- 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
- 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
- Bounded posteriorly by Visceral Cervical
- 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
- 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.
Potential Cavity within the carotid sheath which extends into the mediastinum
- Common and internal carotid arteries
- Internal Jugular vein
- Vagus nerve (CN X)
- Deep cervical lymph nodes
- Carotid sinus nerve
- 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
can be involved in any neck infection because it is made of those three layers:
Investing, Pretracheal and Prevertebral Fascia.
tend to be localized within the cervical region (between hyoid and root
of the neck) because the sheath is closely adherent to vessels ·
usually arises from thrombosis of the internal jugular vein or from infection
of those deep cervical lymph nodes that lie within the sheath ·
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. ·
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
- Largest interfascial space in the
neck which permits movement of the pharynx, esophagus, larynx, and trachea
- Lateral to and bounded anteriorly by the Visceral
- 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
- 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.
- Important pathway by which infections orginating from various locations
in the head and the upper portion of the neck reach the mediastinum.
- The retrovisceral space may also be infected directly from posterior perforations
of the esophagus or by infections of the deep cervical nodes lying adjacent
- 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
Danger Space 4
- 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
- Infection can communicate from posterior wall of
the oropharynx and oral cavity to the thorax by traveling from the Retropharyngeal
Space, and passing downward to the Retrovisceral space (which begins below
the pharynx). It can then pierce thru the weak alar fascia - into Danger
- "Dangerous" because an infection can easily travel to the thoracic
cage and mediastinum, i.e., mediastinitis. Abscess in the mediastinum could
go anteriorly to the pericardial area and could affect the manubrium, sternum,