorly from the middle incisor teeth, posteriorly to the superior nuchal lines and laterally to the mastoid processes and zygomatic arches
121
the base of the skull is often divided into:
an anterior part, which includes the teeth and the hard palate;
a middle part, which extends from behind the hard palate to the anterior margin of the foramen magnum;
a posterior part, which extends from the anterior edge of the foramen magnum to the superior nuchal lines
122
Main features of the anterior part
The teeth project from the alveolar arches of the two maxillae
These arches are arranged in a U-shaped configuration that borders the hard palate on three sides
The hard palate is composed of the palatine processes of each maxilla anteriorly and the horizontal plates of each palatine bone posteriorly
The paired palatine processes of each maxilla meet in the midline at the intermaxillary suture
and the paired horizontal plates of each palatine bone meet in the midline at the interpalatine suture
the paired maxilla and the paired palatine bones meet at the palatomaxillary suture
123
Several additional features are also visible when the hard palate is examined:
incisive fossa
Greater palatine formaina
Lesser palatine formaina
Posterior nasal spine
124
the incisive fossa for the passage of
nasoplatine and sphenopalatine vessels
125
the greater palatine foramina for the passage of
greater palatine vessels and nerve
126
just posterior to the greater palatine foramina is the lesser palatine foramina for the passage of _______________
lesser palatine vessels and nerve
127
a midline pointed projection in the free posterior border of the hard palate called the_____________
posterior nasal spine
128
Briefly describe the middle part of the base of the skull
forming the anterior half are the vomer and sphenoid bones;
forming the posterior half are the occipital and paired temporal bones.
129
Vomer
Vomer
Anteriorly, the small vomer is in the midline, resting on the sphenoid bone
It contributes to the formation of the bony nasal septum separating the two choanae
130
Sphenoid
Only 3 parts of the spheniod is seen in the inferior view
They are:
body
Greater wings
2 pterygoid processes on each side
131
The pterygoid process consist of a___________
medial plate and a lateral plate separated by the pterygoid fossa
132
The body:
It articulates anteriorly with the_______, _______, and posterolaterally with the __________ bones, and posteriorly with the __________ bone
the vomer, ethmoid, and posterolaterally with the temporal bones, and posteriorly with the occipital bone
133
The greater wing:
Articulates laterally and posteriorly with the_______
temporal bone
134
Important features on the greater wing are:
Foramen ovale: passage of mandibular nerve (V3)
Foramen spinosum: passage of middle meningeal artery
135
Posterior half
Made up of
Part of Occipital bone
Parts of paired temporal bones
136
Occipital bone description
This include the basilar part of the occipital bone, which is posterior to the body of sphenoid
posterior to this part is the foramen magnum and it is bounded laterally by the temporal bone
Prominent structure on the basilar part is the pharygeal tubercle
137
Temporal bone description
Has a rough petrous part
Features here include:
Carotid canal for the passage of internal carotid artery
Mandibular fossa for the head of the mandible (condylar process)
External acoustic meatus
138
posterior part
Extend from the anterior edge of foramen magnum to the superior nuchal line posteriorly
Consist of the occipital bone in the central and posterior part and the temporal bone laterally
139
Features on the occipital bone
1. Jugular notch: present in the temporal bone for the passage of
Cranial nerve IX to XI
Internal jugular vein
2. Foramen magnum located in the occipital bone for the passage of:
The spinal cord which is continuous with the medullar oblongata
The two vertebral arteries
The spinal contribution of accessory nerve, the spinal accessory nerve
3. Occipital condyles: located on each side on the anterolateral margin of the foramen magnum for articulation with the atlas (the 1st cervical verterbra)
140
Features on the temporal bone:
Mastoid process
Styloid process
141
The following seven bones form the orbit:
Sphenoid.
Frontal.
Zygomatic.
Ethmoid.
Lacrimal.
Maxilla.
Palatine.
142
The external acoustic meatus is also known as
the ear canal
143
The frontal crest allows for the attachment of_________
falx cerebri
144
The anterior clinoid process allows for the attachment of the____________
tentorium cerebelli
145
146
Describe the scalp and it’s boundaries
covers the neurocranium,
•part of the head that extends from the superciliary arches anteriorly to the external occipital protuberance and superior nuchal lines posteriorly
• Laterally it continues inferiorly to the zygomatic arch
147
What are the layers of the scalp?
S- skin
•C- connective tissue (dense)
•A- aponeurotic layer
•L- loose connective tissue
•P- pericranium
148
Describe the skin of the scalp
Is the outer layer of the scalp
•It is thin, except in the occipital region
•It contains many sweat and sebaceous glands and hair follicles
•It is similar structurally to skin throughout the body with the exception that hair is present on a large amount of it
• It has an abundant arterial supply and good venous and lymphatic drainage
149
Describe the connective tissue of the scalp
Connective tissue
•forms the thick, dense, richly vascularized subcutaneous layer that is well supplied with cutaneous nerves
150
Describe the aponeuroses of the scalp
Aponeurosis (epicranial aponeurosis):
• is a broad, strong, tendinous sheet that covers the calvaria
•this layer consists of the occipitofrontalis muscle, which has
•A frontal belly anteriorly,
•an occipital belly posteriorly,
•and an aponeurotic tendon called the ‘epicranial aponeurosis’ or ‘galea aponeurotica’ connecting the two
151
Describe loose areolar tissue of the scalp
Loose areolar tissue
• a sponge-like layer including potential spaces that may distend with fluid as a result of injury or infection
•This layer allows free movement of the scalp proper over the underlying calvaria
152
Describe the pericardium of the scalp
Pericranium:
• a dense layer of connective tissue that forms the external periosteum of the neurocranium
•It is firmly attached, but can be stripped fairly easily from the cranial of living persons, except where the pericranium is continuous with the fibrous tissue in the cranial sutures
153
Describe the Innervation of the scalp (general)
Portion anterior to the ear and vertex are innervated by branches of the trigeminal nerve ‘V’
•Portion posterior to the ear and vertex are innervated by branches of the cervical nerves ( specifically C2 and C3 )
154
Describe the Innervation of the scalp (specific)
➢Anterior to the ear and vertex
•supratrochlear V1
•Supraorbital VI
•Zygomaticotemporal V2
•Auriculotemporal V3
posterior to the ear and vertex
•Lesser occipital nerve (C2)
•Greater occipital nerve (C2, C3)
•Occipital nerve (C3)
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What are the arteries that supply the scalp?
Supratrochlear artery
Supraorbital artery
Superficial temporal artery
Posterior auricular artery
Occipital artery
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What are the veins that drain the scalp?
Supratrochlear vein
Supraorbital vein
Superficial temporal vein
Posterior auricular vein
Occipital vein
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Describe the lymphatic drainage of the scalp
Lymphatic channels from the:
anterior half of the scalp drain into the parotid nodes
posterior half of the brain drains to the occipital and posterior auricular nodes
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Discuss scalp infections
The loose connective tissue layer (layer four) of the scalp is the danger area of the scalp because pus or blood spreads easily in it
Infection in this layer can also pass into the cranial cavity through emissary veins, which pass through parietal foramina in the calvaria, and reach intracranial structures such as the meninges
which can lead to meningitis
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