11. Fascia of the Face
Superficial
fascia is
copious and
loose –
however,
there is no
discrete layer
of deep fascia
of the face
except …
12. Deep fascia does
exist in the regions
of the parotid
glands and the
masseter muscles.
It forms capsules
around these
structures.
The other regions of the face
have much subcutaneous
tissue, but no deep fascia.
13. Salivary glands
• A network of secretory glands and ducts
• Keep oral cavity moist, dissolve water soluble
compounds and begin digestion of starches.
• 3 pairs of major salivary glands and hundreds
minor salivary glands.
• Histologically consist of 2 major cell types:
serous and mucous
14. Parotid glands
• Retromandibular fossae posterior to the
ascending ramus of mandible and anterior
inferior to external auditory canal.
• Unilobular, pyramidal, 2 capsules
• Traversed by extracranial portion of facial
nerve
• Superficial and deep (20%, medial) portions
• Drains into oral cavity via Stenson’s duct
The oral cavity is defined as the area from the start of the lip vermillion to the junction of the hard and soft palates above to the circumvallate papillae below..
The oropharynx extends from there back to the tip of the epiglottis, which is at the level of the hyoid.
The hypopharynx extends from the lower point of the oropharynx above to the plane of the inferior border of the cricoid cartilage below.
Cosmesis – the preservation, restoration, or bestowing of bodily beauty
Deglutition - swallowing
The oral cavity is bounded anteriorly by the skin and the vermillion border of the upper and lower lips. The oral cavity extends posteriorly to the circumvallate papillae of the tongue, the junction of the hard and soft palates, and the anterior faucial arch.
The tonsil, soft palate and posterior one third of the tongue are oropharangeal structures and are not considered in our discussion of the oral cavity.
Laterally the oral cavity is bounded by the buccal mucosa.
The oral submucosa contains minor salivary glands, copious lymphatic vessels, blood vessels and sensory nerves
The oral cavity is divided into the following subsites;
The lip, anterior two thirds of the tongue, floor of the mouth, gingiva, retromolar trigone, buccal mucosa and hard palate.
The buccal mucosa lines the lateral oral cavity and blends with the gingiva superiorly and inferiorly and with the retromolar trigone posteriorly. The mucosa is pierced by the Stenson’s duct of the parotid gland at the papilla adjacent to the second maxillary molar tooth.
The gingiiva consists of thick keratinised mucosa with submucosal adherence to the periosteum. The mucosa covers the alveolar processes of the mandible and the maxilla.
The retromolar trigone is that portion of adherent keratinised mucosa covering the ascending ramus of the mandible from the third mandibular molar to the maxillary tubercle. It represents the area between the buccal mucosa laterally and the anterior tonsillar pillar medially and posteriorly.
The Hard Palate is bounded in front and at the sides by the alveolar arches and gums; behind, it is continuous with the soft palate. It is covered by a dense structure, formed by the periosteum and mucosa of the mouth, which are intimately adherent. Along the middle line is a linear raphæ/seam, which ends anteriorly in a small papilla corresponding with the incisive canal. On either side and in front of the raphé the mucous membrane is thick, pale in color, and corrugated; behind, it is thin, smooth, and of a deeper color; it is covered with stratified squamous epithelium, and furnished with numerous palatal glands, which lie between the mucous membrane and the surface of the bone.
The Soft Palate is a movable fold, suspended from the posterior border of the hard palate, and forming an incomplete septum between the mouth and pharynx. It consists of a fold of mucous membrane enclosing muscular fibers, an aponeurosis, vessels, nerves, adenoid tissue, and mucous glands. When occupying its usual position, i. e., relaxed and pendent, its anterior surface is concave, continuous with the roof of the mouth, and marked by a median raphé. Its posterior surface is convex, and continuous with the mucous membrane covering the floor of the nasal cavities. Its upper border is attached to the posterior margin of the hard palate, and its sides are blended with the pharynx. Its lower border is free. Its lower portion, which hangs like a curtain between the mouth and pharynx is termed the palatine velum. 13 Hanging from the middle of its lower border is a small, conical, pendulous process, the palatine uvula; and arching lateralward and downward from the base of the uvula on either side are two curved folds of mucous membrane, containing muscular fibers, called the arches or pillars of the fauces.
The lip is a common site of skin cancer. The layers of the lip, from external to internal ,include the epidermis, dermis, subcutaneous tissue, the orbicularis oris, and attached musculature, the oral submucosa and the oral mucosa.
The upper lip possesses 2 peaks forming a cupid’s bow where the filtrum ascends to the columella of the nasal septum.
The blood supply for the lips comes from the superior and inferior labial branches of the facial artery, one of the six non-terminal branches of the external carotid artery. More than just supplying nutrients to lip tissue, blood also figures prominently in lip color.
Sensation of the lower lip is provided by the mental nerve, the terminal segment of the alveolar branch of the mandibular division of the trigeminal nerve. The nerve exits the mental foramen of the mandible near the root of the canine tooth. Paraesthesia of the chin suggests extensive mandible invasion and inferior alveolar nerve involvement by oral carcinoma.
The orbicularis oris muscle receives motor innervation from the marginal and buccal branches of the facial nerve and performs a sphincteral function to maintain oral competence and to facilitate articulation of speech. This Muscle has many attachments from other muscles of facial expression that elevate and depress the lips. Of clinical importance is the innervation of depressor anguli oris muscle by the marginal mandibular branch of the facial nerve
Reapproximation of the orbicularis oris muscle.
Reapproximation of the vermilion-cutaneous border.
The floor of the mouth is a soft thin layer of u-shaped mucosa overlying the insertion of the mylohyoid muscle laterally, the hyoglossus muscle medially, and the insertion of genioglossus muscle anteriorly. It covers the sublingual salivary glands, submandibular (Wharton’s) duct, and the lingual nerve. The blood supply is from the lingual vessels. Its lymphatic plexus is copious and drains bilaterally in the midline.
Figure 2. Tongue elevated.
1. frenulum of tongue
2. ridge formed by deep lingual vein
3. sublingual fold
4. sublingual caruncle
5. opening of submandibular duct
The sublingual gland forms the sublingual fold and sends multiple small ducts into the mouth along the fold.
The anterior two thirds of the tongue is called the oral or mobile tongue and is bounded posteriorly by the v-shaped line of the circumvallate papillae. Posterior to this line is the base of the tongue, which is part of the oropharanx. The oral tongue has ventral and dorsal surfaces. The mucosa of the tongue is simple stratified epithelium with interspersed papillae or taste buds.
The tongue is comprised of intrinsic and extrinsic muscles. The intrinsic muscles are arranged in vertical and horizontal fascicles that allow the mobile tongue to change shape and consistency.
There are 3 pairs of extrinsic muscles that provide mobility of the tongue: genioglossus, hyoglossus and styloglossus.
Protrusion of the tongue is primarily accomplished by the action of the genioglossus muscle which originates from the mandibular tubercles on the lingual surface of the arch of the mandible, and inserts diffusely into the substance of the intrinsic musculature on each side of the tongue.
The motor supply to the intrinsic and extrinsic tongue muscles is the hypoglossal nerve.
The sensation of the tongue is supplied by the lingual nerve, a branch of the mandibular division of the trigeminal nerve.
The blood supply to the tongue is derived from the paired lingual arteries.
Salivary gland system consists of-
The function of which is to –
Minor salivary glands present beneath the mucosa of the upper aerodigestive tract starting from the nasal cavity, the paranasal sinuses, nasopharanx, oral cavity, oropharynx, hypopharnyx and larynx.
The serous cells are polyhedral and form globular acini located at the end of microscopic ducts. Serous secretions from these acini empty into smaller duct systems which lead to larger duct systems and eventually into the main excretory duct. Mucous cells are cuboidal and also form acini. Secretions from these glands are viscous mucus which drains through similar duct systems.
Stenson’s duct – located in cheek mucosa adjacent to occlusal line of teeth
2 capsules;
True capsule – fibrous condensation of gland proper
False capsule – part of deep cervical fascia – splits into 2 layers to enclose the gland
Superficial layer is thick – attached to zygoma = Parotid fascia
Deeper layer attaches to the styloid process and mandible = stylomandibular ligament
The anatomic landmarks for the main trunk of the facial nerve, which measures anywhere from 5-15mm are at a point where the tip of the mastoid process, cartiliginous auditory canal, and superior border of the posterior belly of the digastric muscle meet.
The facial nerve exits from the stylomastoid foramen and passes anterior to the posterior belly of the digastric muscle, lateral to the styloid process, inferior to the auditory canal, and enters the substance of the parotid gland.
The main trunk branches into the zygomaticotemporal and cervicofacial divisions and as it runs through the substance of the parotid, subsequently into its 5 main branches. There are significant anatomic variations in the intraglandular branching of the facial nerve. The plane of the facial nerve is used to divide th gland into its superficial and deep lobes, with about 20% of the substance of the gland lying beneath the nerve.
The greater auricular nerve enters the tail of the parotid gland and divides into anterior and posterior branches. It provides sensation to the skin of the face near the tragus as well as the earlobe.
The auriculotemporal nerve is a branch of the mandibular division of the 5th cranial nerve. It contains the parasympathetic fibres sent to the paraotid gland by the otic ganglia, and carries sympathetic fibres to sweat glands.
Nerve supply to parotids;
Sympathetic – Plexus around external carotid artery
Parasympathetic – Auriculotemporal, glossopharyngeal nerve
From a surgical standpoint it is important to understand the anatomic relationships of the neurovascular structures in the parapharangeal space with the deep lobe parotid tissue.
The anatomic relationship of the parotid gland are shown.
The structures coursing through the parotid gland from superficial to deep are the facial nerve, retromandibular vein, external carotid artery and the auriculotemporal nerve (from V3)
Nerves: facial, greater auricular and auriculotemporal
Venous: Retromandibular vein
Arterial: External carotid, Superficial temporal/Transverse facial
Figure 2. Drawing shows the major blood vessels in the area of the salivary glands. 1 = retromandibular vein, 2 = external carotid artery, 3 = facial artery and vein, 4 = lingual artery and vein, 5 = external carotid artery, 6 = internal jugular vein, 7 = external jugular vein.
The submandibular glands reside in the submandibular space within the digastric triangle and beneath and anterior to the angle of the mandible. They overlie the mylohyoid muscle and extend around its free border in the floor of the mouth along the course of Wharton’s duct. The gland lies on the hyoglossus muscle and is in direct contact with the stylomandibular ligament posteriorly.
The submandibular gland abuts the body of the mandible superolaterally, the lingual and hypoglossal nerves medially, the mylohyoid muscle anteriorly and the tail of the parotid gland posteriorly. The marginal branch of the facial nerve runs along the lateral surface of the gland, just deep to the platysma.
Three important nerves are in direct contiguity to the gland: the marginal branch of the facial nerve, the hypoglossal nerve, and the lingual nerve.
Submandibular glands drain into the anterior floor of the mouth through the Wharton’s duct, the papilla of which opens just lateral to the frenulum of the tongue.
The smallest of the major salivary glands are the sublingual glands located just beneath the mucous membrane of the floor of the mouth. They are poorly encapsulated and drain by way of several small ducts directly into the oral cavity or into the submandibular duct.
