H&N Neck anatomy Flashcards
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
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
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.
How is level IB distinguished from level IIA
surgically and radiographically?
Posterior edge of the submandibular gland
How is the lateral border of level IIA defined
radiographically?
Posterior border of the internal jugular vein
What anatomical structure divides lymph node
level II into IIA and IIB surgically?
Spinal accessory nerve (CN XI)
How are the superior and inferior boundaries of
level IIA surgically defined?
● Superior: Skull base
● Inferior: Carotid bifurcation
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)
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
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)
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.
What are the surgical landmarks that define level
VI (central compartment) lymphatics?
Hyoid bone superiorly, suprasternal notch inferiorly, and common carotid arteries laterally
Level VI lymph nodes are at greatest risk for
metastasis from which primary locations?
● Glottic and subglottic larynx
● Pyriform sinus
● Cervical esophagus
● Thyroid gland
What are the major divisions of cervical fascia in
the neck?
● Superficial cervical fascia
● Deep cervical fascia: Superficial (investing), middle
(visceral), and deep layers
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
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
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).
Name the fascial layers that line the inner (pharyngeal) and outer (cervical) surface of the pharyngeal constrictor muscles.
● Inner: Pharyngobasilar fascia
● Outer: Buccopharyngeal fascia
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
What layer(s) of cervical fascia form the carotid sheath?
The superficial (investing), middle (visceral), and deep layers of the deep cervical fascia
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)
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
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
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