43 Neck Layers Spaces

Neck general boundaries

Superior

• inferior margin of mandible

• posterior skull

Inferior

• sternum + clavicle + acromion process

• thoracic aperture

Neck compartments (4)

investing compartment

• contains investing fascia

• trapezius m. + sternocleidomastoid m.

visceral compartment

• trachea + esophagus

• parathyroid + thyroid glands

vascular compartment

• carotid sheath

  • internal jugular v.

  • common carotid a.

  • vagus n.

vertebral compartment

• deep back muscles

Anterior triangle of neck

Borders

• anterior to sternocleidomastoid m.

• inferior to mandible

• 
  

Structures pathway

• anterior structures pass into thorax + head

Posterior triangle of neck

Borders

• posterior to sternocleidomastoid m.

• anterior to trapezius m.

Structures pathway

• posterior structures pass into upper limb

  • (eg) brachial plexus

Deep cervical fascial layers (5)

• investing fascia

• infrahyoid fascia

• pretracheal fascia

• prevertebral fascia

• carotid sheath

Superficial cervical fascia

subcutaneous CT: superficial fatty layer + deep fibrous layer

• contains superficial nerves + vessels + lymph nodes

• contains platysma m.

Investing fascia

deep cervical fascia that completely surrounds neck

• arises from skull + mandible

• extends inferiorly to sternum + clavicle + manubrium

• surrounds sternocleidomastoid m. + trapezius m.

Infrahyoid fascia

cervical fascia that begins at the hyoid bone

• forms investing fascia for infrahyoid muscles

• superficial + deep layers

• continuous across the midline

Pretracheal fascia

continuous fascial tube that surrounds viscera in the neck

• pretracheal proper: attaches to hyoid bone above fibrous pericardium

• buccopharyngeal fascia: attaches to base of skull + posterior to esophagus

  • covers buccinator + pharyngeal constrictors

  • fuses w pretracheal fascia + adventitia of esophagus

Prevertebral fascia

cervical fascia attached to the base of skull + vertebrae

• encloses deep muscles

• has specializations

  • alar fascia

  • axillary sheath

  • Sibson’s fascia

Carotid sheath contents

• internal jugular v.

• common carotid a.

• vagus n.

Retropharyngeal space

btwn buccopharyngeal layer of pretracheal fascia + alar layer of prevertebral fasica

• spans base of skull to upper part of posterior mediastinum (sup/inf border)

• infections can spread inferiorly to lower cervical levels

Pretracheal space

btwn infrahyoid + pretracheal fascia

• spans betwen neck + anterior part of superior mediastinum

• infections can spread inferiorly into superior mediastinum

Third space AKA danger space

within alar + prevertebral fascia

• extends from base of skull towards diaphragm (sup/inf border)

• susceptible to infections

  • can spread inferiorly to diaphragm

  • can spread superiorly to base of skull

• air from ruptured esophagus or airway can cause pneumomediastinum

Retropharyngeal abscess

infection btwn cervical vertebrae + pharyngeal wall

• Causes

  • oral cavity → dental abscess

  • nasopharynx → tonsilitis + peritonsillar abscess

  • retropharyngeal space infectious spread

  • danger space infectious spread

• S/S

  • fever + sore throat + neck and back pain + dysphagia (difficulty + pain when swallowing) + odynophagia (painful swallowing)

• Complications

  • airway obstruction

  • sepsis + mediastinitis + pneumonia + empyema (pus in pleural space)

  • jugular vein thrombosis + carotid artery erosion