H&N Neck anatomy Flashcards by Evan Cumpston

How are the lymph node levels divided in the

neck?

They are separated into levels based on anatomic or surgical
and radiographic criteria. The following are the most
commonly involved groups:
● Level I (IA/IB)
○ IA: Submental triangle
○ IB: Submandibular triangle
● Level II (IIA/IIB)
○ IIA: Upper jugular chain
○ IIB: Submuscular recess
● Level III: Middle jugular chain
● Level IV: Lower jugular chain
● Level V (VA/VB): Posterior triangle
○ VA: Spinal accessory chain
○ VB: Supraclavicular and transverse cervical chain
● Level VI: Anterior jugular chain

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In addition to the six nodal levels, there are additional, unclassified nodal groups that are
important in the surgical management of the
neck. What are these, and where are they found?

● Suboccipital nodes: Deep to the insertion of the trapezius
muscle
● Retroauricular nodes: Superficial postauricular region
● Parotid nodes: Can be superficial to, within or deep to the
parotid gland
● Retropharyngeal nodes: Between the prevertebral fascia
and the pharyngeal constrictor muscles
● Facial nodes: Superficial and deep to the facial artery and
vein

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What lymph node levels in the neck are unpaired?

Level IA. Level VI is often considered to have a right and a

left but may also be considered as a single compartment.

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How is level IB distinguished from level IIA

surgically and radiographically?

Posterior edge of the submandibular gland

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How is the lateral border of level IIA defined

radiographically?

Posterior border of the internal jugular vein

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What anatomical structure divides lymph node

level II into IIA and IIB surgically?

Spinal accessory nerve (CN XI)

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How are the superior and inferior boundaries of

level IIA surgically defined?

● Superior: Skull base

● Inferior: Carotid bifurcation

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What are the radiographic and surgical landmarks

that separate neck levels II and III?

Inferior border of the hyoid bone (radiographic) and carotid

bifurcation (surgical)

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What are the superior and inferior borders of level

III radiographically?

● Superior: Horizontal plane from the inferior border of the
hyoid bone
● Inferior: Horizontal plane from the inferior border of the
cricoid cartilage

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What are the radiographic and surgical landmarks

that separate neck levels III and IV?

Inferior border of the cricoid cartilage (radiographic) and

the omohyoid muscle (surgical)

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What anatomical structure divides lymph node

level V into VA and VB?

A horizontal plane from the inferior border of the cricoid cartilage
Note: Level VA includes the spinal accessory nodes, VB includes the transverse cervical nodes and supraclavicular
nodes. Just inferior to the clavicle lies the sentinel node or Virchow node.

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What are the surgical landmarks that define level

VI (central compartment) lymphatics?

Hyoid bone superiorly, suprasternal notch inferiorly, and common carotid arteries laterally

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Level VI lymph nodes are at greatest risk for

metastasis from which primary locations?

● Glottic and subglottic larynx
● Pyriform sinus
● Cervical esophagus
● Thyroid gland

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What are the major divisions of cervical fascia in

the neck?

● Superficial cervical fascia
● Deep cervical fascia: Superficial (investing), middle
(visceral), and deep layers

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What layer of cervical fascia covers the superficial
surface of the platysma muscle and is continuous
with the superficial muscular aponeurotic system
(SMAS) superiorly in the face and fascia overlying
the chest, shoulder, and axilla?

Superficial cervical fascia

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Which layer of cervical fascia arises from the
vertebral spinous processes, wraps around the
SCM and trapezius muscles, covers the mylohyoid
muscle and anterior bellies of the digastric muscle,
attaches to the hyoid bone, forms the floor of the
submandibular and posterior triangle, wraps around
the submandibular gland and parotid glands, and
splits at the mandible into the internal layer, which
lies over the medial surface of the medial pterygoid
muscle and inserts onto the skull base, while the
outer layer passes over the masseter muscle and
inserts onto the zygomatic arch?

Superficial (investing) layer of the deep cervical fascia

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What are the two subdivisions of the middle layer

of the deep cervical fascia?

● Muscular division: Surrounds infrahyoid strap muscles,
attached superiorly to the hyoid bone and thyroid
cartilage and inferiorly to the sternum
● Visceral division: Surrounds the thyroid, trachea, and
esophagus and extends into the mediastinum to connect
with the fibrous pericardium. Superiorly, the fascia may
blend with the buccopharyngeal fascia (controversial).

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Name the fascial layers that line the inner (pharyngeal) and outer (cervical) surface of the pharyngeal constrictor muscles.

● Inner: Pharyngobasilar fascia

● Outer: Buccopharyngeal fascia

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What are the two named divisions of the deep

layer of the deep cervical fascia?

● Prevertebral fascia: Fused to the transverse processes of
the vertebral bodies with extension medially to cover the
prevertebral musculature and vertebral bodies. Continues
posteriorly to cover the extensor muscles and insert onto
the vertebral spinous processes
● Alar fascia: Located between the prevertebral fascia and
the visceral division of the middle layer of the deep
cervical fascia

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What layer(s) of cervical fascia form the carotid
sheath?

The superficial (investing), middle (visceral), and deep
layers of the deep cervical fascia

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What is enveloped by the superficial (investing)

layer of the deep cervical fascia?

● Two muscles (SCM and trapezius)
● Two glands (parotid and submandibular gland)
● Two spaces (Posterior triangle, suprasternal space of
Burns)

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What is the vascular supply and innervation of the

platysma muscle?

● Innervation: Cervical branch of the facial nerve (CN VII)
● Arterial supply: Submental branch of the facial artery and
suprascapular artery

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The SCM extends from the mastoid process of the
temporal bone to the clavicle and manubrium,
where it inserts as two separate heads (medial/
sternal and lateral/clavicular) forming the lesser
supraclavicular fossa. What is the innervation and
blood supply to this muscle?

● Innervation: Spinal accessory nerve (CN XI), ventral rami
of C2–4
● Arterial supply:
○ Occipital and posterior auricular arteries
○ Superior thyroid artery
○ Suprascapular artery

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Describe the innervation and arterial supply to the
anterior and posterior bellies of the digastric
muscle.

● Innervation
○ Anterior: mylohyoid branch of the inferior alveolar
nerve (CN V3)
○ Posterior: facial nerve (CN VII)
● Arterial supply
○ Anterior: submental branch of the facial artery
○ Posterior: posterior auricular and occipital arteries

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Name the four paired infrahyoid strap muscles in | order from superficial to deep.

● Superficial: sternohyoid and omohyoid | ● Deep: sternothyroid and thryohyoid

What is the predominant innervation and vascular | supply to the infrahyoid strap musculature?

● Innervation: Ansa cervicalis (C1–3) | ● Arterial supply: Superior thyroid artery and lingual artery

What muscle can be found in the lateral neck extending from the transverse processes of C3 through C6 to the first rib, passing just posterior to the phrenic nerve, just anterior to the subclavian artery, and just medial to the brachial plexus?

Anterior scalene muscle

What spinal nerves provide sensory innervation to | the cervical skin?

Ventral rami of C2–4 from the cervical plexus ● Lesser occipital nerve (C2): Posterior scalp and ear ● Great auricular nerve (C2, C3): Anterior branch → skin over parotid gland; posterior branch → mastoid area, lower ear and lobule ● Transverse cutaneous nerve (C2, C3): Ascending/de- scending branches → anterolateral neck skin ● Supraclavicular nerve (C3, C4): Medial, intermediate and lateral (posterior) branches → supraclavicular skin from second rib to shoulder

What anatomical location describes the point where the cutaneous nerves of the cervical plexus exit posterior to the sterncleidomastoid muscle, and what is the relationship between this point and the spinal accessory nerve (CN XI)?

Erb’s point The spinal accessory nerve (CN XI) passes approximately 1 cm superior and deep to the sternocleidomastoid muscle and Erb’s point.

What are the muscular branches that constitute | the cervical plexus?

● Phrenic nerve (C3–5) ● Inferior branch of ansa cervicalis (C1–3) ● Segmental branches including cervical branches of the spinal accessory nerve (C1–4)

What structure travels deep to the deep cervical fascia and superficial to the anterior scalene and can be found when dissecting levels III and IV?

Phrenic nerve (C3–5)

The submandibular duct passes between what | two nerves?

Lingual nerve and hypoglossal nerve

The sympathetic trunk travels deep and medial to the carotid sheath and is just superficial to the prevertebral fascia and what muscle?

Longus colli

What structure branches off the vagus nerve (CN X) at approximately T1–2, wraps around the subclavian artery from anterior to posterior, ascends in the neck along the tracheoesophageal groove, generally posterior to the inferior thyroid artery, and enters the larynx at a 30- to 45-degree angle by passing under the inferior constrictor muscle and through the cricothyroid joint space?

Right recurrent laryngeal nerve

The left recurrent laryngeal nerve wraps around the aortic arch before passing superiorly in the neck in the tracheoesophageal groove to enter the larynx at a 0- to 30-degree angle by passing under the inferior constrictor muscle and through what laryngeal space?

Cricothyroid

Describe the classic relationship between the inferior thyroid artery and the recurrent laryngeal nerve.

● 50%: Nerve passes deep to artery. ● 25%: Nerve passes between arterial branches. ● 25%: Nerve passes anterior to artery. Note: This relationship is extremely variable and may not represent a reliable landmark for identifying the nerve.

What is the incidence of a right nonrecurrent | inferior/recurrent laryngeal nerve?

0.5 to 1%

What anomaly is associated with a right aberrant | retroesophageal subclavian artery? Situs inversus?

● Right nonrecurrent inferior/recurrent laryngeal nerve | ● Left nonrecurrent inferior/recurrent laryngeal nerve

``` What structure is formed by the anastomoses of the posterior (dorsal) recurrent laryngeal nerve fibers and the posterior (dorsal) fibers of the internal branch of the superior laryngeal nerve, and what is its function? ```

Galen anastomosis (aka ramus anastomaticus)

What artery branches from the aortic arch, passes over the trachea from left to right and branches into the right common carotid artery and right subclavian artery?

Innominate (brachiocephalic) artery

What are the major divisions of the right | subclavian artery?

● First part: Right, from innominate artery just posterior to the sternoclavicular joint to the medial border of the anterior scalene muscle; may rise 2 cm above the clavicle. Left, from aortic arch at T3–4 to the medial border of the anterior scalene muscle ● Second part: Highest point, spans the width of the anterior scalene muscle. ● Third part: Lateral border of anterior scalene muscle to outer border of the first rib → axillary artery

What artery branches off the first part of the subclavian artery, ascends in the neck by passing through the foramina of the transverse processes of C1–C6, and enters the foramen magnum and joins with its paired contralateral vessel to form the basilar artery?

Vertebral artery

What are the three arteries that arise from the first | part of the subclavian artery?

● Vertebral artery ● Thyrocervical trunk ● Inferior thoracic artery

Name the branches of the thyrocervical trunk that branch off the first part of the subclavian artery at approximately the medial border of the anterior scalene muscle?

● Inferior thyroid artery ● Suprascapular artery ● Superficial/transverse cervical artery

On the left, the costocervical trunk arises from the first part of the subclavian artery, and on the right it arises from the second part. To what vessels does it give rise?

● Deep cervical artery | ● Superior intercostal artery

What structures are contained within the carotid | sheath?

● Carotid arteries: Medial ● Internal jugular vein: Lateral ● Vagus nerve: Posterior

At what vertebral level(s) is the carotid bifurcation | in the majority of people?

C3–4 (~ at the level of the superior border of the thyroid | cartilage)

What bony skull base structure runs between the | internal and external carotid arteries?

Styloid process

What are the branches of the external carotid artery, and to what named branches do these arteries give rise?

● Superior thyroid artery → infrahyoid, superior laryngeal, cricothyroid and sternocleidomastoid arteries ● Ascending pharyngeal artery → pharyngeal, inferior tympanic, and meningeal arteries ● Lingual artery → suprahyoid, dorsal lingual, and sub- lingual arteries ● Facial artery → ascending palatine, tonsillar, submental and glandular arteries ● Occipital artery → Upper and lower branches to the sternocleidomastoid muscle ● Posterior auricular artery → stylomastoid artery ● Internal maxillary artery → see below ● Superficial temporal artery → frontal and parietal branch

What artery arises at the level of the greater cornu of the hyoid bone from the external carotid, runs deep to the posterior belly of the digastric muscle and stylohyoid muscle, turns at the middle constrictor to follow the posterior boundary of the submandibular gland and medial border of the medial pterygoid muscle, and then winds around the mandible at the level of the facial notch?

Facial artery

What artery, or branch of this artery, often transverses level IIB in the neck and “tethers” the hypoglossal nerve in level IIA?

Occipital artery

What are the three parts of the internal maxillary | artery?

● First part/mandibular portion: Arises between the ramus of the mandible and the sphenodmandibular ligament, passes the posterior to the lateral pterygoid muscle ● Second part/pterygoid portion: Within the lateral pterygoid muscle ● Third part/pterygopalatine portion: Pterygopalatine fossa

What are the branches of the first part (man- | dibular portion) of the internal maxillary artery?

``` ● Deep auricular artery ● Anterior tympanic artery ● Middle meningeal artery ● Accessory meningeal artery ● Inferior alveolar artery ● Mylohyoid artery ```

What are the branches of the second part | (pterygoid part) of the internal maxillary artery?

``` ● Anterior deep temporal artery ● Posterior deep temporal arteries ● Pterygoid branches ● Masseteric artery ● Buccinator/buccal artery ```

What are the branches of the third part (pter- | ygopalatine part) of the internal maxillary artery?

``` ● Posterior superior alveolar artery ● Infraorbital artery ● Sphenopalatine artery ● Artery of the pterygoid (vidian) canal ● Pharyngeal artery ```

What sensory organ(s) is located at the bifurcation of the common carotid artery, and what is the innervation?

● Carotid sinus → internal carotid artery, baroreceptor, glossopharyngeal nerve (IX), vagus nerve (X), sympathetics ● Carotid body → posterior or between the carotid bifurcation, chemoreceptor, same innervation

What veins give rise to the external jugular vein, what structures does it drain, and where does it drain into?

● Retromandibular vein and postauricular vein ● Scalp and face ● Subclavian vein

What superficial veins drain the anterior neck by | emptying into the external jugular vein or the subclavian vein and are at risk during thyroidectomy and tracheostomy?

Anterior jugular veins

What structures exit the skull base through the | jugular foramen with the internal jugular vein?

``` Glossopharyngeal nerve (IX), vagus nerve (X), accessory nerve (XI), inferior petrosal sinus, and internal jugular vein ```

The internal jugular vein drains most of the head | and neck into what venous structure?

Subclavian vein → brachiocephalic vein

What structure most commonly passes from the superior mediastinum, through the thoracic inlet on the left into level IV, passing anterior to the phrenic nerve and anterior scalene muscle, posterior to the carotid sheath, and most commonly terminates at the confluence of the left subclavian vein and internal jugular vein?

Thoracic duct

What is the incidence of right-sided thoracic duct | in the neck? Bilateral?

● Right-sided only: 4% | ● Bilateral thoracic ducts: 12 to 15%