Date post: | 01-Jun-2015 |
Category: |
Health & Medicine |
Upload: | ahmed-bahnassy |
View: | 4,368 times |
Download: | 9 times |
Neck Spaces and mediastinum ..Dangerous relation
Dr/Ahmed BahnassyConsultant radiologist
RMH
Deep Neck Spaces
Anatomy of the Cervical Fascia
Anatomy of the Deep Neck Spaces
Neck infections and relation to mediastinum.
Cervical Fascia Superficial Layer
Deep Layer Superficial Middle Deep
Cervical Fascia..Superficial layer
Superficial Layer Platysma Muscles of Facial
Expression
Cervical Fascia Superficial Layer of the
Deep Cervical Fascia (rule of two’s)
Muscles Sternocleidomastoid Trapezius
Glands Submandibular Parotid
Spaces Posterior Triangle Suprasternal space of
Burns
Cervical Fascia..Middle layer
Middle Layer of the Deep Cervical Fascia
Muscular Division Infrahyoid Strap
Muscles Visceral Division
Pharynx, Larynx, Esophagus, Trachea, Thyroid
Buccopharyngeal Fascia
Cervical Fascia..deep layers
Deep Layer of Deep Cervical Fascia Alar Layer
Posterior to visceral layer of middle fascia
Anterior to prevertebral layer
Prevertebral Layer Vertebral bodies Deep muscles of the
neck
Cervical Fascia..Highway of infection
Carotid Sheath Formed by all three
layers of deep fascia Contains carotid
artery, internal jugular vein, and vagus nerve
“Lincoln’s Highway”
Deep Neck Spaces..relation to mediastinum
Described in relation to the hyoid Entire length of
the neck Suprahyoid Infrahyoid
Deep Neck Spaces Entire Length of
Neck: 1.Retropharyngeal Space Posterior to pharynx
and esophagus Anterior to alar layer
of deep fascia Extends from skull
base to T1-T2
Deep Neck Spaces
Entire Length of Neck: 2.Danger Space
Anterior border is alar layer of deep fascia
Posterior border is prevertebral layer
Extends from skull base to diaphragm and is so named because it contains loose areolar tissue and offers little resistance to the spread of infection.
Deep Neck Spaces
Entire Length of Neck: 3.Prevertebral Space
Anterior border is prevertebral fascia
Posterior border is vertebral bodies,ALL and deep neck muscles
Extends along entire length of vertebral column. Infection in this space tends to stay somewhat localized due to the dense fibrous attachments between the fascia and the deep muscles.
Deep Neck Spaces Entire Length of Neck:
4.Visceral Vascular Space Carotid Sheath Like the prevertebral space the
visceral vascular space is quite compact, contains little areolar tissue and is resistant to the spread of infection. It is termed the “Lincolin’s highway” of the neck . It extends from the base of skull into the mediastinum and because it receives contributions from all three layers of deep fascia it can become secondarily involved by infection in any other deep neck space by direct spread.
Deep Neck Spaces Suprahyoid:
1.Submandibular Space Anterior/Lateral—
mandible Superior—mucosa Inferior—superficial layer
of deep fascia Posterior/Inferior--hyoid
Deep Neck Spaces Suprahyoid: Submandibular
Space comprises Sublingual Space
Areolar tissue Hypoglossal and lingual nerves Sublingual gland Wharton’s duct
Submylohyoid Space Anterior bellies of digastrics Submandibular gland (These two subdivisions freely
communicate around the posterior border of the mylohyoid. )
Deep Neck Spaces
Suprahyoid: 2.Parapharyngeal Space
(pharyngomaxillary space ) Superior—skull base-petrous
portion of temporal bone vs. sphenoid
Inferior—hyoid Anterior—ptyergomandibular
raphe Posterior—prevertebral fascia Medial—buccopharyngeal fascia Lateral—superficial layer of deep
fascia,medial pterygoid and parotid .
The parapharyngeal space communicates with submandibular , retropharyngeal, parotid and masticator spaces with important implications in spread of infection .
Deep Neck Spaces Suprahyoid: Parapharyngeal
Space comprises: Prestyloid
Medial—tonsillar fossa Lateral—medial pterygoid Contains fat, connective tissue,
nodes Poststyloid
Carotid sheath Cranial nerves IX, X, XII The stylopharyngeal aponeurosis
of Zuckerkandel is formed by the intersection of the alar, buccopharyngeal and stylomuscular fascia and acts as a barrier to the spread of infection from the prestyloid compartment to the poststyloid compartment.
Relations to other spaces
Normal anatomy of parapharyngeal space. BS = buccal space, ICA = internal carotid artery, IJV = internal jugular vein, MS = masticator space, PMS = pharyngeal mucosal space, PPS = parapharyngeal space, PS = parotid space, PVS = prevertebral space, RPS = retropharyngeal space, SMS = submandibular space, T = torus tubarius. Axial schematic at nasopharynx level shows that parapharyngeal space is divided into prestyloid and poststyloid compartments by tensor-vascular-styloid fascia connecting tensor veli palatini muscle with styloid process.
Deep Neck Spaces Suprahyoid: Peritonsillar Space
Medial—capsule of palatine tonsil
Lateral—superior pharyngeal constrictor
Superior—anterior tonsil pillar Inferior—posterior tonsil pillar. This space contains loose
areolar tissue, primarily in the area adjacent to the soft palate, which explains why the majority of peritonsillar abscesses will localize to the superior pole of the tonsil.
Deep Neck Spaces Suprahyoid:3.Masticator and
Temporal Spaces Formed by the superficial layer
of deep cervical fascia and contains.
Masseter and pterygoids Temporalis. The masticator space is in direct
communication with the temporal space superiorly deep to the zygoma. The temporal space has as its lateral boundary the superficial layer of deep fascia and its medial boundary the periosteum of the temporal bone. It is subdivided into superficial and deep spaces by the body of the temporalis muscle. This space contains the internal maxillary artery and the mandibular nerve.
Deep Neck Spaces Suprahyoid:4. Parotid Space
Formed by superficial layer of deep fascia and dense septa from capsule into gland.
In addition to the parotid gland, this space contains the parotid lymph nodes, the facial nerve and posterior facial vein.
The fascial envelope is deficient on the supero-medial surface of the gland, facilitating direct communication between this space and the parapharyngeal space.
Deep Neck Spaces Infrahyoid: Anterior
Visceral Space Formed by middle layer of
deep fascia Contains thyroid, trachea,
esophagus. This potential space runs from the thyroid cartilage into the anterior superior mediastinum to the arch of the aorta. Below the level of the thyroid gland this space communicates laterally with the retropharyngeal space .
Deep Neck Space Infections
Pathophysiology
Deep neck space infections can arise from a multitude of causes., as follows:
1. Spread of infection can be from the oral cavity, face, or superficial neck to the deep neck space via the lymphatic system.
2. Lymphadenopathy may lead to suppuration and finally focal abscess formation.
3. Infection can spread among the deep neck spaces by the paths of communication between spaces.
4. Direct infection may occur by penetrating trauma.
Spread of infection Tonsillitis may lead to peritonsillar abscess. If not
treated successfully, peritonsillar abscess may spread to the lateral pharyngeal space. From thereto the posterior pharyngeal and prevertebral spaces and into the chest. Mediastinitis and empyema may ensue.
Spread of infection
Alternatively, infection may spread from the lateral pharyngeal space to the contents of the carotid sheath, leading to internal jugular vein thrombosis, subacute bacterial endocarditis, pulmonary emboli, carotid artery thrombosis cerebrovascular insufficiency, Horner syndrome ,or may cause even airway obstruction .
Retropharyngeal Abscess 50% occur in patients 6-12 months of age 96% occur before 6 years of age
Retropharyngeal phlegmon. Axial CT section through the lower nasopharynx shows a well-marginated lucent area in the retropharyngeal/parapharyngeal space with an enhancing
wall and surrounding edema
Pediatrics Cause—suppurative
process in lymph nodes Nose, adenoids,
nasopharynx, sinuses
Adults Cause—trauma,
instrumentation, extension from adjoining deep neck space
Danger Space Cause—extension from retropharyngeal,
prevertebral or parapharyngeal space Can extend to mediastinum .
Prevertebral Space Back, shoulder, neck
pain made worse by
deglutition Dysphagia or
dyspnea Cause—Pott’s
abscess, trauma, osteomyelitis,
extension from retropharyngeal and
danger spaces
Tuberculous abscess in prevertebral space
Submandibular Space Anterior neck swelling,
floor of mouth edema Cause—70-85% have
odontogenic origin First molar and
anterior Second and third
molars Sialadenitis,
lymphadenitis, mandible fractures,etc.
Right submandibular gland infection with a stone
Ludwig’s angina
Tender, firm anterior neck edema without fluctuance
Contrast CT scan through the tongue and oral cavity demonstrates an enhancing inflammatory mass with abscess in the right tongue and oral cavity with extension into the parapharyngeal space and masticator space.
Ludwig's angina. Axial CT section through the tongue demonstrates diffuse enlargement of the tongue associated with low attenuation areas consistent with phlegmon.
Parapharyngeal Space Cause—infection
of pharynx, tonsil, adenoids, dentition, parotid, mastoid, suppurative lymphadenitis, extension from other deep neck spaces
Middle ear infections or mastoiditis may involve the parapharyngeal space after rupture of a Bezold’s abscess on the inner aspect of the mastoid tip along the digastric ridge.
. Bezold's abscess, upper left neck. A, Axial noncontrast CT section defines an ill-defined mass in the upper posterior left neck. B, Axial CT section (bone window setting) demonstrates lytic destruction in the lower left mastoid secondary to coalescent mastoiditis.
Peritonsillar Space Fever, malaise “Hot-potato” voice,
trismus. Cause—extension
from tonsillitis. These infections are uncommon in the pediatric population, but instead tend to effect post-pubescent individuals.
CT section demonstrates an enhancing mass in the right peritonsillar region with a low-attenuation area centrally consistent with an abscess cavity
Masticator Temporal Space Swelling along
ramus of mandible Cause—
odontogenic, from third molars
Parotid Space Medial bulge
of posterior lateral pharyngeal wall
Cause—parotitis, sialolithiasis, Sjogren’s syndrome
Right neck abscess with extension to the masticator space
Complications
Internal Jugular Vein Thrombosis Lemierre’s syndrome Pulmonary embolism
occurs in up to 5%
Right jugular vein thrombosis. Axial CT section through the neck below the angle of the mandible demonstrates a low attenuation area with an enhancement wall in the right neck medial to the indistinct and enlarged sternocleidomastoid muscle.
Complications
Carotid Artery Rupture Mortality of 20-40% Majority from internal carotid, less from external
carotid, and fewest from common carotid
Dental infections..the ticking bomb The apex of the first molar is above
the mylohyoid, so involvement of this tooth, or teeth anterior to this, will first involve the sublingual space.
In contrast, the apices of the second and third molars are below the mylohyoid and infection here will first spread to the submylohyoid space. However, both subspaces may be involved.
The sad story
From neck infection to Mediastinitis
A- MDCT of the neck shows two large fluid collections containing gas in both the submandibular spaces
At the level of the hyoid bone, a large fluid collection is seen in the visceral space
Large fluid collection in the visceral space
The fluid collection
spreads to the anterior
mediastinum
Sagittal multiplanar reformatted CT image shows spread of descending necrotizing mediastinitis