Suprasternal Space

• Formed superior to the manubrium where the Investing Fascia divided into two layers attached to the anterior and posterior surfaces of the manubrium.
• Encloses the sternal heads of the SCM’s, the inferior ends of the anterior jugular veins, the jugular venous arch, fat and a few lymph nodes
• Clinical: Trauma to this area can cause a bleeder and subsequently a large bulging above the manubrium and even might distend down posterior to the manubrium into the superior mediastinum.

• Surrounding the trachea and lying against the anterior wall of the esophagus
• Bounded anteriorly by the Investing Cervical Fascia
• Bounded posteriorly by Visceral Cervical Fascia
• Limited above by the attachments of the infra-hyoid muscles and their fascia to the thyroids cartilage and to the hyoid bone
• Below, continues into the anterior portion of the superior mediastinum
• Bounded inferiorly by the sternum and scalene fascia
• Extends to approximately the arch of the aorta to about the level of the T4 vertebrae where the posterior surface of the sternum and the fibrous pericardium are united by denser connective tissue
• Contents: Infrahyoid Strap muscles
• Clinical: Can be infected directly by anterior perforations or rupture of the esophagus or indirectly by spread from the retrovisceral portion, around the sides of the esophagus and thyroid gland between the levels of the inferior thyroid artery and the oblique line of the thyroid cartilage. Both pretracheal and retrovisceral spaces descend into the superior mediastinum.

• 3 Deep Cervical fascial layers: Investing, Pretracheal, and Pre-Vertebral Condenses to form Carotid Sheath

(Click here to show another perspective)

Tubular space created, extending from the base of the skull to the root of the neck
• Anterior to cervical sympathetic trunk which lies on longus colli and longus capitis muscles in front of cervical vertebrae.
• Anterolateral wall is composed of the Investing Layer deep to SCM, and Pretracheal Layers
• Blends posteriorly and medially with the Prevertebral Layer of cervical fascia** (Sympathetic trunk lies posterior and intervenes between the sheath and the prevertebral fascia)

1. Common and internal carotid arteries
2. Internal Jugular vein
3. Vagus nerve (CN X)
4. Deep cervical lymph nodes
5. Carotid sinus nerve
6. Sympathetic fibers

• Sheath is extremely strong which prevents easy compression. Therefore a problem in the carotid sheath can crush the internal jugular vein and vagus nerve
• Clinical: It can be involved in any neck infection because it is made of those three layers: Investing, Pretracheal and Prevertebral Fascia.
  • Infections tend to be localized within the cervical region (between hyoid and root of the neck) because the sheath is closely adherent to vessels ·
  • Infection usually arises from thrombosis of the internal jugular vein or from infection of those deep cervical lymph nodes that lie within the sheath ·
  • Thrombosis of the jugular vein from a deep infection of the neck is probably not due to direct infection of the carotid sheath, but rather to the fact that infectious material follows tributaries of the internal jugular vein to reach the sheath. ·
  • Drug use (Heroin) usually use carotid route to obtain a fast high. A result can be abscess of the carotid sheath presenting in a patient who is groggy with a weak pulse (bradycardia) and low blood pressure due to the compression of the carotid sinus and irritation of the vagus nerve.

   

(Retro) Pharyngeal Space

• Area of loose connective tissue lying posterior to the pharynx and anterior to the alar layer of the prevertebral fascia
• Largest interfascial space in the neck which permits movement of the pharynx, esophagus, larynx, and trachea during swallowing
• Lateral to and bounded anteriorly by the Visceral (Retropharyngeal) Fascia
• Extends inferiorly behind the lower portion of the pharynx and the esophagus to form the posterior portion of the visceral compartment of the neck, communicate with the pretracheal space, and end at about the level of the bifurcation of the trachea (T1-T2). It is here where the Retropharyngeal Space is closed by the fusion of the Retropharyngeal Fascia with the Alar Fascia.
• Passes downward and is continuous with the (Retro)Visceral (retroesophageal) space (which begins below the pharynx) and opens inferiorly into the posterior mediastinum
• Closed superiorly by the base of the skull, superficial layer of fascia of the masticator space, submandibular space and laterally by the carotid sheath
• Contains retropharyngeal lymph nodes which drain the adenoids, nasal cavities, nasopharynx, and posterior ethmoid sinuses
• Clinical

• Key to an understanding downward spread of infections of the head and neck: Commonly regarded as a route through which infections of the mouth and throat reach the mediastinum. It can break through the posterior wall of the space through the alar fascia, and can enter Danger Space 4, between the two lamellae of the prevertebral layer of fascia (extends from the base of the skull to the level of the diaphragm).
• Fatal hemorrhage could potentially result from an extension of a retropharyngeal abscess to the deep vessels of the neck

  Majority of cases arising from the internal carotid artery rather than from the jugular vein: the vein is more often occluded by the infectious process than it is eroded to the point of hemorrhage. A sudden enlargement of a retropharyngeal mass may indicate erosion of a large vessel and that in such a case aspiration of the mass before its incision may prevent fatal hemorrhage.

• Spaces lying behind the esophagus and the lower part of the pharynx has been variously termed the retrovisceral, retropharyngeal, retroesophageal, or postvisceral space. It is clear that this is confusing... But for simplicity: The space posterior to pharynx is termed the retropharyngeal space. The space below C4 is normally termed retrovisceral. The space located posterior to the esophagus can be called retrovisceral as well, however if you wish to be specific, this space can be termed the retroesophageal space.
• Inferiorly, like the pretracheal, it extends into the mediastinum and ends at T1-T2, where the space is obliterated through fusion of the connective tissue on the posterior surface of the esophagus to the prevertebral Alar layer of fascia. A prevertebral space exists below this level- Danger Space 4.
• Clinical

• Potential pocket existing between the "prevertebral" fascia and the vertebral bodies.
• Intervertebral discs exist between vertebrae and are vulnerable to an infection traveling in this space
• It extends from skull base to coccyx, allowing for infection from the neck to the psoas muscle. (T.B. commonly presented this way prior to effective T.B. treatment.)

• An area of delicate loose connective tissue that lies between the alar and prevertebral fascia
• Extends from the base of the skull to the mediastinum

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