Parotid fascia

The parotid fascia is a tough, fibrous capsule derived from the investing layer of the deep cervical fascia, which splits to enclose the parotid gland within its superficial and deep layers. It forms part of the larger parotidomasseteric fascia complex.

Location and Attachments

• The superficial layer attaches to the zygomatic arch, external acoustic meatus, and mastoid process, and is continuous anteriorly with the masseteric fascia. Superiorly, it fuses with the temporal fascia.

• The deep layer attaches to the mandible, styloid process, and tympanic plate, separating the parotid gland from the styloid process and digastric muscles.

The superficial layer is also continuous with the fascia of the SMAS (Superficial Musculoaponeurotic System), particularly in its lower part where it contains muscle fibres of the platysma. This reflects the dual origin of the parotid fascia from both deep cervical fascia and the facial musculoaponeurotic system.

Innervation

The parotid fascia receives sensory innervation from branches of the great auricular nerve (C2, C3) — a branch of the cervical plexus. Additional minor sensory contributions may come from the auriculotemporal nerve (branch of the mandibular division of the trigeminal nerve, CN V3); especially in the anteroinferior region. The latter is the main visceral sensory innervation to the parotid capsule.

Functional and clinical significance

The parotid fascia stabilizes the parotid gland, limits its expansion during inflammation (causing pain in parotitis), and serves as a surgical landmark in parotidectomy. Its continuity with the SMAS, masseteric fascia, and deep cervical fascia creates a fascial continuum that integrates the facial expression system with the masticatory and cervical regions.