General anatomy and Lymphatic drainage

of Neck

Dr. Krishna KoiralaMBBS, MS (ENT-HNS)

2016/12/262016/12/26

• Neck : Area between the lower border of mandible above and suprasternal notch and clavicle below

• Complex region :

– Passageway for communication between head and rest of the body

• Contains vital structures like larynx, trachea, esophagus, great vessels, cranial nerves, sympathetic trunk, spinal cord

Fascia and fascial spaces of Neck

• Importance of fascial planes

−Localization and spread of neck space infections is dependent upon the facial planes

− Dissection is easier, better controlled and more bloodless if it proceeds along the fascial planes

• Skin

– Contains constant natural lines of cleavage horizontally

– Incision along the cleavage line gives narrow scar

• Superficial fascia

− Thin layer that encloses platysma, cutaneous nerves, superficial veins, superficial lymph nodes

• Deep fascia

– Investing layer ,Visceral layer , Internal layer

• Investing layer • Superiorly attached to the nuchal line,

mastoid process and mandible

• Inferiorly attached to the spine of C7, clavicle and manubrium

• Splits to surround trapezius and sternomastoid

• Forms sheaths to parotid and submandibular gland , carotid sheath and cranial nerves

Superior nuchal line of occipital bone (a)Spinous processes of cervical vertebrae and nuchal ligament(b)Mastoid processes of temporal bones(c)Zygomatic arches(d)Inferior border of mandible(e)Hyoid bone(f)Manubrium(g)Clavicles(h)Acromion(i)

Folds to form the stylomandibular ligament(j)

• Middle layer ( Two subdivisions)

−Muscular division surrounds the

infrahyoid strap muscles

−Visceral division envelops the

pharynx, larynx, esophagus, trachea,

and thyroid gland

• Deep Layer (Prevertebral fascia)

• Surrounds deep muscles of neck

• Cervical sympathetic trunk lies superficial to fascia

• Cervical plexus, phrenic nerve and brachial plexus lie deep to fascia

Deep Neck Spaces• Described in relation to the hyoid bone• Those traverse the entire length of the neck

– Retropharyngeal space, Danger space, Prevertebral space, Visceral vascular space ( Carotid sheath)

• Suprahyoid

− Submandibular space, Parapharyngeal space, Peritonsillar , Masticator, Parotid, Temporal space

• Infrahyoid – Anterior visceral space

Parapharyngeal Space Boundaries

Base and superior limit - Skull Base

Apex – Lesser cornu of hyoid

Lateral – Ascending ramus of mandible, Medial Pterygoid, Parotid fascia and gland

Medial – Buccopharyngeal fascia

Anterior - Pterygomandibular raphe

Posterior -Prevertebral fascia

Inferior -Fascia lateral to angle of mandible

Parapharyngeal Space

• Subdivisions• Prestyloid• Poststyloid (neurovascular)

• Contents• Prestyloid compartment

• Retromandibular portion of the deep lobe of the parotid gland, adipose tissue, lymph nodes associated with the parotid gland

• Poststyloid compartment • Internal carotid artery, internal jugular vein, CNS IX- XII, sympathetic chain, lymph nodes

Retropharyngeal space• Immediately posterior to the nasopharynx,

oropharynx, hypopharynx, larynx, and trachea

• Boundaries • Buccopharyngeal fascia anteriorly • Alar fascia posteriorly • Carotid sheath and parapharyngeal space

laterally • Base of the skull superiorly• Inferiorly to the mediastinum at the level

of the tracheal bifurcation

• Divided into two lateral compartments (space of Gillette) by a fibrous raphe

• Each lateral space contains retropharyngeal nodes which usually disappear after 4-5 years of age

• Communicates with the parapharyngeal space and the posterior mediastinum so infection can spread to these areas

• Danger space

• Formed anteriorly by the alar fascia and posteriorly by the prevertebral fascia

• Extends down the mediastinum to the level of the diaphragm

• Prevertebral space

• Bounded anteriorly by the prevertebral fascia and posteriorly by the longus coli muscles of the spine

• Continues to the insertion of the psoas muscles

Submandibular space• Boundaries

– Inferior : superficial layer of the deep cervical fascia extending from hyoid to the mandible

– Lateral : body of the mandible

– Superior : mucosa of the floor of mouth

Subdivisions • Divided by the myelohyoid muscle into• Sublingual space ( Supramyelohyoid)– Contains sublingual gland,

hypoglossal nerve and Wharton’s duct – Continuous with the submaxillary

space via the posterior margin of the myelohyoid muscle

• Submaxillary space ( Inframyelohyoid)

Triangles of Neck

Anterior triangle Anteriorly - midline of neck

Posteriorly - anterior border of Sternocleidomastoid

Superiorly -lower border of mandible

Floor - myelohyoid, hyoglossus

Subdivided by bellies of digastric and omohyoid muscles into submental, submandibular, carotid, muscular triangles

Chief contents of anterior triangle Common carotid , external and

internal carotid arteries

Internal jugular vein

Vagus and recurrent laryngeal nerves

Submandibular gland

Lymphatic tissue

Posterior Triangle• Anteriorly by posterior border of SCM• Posteriorly by trapezius• Inferiorly - middle 3rd of clavicle• Floor - deep layer of deep cervical fascia• Roof - superficial layer of deep cervical

fascia• Subdivided to occipital and subclavian

by posterior belly of omohyoid muscle

Contents of posterior triangle Subclavian artery Brachial plexus Spinal accessory nerve Posterior cervical nodes

Lymph node Levels of Neck

( The Memorial Sloan Kettering Hospital –New

York Classification )

Level I ( Submental / Submandibular) Below myelohyoid muscle and above the lower

margin of the hyoid bone  Anterior to the posterior border of the

submandibular glands Level I a : Submental ( between the anterior

bellies of the digastric muscle) Level I b : Submandibular (posterolateral to

the anterior belly of digastric)

Level II ( Upper jugular / upper deep cervical)

Base of skull to lower margin of hyoid bone Anterior to the posterior border of

sternomastoid and posterior to the posterior border of submandibular glands Level II a : Anterior, lateral or medial to the

internal jugular vein Level II b : Posterior to the internal jugular

vein with a fat plane separating the nodes and the vein 

Level III (Middle jugular/ middle deep cervical nodes)

Lower margin of hyoid to lower margin of cricoid cartilage

Anterior to the posterior border of SCM and lateral to the medial margin of the CCA / ICA

Level IV ( Lower jugular / lower deep cervical nodes)

Lower margin of cricoid cartilage to level of the clavicle

Anterior and medial to an oblique line drawn through the posterior edge of the sternocleidomastoid muscle and the posterolateral edge of the anterior scalene muscle and lateral to the medial margin of the CCA

Level V (Posterior triangle nodes ) Level V a :  superior half, posterior to levels II and

III Level V b :  inferior half, posterior to level IV

Level VI (prelaryngeal /pretracheal /Delphian node)

From inferior margin of hyoid to manubrium In front of levels III and IV

Level VII  (superior mediastinal ) Between CCAs, below top of manubrium