``` • Continuation of sigmoid sinus • Exits skull via the jugular foramen & enters carotid sheath • Runs lateral to CCA • Omohyoid muscle runs across ```

4. Anterior triangle - neurovascular bundle Flashcards by Alix Wrighton

Contents of carotid triangle (subdivision of anterior triangle)?

Carotid triangle: Contains thyroid gland, larynx, pharynx, carotid sheath (& contents), branches of cervical plexus, superior root of the ansa cervicalis, deep cervical lymph nodes, & (parts of) CN XI & XII

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Vascular compartment contents?

Medially
• Common carotid artery
• Internal carotid artery
• External carotid artery (part)

Laterally
• Internal jugular vein

Posteriorly
• CNX

bifurcates at C3/4

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Difference between origin of R and L CCA?

Right CCA
• Branch of the brachiocephalic trunk

Left CCA
• Direct branch from the arch of the aorta

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When does CCC bifurcate?

ICA & ECA: Branches of CCA at C3/C4

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When does ICA branch?

ICA has no branches in the neck & ascends to enter carotid canal to supply the brain

Provides the Anterior circulation of the brain

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What is carotid sinus? Importance?

Carotid sinus: Enlargement/dilation at bifurcation of common carotid artery containing baroreceptors/pressoreceptors in wall of ICA
• Important in monitoring blood pressure
• Baroreceptors are sensitive to stretch
(baroreceptor reflex)
• Helps keep blood pressure within
homeostatic values

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Innervation fo the carotid sinus?

Innervated by CN IX via carotid sinus nerve & CN X (back to the tractus solitarius)
Action potentials travel from the baroreceptors through CN IX to the cardioregulatory & vasomotor centres in the medulla (vital centres…)

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What are fibres that surround solitary nucleus?

tractus solitarius

or “Solitary tract”

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What is the carotid body?

Function

Carotid body: Small organ (~2-5mm) which houses chemoreceptors located at bifurcation of CCA near the carotid sinus

Function:
• Important in monitoring blood O2, CO2, & pH (& temperature)
• Responds in emergency situations by increasing respiration, blood pressure & cardiac rate (not as much at rest)

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Innervation of the carotid body?

Innervated by CN IX via carotid sinus nerve & CN X (back to the
tractus solitarius)
• Afferent fibres from the carotid body travel to the cardioregulatory & vasomotor centres in the medulla (vital centres…)

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Branches of the ECA?
S t
A p
L
F
O
P a
S t
M

Superior thyroid
Ascending pharyngeal
Lingual
Facial
Occipital
Posterior auricular
Superficial temporal (terminal branch)
Maxillary (terminal branch)

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Majority of scalp & facial blood supply is from the _________ carotid artery with some from the internal carotid

Majority of scalp & facial blood supply is from the external carotid artery with some from the internal carotid

ICA gives off the supratrochlear and supra-orbital artery (at the forehead)

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Middle meningeal artery is a branch of…

the maxillary branch of ECA

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Course of IJV?

• Continuation of sigmoid sinus
• Exits skull via the jugular
foramen &amp; enters carotid
sheath
• Runs lateral to CCA
• Omohyoid muscle runs
across

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Veins draining into IJV?

Inferior petrosal sinus
Pharyngeal
Occipital
Facial
Lingual
Superior thyroid
Middle thyroid

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IJV joins _______ vein to become brachiocephalic vein (left & right)

IJV joins subclavian vein to become brachiocephalic vein (left & right)

IJV has what which helps prevent infection spread?

Valve system (one found at inferior bulb)

How is the EJV formed? Which vessels?

EJV begins at angle of mandible, joining RETROMANDIBULAR & POSTERIOR AURICULAR veins
• Post auricular – from scalp behind ear
• Retromandibular (posterior division) – from superficial temporal & maxillary veins

Veins draining into EJV?

Veins draining into EJV:
• Posterior external jugular
• Transverse cervical
• Suprascapular

Anterior jugular vein, course and drainage?

Anterior jugular veins arise near the hyoid bone and run on either side of midline through subcutaneous tissue communicating across the midline via the JUGULAR VENOUS ARCH.
Drains into EJV; in some instances, will drain directly into subclavian vein

Cervical branch of CN VII innervates ________ muscle Digastric branch of CN VII innervates ____ muscle

Cervical branch of CN VII innervates platysma muscle Digastric branch of CN VII innervates digastric muscle

Stylohoid supplied by

CN VII

Course of the CN IX in the neck?

Include the vascular relations

CN IX exits the jugular foramen & travels downward between the IJV & ICA
Much of the nerve then travels forward to oral cavity, but some branches travel downward to carotid sinus (& body), pharynx (sensory) & stylopharyngeus (motor)

Course of the CN X in neck and the vascular relations?

CN X exits the jugular foramen & travels downward within carotid sheath with
IJV & CCA (ICA)
As it travels downward, a motor branch to the pharynx arises as well as a branch to the carotid body, the superior laryngeal nerve & a cardiac branch
Recurrent laryngeal nerves arise inferiorly near to the subclavian artery (R) or arch of aorta (L)

Course of the CN XI in the neck? | Arterial relations and muscles innervated?

CN XI (spinal) exits the jugular foramen & travels downward between the IJV & ICA It then crosses the lateral surface of the IJV to descend to the posterior triangle of the neck It innervates SCM & trapezius

Course of CN XII in the neck?

CN XII exits the hypoglossal canal & is between the IJV & ICA It then crosses the ICA & ECA laterally on its way to the oral cavity There are no branches to the anterior triangle of the neck

Supply of the transverse cervical nerve in neck?

supply cutaneous innervation over SCM & anterior triangle

Cutaneous supply of the great auricular nerve from C2 and C3?

Angle of the mandible | NOT THE TRIGEMINAL

What nerve innervates the ansa cervicalis?

Ansa cervicalis (anterior rami of C1-C3) innervates infrahyoid muscles

Two plexus's of the neck?

``` Cervical plexus (anterior rami of C1, C2-4) Branchial plexus from C5 to T1 ```

Which motor and cutaneous supply is from the cervical plexus C1-C4?

Infrahyoid Diaphragm (via phrenic) Skin of anterior/lateral neck Skin of inferior neck

Which branches of the brachial plexus are seen in the neck?

Dorsal scapular nerve C5 branch to the phrenic nerve Suprascapular nerve

Which sympathetic truck ganglia are found in the neck?

Cervical part of sympathetic trunk gives of superior, middle and inferior cervical ganglia

What is the ansa cervicalis? What is it's function?

The ansa cervicalis is a loop of nerves, formed by nerve roots C1-C3. It gives off four muscular branches: -Superior belly of the omohyoid muscle -Inferior belly of omohyoid muscle - Sternohyoid - Sternothyroid These muscles (the infrahyoids) act to DEPRESS the HYOID bone; an important function for swallowing and speech.