Diagnostic ultrasound ( PDFDrive )

CHAPTER 48 The Pediatric Head and Neck 1629
Platysma
muscle
2
mh
4
2
3
1
scm
5
FIG. 48.1 Supericial and Deep Cervical Boundaries. Axial image
of the neck at the level of the thyroid demonstrates the platysma muscle,
which separates the peripheral supericial from central deep cervical
fascial layers.
FIG. 48.3 Deep Cervical Fascial Layers of Suprahyoid Neck, Axial
Image. The parotid, masticator, and submandibular spaces represent
the supericial layer. 1, Parotid gland. 2, Submandibular space contains
the sublingual (brown) and submandibular (orange) glands. 3, Masticator
space contains the masseter muscle. 4, Middle layer; 5, Deep fascial
layer; mh, Mylohyoid muscle; scm, sternocleidomastoid muscle.
Hyoid
bone
Thyroid
gland
FIG. 48.2 Deep Cervical Fascial Layers. Sagittal image of the neck
separates the deep cervical fascia into three boundaries: supericial
(blue), middle (orange), and deep (yellow).
fascial planes and lesions extend within both the infrahyoid and
the suprahyoid space. hese spaces and lesions are described as
“lacking deinition by the hyoid.” Using this organization, with
the knowledge of the normal anatomic elements in each space,
the appropriate diferential diagnosis for a mass can be
proposed.
SUPRAHYOID SPACE
he suprahyoid space includes the supericial, middle, and deep
layers of the deep cervical fascia 9 (Fig. 48.3). he supericial layer
envelops three spaces. he parotid space includes the parotid
gland, intraparotid facial nerve, retromandibular vein, lymph
nodes, and external carotid artery. he masticator space includes
muscles of mastication and the posterior body of the mandible.
he submandibular space includes the sublingual and submandibular
glands, as well as the adjacent lymph nodes, muscles of
the tongue, and hypoglossal nerve. Ultrasound is most useful
in evaluation of the spaces in the supericial fascial layer.
he middle territory of the suprahyoid space lies between
fascial layers and includes the parapharyngeal and pharyngeal
spaces. his middle layer, which includes lymphoid tissue, minor
salivary glands, and fat encircling the pharynx, is diicult to
visualize with ultrasound and is not discussed separately. he
carotid space is formed from ibers of the middle and deep
layers of cervical fascia. he retropharyngeal space is contained
by layers of the middle cervical space anteriorly and deep cervical
layers posteriorly. However, because the retropharyngeal space
and prevertebral layer, a deep cervical space, cannot be separated,
it is easiest to consider these layers together in the deep cervical
facial layer as the retropharyngeal space. he carotid space and
retropharyngeal space extend above and below the hyoid and
are discussed later.
Salivary Glands
Because the parotid and submandibular areas primarily contain
salivary tissue and thus have similar pathology, these two spaces
are considered together. he major salivary glands that occupy
these spaces include the parotid glands, the submandibular glands,
and the sublingual glands.