Session 1.3d - Lecture (Blood Vessels of the Head and Neck) Flashcards
(358 cards)
1
Q
Major Blood Vessels of the Head & Neck - ILO
- Arteries and veins in the neck
- Carotid triangle
- Blood supply/venous drainage
- Clinical relevance
A
- Arteries and veins in the neck
- Review the carotid triangle
- Blood supply and venous drainage of the neck, face, scalp, dura and skull
- Clinical relevance
- —- Pulses and JVP (how that’s measured)
- —- Routes of infection
- —- Atheroma
2
Q
Slide 4
Label the:
- Left and right side
- Sternocleidomastoid (and its two heads)
- External jugular vein (x2)
- Internal jugular vein
- Common carotid artery
- Sternohyoid muscle
A
See lecture
3
Q
Slide 4
Identify SCM and its two heads.
A
(See slides) SCM muscle and its two heads visible on the RHS.
LHS - SCM has been removed.
4
Q
Slide 4
Identify the sternohyoid muscle.
A
(See Notability) Thin, narrow, muscle that runs longitudinally from the hyoid bone down to the sternum. Visible on the RHS behind (deep) the SCM; partially cut away on the LHS.
5
Q
Slide 4
Identify the:
- thyroid gland
- trachea
- thyroid cartilage
A
See Notability
6
Q
Where does the common carotid artery lie?
A
Lies deep to the SCM - cannot be viewed until SCM has been moved aside
(apart from in a section just inferior to the hyoid bone, and medial to the SCM - shown on Slide 4 RHS)
7
Q
Where does the internal jugular vein lie?
A
Lateral to the CCA, but similarly to the CCA it is hidden by the SCM muscle.
8
Q
Where does the IJV drain into?
A
This major vein drains into the brachiocephalic vein (also covered by the SCM).
9
Q
Which vein in the neck is more readily visible?
A
The EJV is more readily visible because it’s coursing more superficially over the SCM.
10
Q
Slide 5
Label the: - left and right - arch of aorta - brachiocephalic trunk - left subclavian artery - left common carotid artery (And any other structures [not arteries] you can label)
A
See slides
11
Q
The brachiocephalic trunk is found on which side of the body?
A
Right
12
Q
The brachiocephalic trunk gives rise to which two arteries?
A
The common carotid artery and the subclavian artery.
13
Q
The right CCA and right subclavian artery arise from where?
A
Brachiocephalic trunk
14
Q
The left CCA and left subclavian artery arise from where?
A
Directly off the arch of aorta
15
Q
The arch of aorta gives rise to which arteries?
A
The brachiocephalic trunk (right), the left CCA and the left subclavian artery.
16
Q
The CCA bifurcates to give what?
A
The internal and external carotid arteries
17
Q
The internal and external carotid artery arise from where?
A
The bifurcation of the CCA (at about C4 level)
18
Q
Where does the CCA bifurcate?
A
At the superior border of the thyroid cartilage - which is approximately C4 level.
19
Q
Which artery(s) gives off branches in the neck - the external, internal or common carotid artery?
A
ECA
The ICA and CCA do not give off any branches in the neck.
20
Q
The vertebral artery comes from which artery on which side?
A
The subclavian artery on both sides
the right and left vertebral artery arise from the right and left subclavian artery, respectively
21
Q
What branches does the vertebral artery give off in the neck?
A
It doesn’t (like the ICA, heads up into the skull)
22
Q
The thyrocervical trunk arises from which artery?
A
The subclavian artery
23
Q
The inferior thyroid artery arises from where?
A
The thyrocervical trunk (from the subclavian artery).
It loops behind the CCA so appears that it branches off there but it doesn’t, it arises from the subclavian
24
Q
What does the inferior thyroid artery supply?
A
The lower lobe of the thyroid gland.
25
What is the arterial supply to the lower lobe of the thyroid gland?
The inferior thyroid artery
26
The internal thoracic artery comes from which artery?
The subclavian artery (we have one on each side)
27
What is another name for the internal thoracic artery?
The internal mammary arteries
28
The internal mammary arteries can also be known as ___?
The internal thoracic artery
29
Where does the internal thoracic artery travel?
Down within the thoracic cage
30
The internal thoracic artery travels down within the thoracic cage, and continues down to become what?
The superior epigastric arteries
31
The vertebral, internal thoracic and thyrocervical arteries all arise from where?
The subclavian artery in the base of the neck
32
The subclavian artery gives rise to which arteries?
The vertebral, internal thoracic and thyrocervical arteries in the base of the neck.
33
Slide 5
Identify the following arteries:
- common carotid
- subclavian
- external carotid
- internal carotid
- vertebral
- thyrocervical trunk
- inferior thyroid
- internal thoracic
See slides
34
Describe the inferior thyroid artery.
It comes off the thyrocervical trunk, curving behind the CCA and supplies the inferior lobe (lower pole) of the thyroid gland.
35
The suprascapular artery arises from where?
The thyrocervical trunk
36
The suprascapular artery supplies what?
The shoulder
37
The ascending cervical artery arises from where?
The inferior thyroid artery
38
The transverse cervical artery arises from where?
The inferior thyroid artery
39
The transverse cervical artery supplies what?
Structures in the neck
40
The thyrocervical trunk gives off which arteries?
The inferior thyroid and the suprascapular arteries.
41
The suprascapular and the inferior thyroid arteries come from where?
The thyrocervical trunk (off the subclavian artery).
42
The inferior thyroid artery gives off which branches?
The ascending cervical and transverse cervical
43
The ascending cervical artery supplies what?
Structures in the neck
44
The ascending cervical and transverse cervical arise from where?
The inferior thyroid artery
45
Describe the route from the arch of aorta to the ascending cervical artery on the right hand side. Name all the branches each structure gives off.
- Arch of aorta (braciocephalic trunk, left subclavian, left CCA)
- Brachiocephalic trunk (right subclavian, right CCA)
- Right subclavian artery (vertebral, internal thoracic, thyrocervical)
- Thyrocervical trunk (suprascapular, inferior thyroid)
- Inferior thyroid artery (ascending cervical, transverse cervical)
- Ascending cervical artery
46
Slide 6
Label the following arteries.
(Top to bottom)
- Ascending cervical
- Transverse cervical
- Suprascapular
- Inferior thyroid
47
What do the vertebral and ICA supply?
Intracranial structures - hence why they do not give off any branches in the neck, and head straight up into the skull.
48
The vertebral arteries arise from ___?
The subclavian arteries on the left and right
49
The vertebral arteries travel up the neck how?
Through the transverse foramina of cervical vertebrae 6-1
50
The vertebral arteries travel up the neck via which part of the cervical vertebra?
The transverse foramina
51
The vertebral arteries travel through the transverse foramina of which vertebrae?
C6 up to C1
52
The vertebral arteries enter the skull via the ___?
Foramen magnum
53
The vertebral arteries of each side (left and right) fuse to form ___?
The basilar artery
54
The basilar artery is created by the ___?
Left and right vertebral arteries fusing together
55
The ICA enters the skull via the ___?
Carotid canal
56
Where do the vertebral and ICA enter the skull?
Vertebral - foramen magnum
| ICA - carotid canal
57
The ICA after it enters the skull, and the basilar artery, along with other arteries form what?
An anastomosing circle of arteries called the circle of Willis in the brain.
58
What do the vertebral and ICA do?
Supply structures within the skull (intracranial structures) i.e. the brain.
59
Slide 7
```
Label the:
- vertebral artery
- internal carotid artery
- subclavian artery (right)
- transverse foramina of cervical vertebra
- C1-C6
- foramen magnum
- basilar artery
- carotid canal
(And any other structures)
```
- Vertebral: runs up through transverse foramina of cervical vertebra
- ICA: runs up from bifurcation of CCA into skull
- Subclavian: off brachiocephalic trunk from arch of aorta
- Transverse foramina: holes in which vertebral artery pass
- C1-C6: from top to bottom
- Foramen magnum: place where vertebral artery enters skull
- Basilar artery: junction where vertebral arteries fuse in skull
- Carotid canal: where ICA enters skull
60
What muscle forms the medial border of the carotid triangle?
Superior belly of omohyoid
61
What muscle forms the medial border of the carotid triangle?
```
A. anterior belly of digastric
B. inferior belly of omohyoid
C. posterior belly of digastric
D. sternocleidomastoid
E. superior belly of omohyoid
```
E. Superior belly of omohyoid
62
What are the boundaries of the carotid triangle?
Superior belly of omohyoid, Sternocleidomastoid, Posterior belly of digastric
63
What are the boundaries of the carotid triangle?
A. Midline of anterior aspect of the neck, Sternocleidomastoid muscle, Lower border of the mandible
B. Inferior belly of omohyoid, Sternocleidomastoid, Anterior belly of digastric
C. Superior belly of omohyoid, Sternocleidomastoid, Posterior belly of digastric
D. Superior belly of omohyoid, Sternocleidomastoid, Lower border of the mandible
E. Inferior belly of omohyoid, Sternocleidomastoid, Posterior belly of digastric
C. Superior belly of omohyoid, Sternocleidomastoid, Posterior belly of digastric
64
What occurs in the carotid triangle?
This is the location of the bifurcation of the CCA into the ICA and ECA.
65
The CCA bifurcates at which level (roughly)?
At the superior border of thyroid cartilage (C4 level)
66
Where does the IJV lie?
Lateral to the CCA, mostly under SCM.
67
Slide 9 (left)
Label the:
- superior belly of omohyoid
- anterior belly of digastric
- posterior belly of digastric
- sternocleidomastoid
- internal jugular vein
- common carotid artery
- external carotid artery
- internal carotid artery
See Notability
- SCM is cut back and reflected to show IJV and CCA
- ECA has many branches
- ICA has no branches in the neck
68
Slide 9 (right)
Label CCA, ICA, ECA and the thyroid cartilage
Arrow (CCA)
ICA - No branches
ECA - branches
Thyroid cartilage - grey pentagon
69
http://www.netanatomy.com/GAs/GAhns/hnGAcommon1si.html
Identify the:
- carotid triangle
- its borders
- IJV
- ECA
- ICA (not visible here but locate)
See Extra Notes (also website for further information/tests)
*Note: ICA cannot be seen; the IJV would have to be reflected to visualise it!)
70
Describe the borders of the carotid triangle in detail.
Lateral border - anterior border of SCM
Medial border - superior belly of omohyoid
Superior border - posterior belly of digastric
71
Where does the ICA lie?
Behind the IJV, so cannot see it on this cadaver
72
Bifurcation of the carotid artery is a common site for what?
Atheroma formation
73
Why is the bifurcation of the CCA a common site for atheroma formation?
Bifurcation at this point causes turbulence, and where you get turbulence is where you can have an atheroma forming
74
What do atheromas do to an artery?
They cause a narrowing (stenosis) of the artery
75
How much does the artery need to be narrowed by to cause symptoms?
>70%
76
What complications can occur from an atheroma
Ischaemia - not enough blood getting to the brain
Embolus
77
Other than ischaemia, what complications can occur from an atheroma?
Rupture of the clot can cause an embolus to travel to the brain.
78
Rupture of an atheromatic clot can cause what?
An embolus
79
How can an embolus in the CCA be a cause of TIA or stroke?
If an embolus comes off the ICA, it will travel up the brain, and if it lodges in an artery supplying a region of the brain then it will cause TIA or a thrombotic stroke.
80
What can an embolus in the CCA be a cause of?
- Transient ischaemic attack (TIA)
| - Thrombotic stroke
81
Slide 10
Describe the picture, and explain how you can get TIA or stroke.
- Bifurcation of the carotid artery causes turbulence
- Turbulence is a common place for atheroma formation
- This causes an artery to narrow (stenosis
- If the artery is stenoses by >70%, then that can cause symptoms such as ischaemia
- Another complication is an embolus, due to rupture of the clot
- If this occurs in the ICA, then this can travel straight up to the brain, lodging in an artery there
- If this artery supplies the brain, then this can be the cause of TIA or stroke
82
What structures appear at the site of bifurcation of the carotid artery?
- Carotid sinus
| - Carotid body
83
What is the bulge of the ICA, at the bifurcation point, called?
Carotid sinus
84
Where is the carotid sinus?
It is a swelling on the ICA at the region of bifurcation.
85
Where are baroreceptors located?
Within the artery wall of the carotid sinus
86
The carotid sinus is the location for what?
Baroreceptors
87
What are baroreceptors?
Pressure sensors for detecting changes in arterial blood pressure
88
What detects changes in blood pressure?
Baroreceptors (found in the carotid sinus)
89
How do baroreceptors act to change blood pressure?
If the blood pressure is higher, then the baroreceptors stretch and send more action potentials to the cardiovascular control centre in the brain.
90
What does the carotid body do?
They are a small cluster of peripheral chemoreceptors which detect arterial oxygen.
91
What is the carotid body?
A cluster of richly vascularised cells (getting a really rich blood supply - they are not in the artery wall)
92
Where are the chemoreceptors that detect arterial oxygen found?
In the carotid body
93
Describe the similarities and differences between the carotid sinus and carotid body
Similarities:
- both occur due to the bifurcation of the carotid artery
Differences (Carotid sinus/Carotid body):
- Swelling at region of bifurcation/cluster of richly vascularised cells not in the arterial wall
- Location of baroreceptors/chemoreceptors
- Detects changes in blood pressure/arterial oxygen
94
Slide 11
Label the carotid sinus and the carotid body. Describe their structure and function.
See slides
Carotid sinus/carotid body:
- swelling/cluster of cells
- location of baroreceptors/chemoreceptors
- arterial BP/arterial O2
95
Why is the carotid triangle important clinically?
- Surgery, e.g. if someone has an atheroma present and the artery is really narrow (>70%) then may need plaque removed via surgery
- For reaching the IJV
96
What is the most appropriate method of removing an atheroma in the carotid artery?
- Patients assessed individually, so many factors will be looked at
- For some patients, most appropriate treatment is surgery (carotid endarterectomy)
97
Explain how a surgeon would remove an atheromatous plaque in the carotid artery.
- Find the carotid triangle, as the carotid artery is easily accessible here
- Surgically open the carotid artery to remove the plaque
- Stitch it up again
98
What is a carotid endarterectomy?
Carotid endarterectomy is a surgical procedure to remove a build-up of fatty deposits (plaque), which cause narrowing of a carotid artery. (NHS)
99
What is the name for the surgical procedure which involves a removal of the fatty deposits in a carotid artery?
Carotid endarterectomy.
100
What is an SVT?
Supraventricular tachycardia
101
What is SVT?
When the heart is racing because of a problem above the ventricles and atria
102
What is a treatment for SVT?
Carotid sinus massage
103
What is the physiological mechanism of a carotid sinus massage for patients with SVT?
- The carotid sinus is the location of the baroreceptors.
- If a patient has SVT, then you want to slow conducting getting through the AVN by increasing vagal tone (reduce the heart rate)
- Massaging the carotid triangle area allows you to massage over the carotid sinus
- This activates baroreceptors, which in turn, will enhance vagal input
- Similarly, the vagal nerve is found in this area so you may be stimulating the vagus nerve directly to increase vagal tone
104
Which nerves can be accessed in the carotid triangle?
The vagus and hypoglossal nerves
105
Where can the carotid pulse be felt?
In the carotid triangle, just below the bifurcation
| - may also be palpated more inferiorly
106
Slide 12
Explain the picture (top)
1) Before - plaque - restricted blood flow
2) Plaque is removed
3) After - Normal blood flow
107
Slide 12
What procedure is this image showing (bottom)?
Carotid sinus massage
108
Where does the ICA enter the skull?
Through the carotid canal
109
Where is the carotid canal?
A canal in the petrous part of the temporal bone
110
What happens to the ICA when it enters the skull through the carotid canal?
It immediately turns medially and horizontally
111
Slide 13
Identify the ICA and carotid canal
The artery that arises from the bifurcation point of the CCA, where it enters the skull is the carotid canal. Note how it turns medially and horizontally as it enters the skull.
112
What is the route of the ICA?
It enters the skull through the carotid canal in the petrous part of the temporal bone, then turned medially and horizontally.
113
What happens to the ICA when it enters the skull?
It enters the cranial cavity then makes S-shaped bend - it appears tortuous and curved.
114
What sort of shape does the ICA make when it enters the cranial cavity?
It appears tortuous and curved, making an S-shaped bend
115
After the ICA makes its S-shaped bend once it enters the cranial cavity, what does it do?
It courses through the cavernous sinus
*must know this!*
116
Slide 14
What section is the right image taken from?
Coronal, see left image
117
Slide 14
Describe the route of the ICA.
Correctly identified:
- carotid canal
- temporal bone
- S-shaped curve of the ICA
- cavernous sinus
118
How many cavernous sinuses are there?
Two, one on each side
119
Where does the cavernous sinus sit?
Either side of the sphenoid bone, in the sella turcica, where the pituitary gland sits.
120
Which bone is the cavernous sinus associated with?
The sphenoid bone
121
What is the depression in which the cavernous sinus lies called?
The sella turcica
122
What sits in the sella turcica?
The cavernous sinus and the pituitary gland
123
What is the sella turcica?
A depression in the sphenoid bone in which the pituitary gland sits.
124
What lies either side of the sphenoid bone?
The cavernous sinus which is part of the dural venous plexuses
125
Within the venous plexus, what structures pass through?
Many other structures, including:
- ICA
- many other cranial nerves
126
What is found on the upper surface of sphenoid?
A plexus of extremely thin-walled veins
127
What and where is the cavernous sinus?
A plexus of extremely thin-walled veins on the upper surface of sphenoid
128
What structures are found in the cavernous sinus?
- Internal carotid artery
- CNIII oculomotor
- CNIV trochlear
- CNVI abducent
- 2 branches of trigeminal
- ---- CNV1 ophthalmic and CNV2 maxillary
129
Which cranial nerves are found in the cavernous sinus?
Cranial nerve 3, 4 and 6; plus two branches of cranial nerve 5
i.e. oculomotor, trochlear, abducent and two branches of trigeminal (opthalmic and maxillary)
130
What is cranial nerve III?
Oculomotor
131
Oculomotor is cranial nerve ___?
III (3)
132
What is cranial nerve IV?
Trochlear
133
Trochlear is cranial nerve ___?
IV (4)
134
What is cranial nerve VI?
Abducent
135
Abducent is cranial nerve ___?
VI (6)
136
What is cranial nerve V?
Trigeminal
137
Trigeminal is cranial nerve ___?
V (5)
138
Which cranial nerve has two branches found in the cavernous sinus?
Trigeminal
139
Which two branches of the trigeminal nerve are found in the cavernous sinus?
Ophthalmic and maxillary (CNV1 and CNV2)
140
What nerves are CNV1 and CNV2?
The ophthalmic and maxillary branches of the trigeminal nerve
(Mandibular = CNV3)
141
What do the oculomotor, trochlear and abducent cranial nerves supply?
The muscles controlling the movement of the eye
142
Which cranial nerves control the movement of the eye?
III, IV and VI = oculomotor, trochlear and abducent
143
Slide 15
What section is this image (bottom)?
Coronal section of cavernous sinus (see top image)
144
Slide 15 (bottom image)
Identify the:
- cavernous sinus
- sphenoid bone
- sella turcica
- pituitary gland
- ICA
- cranial nerves
- CS: blue on each side
- Sphenoid: cream bone
- Sella turcica: darker cream depression
- Pituitary: pink
- ICA: red
- CN: yellow
145
What is an arteriogram?
An x-ray of arteries
146
How do you take an arteriogram?
Put radiopaque dye in carotid system
147
What is radiopaque dye?
Dye that does not allow the passage of X-rays or other radiation - allows certain structures to be outlined (e.g. in arteriograms, outlines arterial system).
148
Slide 16
Caption this image
Arteriogram of the carotid system, using radiopaque dye
149
Slide 16
Highlight the S-shape of the ICA
See Notability
This shows the ICA takes a tortuous course.
150
The ophthalmic artery is a branch of which artery?
The ICA
151
The ophthalmic artery is one of the first branches that the ICA gives off when it ______ the _____.
Enters the skull
152
The ophthalmic artery runs along with which nerve?
The optic nerve (CN II)
153
The ophthalmic artery gives off a branch which supplies the retina of the eye. What is this called?
The central retinal artery
154
The central retinal artery supplies what?
The retina of the eye
155
The eyeball is supplied by ___?
Branches of the ophthalmic artery (a branch of the ICA)
156
The orbit of the eye is supplied by ___?
Branches of the ophthalmic artery (a branch of the ICA)
157
The ophthalmic artery branches to supply ___?
The retina of the eye, the eyeball and the orbit of the eye.
158
What is the first branch of the ICA?
The ophthalmic artery
159
The supratrochlear and supraorbital artery arise from where?
The ICA via its first branch, the ophthalmic artery.
160
Slide 17
Identify the:
- ICA
- Opthalmic a
- Optic nerve (CN II)
- Central retinal a
- Retina of the eye
- Supratrochlear a
- Supra-orbital a
See slides (retina is back of eye)
161
Which cranial nerve is the optic nerve?
CN II
162
Which is cranial nerve II?
Optic nerve
163
How many branches in the neck do the ICA and ECA give off?
ICA - 0
ECA - 6 + 2 terminal branches
164
How many branches does the ECA give off?
6 + 2 terminal branches.
165
What is the first branch of the ECA?
Superior thyroid artery
166
What does the superior thyroid artery supply?
The thyroid gland
167
What arteries supply the thyroid gland?
The superior thyroid artery and the inferior thyroid artery
168
Where do the superior and inferior thyroid arteries arise from?
Superior - first branch of ECA (from CCA)
Inferior - branch of the thyrocervical (from subclavian a)
169
What is the second branch of the ECA?
Lingual artery
170
What does the lingual artery supply?
The tongue
171
What is the third branch of the ECA?
Facial artery
172
Where does the facial artery lie?
Goes along the mandible and comes up just in front of the masseter muscle.
The facial artery has several branches.
173
How do you find your facial pulse?
Clench your jaw (mandible), feel masseter muscle tense up. Palpate just in front of here, can feel pulse of facial artery.
174
What is the fourth branch of the ECA?
Ascending pharyngeal artery
175
Describe the structure of the ascending pharyngeal artery.
Tiny branch that ascends up the neck
176
What is the fifth branch of the ECA?
Occipital
177
Where does the occipital artery lie?
Around the posterior aspect of the scalp
178
What does the occipital artery supply?
The scalp
179
What is the sixth branch of the ECA?
Posterior auricular
180
Where does the posterior auricular artery lie?
It runs up the neck and travels behind the ear, hence the name
181
What does the posterior auricular artery supply?
The scalp
182
What are the two terminal branches of the ECA?
- Superficial temporal a
| - Maxillary a
183
Describe the superficial temporal artery.
It is one of two terminal branches of the ECA. It gives off lots of other branches in the skull which anastomose with other arteries.
184
Where does the maxillary artery lie?
Deep behind the mandible
185
The superficial temporal artery and the ________ artery are terminal branches of the ECA.
Maxillary
186
Slide 18
Identify the 6 branches of the ECA and the 2 terminal branches.
Label the other arteries for bonus points
See slides
Note: Maxillary artery has a marking at the posterior of the skull and a small red arrow deep to the maxilla.
187
What is the blood supply to the scalp?
- Supraorbital
- Supratrochlear
- Superficial temporal
- Posterior auricular
- Occipital
188
How is blood supplied to the scalp?
By branches of the ECA and ICA anastomosing over the head and giving blood supply to the scalp.
189
What are the branches of the ECA that supply blood to the scalp?
- Superficial temporal
- Posterior auricular
- Occipital
190
What are the branches of the ICA that supply blood to the scalp?
- Supraorbital
| - Supratrochlear
191
Where do the supraorbital and supratrochlear arteries come from?
Branches of the ophthalmic artery from the ICA.
192
The superficial temporal, posterior auricular and occipital arteries are branches of ___?
The ECA
193
Slide 19 (left)
Identify roughly the following arteries:
- Supraorbital
- Supratrochlear
- Superficial temporal
- Posterior auricular
- Occipital
See slides
194
Slide 19 (right)
Identify the following arteries:
- Supraorbital
- Supratrochlear
- Superficial temporal
- Posterior auricular
- Occipital
See slides
195
Describe the blood supply to the scalp.
Rich blood supply with many anastomoses.
196
The blood supply to the scalp is largely branches of ___.
ECA
197
The blood supply to the scalp is largely branches of ___ except for the _____________ and ___________ arteries, which arise from ___?
ECA; supratrochlear and supraorbital; ICA (via its first branch ophthalmic a)
198
Slide 20
Label the different arteries
- Supratrochlear
- Supraorbital
- Superficial temporal
- Posterior auricular
- Occipital
(See slides)
199
Which layer of the scalp do the blood vessels lie?
In the dense connective tissue layer, the subcutaneous connective tissue layer
200
What are the different layers of the scalp?
- Skin
- Connective tissue (dense)
- Aponeurosis
- Loose connective tissue
- Periosteum (CT on the bone)
201
The subcutaneous connective tissue layer of the scalp is which layer and holds what?
Connective tissue (dense) [second layer from superficial to deep] and holds blood vessels.
202
Slide 21
Name the layers of the scalp
- Skin
- Connective tissue (dense)
- Aponeurosis
- Loose connective tissue
- Periosteum
203
What is the clinical relevance of blood supply to the scalp?
Because the walls of arteries are closely attached to connective tissue, if there's a cut, it tends to pull them apart and limits constriction of arteries.
The structure of the scalp means that a cut to the scalp can lead to profuse bleeding
204
Why do anastomoses lead to profuse bleeding on a cut to the scalp?
Due to numerous anastomoses on the scalp, it's difficult to apply pressure to the vessels to stop the bleeding, leading to profuse bleeding.
205
Why does the epicranial aponeurosis lead to profuse bleeding on a cut to the scalp?
The occipitalis and frontalis muscles are connected via the epicranial aponeurosis. However, these two muscles (collectively, occipitofrontalis) are pulling in different directions. This can actually pull a cut open to make it worse and bleed more profusely, so deep lacerations involving the epicranial aponeurosis can cause profuse bleeding due to the opposing pull of occipitofrontalis.
206
Why can a cut to the scalp lead to profuse bleeding?
- Arteries closely attached to connective tissue: this limits constriction so profuse bleeding can occur
- Numerous anastomoses: makes it difficult to apply pressure to stop the bleeding
- Epicranial aponeurosis (occipitofrontalis): opposing pull of muscle can pull the vessels open and make the cut worse
207
Why does loss of scalp tissue not lead to bone necrosis?
The blood supply to the scalp is different to the blood supply to the skull (middle meningeal artery) - so those that suffer scalp injuries alone will not endure necrosis of bone.
208
What is the main blood supply to the skull?
Middle meningeal artery
209
What can happen to the skull if you have a scalp injury?
Nothing, you will not get bone necrosis because the blood supply to the skull is differently to the blood supply to the scalp. (Blood supply to the skull is mostly the middle meningeal artery.)
210
Slide 22
What is the arrow indicating?
Epicranial aponeurosis
211
What are the superficial arteries of the face?
- Facial
- Supraorbital
- Supratrochlear
- Superior & inferior labial
- Angular
- Lateral nasal
212
The facial artery comes off which artery?
ECA
213
The facial artery gives off which arteries around the lips?
Superior & inferior labial arteries
214
Where do the superior and inferior labial arteries arise?
From the facial artery
215
All the superficial arteries of the face arise from the ECA except the ___ and ___?
Supraorbital and supratrochlear - these are from the ICA (via ophthalmic).
216
The facial artery gives off which arteries around the nose?
- Angular
| - Lateral nasal
217
Slide 23
Label the structures. Which of these two structures supply deeper structures?
- Supraorbital
- Supratrochlear
- Transverse facial
- Angular
- Lateral nasal
- Maxillary
- Superior & inferior labial
- Facial
The transverse facial and maxillary supply deeper structures.
218
Where can the facial artery pulse be felt?
At the inferior border of the mandible, anterior to the masseter muscle.
219
What do the branches of the maxillary artery supply?
The maxillary artery has many branches supplying muscles and deeper structures in face
220
What are the two branches of the maxillary artery *need to know*?
Sphenopalatine
Middle meningeal
*Need to know*
221
What does sphenopalatine artery supply?
An anastomosis to the nasal septum
222
What does the middle meningeal artery supply?
Blood to the skull and the dura
223
Sphenopalatine is a branch of which artery?
Maxillary
224
Middle meningeal is a branch of which artery?
Maxillary
225
Slide 24
Label the following arteries:
* Sphenopalatine
* Middle meningeal
and Maxillary (1st part)
See slides
226
Which arteries supply the nasal septum?
* Septal branch of sphenopalatine artery
* Anterior ethmoidal arteries
(There are others, e.g. posterior ethmoidal, septal branch of labial artery etc., but you do not need to know them!)
227
How is the blood supply to the nasal septum arranged?
Arteries supplying the septum anastomose in Kiesselbach's area
228
What is Kiesselbach's area?
An anastomosis of blood vessels in the nasal septum
229
Where does the sphenopalatine artery come from?
The maxillary artery
230
Where does the anterior ethmoidal artery come from?
The ophthalmic artery
231
What is the medical terminology for a nose bleed?
Epistaxis
232
What is epistaxis?
A nosebleed
233
Describe how the sphenopalatine artery relates to nose bleeds.
This artery joins with other arteries (such as the anterior ehtmoidal) to anastomose in the nasal septum. They anastomose in an area called Kiesselbach's area, which because of the rich blood supply, is a common site for nosebleeds.
234
What is the clinical relevance of Kiesselbach's area?
It is a site of anastomosis in the nasal septum, and because of this, is a common site for epistaxis (nosebleeds) - the anastomosis makes it difficult to stop that nosebleed.
235
Slide 25
Label the diagram.
See slides
Important is *Sphenopalatine
* Anterior ethmoidal
* Kiesselbach area
236
What is the blood supply to the skull and the dura that surrounds the brain?
The middle meningeal artery
237
The middle meningeal artery is a branch of the ___?
Maxillary artery
238
Where does the middle meningeal artery pass (in relation to the skull)?
Deep to the zygomatic arch
239
What does the middle meningeal artery split into and where?
Inside the skull, it splits into the anterior and posterior branch (of the middle meningeal artery)
240
The frontal, parietal, temporal and sphenoid bones join together. What is this region called?
The pterion
*need to know*
241
What is the pterion?
The region where the skull bones join together
242
Why is the pterion clinically significant?
The pterion is a particularly thin area of skull where the bones of the skull join together. The middle meningeal artery also courses over this.
This means that if you get a blow to the side of the head at this region, the middle meningeal artery can be damaged, as this area of the skull is a little bit thinner and more easily damaged.
243
Slide 26 (left)
Label the:
- maxillary a
- middle meningeal a
- anterior branch of middle meningeal a
- posterior branch of middle meningeal a
- pterion
See slides
| anterior and posterior branches are shaded paler to represent they are inside the skull
244
Slide 26 (right)
Identify the pterion
See slides
| where the skull bones join together
245
Where does the middle meningeal artery enter the skull?
Through the foramen spinosum
246
Slide 27
- Identify the foramen spinosum.
- Identify the grooves made by the middle meningeal artery
See Notability
247
Describe the landmark made by the middle meningeal artery in the skull.
It makes grooves in the skull as it supplies the skull, after it enters through the foramen spinosum.
248
What does the middle meningeal artery supply?
The skull and the dura
249
What is the brain covered by?
A double layer of dura mater - one layer is attached to the skull (periosteum)
250
Describe the two layers of dura mater attached to the skull.
One layer is attached to the skull as periosteum
251
Slide 28 (left)
- Label the arrows
- Identify the covering of the skull
Arrows: anterior branches of middle meningeal artery
Brain covered by double layer of dura mater (shown by window)
(See Notability)
252
Slide 28 (right)
- Label the red arrows
- Caption the image by its view
- Describe how this view was taken
- Coronal suture
- Grooves formed by anterior branch of middle meningeal artery
Caption: Internal view of calvaria (skull)
The view of this skull is taken as if you've taken the top bit of the skull off and looking inside at the concave bit.
253
What does "calvaria" mean?
Skull
254
What is the Latin name for skull?
Calvaria
255
What does the middle meningeal artery supply?
The skull and dura
256
Where is a common site of middle meningeal artery rupture?
At the pterion
257
Where can you fracture the skull?
At the pterion
258
Fracture of skull at pterion can ___?
Rupture the middle meningeal artery
259
What happens if the middle meningeal artery ruptures?
Blood comes out, which actually peels the dura off the skull
260
What are the two layers of dura?
- Layer attached to the skull
| - Layer surrounds the brain
261
What is an extradural haemorrhage?
When bleeding occurs between the tough outer layer of the skull and the brain i.e. outside the dura.
For example, fracture of the skull at pterion can rupture the middle meningeal artery, pulling the dura away from the skull, causing a haemorrhage in the space between the skull and the dura.
(See extra notes for full explanation if not understood)
262
How would an extradural haemorrhage appear in a CT scan of the brain?
There would be a crescent-shaped protrusion of the outer edges of the skull where blood has pooled - however, the blood is limited by the dura so does not extend further.
263
Slide 29 (left)
Explain what the left image is showing. The portion of the skull shown is the pterion.
- Fractures of the skull at the pterion can rupture the middle meningeal artery.
- This peels the dura away from the skull (thin light pink layer) as blood pools.
- However, the blood is limited by the dura (double layer - thin light pink and thin light yellow) so does not touch the brain.
- Note the crescent shape the blood makes.
264
Slide 29 (right)
Explain what the image is showing.
- This is a CT scan of the brain.
- The scan is showing an extradural haemorrhage in a patient.
- This is characterised by the crescent-shaped protrusion at the edges.
- The crescent-shape is present because fractures of the skull, particularly at the pterion, at the side of the head (as in this image), fracture the middle meningeal artery
- This then peels the dura away from the skull.
- However, the blood is limited by the dura so does not extend into the skull, and therefore forms the crescent-moon shape (the dura which formerly attached to both skull and brain is now being pushed so there is now skull --> blood --> both dural layers --> brain)
265
What is a craniotomy?
Surgery to cut a bony opening in the skull
266
How can a surgeon gain access to the cranial cavity?
By performing a craniotomy
267
What is the cranial cavity?
Space within the skull
268
How is a craniotomy performed?
The bon and scalp flap is reflected inferiorly to preserve the blood supply by keeping the arteries intact (?)
269
Slide 30
Label the image
- Dura mater
- Bone flap
- Scalp & muscle
270
In venous drainage of the scalp - what do the superficial veins generally do (as is typical).
They generally accompany arteries of the same name.
271
What are some of the superficial veins of the scalp?
- Superficial temporal veins
- Occipital veins
- Posterior auricular veins
272
The superficial veins of the scalp general accompany arteries of the same name. Name some of these.
- Superficial temporal
- Occipital
- Posterior auricular
273
Name some veins of the scalp which drain a different direction to their respective arteries.
- Supraorbital vein
| - Supratrochlear vein
274
How do the supraorbital and supratrochlear arteries and veins differ?
The arteries came as branches off the ICA and ophthalmic.
The veins, instead of following the same direction, unite at the medial angle of the eye to form an angular vein, which drains into the facial vein.
275
Where are the supraorbital and supratrochlear veins found?
These unite at the medial angle of the eye to form an angular vein, which drains into the facial vein.
276
Which vein does the supraorbital and supratrochlear vein drain into?
The facial vein
277
Where are some of the deep veins in the scalp found?
In the temporal region
278
Some of the deep parts of the scalp in the temporal region have veins which drain where?
Into the pterygoid venous plexus.
279
Slide 32
Explain what this image is showing.
Venous drainage of the scalp.
Note: the diagram is only showing the skull - but imagine there is scalp etc. there
280
Slide 33
Identify the following veins:
- supraorbital
- supratrochlear
- angular
- facial
- superficial temporal
- occipital
- posterior auricular
Any other veins
See Notability
281
Structures that drain the brain drain into where?
Structures called dural venous sinuses.
282
Cerebral veins drain where?
Into dural venous sinuses
283
What are dural venous sinuses?
Essentially venous channels covered in dura
284
Where are dural venous sinuses found?
Between the double layer of dura (i.e. between the dura that covers the brain and between the dura under the bone of the skull)
This occurs at certain parts of the skull - the dura separates to form venous sinuses.
285
Most of the venous drainage to the skull is going to drain into the dural venous sinuses. What else drains here?
Emissary veins which go from the scalp and drain through into the dural venous sinus.
286
How does venous drainage of the scalp enter the dural venous sinus?
Via emissary veins
287
What are emissary veins of the skull?
These connect venous drainage of the scalp to the dural venous sinuses.
288
What are veins of the skull called?
Diploic veins
289
How do the veins of the scalp connect to the diploic veins of the skull (and thus to dural venous sinuses)?
Via several emissary veins
290
What is a distinctive component of emissary veins?
They are valveless
291
Emissary veins are valveless. What does this mean for blood flow?
Blood can move in either direction.
292
Why can blood move in either direction for emissary veins?
Because they are valveless.
293
Why are emissary veins important to know about clinically?
They can act as a route for infection from the scalp to the cranial cavity.
If serious, this can lead to meningitis.
294
How can an infection in the scalp spread to the cranial cavity?
Via emissary veins which connect the scalp to the skull, allowing blood to travel and therefore infections.
295
What is a complication of an infection in the dural venous sinus?
The infection can get into the cranial cavity and affect the meninges covering the brain - leading to meningitis.
296
Slide 33
Label the diagram (include the hemispheres of the brain)
See Slides/Notability
297
Slide 34
Label the veins depicting venous drainage of the face
- Supraorbital
- Supratrochlear
- Angular
- Superior & inferior labial
- Facial
- Common facial
- Internal jugular
- External jugular
298
Describe the path from the supraorbital and supratrochlear veins to the internal jugular vein
Supraorbital/supratrochlear --> angular --> facial --> common facial --> IJV
299
Describe the path from the superior & inferior labial veins veins to the internal jugular vein
Superior & inferior labial veins --> facial --> common facial --> IJV
300
Slide 34
Identify the superficial temporal vein and comment on its drainage
See Notability
You can get a little bit of variability in the superficial temporal vein - part of it comes down into the IJV but it also drains into the EJV
301
What is a structural components of veins of the face?
They are valveless
302
Slide 34
Label the cavernous sinus
See Notability
| pale plexus of veins in skull
303
As well as drainage of the eye coming down towards the facial vein, where else can these veins drain?
Back towards the cavernous sinus
304
What does the cavernous sinus hold (other than veins)?
The internal carotid artery, either side of the sphenoid bone
305
Where is the cavernous sinus?
Either side of the sphenoid bone.
306
Which veins around the orbit can drain back to the cavernous sinus?
The superior and inferior ophthalmic veins
307
Where can deep facial veins drain into?
The pterygoid venous plexus
308
Where is the pterygoid venous plexus?
Extracranial - i.e. not in the cranial cavity
309
How are the pterygoid venous plexus and cavernous sinus connected?
Via emissary veins
310
The pterygoid venous plexus connects to which other plexus via emissary veins?
The cavernous sinus
311
Why are the emissary veins connecting the pterygoid venous plexus and the cavernous sinus clinically important?
- This allows for a route of infection from the superficial face into the intracranial cavity
- If there is a clot (infected) in the facial vein that can travel to the cavernous sinus
- This can be from the infections travelling to the the deep facial veins, which travel to the pterygoid venous plexus and travel up via emissary veins to the cavernous sinus
- Or the clot from the facial vein can travel up towards the superior ophthalmic vein, where it can enter the cavernous sinus directly
Note that this is RARE but can happen.
*Veins in the face are valveless and therefore travel both direction!*
312
Which veins communicate at the medial angle of the eye?
The superior ophthalmic and facial veins
313
What is the significance of veins in the face being valveless?
The blood can drain in both directions
314
Infection from the facial vein can spread where?
To dural venous sinuses e.g. cavernous sinus
315
What is thrombophlebitis?
An inflammatory process that causes a blood clot to form and block one or more veins.
316
What can occur if you get thrombophlebitis of the facial vein?
- Thrombophlebitis is an inflammatory process, causing a blood clot to block 1(+) vein(s).
- The infected clot can travel around the veins of the face (as these are valveless)
- This can either travel to the pterygoid venous plexus, which travels to the cavernous sinus via emissary veins; or up to the medial angle of the eye, where it meets the superior ophthalmic vein which drains directly into the cavernous sinus
- This means thrombophlebitis (blood clots of the vein) can travel to the intracranial venous system and cause infections here
- Note, these complications are rare but can occur and are serious
317
Slide 35
Label the arrows
- Superior ophthalmic v
- Cavernous sinus
- Inferior ophthalmic v
- Pterygoid venous plexus
- Facial v
- Deep facial v's
318
Why is it important that the cavernous sinus does not get infected?
Has many structures in it
- ICA
- number of cranial nerves
as well as close it it
- pituitary gland
It is also a sinus draining the brain.
319
Slide 36
Looking at the image - why might a cavernous sinus infection be serious?
The cavernous sinus (a plexus of extremely thin-walled veins on upper surface of sphenoid)
holds the
- ICA
- oculomotor n
- trochlear n
- abducent n
- -- ophthalmic and maxillary branch OF trigeminal n
(It is also close to the pituitary gland and is a sinus draining the brain)
320
What is the danger triangle of the face?
The danger triangle is where the facial vein can drain back into the cavernous sinus.
321
Why is it clinically important to know about the danger triangle?
Infections in this region can spread through the venous system (via the facial nerve) to the dural venous sinuses (cavernous sinus)
322
Which area of the face are infections most likely to spread back to the cavernous sinus?
The danger triangle (from bridge of nose to corners of mouth)
323
Slide 37
What is this triangle called and why is it important?
The danger triangle - superficial infections of the face in this triangle can spread deep intracranially into the dural venous sinuses
324
What are dural venous sinuses?
Sinuses where the cerebral veins drain into
325
Where do veins from the brain drain into?
Cerebral veins drain into dural venous sinuses
326
What is the venous drainage of the brain?
Dural venous sinuses
327
Where do the superior and inferior sagittal sinuses join?
At the posterior head, where there is a confluence of isnuses, including the transverse sinus.
328
Where does the sigmoid sinus head out of the skull
A hole in the bottom of the skull called the jugular foramen
329
The sigmoid sinuses leave the skull via the _____ and continue as the ___
jugular foramina; IJV
330
Slide 38
Label the diagrams
See slides
331
Slide 38
Identify where the superior and inferior sagittal sinuses meet on both images.
Identify the jugular foramen (right image)
See Notability
332
Slide 38
What plane of the head are these cross-sections taken in?
Left - sagittal
| Right - transverse(?)
333
What is the route of the superior sagittal sinus into the neck?
Superior sagittal sinus --> confluence of hte sinuses --> transverse sinus --> sigmoid sinus --> leaves neck at jugular foramen --> internal jugular vein
334
How does the superior sagittal sinus reach the neck?
It leaves the skull via the jugular foramen from the sigmoid sinus
335
Where does the facial vein drain into?
IJV
336
Where does the superficial temporal vein drain into?
IJV
337
Where does the EJV drain into?
Subclavian vein
338
Slide 39
Label this image of venous drainage of the head
- Superior sagittal sinus
- Superficial temporal v.
- Cavernous sinus
- Confluence of the sinuses
- Transverse sinus
- Sigmoid sinus
- Facial v.
- External, Internal and Anterior Jugular vv.
- Suprascapular v.
- Left brachio-cephalic v.
- Subclavian v.
(See Slides)
339
Which veins run in association with SCM?
The EJV runs over SCM and the IJV is hidden by it.
340
EJV runs over which muscle?
SCM
341
IJV runs ____ to which muscle?
deep/under; SCM
342
Which vein is easier to see - EJV or IJV?
EJV
343
Which vein do we use to measure jugular venous pressure, and why?
IJV - comes directly down to join the brachiocephalic vein, so is a better indication of pressure in the right atrium.
344
Why don't we use EJV to measure JVP, rather than IJV?
Although EJV is easier to see, IJV comes directly down to join the brachiocephalic vein, so is a better indication of pressure in the right atrium.
345
Slide 40
Label the diagram. Include the brachiocephalic vein.
- SCM
- EJV (both sides)
- IJV
- CCA
(See Notability)
346
Answer specifically - which vein do we use to measure jugular venous pressure?
The right internal jugular vein
347
How do we measure right atrial pressure?
By looking at the pulse in the right internal jugular vein (jugular venous pressure) - this is effectively a direct connection to the right atrium
348
How do we position patients clinically to measure jugular venous pressure?
- The patient needs to be sat at a 45 degree angle
- Their head needs to be turned to the left, so we can see the SCM muscle on their RIGHT-hand side (to view the right IJV)
349
How do you measure JVP clinically?
- You measure the height you get pulsations of the IJV from the sternal angle + 5cm
350
How do you look for JVP clinically?
- You are looking for pulsations occurring under/through the SCM muscle - IJV is largely hidden by SCM
- Although the EJV is much more visible - avoid looking at that and look for pulsations you see
351
What is JVP measured in?
cmH2O
352
Describe how you would measure JVP.
- Put patient at 45 degree incline
- Tilt head slightly to left, to visualise right SCM and IJV
(Right IJV is directly connected to the right atrium)
- Visualise pulsations through the muscle
- Measure the height of these pulsations from the sternal angle + 5cm
- This is your JVP in cmH2O
353
Slide 41
Label the diagram and the angle for measuring JVP.
Explain how JVP is measured.
See slides
354
IMAGE
| See extra info, Fig. 3
Label IJV, EJV and SCM
- IJV hidden by SCM
| - EJV easily visible
355
Summary
Describe the carotid triangle
*remember this - it is important!*
- boundaries
- relevance
356
Summary
Describe the carotid sheath
- Contents
| - Location
357
Summary
Describe the blood supply to the scalp
- Many anastomoses
| - Deep lacerations = profuse bleeding
358
Summary
Describe the venous route for spread of inections
- Scalp to cranial cavity via emissary veins
| - Face to cavernous sinus via inf. & sup. ophthalmic veins & deep facial veins
