Fascia of the neck

Superficial cervical fascia

The contents of the superficial cervical fascia will vary depending upon location but include:
- Platysma (and cervical branch of facial nerve that innervate the muscle)
- Cutaneous nerves of the cervical plexus:
  - Lesser occipital
  - Great auricular
  - Transverse cervical (largest sensory contribution)
  - Supraclavicular
Deep to the superficial cervical fascia is the investing (or superficial) layer of deep cervical fascia

Lies superficial to Investing Layer of Deep Cervical Fascia
Extends from fascia over upper parts of Pectoralis Major and Deltoid to lower border of Mandible
Some fibres extend into face blending with fascial expression muscles
Covers External and Anterior Jugular Veins
Separated below but converge above towards midline just beneath chin
Nerve Supply:
- Cervical Branch of Facial Nerve
- Afferent (proprioceptive) fibres run with Transverse Cervical Nerve
Action:
- Involved in facial expression
- May assist in mouth opening

Commence beneath chin and pass downwards
Side by side beneath Platysma
Reaches Suprasternal region
Pierce Deep Fascia and come to lie in Suprasternal Space (often connected by a short anastomotic vein)
Angles laterally to pass deep to Sternocleidomastoid but superficial to Strap muscles
Opens into the External Jugular Vein near its termination

Four parts:
1. Superficial (Investing) Layer
2. Pretracheal Fascia
3. Prevertebral Fascia
4. Carotid Sheath

Superficial part:
- Extends superiorly as the Parotidomasseteric Fascia
- Reaches Zygomatic Arch
Deep part:
- Extends to Base of Skull
- Forms the Stylomandibular Ligament between the Styloid Process and Angle of Mandible
Below:
- Investing Layer attached to Spine and Acromion of Scapula and Clavicle with Trapezius
- Attached to Clavicle and Manubrium with Sternocleidomastoid
- In between these muscles, attached to both Clavicles and Jugular (Suprasternal) Notch by 2 layers into which it splits a short distance above them
- Suprasternal Space:
  - Formed between layers of Investing Layer attached to anterior and posterior borders of Jugular Notch
  - Contents include:
    - Lower parts of the Anterior Jugular Veins
    - An anastomotic arch between them
    - Sternal Heads of Sternocleidomastoids
    - Sometimes a Lymph Node
- In the middle third of the Clavicle – the deeper of the two layers splits around Inferior Belly of Omohyoid – forms a fascial sling keeping the muscle belly low down in the neck
  - Two layers pierced by External Jugular Vein

Lies in front of the Prevertebral muscles
Extends from Base of Skull downwards to blend with Anterior Longitudinal Ligament of T4 Vertebral Body in the Superior Mediastinum
- Thus, infections behind the Prevertebral Fascia imprisoned in the Superior Mediastinum in front of the vertebral bodies
Anterior to Longus Capitis, Rectus Capitis Lateralis, Longus Colli
Extends sideways across Scalenus Anterior, Scalenus Medius, Levator Scapulae Muscles
Gets thinner further out laterally
Fades under cover of anterior border of Trapezius
Covers muscles that form the floor of the Posterior Triangle of the Neck and all Cervical Nerve Roots
- Thus, Cervical Plexus and Trunks of Brachial Plexus lie deep to it
- Lymph Nodes of Posterior Triangle and Accessory Nerve lie superficial to it
Cervical Sympathetic Trunk does NOT lie deep to the Prevertebral Fascia
3rd part of Subclavian Artery – deep to Prevertebral Fascia
Prevertebral Fascia becomes prolonged over the Subclavian Artery and the Brachial Plexus below the Clavicle as the Axillary Sheath
- Does not invest the Subclavian or Axillary Vein
  - These lie in loose areolar tissue anterior to it
  - Free to dilate during times of increased venous return from the upper limb
Prevertebral Fascia pierced by 4 cutaneous branches of the Cervical Plexus
- Great Auricular Nerve
- Lesser Occipital Nerve
- Transverse Cervical Nerve
- Supraclavicular Nerve

Deep to Infrahyoid Strap muscles (Sternothyroid, Sternohyoid, Omohyoid)
Upward attachment limited by respective attachments of those muscles
- I.e. Body of Hyoid Bone and Oblique Line of Thyroid Cartilage
Splits to enclose Thyroid Gland
Not adherent to Thyroid except:
- At back of Isthmus – attached to 2nd, 3rd and 4th Tracheal Rings
Laterally – fuses with front of Carotid Sheath on deep surface of Sternocleidomastoid
Inferiorly – passes behind Brachiocephalic Veins to blend with Adventitia of Aortic Arch and Fibrous Pericardium
- Thus, neck infections in front of the Pretracheal Fascia is directed into the anterior mediastinum
Part of Cervical Visceral Fascia surrounding Pharynx, Oesophagus, Larynx and Trachea

Feltwork of areolar tissue
Surrounds Common and Internal Carotid Arteries, Internal Jugular Vein, Vagus Nerve, and Deep Cervical Lymph Nodes
- Common Carotid Artery is medial to the Internal Jugular Vein
  - Vagus Nerve deeply place between the two vessels
Thin where it overlies Internal Jugular Vein – allows venous dilatation
Attached to Base of Skull at margins of Carotid Canal and Jugular Fossa
Continued downwards to blend with Adventitia of Aortic Arch
Anteriorly – lower part of Sheath fuses with fascia on deep surface of Sternocleidomastoid
Blends with Pretracheal Fascia where they lie alongside
Posteriorly – minimum loose areolar tissue between it and Prevertebral Fascia
- Cervical Sympathetic Trunk lies in this space anterior to Prevertebral Fascia