2 - Ant cervical triangle Flashcards
1
Q
Posterior Cervical Triangle:
A
Anterior boundary = SCM
Posterior boundary = Trapezius m.
Inferior boundary = middle 1/3 of clavicle
2
Q
Anterior Cervical Triangle Boundaries:
A
Lateral: anterior border of SCM m.
Superior: inferior border of mandible
Medial: midline of neck
Roof – Skin & platysma m. (contained within the skin)
Floor – formed by muscles
Viscera – considered “contents”
3
Q
Roof” of anterior cervical triangle:
A
formed by skin & platysma m.
4
Q
Platysma m. innervation
A
Cervical Branch of Facial n. (CN VII)
5
Q
Anterior Cervical Triangle can be subdivided into 4 smaller triangles:
A
Submental triangle
Submandibular triangle
Muscular triangle
Carotid triangle
6
Q
Anterior cervical triangle contents:
A
Muscles Veins Arteries Nerves Cervical viscera
7
Q
Muscles of anterior cervical triangle can be grouped based upon their
A
position relative to the hyoid bone
8
Q
Suprahyoid muscles
A
Located superior to hyoid bone
Elevate hyoid bone
4 muscles: Stylohyoid m. Digastric m. Mylohyoid m. Geniohyoid m.
9
Q
Stylohyoid m. Action
A
Pulls hyoid bone upward in posterosuperior direction
10
Q
Stylohyoid m. Innervation
A
Facial n. (CN VII)
11
Q
Digastric m. Action
A
Mandible fixed – raises hyoid bone
Hyoid bone fixed – opens mouth (by lowering mandible)
12
Q
Digastric m. Innervation
A
Ant. belly – Mandibular division of trigeminal n. (V3) (mylohyoid branch)
Post. belly – Facial n. (CN VII)
13
Q
Mylohyoid m. Action
A
Supports & elevates floor of mouth; elevates hyoid
14
Q
Mylohyoid m Innervation
A
Mandibular division of trigeminal n. (V3) (mylohyoid branch)
15
Q
Geniohyoid m. Action
A
Mandible fixed – elevates & pulls hyoid forward
Hyoid fixed – pulls mandible downward & inward
16
Q
Geniohyoid m. Innervation
A
branch from anterior ramus of C1 carried via hypoglossal n. (CN XII)
17
Q
Infrahyoid mm.
A
Located inferior to the hyoid bone
Depress the hyoid bone
4 muscles: Omohyoid m. Sternohyoid m. Thyrohyoid m. Sternothyroid m.
18
Q
Sternohyoid m. action (infrahyoid group)
A
Depresses hyoid bone after swallowing
19
Q
Sternohyoid m. Innervation (infrahyoid group)
A
anterior rami of C1-C3 via ansa cervicalis
20
Q
Omohyoid m. (infrahyoid group)
A
two bellies (superior & inferior) connected by an intermediate tendon
21
Q
Omohyoid m. innervation (infrahyoid group)
A
anterior rami of C1-C3 via ansa cervicalis
22
Q
Omohyoid m. action (infrahyoid group)
A
depresses & fixes hyoid bone
23
Q
Thyrohyoid m. Action (infrahyoid group)
A
Depresses hyoid bone
When hyoid is fixed, it raises the larynx
24
Q
Thyrohyoid m. innervation (infrahyoid group)
A
fibers from anterior ramus of C1 carried via the hypoglossal n. (CN XII)
Nerve to thyrohyoid m.
25
Sternothyroid m. Action (infrahyoid group)
Draws larynx (thyroid cartilage) downward
26
Sternothyroid m. Innervation (infrahyoid group)
anterior rami of C1-C3 via ansa cervicalis
27
Anterior jugular vein:
Drains anterior neck; located in midline
| Empties into subclavian v. (most commonly) or external jugular v.
28
Communicating branch:
| connects the
common facial v. with the anterior jugular v.
29
Common facial v.
formed from the joining of the anterior division of retromandibular v. with the facial v.
30
Retromandibular vein:
| formed by
superficial temporal v. & maxillary v.
31
Retromandibular vein: divides into
anterior & posterior divisions
32
Retromandibular vein: Anterior div. + Facial v. =
Common facial v. (drains into internal jugular v.)
33
Retromandibular vein: Posterior div. + Posterior auricular v. =
External jugular v.
34
Facial vein:
Originates at angle of eye
Receives tributaries from veins draining face
Drains into internal jugular v.
35
Internal jugular vein drains
blood from skull, brain, superficial face, & cervical viscera
36
Internal jugular vein joins with
subclavian v. to form brachiocephalic v.
37
Internal jugular vein Traverses neck within
carotid sheath
38
Common carotid a.
Right and left common carotid
39
Right Common Carotid a.
from brachiocephalic trunk
40
Left Common Carotid a.
– direct branch off arch of aorta
41
Internal carotid a. –
gives off no branches in the neck
42
External carotid ar.
External carotid a. – gives off branches immediately after bifurcation of common carotid a.
43
The common carotid a. bifurcates at
C3-C4 vertebral level
44
The internal carotid a. does NOT give off any
branches within the neck! There are no branches off of the internal carotid a. outside of the skull
45
Branches of External Carotid a.
3 anterior, 3 posterior
46
3 anterior branches of external carotid a.
Superior thyroid a.
Lingual a.
Facial a.
47
3 posterior branches of external carotid ar.
Ascending pharyngeal a.
Occipital a.
Posterior auricular a.
48
External carotid a. terminates as
superficial temporal a. and maxillary a.
49
Superior Thyroid a.
1st anterior branch of external carotid a.
50
Superior thyroid a. Arises from
anterior surface near bifurcation
51
Superior thyroid a. Gives off the
superior laryngeal a.
52
Superior laryngeal a. pierces
thyrohyoid membrane together with internal branch of superior laryngeal n.
53
Superior thyroid a. supplies
superior portion of thyroid gland
54
Lingual a.
2nd anterior branch from external carotid a
55
Lingual a. arises just above
superior thyroid a. at level of greater horn of the hyoid bone
56
Lingual a. passes deeply into the
muscles of the tongue
57
Facial a.
3rd anterior branch of external carotid a.
58
Facial a. arises just superior
to lingual a.
59
Facial a. Crosses the
inferior border of mandible to supply the face
60
Ascending pharyngeal a.
1st posterior branch of external carotid a.
61
Ascending pharyngeal a. Arises close to
bifurcation of common carotid a
62
Ascending pharyngeal a. Ascends to supply
pharynx & tonsils
63
Occipital a.
2nd posterior branch of external carotid a.
64
Occipital a. Arises near
level of origin of facial a.
65
Occipital a. Passes deep to
posterior belly of digastric m.
66
Occipital a Ascends to supply
neck & scalp
67
Occipital a. Sends off
muscular branch to SCM (*hooks over CN XII)
68
Posterior Auricular a.
3rd posterior branch of external carotid a.
69
Posterior Auricular a. Arises superior to
origin of occipital a.
70
Posterior Auricular a. Superior to
posterior belly of digastric m.
71
Posterior Auricular a. Passes upward & posteriorly to supply
scalp posterior to ear
72
Carotid sinus
dilation of internal carotid a. near bifurcation of common carotid a.; contains receptors that monitor blood pressure changes (baroreceptors)
73
Carotid sheath
```
Carotid a.
-Common carotid a.
-Internal carotid a.
*Carotid sinus
Internal jugular v.
Vagus n. (CN X)
```
74
Nerves associated with the anterior cervical triangle:
Spinal nerve branches:
```
Transverse cervical n. (C2-C3)
Ansa cervicalis (C1-C3)
```
Cranial nerves:
```
Facial n. (CN VII)
Glossopharyngeal n. (CN IX)
Vagus n. (CN X)
Accessory n. (CN XI)
Hypoglossal n. (CN XII)
```
75
Transverse cervical n.
(C2-C3) Branch arising from cervical plexus
76
Transverse cervical n. Provides cutaneous innervation to
skin overlying anterior cervical triangle
77
Transverse cervical n. Emerges from
deep to posterior border of SCM & travels transversely across middle of SCM
78
Ansa cervicalis
nerve loop formed from anterior rami of cervical nerves C1-C3
79
Ansa cervicalis innervates
infrahyoid mm.*
*Innervates all infrahyoid mm. EXCEPT thyrohyoid m. (anterior ramus of C1 via hypoglossal n.)
80
Ansa cervicalis Superior root
mainly of C1 fibers from anterior rami
81
Ansa cervicalis Inferior root
anterior rami of C2 & C3
82
Submental triangle Borders
Inferior = Hyoid bone
Lateral (right) = anterior belly of digastric m.
Lateral (left) = anterior belly of digastric
83
Submental triangle contents
Mylohyoid m.
Submental lymph nodes
Some small veins
84
Submandibular (Digastric) triangle
| borders
```
Superior = Inferior border of mandible
Anterior/inferior = Ant. belly of digastric m.
Posterior/inferior = Post. belly of digastric m.
```
85
Submandibular (Digastric) triangle
| contents
```
Submandibular gland
Submandibular lymph nodes
Marginal mandibular branch of facial n. (CN VII)
Hypoglossal n. (CN XII)
Mylohyoid n. (of CN V3)
Facial a. & v.
```
86
Marginal mandibular branch of facial n. (CN VII
supplies mm. of facial expression
87
Mylohyoid n. (of CN V3) –
supplies mylohyoid m. & anterior belly of digastric m.
88
Muscular triangle Borders
```
Superior = Hyoid bone
Lateral = Superior belly of omohyoid m. & anterior border of SCM m.
Medial = midline of neck
```
89
Muscular triangle Contents - muscles
Muscles:
*Omohyoid m. - Omohyoid m. forms part of the boundary, so technically, it’s not really a content
Sternohyoid m.
Sternthyroid m.
Thyrohyoid m.
90
Muscular triangle Contents - Viscera
```
Thyroid gland
Parathryroid glands
Trachea
Esophagus
Common carotid a.
Internal Jugular v.
```
91
Carotid triangle Borders
```
Superior = Stylohyoid m. & posterior belly of digastric m.
Posterior = Anterior border of SCM m.
Anteroinferior = Superior belly of omohyoid m.
```
92
Carotid triangle Content:
Nerves
Vagus (CN X), Laryngeal nn. (CN X branches), Accessory (CN XI), Hypoglossal (CNXII), Ansa cervicalis (C1-C3)
Arteries
Common, Internal & External carotid aa., 6 branches of ext. carotid a. (3 ant. & 3 post.)
Veins
All branches have accompanying vv. draining into IJV
93
Cervical viscera
```
Larynx & Trachea
Pharynx & Esophagus
Thyroid Cartilage
-Thyrohyoid membrane
-Cricothyroid membrane
Cricoid cartilage
Thyroid & Parathyroid glands
Carotid Sheath
Common carotid a., IJV, Vagus n.
```
94
Larynx & Trachea
Larynx continuous with trachea inferiorly (vertebral level C6)
95
Pharynx & Esophagus
Pharynx continuous with esophagus inferiorly (vertebral level C6)
96
Trachea
begins at vertebral level C6; continuous with larynx superiorly; trachea lies directly anterior to the esophagus
97
Pharynx
common pathway for air and food; pharynx ends at C6 where it is continuous with the esophagus inferiorly
98
Thyroid Cartilage
```
Laryngeal Prominence (“Adam’s apple”)
Thyrohyoid membrane
```
99
Cricoid cartilage
Cricothyroid membrane
100
Cricothyrotomy
emergency procedure to establish airway
when airway is blocked above level of vocal folds.
There are few structures present to be damaged, except for small vessels and pyramidal lobe of thyroid gland (which is only sometimes present).
101
Cricothyroid membrane
between thyroid cartilage and cricoid cartilage
102
Tracheotomy (tracheostomy)
creation of midline incision in trachea & insertion of tube to enable ventilation
Performed in cases of airway obstruction
Opening made in midline between the infrahyoid mm.
Typically performed when there is an obstruction to the larynx due to inhalation of a foreign body, severe edema (i.e. due to anaphylaxis), or severe head and neck trauma; it is generally performed in an operating room.
103
High tracheotomy =
superior to isthmus of thyroid
104
Low tracheotomy =
inferior to isthmus of thyroid
105
Isthmus of thyroid may also be
divided surgically
106
Thyroid gland
large, unpaired endocrine gland located inferior (and lateral) to thyroid cartilage
107
Thyroid gland right and left lobes connected by
isthmus
108
Thyroid gland Isthmus usually covers
2nd to 4th tracheal rings
109
Thyroid gland Pyramidal lobe frequently present;
extends superiorly from isthmus
110
Arteries of the Thyroid Gland
Superior thyroid a.
Inferior thyroid a.
Thyroid ima a.
111
Superior thyroid a.
1st branch off external carotid a.
112
Superior thyroid a. supplies
superior pole of lateral lobe of thyroid gland
113
Inferior thyroid a.
Branch off thyrocervical trunk (from subclavian a.)
114
Inferior thyroid a. supplies
inferior pole of lateral lobe of thryoid gland
115
Thyroid ima a.
Small artery occasionally found arising from either brachiocephalic trunk or arch of aorta
116
Thyroid ima a. ascends
anterior surface of trachea to supply thyroid gland
117
Veins of the Thyroid Gland
Superior, middle, inferior thyroid v.
118
Superior thyroid v.
Drains into internal jugular v.
119
Middle thyroid v.
Drains into internal jugular v.
120
Inferior thyroid v.
Drains into brachiocephalic vv.
121
Parathyroid glands
usually 4 glands within the posterior surface of the thyroid
Small (~5mm diameter), ovoid, yellowish structures on deep surface of right/left lobes of thyroid
Denoted as superior & inferior, but position is variable – can be anywhere (from carotid bifurcation superiorly to mediastinum inferiorly)
122
The parathyroid glands may be
darker in color and harder in texture than thyroid gland.
123
There are usually 2 parathyroid glands
on each side of the thyroid gland, but the number can vary from 1 to 3.
124
Thyroidectomy
excision of part of/most of thyroid gland
125
Parathyroid glands
May be damaged/removed
126
External laryngeal n. damage leads to
paralysis of cricothyryoid m. & damage to inferior pharyngeal constrictor m.
127
Recurrent laryngeal .
| damage leads to
paralysis of most laryngeal mm.
128
Parathyroid glands play an important role in the regulation of
calcium metabolism. During thryoidectomy, parathyroid glands are in danger of being damaged or removed. In order to maintain proper serum calcium levels without medication, at least 1 parathyoid gland must be retained.
129
External laryngeal n. innervates
cricothryoid m. (action: pulls thyroid cartilage forward and rotates it down lengthening/tensing vocal folds) and inferior pharyngeal constrictor m.
130
The recurrent laryngeal n. innervates all of the
intrinsic laryngeal mm. except for cricothyroid (innervated by external laryngeal n.). Paralysis of laryngeal mm. leads to hoarseness of the voice.
131
Root of neck
junction between thorax and neck; lies superior to superior thoracic aperture
Contains structures passing between the neck, thorax, & upper limb
Extension of thoracic cavity projects into neck; consists of upward projection of pleural cavity & includes:
Cervical part of parietal pleura (cupula) & apical part of superior lobe of each lung
132
Arteries
Subclavian a.
- Vertebral a.
- Thyrocervical trunk
- Internal thoracic a.
133
Thyrocervical trunk
arises from subclavian a., medial to anterior scalene m.
134
Thyrocervical trunk 3 branches
Inferior thyroid a.
Transverse cervical a.
Suprascapular a.
135
Inferior thyroid a.
Gives off ascending cervical a.
| Runs posterior to carotid sheath & thyroid gland
136
Suprascapular a.
Transverse cervical a. & suprascapular a. cross over ant. surface of ant. scalene m. & phrenic n.
137
the transverse cervical artery and transverse cervical nerve run in
OPPOSITE directions
138
Vertebral a.
First branch off subclavian a.
Medial to anterior scalene m.
Enters transverse foramen of C6, passes up to C1
139
vertebral a. Enters
transverse foramen of C6, passes up to C1
140
Vertebral v.
Drains into brachiocephalic v.
Travels in transverse foramen of C1-C6
Remember: like the vertebral a., the vertebral v. also travels in the transverse foramina of the cervical vertebrae (C1-C6).
141
Nerves of Root of Neck:
Phrenic n. (C3-C5)
Vagus n. (CN X)
-Recurrent laryngeal n.
Sympathetics
142
Phrenic n. (C3-C5)
Phrenic nn. are branches of cervical plexus
143
Phrenic n. passes
inferiorly across ant. surface of anterior scalene m.
144
Phrenic n. Passes between
subclavian v. & a.; enters thorax & continues to diaphragm
145
Vagus n. (CN X)
Descends through neck in carotid sheath
| Provides all parasympathetic innervation to neck
146
Recurrent laryngeal n. (right & left) –
branch of vagus n.
147
Recurrent laryngeal n ascends in
groove between trachea & esophagus; enters larynx
148
recurrent laryngeal n. Innervates all
intrinsic laryngeal mm. (*except cricothryoid m.)
149
Right recurrent laryngeal n. loops
around right subclavian a., & upward to larynx
150
Left recurrent laryngeal n.
| loops
below & behind arch of aorta, & upward to larynx
151
Cricothryoid m. innervated by external branch of
superior laryngeal n.
152
Sympathetic trunk (chain)
extends from base of skull to coccyx; punctuated by ganglia along extent of trunk/chain
153
Cervical part of sympathetic trunk is
anterior to prevertebral mm. & posterior to cervical viscera
154
Sympathetic trunk (chain) is connected to each
spinal nerve by a gray ramus communicans
| No white rami communicantes in cervical region
155
3 sympathetic ganglia found in cervical region:
Superior, middle, inferior cervical ganglion
156
Superior cervical ganglion
High in neck, near level of mastoid process of temporal bone
157
Middle cervical ganglion
posterior to thyroid gland
158
Inferior cervical ganglion
At lower end of cervical part of symp. trunk
| Combines with first thoracic ganglion & forms the cervicothoracic (stellate) ganglion
159
All lymphatic vessels coalesce to form larger trunks or ducts, which drain into the venous system at the
venous angle
160
Thoracic duct
Major lymphatic channel that drains lymph from left upper limb, head, neck, thorax, abdomen, & lower limbs
Lies posterior to esophagus, between azygos v. & thoracic aorta
161
Thoracic duct drains into
left venus angle
162
Left venous angle
Junction between left internal jugular v. & left subclavian v.
163
Right lymphatic duct
Lymphatic duct draining right upper limb, head, neck, & thorax
164
Righty lymphatic duct drains into
right venous angle:
165
Right venous angle
Junction between right internal jugular v. & right subclavian v.
166
Digastric - 2 heads converge to
tendon which connects to hyoid
167
digstric anterior belly
pharyngeal arch 1
168
digastric posterior belly
pharyngeal arch 2
169
Cricoid cart
only cartilage to completely encircle airway
170
During thyroidectomy, you need to maintain at least
1 parathyroid gland, otherwise you will have issues with maintaining serum calcium levels.
