Fasciae of the Neck

Superficial cervical fascia

Contents:

1. Platysma muscle
2. Cutaneous nerves, blood vessels and lymphatics
3. Superficial lymph nodes
4. Fat

Deep cervical fascia or Fascia colli

1. Investing layer

• Mnemonic: Encloses 2 muscles, 2 salivary glands and 2 spaces
• 2 muscles: Sternocleidomastoid and Trapezius
• 2 glands: Submandibular and Parotid
• 2 spaces: Suprasternal and Supraclavicular

2. Pretracheal layer

• Muscular layer: encloses infrahyoid muscles
• Visceral layer: encloses thyroid gland (forms false capsule and posteriorly suspensory ligament of Berry), trachea and esophagus
  • Posterior part: form buccopharyngeal fascia (outside pharyngeal muscles)

3. Carotid sheath: Formed anteriorly by pretracheal fascia and posteriorly by prevertebral fascia

Encloses:

• CCA
• IJV
• CN X
• CN IX, XI and XII also present in upper part, but they pierce out

Relations:

• Anteriorly: Ansa cervicalis (CN XII + C1, C2, C3 spinal nerves)
• Posteriorly: Cervical sympathetic chain

4. Pharyngobasilar fascia (deep to pharynx): lines the inner surface of pharyngeal muscles

• Retropharyngeal space exists between buccopharyngeal fascia and pharyngobasilar fascia

5. Prevertebral layer

• Encloses vertebrae and prevertebral muscles
• Forms floor of posterior triangle of neck
• Extends with brachial plexus as axillary sheath (subclavian and axillary veins lie outside the sheath)
• Alar fascia: between buccopharyngeal fascia and prevertebral fascia

Spread of Infections

1. Infection between investing layer and muscular layer of pretracheal fascia: Upto superior edge of manubirum

2. Infection between investing layer and visceral layer of pretracheal fascia: Into thoracic cavity anterior to pericardium

3. Retropharyngeal space infections (suppuration of retropharyngeal lymph nodes): Through the superior mediastinum into the posterior mediastinum

4. Infection behind prevertebral fascia (vertebral TB): May spread to various directions –

• Anterior: Chronic retropharyngeal abscess
• Lateral: Through axially sheath and point in posterior triangle or lateral wall of axilla
• Inferior: Superior mediastinum