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 42th 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 gone through multiple revised editions and the current edition, the 42nd (Octob ...

(2020) describes a parotid-masseteric fascia as a thin and translucent yet tough fascia that covers the

parotid duct The parotid duct, or Stensen duct, is a salivary duct. It is the route that saliva takes from the major salivary gland, the parotid gland, into the mouth. Structure The parotid duct is formed when several interlobular ducts, the largest ducts insi ...

, 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 nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which contain only aff ...

where these structures lie upon the surface of the masseter muscle. Anteriorly, the fascia is said to overlie the

buccal fat pad The buccal fat pad (also called Bichat’s fat pad, after Xavier Bichat, and the buccal pad of fat) is one of several encapsulated fat masses in the cheek. It is a deep fat pad located on either side of the face between the buccinator muscle and se ...

(that in turn overlies the buccinator muscle) before blending with the epimysium of the buccinator muscle; 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 a ...

: the outer leaf represents parotideomasseteric fascia and extends superiorly to the zygomatic arch; 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 {{musculoskeletal-stub