Understanding the organization of fascial layers in the neck is important because they form pathways and/or limitations to the spread of infection, fluid, air, and tumors between the head, neck, and arms. They also offer planes of access in surgeries.
Connections between regions enclosed by neck fascias
An infection between the investing layer and muscular pretracheal layers of deep cervical fascia cannot move more inferior than the superior border of the manubrium because these layers come together and fuse at that point.
An infection between the investing and visceral pretracheal layers is able to spread inferiorly to the thoracic cavity, pericardium, and mediastinum because this space is continuous.
Abscesses within the prevertebral layer of deep cervical fascia can extend laterally into the axilla, as this layer forms the axillary sheath covering the brachial plexus and subclavian vessels.
Abscesses related to the retropharyngeal space cause difficulties swallowing and speaking; these infections may spread inferiorly towards the mediastinum.
Air from ruptured respiratory structures or the esophagus can move superiorly into the neck.