The masseteric fascia and parotideomasseteric fascia (or masseteric-parotid fascia) are fascias of the head varyingly described depending upon the source consulted. They may or may not be described as one and the same structure.
Descriptions
The 42nd edition of
Gray's Anatomy
''Gray's Anatomy'' is a reference book of human anatomy written by Henry Gray, illustrated by Henry Vandyke Carter and first published in London in 1858. It has had multiple revised editions, and the current edition, the 42nd (October 2020 ...
(2020) describes a parotid-masseteric fascia as a thin and translucent yet tough fascia that covers the
parotid duct,
buccal branches of facial nerve (CN VII), and branches of the
mandibular nerve
In neuroanatomy, the mandibular nerve (V) is the largest of the three divisions of the trigeminal nerve, the fifth Cranial nerves, cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which ...
where these structures lie upon the surface of the masseter muscle. Anteriorly, the fascia is said to overlie the
buccal fat pad (that in turn overlies the buccinator muscle) before blending with the
epimysium of the
buccinator muscle
The bucinator () is a thin quadrilateral muscle occupying the interval between the maxilla and the Human mandible, mandible at the side of the face. It forms the anterior part of the cheek or the lateral wall of the oral cavity.Illustrated Anatom ...
; inferiorly, it is said to become continuous with the
investing layer of deep cervical fascia
The investing layer of deep cervical fascia is the most superficial part of the deep cervical fascia, and encloses the whole neck.
It is considered by some sources to be incomplete or nonexistent.
Attachments
It surrounds the neck like a collar, ...
inferior to the inferior margin of the mandible. The masseteric fascia is said to be derived from the deep cervical fascia and be overlied by but separate from the parotid fascia.
The Sobotta Anatomy Textbook (2018) describes the masseteric fascia and parotideomasseteric fascia as two distinct but related structures. The masseteric fascia is said to cover the masseter muscle, dividing into a superficial layer and a deep layer - the two layers together constituting the parotideomasseteric fascia - to form a fascial compartment that encloses the masseter muscle as well as the
medial and
lateral pterygoid muscles (the pterygoid muscles being enclosed by the deep layer). The superficial layer is said to connect with the
parotid fascia.
The Farlex Medical Dictionary (2012) describes the masseteric fascia as a fascia covering the superficial surface of the masseter muscle, and the parotideomasseteric fascia as a dense membrane covering both surfaces of the parotid gland that is anteriorly continuous with the masseteric fascia.
The 12th edition of Last's Anatomy (2011) describes the masseteric fascia and parotideomasseteric fascia as distinct structures related to the
parotid fascia. The parotid fascia is described as consisting of an outer leaf and an inner leaf that are formed by a split of the
deep cervical fascia
The deep cervical fascia (or fascia colli in older texts) lies under cover of the platysma, and invests the muscles of the neck; it also forms sheaths for the carotid vessels, and for the structures situated in front of the vertebral column. Its ...
: the outer leaf represents parotideomasseteric fascia and extends superiorly to the
zygomatic arch
In anatomy, the zygomatic arch (colloquially known as the cheek bone), is a part of the skull formed by the zygomatic process of temporal bone, zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the ...
; the parotid fascia is said to be considered the parotid capsule where it covers the gland while anteriorly to the gland it becomes known as the masseteric fascia.
The 5th edition of Illustrated Anatomy of the Head and Neck describes a masseteric-parotid fascia as covering the masseter muscle and structures inferior to the zygomatic arch, surrounding the parotid salivary gland.
References
Fascial spaces of the head and neck
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