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M01.04.022 Fascial Layers
Fascia is a type of internal connective tissue that forms bands or sheets, surrounding and supporting muscles, vessels, and nerves in the body. In the neck, fascia serves to:
- Support internal structures
- Compartmentalize structures, limiting the spread of infections
The fascial layers of the neck are classified into:
- Superficial Cervical Fascia
- Deep Cervical Fascia
This guide delves into their anatomy, attachments, and clinical importance.
1. Superficial Cervical Fascia
Location and Components
The superficial cervical fascia lies between the dermis and the deep cervical fascia. It contains:
- Neurovascular supply to the skin
- Superficial veins, e.g., the external jugular vein
- Superficial lymph nodes
- Fat
- Platysma muscle
Platysma Muscle
- Structure: A broad, thin muscle located anteriorly in the neck.
- Origin: Fascia of the pectoralis major and deltoid muscles.
- Insertion: Inferior border of the mandible; fuses with facial muscles at the midline.
- Innervation: Cervical branch of the facial nerve.
2. Deep Cervical Fascia
General Overview
Located deep to the superficial fascia and platysma, the deep cervical fascia is organized into layers that resemble a shirt collar. It supports the neck’s structures.
Layers of the Deep Cervical Fascia
| Layer | Location | Attachments | Contents |
|---|---|---|---|
| Investing | Outermost layer | Superior: External occipital protuberance, nuchal line Inferior: Clavicle, sternum Anterior: Hyoid bone Posterior: Nuchal ligament | Surrounds all neck structures, splits to enclose trapezius and sternocleidomastoid muscles |
| Pretracheal | Anterior neck | Superior: Hyoid bone Inferior: Thorax (fuses with pericardium) | Thyroid gland, trachea, esophagus, infrahyoid muscles |
| Prevertebral | Surrounds vertebral column and associated muscles | Superior: Base of skull Anterior: Vertebral bodies and transverse processes Posterior: Nuchal ligament Inferior: Endothoracic fascia | Vertebral column, deep neck and back muscles, brachial plexus, subclavian artery |
| Carotid Sheath | Paired structures enclosing neurovascular bundles | Base of skull to thoracic mediastinum | Common carotid artery, internal jugular vein, vagus nerve, cervical lymph nodes |
3. Clinical Relevance
Fascial Spaces and Infection Spread
Fascial compartments in the neck restrict infections, but potential spaces can act as pathways for spread.
| Fascial Space | Location | Spread Extent |
|---|---|---|
| Retropharyngeal Space | Between buccopharyngeal fascia and prevertebral fascia | Base of skull to posterior mediastinum |
| Visceral Space | Enclosed by visceral pretracheal fascia | Hyoid bone to superior mediastinum |
Importance of the Carotid Sheath
The carotid sheath’s continuity from the base of the skull to the thoracic mediastinum allows infections to spread between the neck and mediastinum.
Points to Remember
- Fascia in the neck compartmentalizes structures and limits infection spread.
- Superficial cervical fascia contains the platysma muscle and superficial vessels.
- Deep cervical fascia has multiple layers (investing, pretracheal, prevertebral, carotid sheath).
- Carotid sheath houses critical neurovascular structures, including the common carotid artery and vagus nerve.
Bibliography
- Moore, K.L., Dalley, A.F., & Agur, A.M.R. Clinically Oriented Anatomy.
- Standring, S. Gray’s Anatomy: The Anatomical Basis of Clinical Practice.
- Drake, R.L., Vogl, A.W., & Mitchell, A.W.M. Gray’s Anatomy for Students.