Fascial Layers of the Neck

Author: Oliver Jones

Last modified: March 19, 2014

The fascia of the neck is unique and complex. The different layers of fascia compartmentalise the neck, allowing structure to pass over each other. The fascia also has clinical significance in explaining the spread of infection.


Superficial Fascia

Fig 1.0  - The platysma muscle, found in the superficial fascia

Fig 1.0 – The platysma muscle, found in the superficial fascia

The superficial fascia lies between the dermis and the deep cervical fascia. It contains the cutaneous neuorvascular supply, the platysma muscle, and a some fat. In people with excess body fat, extra fat is deposited in the superficial fascia, creating the morphic ‘double chin’.

The platysma muscle is situated on the anterior portion of the neck. It has two heads, which originate from the fascia of the pectoralis major and deltoid. The heads cross the clavicle, and meet in the midline, before blending with the facial muscles.


Deep Cervical Fascia

The deep cervical fascia is located deep to the superficial fascia. It is organised into several layers. These layers act like a shirt collar, holding the structures and vessels of the neck in place.

We shall now look at the layers of the deep cervical fascia in more detail.


Investing Layer

Fig 1.1 - Transverse section of the neck. The investing layer of fascia in highlighted in blue. Note how the fascia completely envelopes the SCM and trapezius.

Fig 1.1 – Transverse section of the neck. The investing layer of fascia in highlighted in blue. Note how the fascia completely envelopes the SCM and trapezius.

The investing layer is the most superficial of the deep cervical fascial layers. It surrounds all the structures in the neck. When it meets the trapezius and sternocleidomastoid muscles, it splits into two to completely invest the muscle. The fascia can be thought of as a tube, with superior, lateral and inferior attachments.

  • Superior: to the external occipital protuberance and the superior nuchal line.
  • Lateral: to the mastoid process and zygomatic arch.
  • Inferior: to the spine of the scapula, the acromion, the clavicle, and the manubrium of sternum.

Pretracheal Layer

The pretracheal layer of fascia is situated anteriorly. It envelops the trachea, oesophagus, thyroid gland, and the infrahyoid muscles, running from the hyoid bone down to the superior thorax, where it fuses with the pericardium. This layer of fascia can be functionally split into two parts:

  1. Visceral part – encloses the thyroid gland, trachea and oesophagus.
  2. Muscular part – encloses the infrahyoid muscles.

The posterior section of the muscular fascial layer is formed by contributions from the buccopharyngeal fascia.

Fig 1.2 - Transverse section of the neck, showing the pretracheal fascia in red.

Fig 1.2 – Transverse section of the neck, showing the pretracheal fascia in red.


Prevertebral Layer

The prevertebral fascial layer surrounds the vertebral column and its associated muscles (scalence, pre-vertebral, and deep muscles of the back). The anterior portion of the fascia attaches to the transverse processes and vertebral bodies of the vertebral column. Posteriorly, it attaches along the ligamentum nuchae. In the inferior region of the neck, the fascia surrounds the brachial plexus and subclavian artery, and here it is known as the axillary sheath.

Fig 1.3- Transverse section of the neck. The carotid sheaths and prevertebral sheaths are highlighted.

Fig 1.3- Transverse section of the neck. The carotid sheaths and prevertebral sheaths are highlighted.


Carotid sheaths

The carotid sheaths are paired structures, which encloses important vessels and nerves. The fascial layer receives contributions from the pretracheal fascia anteriorly, and the prevertebral fascia posteriorly. The contents of the carotid sheath are :

  • Common carotid artery (which bifurcates within the carotid sheath into the external and internal carotid arteries)
  • Internal jugular vein
  • Vagus nerve
  • Cervical lymph nodes

The carotid fascia is organised into a column, descending from the base of the skull to the thorax. This represents a pathway for the spread of infection, and it clinically very important.


Clinical Relevance: Spread of Infections

The fascia of the neck is important in preventing the spread of infections, and when they do occur, it explains their spread. 

A superficial skin abscess is prevented from spreading further into the neck by the investing layer of fascia.

There are locations deep to the investing layer of fascia where an infection can cause real problems:

1. Posterior to the prevertebral fascia – This can erode through the prevertebral fascia, and drain into the retropharyngeal space (space between the pretracheal and prevertebral fascial layers).  The retropharyngeal space extends into the thorax, and the drainage of pus into the thorax can lead to infection of the mediastinal contents.

2. Between the investing fascia and visceral part of the pretracheal fascia – This can spread inferiorly into the chest, causing infection anterior to the pericardium.