Fascial Layers of the Neck

Fascial layers

They create anatomical spaces that influence the spread of infections

Superficial cervical fascia

A layer of fatty connective tissue located between the skin and the first deep fascial layer

Contains:

• Cutaneous nerves

• Blood and lymphatic vessels

• Superficial lymph nodes

• Variable amounts of fat

Superficial cervical fascia

In which layer is the platysma muscle embedded in?

• Facial expression (depresses lower jaw, draws down lip & mouth corner)

• Tenses the skin (shaving and easing a tight collar)

Functions of the superficial cervical fascia

Cervical branch of the facial nerve (CN VII)

Innervation of the superficial cervical fascia

• Main cutaneous nerves of neck

• External jugular vein

Deep to the platysma, we find _____ (innervation)

Superficial cervical fascia

Attachments:

• Superior: Deep fascia covering pectoralis major & deltoid

• Inferior:

  • Mandible

  • Skin

  • Subcutaneous tissues of lower face

Deep cervical fascia

Supports and compartmentalizes cervical structures

Three main layers:

• Investing fascia

• Pretracheal fascia

• Prevertebral fsascia

*Carotid sheath is also part

Investing layer

Layer of Deep Fascia

• Encircles the entire neck, deep to skin & superficial fascia

• Encloses trapezius and SCM muscle

• Contains:

  • Inferior ends of anterior jugular veins

  • Jugular venous arch

  • Fat and deep lymph nodes

Investing layer

Layer of Deep Fascia

Forms a fibrous capsule around:

• Submandibular gland (splitting below mandible)

• Parotid gland (splitting behind mandible)

Investing layer

Which layer of the deep cervical fascia forms the suprasternal space?

Investing layer

Attachments:

• Superior:

  • Superior nuchal line

  • Mastoid process

  • Zygomatic arch

  • Mandible, hyoid bone, cervical vertebrae

• Inferior:

  • Manubrium of sternum

  • Clavicles

  • Scapulae

Suprasternal space

Space located between the sternal heads of the SCM

Pretracheal layer (Anterior deep fascia)

Layer of Deep Fascia

• Located only in the anterior neck

• Extends from hyoid bone to thorax (merging w/ fibrous pericardium)

• 2 Parts:

  • Muscular part — encloses infrahyoid muscles

  • Visceral part — encloses thyroid gland, trachea, esophagus

Muscular part

Which part of the pretracheal layer encloses infrahyoid muscles?

Visceral part

Which part of the pretracheal layer encloses thyroid gland, trachea, and esophagus?

Buccopharyngeal fascia

Superiorly, the pretracheal layer blends with the ______

Carotid sheath

Laterally, the pretracheal layer blends with the _____

Mediastinum

Inferiorly, the pretracheal layer communicates with the _____

Pretracheal layer

Specialization: Forms pully (trochlea) for the intermediate tendon of the digastric muscle

Prevertebral layer (Deepest deep fascia)

Layer of Deep Fascia

• Surrounds vertebral column and associated muscles:

  • Longus colli

  • Longus capitis

  • Scalene muscles

  • Deep cervical muscles

• Encloses the cervical part of the sympathetic trunk

Prevertebral layer

Attachments:

• Superiorly: Cranial base

• Inferiorly: Blends with endothoracic fascia at T3 vertebra

• Laterally: Extends as axillary sheath (encloses axillary vessels & brachial plexus)

Carotid sheath

Tubular fascial structure that extends from the cranial base to the root of the neck

Carotid sheath

Contents:

• Common and internal carotid arteries

• Internal jugular vein

• Vagus nerve (CN X)

• Deep cervical lymph nodes

• Carotid sinus nerve & sympathetic fibers

Carotid sheath

Fascial connections:

• Anterior: Investing & pretracheal fascia

• Posterior: Prevertebral fascia

• Inferior: Mediastinum

Retropharyngeal space

• Largest potential space in the neck

• Between prevertebral fascia (posteriorly) and buccopharyngeal fascia (anteriorly)

Retropharyngeal space

Allows pharynx, esophagus, larynx, and trachea to move freely during swallowing

Retropharyngeal space

Boundaries:

• Superior: Cranial base

• Lateral: Carotid sheath

• Inferior: Communicates w/ mediastinum

True retropharyngeal space, Danger space

What are the 2 divisions of the retropharyngeal space?

True retropharyngeal space

Division of RP space

• Anterior to alar fascia

• Extends from skull base to C7

Danger space

Division of RP space

• Between alar fascia and prevertebral fascia

• Extends from skull base to diaphragm

• Infections here can spread to the thoracic cavity

Superficial infections

Spread of infections is limited to the superficial fascia

Pretracheal space infections

Infections here may spread to the anterior mediastinum

Retropharyngeal space infections

Infections here may extend to the superior mediastinum

Danger space infections

Infections here can reach the posterior mediastinum and diaphragm, leading to serious complications