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Зміст2. Duration of studies
4. Basic knowledges, abilities, skills, that necessary for the study themes (interdisciplinary integration)
Facial part of the head
Nerves of the Face
The Trigeminal Nerve (CN V)
The Parotid Gland
Structures traversing the Parotid Gland
The Parotid Bed
Profound facial region
5.2. Theoretical questions to studies
5.3. Materials for self-control
A Maxillary (CN V2) and mandibular (CN V3) B
E Facial (CN VII) and vagus (CN X)33.
A the geniculate ganglion B
A in the brain and involves the nucleus of the facial nerve and superior salivatory nucleus B
Ministry of Health of Ukraine
Bukovinian State Medical University
on methodical meeting of the Department of Anatomy, Topographical anatomy and Operative Surgery
“………”…………………….2008 р. (Protocol №……….)
The chief of department
for the 3d-year foreign students of English-spoken groups of the Medical Faculty
(speciality “General medicine”)
for independent work during the preparation to practical studies
the Theme of studies
“Topographical anatomy and operative surgery
of the lateral facial region”
Topographical Anatomy and Operative Surgery
of the Head, Neck, Thorax and Abdomen
Topographical Anatomy and Operative Surgery of the Head and Neck
Chernivtsi – 2008
1. Actuality of theme:
The topographical anatomy and operative surgery of the face are very importance, because without the knowledge about peculiarities and variants of structure, form, location and mutual location of their anatomical structures, their age-specific it is impossible to diagnose in a proper time and correctly and to prescribe a necessary treatment to the patient. Surgeons usually pay much attention to the topographo-anatomic basis of surgical operations on the face.
^ 2 working hours.
3. Objectives (concrete purposes):
To know the definition of regions of the face.
To know classification of surgical operations on the cerebral part of the face.
To know the topographical anatomy and operative surgery of the facial regions.
5. Advices to the student.
5.1. Table of contents of the theme:
The face is the part of the head that is visible in a frontal or anterior view, between the superciliary arches superiorly, the lower edge of the mandible inferiorly, and as far back as the ears on either side.
Despite of the fact mentioned in Nomina Anato-mica among the regions of the face are: orbital, nasal, oral, mental, infraorbital, buccal, zygomatic, the surgical anatomy consider buccal, parotidomasseteric and profound facial regions. The orbital, nasal, oral, and mental regions are studied by ophthalmology, otorhi-nolaryngology and stomatology accordingly.
The boundaries are: superiorly – lower edge of orbit; inferiorly – lower edge of mandible; medially – angle of oral fissure, nasobuccal and oribuccal folds; laterally – anterior margin of the masseter muscle.
The layers are: the skin is thin, mobile, contains many sudoriferous and sebaceous glands; hypodermic fat is advanced well, it is present (in children) buccal fatpad (of Bichat); there are muscles of facial expression; the buccopharyngeal fascia; the buccinator muscle; submucous membrane and mucous tunic of vestibule of mouth.
An infant’s cheeks appear full because of the buc-cal fatpad between the buccinator muscle and the superficial facial muscles. These fatpads in the cheeks are present in adults, but they are much smaller than in infants.
In this region are located: facial, angular, transverse facial, infraorbital, labial superior and inferior vessels; infraorbital (from maxillar n.), buccinator, mental (from mandibular n.) nerves, the branches of facial n. to the muscles of facial expression; parotid (Steno’s, or Stensen’s) duct.
The muscles of facial expression lie in the subcutaneous tissue and are attached to the skin of the face. Most facial muscles are attached to bone or fascia. All facial muscles receive their motor innerva-tion from the facial nerve (CN VII). These muscles surround the facial orifices (mouth, eyes, nose, and ears) and act as sphincters and dilators.
Innervation of the skin of the face is largely through the three branches of CN V, the trigeminal nerve. Some skin over the angle of the mandible and anterior and posterior to the auricle is supplied by the great auricular nerve from the cervical plexus. Some cutaneous fibers of the auricular branch of the facial nerve also supply skin on both sides of the auricle.
^ is the largest of the 12 cranial nerves. It is the principal general sensory nerve to the head, particularly the face, and is the motor nerve to the muscles of mastication (masseter, temporalis, medial and lateral pterygoid muscles).
The Ophthalmic Nerve. This is the superior division of the trigeminal nerve and is the smallest of its three branches. It is wholly sensory and supplies the area of skin derived from the embryonic frontonasal prominence. The ophthalmic nerve (CN V1) divides into three branches: nasociliary, frontal, and lac-rimal, just before entering the orbit through the superior orbital fissure. The five branches of these nerves participate in the sensory supply to the skin of the forehead, upper eyelid, and nose. The nasociliary nerve supplies the tip of the nose through the external nasal branch of the anterior ethmoidal nerve and the root of the nose through the infratrochlear nerve. The frontal nerve, the direct continuation of CN V, divides into two branches: supratrochlear and supraorbital. The supra-trochlear nerve supplies the middle part of the forehead, and the supraorbital nerve supplies the lateral part and the front of the scalp. The lacrimal nerve, the smallest of the main ophthalmic branches, emerges over the superolateral orbital margin to supply the lacrimal gland and the lateral part of the upper eyelid.
The Maxillary Nerve. This nerve (CN V2) is the intermediate division of the trigeminal nerve. It has three cutaneous branches that supply the area of skin derived from the embryonic maxillary prominence. The infraorbital nerve, the large terminal branch of CN V2, passes through the infraorbital foramen and breaks up into branches that convey sensation from skin on the lateral aspect of the nose, upper lip, and lower eyelid. The zygomaticofacial nerve, a small branch of the maxillary, emerges from the zygomatic bone through a small foramen with the same name. It supplies the skin of
the face over the zygomatic bone (i.e., the zygomatic prominence). The zygomaticotemporal nerve emerges from the zygomatic bone through a foramen of the same name and supplies the skin over the temporal region.
For local anesthesia of the inferior part of the face, the infraorbital nerve is often infiltrated with an anesthetic agent at the infraorbital foramen or in the infraor-bital canal (e.g., for treatment of wounds of the upper lip and cheek or for repairing the maxillary incisor teeth). The site of emergence of this nerve can easily be determined by exerting pressure on the maxilla in the region of the infraorbital foramen and nerve. Pressure on the nerve causes considerable pain. Care is exercised when performing an infraorbital nerve block because companion infraorbital vessels leave the infraorbital foramen with the nerve. Careful aspiration of the syringe during injection prevents inadvertent injection of the anesthetic fluid into a blood vessel. The orbit is located just superior to the injection site. A careless injection could result in the passage of anesthetic fluid into the orbit, causing temporary paralysis of the extraocular muscles.
The Mandibular Nerve. This nerve (CN V3) is the inferior division of the trigeminal. CN V3 has three sensory branches that supply the area of skin derived from the embryonic mandibular prominence. It also supplies motor fibers to the muscles of mastication. Of the three divisions of the trigeminal, CN V3 is the only division of CN V that carries motor fibers. The main sensory branches of the mandibular nerve are the buccal, auriculotemporal, inferior alveolar, and lingual nerves. The buccal nerve is a small branch of CN V3 that emerges from deep to the ramus of the mandible to supply the skin of the cheek over the buccinator muscle. It also supplies the mucous membrane lining the cheek and the posterior part of the buccal surface of the gingiva (gum). The auriculotemporal nerve passes medial to the neck of the mandible and then turns superiorly, posterior to its head and anterior to the auricle. It then crosses over the root of the zygomatic process of the temporal bone, deep to the superficial temporal artery. As its name suggests, it supplies parts of the auricle, external acoustic meatus, tympanic membrane (eardrum), and skin in the temporal region. The inferior alveolar nerve is the large terminal branch of the posterior division of CN V3; the lingual nerve is the other terminal branch. It enters the mandibular canal through the man-dibular foramen. In the canal it gives off branches that supply the mandibular (lower) teeth. Opposite the mental foramen, the inferior alveolar nerve divides into its terminal incisive and mental branches. The incisive nerve supplies the incisor teeth, the adjacent gingiva, and the mucosa of the lower lip. The mental nerve emerges from the mental foramen and divides into three branches, which supply the skin of the chin and the skin and mucous membrane of the lower lip and gingiva (gum).
The boundaries are: superiorly – zygomatic arch; inferiorly – lower edge of mandible; medially – anterior margin of masseter; laterally – ramus of mandible.
The layers are: the skin is thin, mobile; the hypodermic fat is developed moderately, it consist of the superficial vessels and nerves (branches of the facial, mandibular nerves); the fascia proper (f. parotideo-masseterica, or investing layer of deep cervical fascia) is divide into two leafs around the parotid gland, which formed the capsule for it.
The parotid gland lies beneath the skin in front of and below the ear. It is contained within the investing layer of the deep fascia, called locally the parotid fascia (f. parotideomasseterica), and the gland can be felt only under pathological conditions.
The boundaries are: anterior – masseter muscle, ramus of mandible, and internal pterygoid muscle; posterior – mastoid process and sternocleidomastoid muscle; superior – external auditory meatus and tem-poromandibular joint; inferior – sternocleidomastoid muscle and posterior belly of digastric muscle; lateral – investing layer of deep cervical fascia, skin, and platysma muscle; medial – investing layer of deep cervical fascia, styloid process, internal jugular vein, internal carotid artery, and pharyngeal wall.
The parotid duct leaves the anterior edge of the parotid gland midway between the zygomatic arch and the corner of the mouth. It crosses the face in a transverse direction and, after crossing the medial border of the masseter muscle, turns deeply into the buccal fat pad and pierces the buccinator muscle. It enters the inside of the vestibule of mouth near the second upper molar tooth.
The parotid gland receives its arterial supply from the numerous arteries that pass through its substance.
Sensory innervation of the parotid gland is provided by the auriculotemporal nerve, which is a branch of the mandibular nerve (V3). This division of the trigeminal nerve exits the skull through the foramen ovale.
The auriculotemporal nerve also carries secretomotor fibers to the parotid gland. These postganglionic parasympathetic fibers have their origin in the otic ganglion associated with the mandibular nerve (V3) and are just inferior to the foramen ovale.
Preganglionic parasympathetic fibers to the otic ganglion come from the glossopharyngeal nerve (CN IX).
The main trunk of the facial nerve enters the posterior surface of the parotid gland about 1 cm from its emergence from the skull through the stylomastoid foramen about midway between the angle of the mandible and the cartilaginous ear canal. At birth the child has no mastoid process and the stylomastoid foramen is subcutaneous.
About 1 cm from its entrance into the gland, the facial nerve divides to form five branches: temporal, zygomatic, buccal, mandibular, and cervical. In most individuals, an initial bifurcation forms an upper temporofacial and a lower cervicofacial division, but six major patterns of branching (from simple to complex) have been distinguished.
The external carotid artery enters the inferior surface of the gland and divides into the maxillary and superficial temporal arteries. The latter gives rise to the transverse facial artery. Each of these branches emerges separately from the superior or anterior surface of the parotid gland.
The superficial temporal vein enters the superior surface of the parotid gland and receives the middle temporal vein to become the posterior facial vein. Still within the gland, the posterior facial vein divides; the posterior branch joins the posterior auricular vein to form the external jugular vein, while the anterior branch emerges from the gland to enter the common facial vein. Remember, the nerve is superficial, the artery is deep, and the vein lies between them.
The preauricular lymph nodes in the superficial fascia drain the temporal area of the scalp, the upper face, and the anterior pinna. Parotid nodes within the gland drain the gland itself, as well as the nasopharynx, nose, palate, middle ear, and external auditory meatus. These nodes, in turn, send lymph to the subparotid nodes and eventually to the nodes of the internal jugular and spinal accessory chains.
The great auricular nerve reaches the posterior border of the sternocleidomastoid muscle and, on the surface of the parotid gland, follows the course of the external jugular vein. It is sacrificed at parotidectomy. Numbness in the preauricular region, the lower auricle, and the lobe of the ear results from injury to this nerve, but it disappears after 4 to 6 months.
The auriculotemporal nerve, a branch of the mandibular nerve (V3), traverses the upper part of the parotid gland and emerges with the superficial temporal blood vessels from the superior surface of the gland. Within the gland, the auriculotemporal nerve communicates with the facial nerve. Usually, the order of the structures from the tragus anteriorly is: auriculotempo-ral nerve, superficial temporal artery and vein, and temporal branch of the facial nerve. The auriculotemporal nerve carries sensory fibers from the trigeminal nerve and motor (secretory) fibers from the glossopharyngeal nerve. Injury to the auriculotemporal nerve produces Frey’s syndrome, in which the skin anterior to the ear sweats during eating (“gustatory sweating”).
Complete removal of the parotid gland reveals the following structures (the acronym VANS may be helpful in remembering them): one Vein: internal jugular; two Arteries: external and internal carotid; four Nerves: glossopharyngeal (CN IX), vagus (CN X), spinal accessory (CN XI), and hypoglossal (CN XII); four anatomical entities starting with “S”: one styloid process and three muscles: styloglossus, stylopharyngeus, and stylohyoid.
The position of this region is under the mandibu-lar ramus. Profound facial region consist of two inter-muscular spaces: interpterygoid and temporopterygoid.
The boundaries of the region are corresponding with the infratemporal fossa. It is an irregular-shaped space lying behind the maxilla, deep to the ramus of the mandible and inferior to the temporal bone.
Bony boundaries of the infratemporal fossa: lateral wall – ramus of the mandible; medial wall – lateral pterygoid plate and free border of this plate followed to the foramen ovale; anterior wall – the infratemporal surface of the maxilla (limited superiorly by the inferior orbital fissure and medially by the pterygomaxillary fissure); posterior wall – the anterior surface of the condy-lar process (head and neck) of the mandible and the styloid process of the temporal bone; roof – inferior surface of the greater wing of the sphenoid (separated from the temporal fossa by the infratemporal crest). The foramen ovale in the roof transmits the mandibular division of the trigeminal nerve (V3); inferior boundary – point where the medial pterygoid muscle inserts into the medial aspect of the mandible near its angle.
Contents of the fossa: (1) Lower portion of the temporalis muscle; (2) Medial and lateral pterygoid muscles; (3) Maxillary artery (larger of 2 terminal branches of the external carotid artery) and its branches; (4) Pterygoid plexus of veins is found around the maxillary artery and may be both superficial and deep to the lateral pterygoid muscle. It drains posteriorly into the maxillary vein and has connections with: the facial vein by way of the deep facial vein, the cavernous sinus in the skull via veins passing through the foramen ovale, and with middle meningeal veins via the foramen spinosum; (5) Mandibular division of trigeminal nerve (V3) – Inferior alveolar nerve, Nerve to the mylohyoid muscle, Lingual nerve, Buccal nerve, Auriculotemporal nerve, Nerves to the muscles of mastication; (6) Chorda tympani (CN VII); 7) Otic ganglion (associated with autonomic fibers of CN IX).
DIRECTIONS: Each question below contains four or five suggested responses. Select the one best response to each question.
31. Injury to the motor root of the mandibular division of the trigeminal nerve (CN V3) would incur paralysis of all the following EXCEPT the
A anterior belly of the digastric muscle
B buccinator muscle
C mylohyoid muscle
D tensor tympani muscle
E tensor veli palatini muscle
32. The pterygomandibular raphe is a useful landmark in the oral cavity. This tendinous tissue marks the juncture of two muscles that are innervated by which of the following cranial nerves?
^ Maxillary (CN V2) and mandibular (CN V3)
B Mandibular (CN V3) and glosso-pharyngeal (CN IX)
C Mandibular (CN V3) and vagus (CN X)
D Facial (CN VII) and glossopharyngeal (CN IX)
^ Facial (CN VII) and vagus (CN X)
33. A lesion involving the inferior salivatory nucleus would affect
A activation of neurons in the otic ganglion
B innervation of the superior tarsal muscle
D mucous release in the nasal passages
E submandibular gland secretion
34. The cell bodies for the sensory nerve fibers that convey pain, touch, and temperature from the posterior third of the tongue are lot cated in
^ the geniculate ganglion
B the pterygopalatine ganglion
C the semilunar ganglion
D the submandibular ganglion
E none of the above
35. A 53-year-old banker develops paralysis on the right side of the face, which produces an expressionless and drooping appearance. He is unable to close the right eye and also has difficulty chewing and drinking. Examination shows loss of blink reflex in the right eye to stimulation of either right or left conjunctiva. Lacrimation appears normal on the right side, but salivation is diminished and taste is absent on the anterior right side of the tongue. There is no complaint of hyperacusis. Audition and balance appear to be normal. The lesion is located
^ in the brain and involves the nucleus of the facial nerve and superior salivatory nucleus
B within the internal auditory meatus
C at the geniculate ganglion
D in the facial canal just distal to the genu of the facial nerve
E just proximal to the stylomastoid foramen
36. In the course of administering a local anesthetic, a needle that is placed too far into the greater palatine canal may paralyze an autonomic ganglion. In addition to dry nasal mucosa from loss of nasal gland secretion, loss of function at this ganglion would result in
A dry eye from loss of lacrimal gland secretion
B dry mouth from loss of parotid gland secretion
C dry mouth from loss of submandibular and sublingual gland secretions
D pupillary constriction
E none of the above
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