Nasal Muscles Anatomy

and is inserted into the skin of the end of the nose. The Dilator Naris Posterior arises from the margin of the nasal notch and sesa- moid cartilages, and is inserted into the skin near the margin of the nostril. The muscle is partly under cover of the levator labii superioris ale que nasi. The Dilator Naris Anterior is in front of the preceding muscle, It arises from the alar cartilage, and is inserted into the skin near the margin of the nose. The Depressor Ale Nasi arises from the incisive fossa, and is inserted into the septum and alar cartilage of the nose, The Buccinator arises from (1) the pterygomaxillary ligament ; (2) the alveolar process of the upper jaw ; (3) the alveolar process of the lower jaw. Insertion : The orbicularis oris in this manner: The upper and lower fibres converge toward the angles of the mouth, where they decussate to become continuous with the fibres of the orbicularis oris. The highest and lowest fibres do not decussate. The buccinator and superior constrictor of the pharynx are united by the pterygo- maxillary ligament, and form a continuous muscular wall for the mouth and pharynx. The pterygomaxillary ligament may be readily felt in a patient. This is one of the structures so painfully put on the stretch in prolonged opera- tions on the mouth and teeth. This ligament extends from the hamular process to the posterior extremity of the mylohyoid ridge near the wisdom tooth. The principal use of the ligament, then, is to form a common attachment for the superior constrictor of the pharynx and buccinator. The buccinator muscle expels air and widens the mouth, but its principal use is to assist the tongue in keeping food between the molar teeth during mastication. (See Muscles of Mastication.) The Buccinator Fascia takes its name from the muscle which it invests and strengthens. This fascia adheres closely to the outer surface of the muscle, and must be removed to appreciate the direction of the muscular fibres. The fascia is thin in front and dense behind, where it is continuous with the aponeurosis of the pharynx ; it strengthens the junction between the mouth and pharynx, and for this reason it is called the buccopharyngeal fascia. Owing to the strength of this fascia, and to the great vitality of the buccinator and superior constrictor muscles of the pharynx, abscesses do not readily break into the mouth and pharynx. 1 Also called attrahens, attollens, and retrahens auriculam. 24 A MANUAL OF DISSECTION. Summary. The facial muscles are called muscles of expression. The three muscles about the ear are no longer muscles of expression in man, but they still retain this function in the horse and some other lower animals, The muscles about the inlet of the nose are all but obsolete in man, and should be studied on lower animals ; their names are perpetuated in human anatomy for comparative and morphological purposes only. The buccinator is intermediate between the muscles of expression and those of mastication. The platysma is given somewhat to expression, being, from an artistic stand-point, the chief agent in derision ; but the main function of this muscle is to depress the mandible. The Nerve-supply of the facial muscles may be summed up: The motor oculi supplies the levator palpebrie. The fifth and seventh nerves supply the bucci- nator. All the others are supplied by the facial nerve. The fifth nerve supplies the skin of the face with sensation. The involuntary muscular fibre of the eyelids and the muscle of Miiller (a name given to some fibres crossing the sphenomaxillary fissure) are supplied by the sympathetic nerves, called white rami communicantes. These white rami originate in the motor roots of the thoracic spinal nerves, pass to corresponding vertebral ganglia of the gangliated cord, in which they ascend to the superior cervical ganglion, where they arborize about the cells, whose axons continue the journey upward with ascending branches of the superior cervical ganglion to the Gasserian ganglion. Here a second arborization occurs, whence axonic processes accompany the first division of the fifth nerve to the orbit. (See Gerrish.) TABLE OF MUSCLES OF EXPRESSION. Name. Origin, Insertion. + Function, Orbicularis oris. Alveolus, Reciprocal. Closes lips. Levator labii superioris, Superior maxilla, Upper lip. Draws lip upward ; ex- presses sadness. Levator anguli oris. Canine fossa. Angle of lip. Elevates angle. Depressor labii inferioris. Oblique line. Lower lip. Depresses lip. Depressor anguli oris. Oblique line. Angle of lip. Depresses angle, Levator menti. Incisive fossa. Skin of chin. Protrudes lip. Zygomati Malar bone. Angle. Laughing. Zygomaticus mi Malar bone. Upper lip. Sadness. Buecinator. Alveolus, pterygomaxil- Orbicularis oris, Assists tongue. lary ligament. Levator labii superioris Nasal process, superior Lip and nose. Elevates lip and nose. ale que nasi. maxillary. Pyramidalis nasi. Occipitofrontalis. Nasal cartilage. Elevates ala, Dilator naris posterior. Nasal notch. Skin of nostril. Enlarges aperture. Dilator naris anterior. _Ala of nose. Skin of ala. Enlarges aperture, Compressor naris. Superior maxillary. Nasal cartilage. Compresses alw. Compressor narium minor. Alar cartilage. Skin. Compresses ale. Depressor alre nasi Incisive fossa, Septum. Depresses. Corrugator supercili Superciliary ridge. Orbicularis palpe- — Frowning. brarum. Orbicularis palpebrarum. Superior maxilla and Surrounds orbit. Closes lids. frontal. Tensor tarsi. Lacrymal bone. Tarsal plate. Compreses lacry ane. Levator palpebrarum. Ala of sphenoi Tarsal plate. Lifts upward lid. Attrahens aurem. Aponeurosis occipito- Helix. Forward, frontalis, Retrahens aurem. Mastoid. Concha. Backward. Attollens aurem. ‘Aponeurosia oceipito- Pinna. Upward. frontalis. Platysma myoides. Deltoid and pectoral Lower lip. Melancholy. fascive. Risorius. Masseteric fascia. Corner of month. Laughing. FACIAL ARTERY AND VEIN. The Facial Artery has two stages: cervical and facinl. The cervical stage extends from the external carotid artery, in the superior carotid triangle, to the anterior part of the masseter muscle, on the lower border and outer surface of THE FACE, 25 the mandible. This artery and the lingual may arise by a common truuk. In its course upward and forward the cervical part of the facial artery passes beneath the hypoglossal nerve, the posterior belly of the digastric, stylohyoid muscle, and aubuiacillary: salivary gland. The vein passes superficial to the four preceding structures, Branches of Cervical Stage. (1) Ascending or inferior palatine; (2) tonsillar ; (3) glandular ; (4) muscular ; (5) submental. The general course of the artery is from a point on the lower border of the mandible, in front of the masseter muscle, to the root of the nose. The facial stage of the artery rests on the mandible, buccinator, and levator anguli oris, aud passes beneath the zygomatics, risorius, and levator labii superioris ‘The arteries of the face and scalp! (Gmay.) muscles, and the supramandibular and buecal branches of the facial nerve. (See Shaw’s Table, Chapter XXXL.) Branches of Facial Stage. (1) Masseteric ; (2) buccal; (3) inferior labial ; (4) inferior coronary ; (5) superior coronary ; (6) lateralis nasi ; (7) angular. The masseteric branches pass to the masseter and anastomose with the transverse facial branch of the temporal and the masseteric branches of the internal maxillary artery. The buccal branches pass to the buccinator and anastomose with the internal maxillary, infra-orbital, and transverse facial arteries. The inferior labial passes beneath the depressor anguli oris and over the depressor labii infe- \ The muscular tissue of the Hips must be supposed to have been cut away, {n order to show the course of the coronary arteries. 26 A MANUAL OF DISSECTION. rioris, supplying the skin and muscles. The inferior coronary passes beneath the depressor anguli oris to the angle of the mouth, thence between the mucous mem- brane and the orbicularis oris to the lower lip, and anastomoses with the fellow of the opposite side. The superior coronary passes beneath the zygomaticus major, between the mucous membrane and orbicularis oris of the upper lip, and anasto- moses with its fellow of the opposite side. The lateralis nasi is given off opposite Fia.7. ANTERIOR JUGULAR Superficial veins of the crantum and face, right lateral view, (Geanisu after TestcT.) the wing of the nose long the side of the nose to anastomose (a) with its fellow of the opposite side ; (6) with the nasal branches of the ophthalmic. The angular is the termination of the facial artery, and i eanthus with the nasal branch of the ophthalmie The Facial Vein has 1 and facial stages, face from the inner angle of the orbit to a poi dible, in front of the masseter muscle, Fro THE FACE. 27 digastric triangle and enters the internal jugular in the superior carotid triangle. In the cervical stage the facial vein passes superficially to: 1. The submaxillary gland. 2. The digastric muscle. 3. The stylobyo . 4. The hypoglossal nerve. On the mandible the vein is posterior tothe artery. In the facial part of the course the vein is superficial to: 1. The levator labii superioris. 2. The levator anguli oris. 3. The levator labii superioris ale que nasi. It passes beneath the platysma and zygomatic muscles. Tributaries: The frontal, lateralis nasi, supra-orbital, transverse facial, superior and inferior coronary veins. Near the angle of the jaw the facial vein communicates with the external jugular. The superficial veins of the face and scalp communicate with the deep veins of the face in the region of the muscles of mastication and with the sinuses of the dura mater as follows: The angular communicates with the ophthalmic. The ophthalmic communicates with the cavernous sinus. The deep facial connects the facial vein and pterygoid plexus. The deep temporal connects the deep and super- ficial temporal veins, The vein of Vesalius connects the cavernous sinus and pterygoid plexus. The pterygoid plexus is between the temporal and external pterygoid muscles. It is formed by the confluence of veins from the region sup- plied by the internal maxillary artery. It communicates with the cavernous sinus in the dura mater through small veins, among which is the vein of Vesalius, as previously stated, FACIAL NERVE. Course in the Temporal Bone. The facial nerve enters the internal auditory meatus on the posterior surface of the petrosa with the auditory nerve and artery, and at the bottom of the meatus enters the facial canal—a fiediichus Fallopii. i its course it passes (1) between the roof and inner wall of the tympanum above the fenestra ovalis ; (2) between the inner and posterior walls of the tympanum to the stylomastoid foramen. The geniculate ganglion is situated on the nerve, where the latter turns backward and outward to enter the tympanic part of its course ; it gives off the large superficial, small superficial, and external petrosal nerves. Fis. 8, ‘The course and connections of the facial nerve inthe temporal bone. (GRaY.) Branches in the Facial Canal. 1. The great superficial petrosal, a branch of the geniculate ganglion, is joined by filaments from the carotid plexus, as it leaves the cranium, under the name of Vidian, through the foramen lacerum medium ; it passes along the Vidian canal and joins Meckel’s ganglion in the sphenomaxil- lary fossa. 2. The small superficial petrosal nerve, a branch of the geniculate ganglion, leaves the cranium through the canalis innominatus, between the foramen ovale and spinosum in the greater wing of the sphenoid bone, and joins the otic gang- lion. The nerve receives the tympanie branch of the glossopharyngeal (Jacob- son’s nerve), which supplies the parotid gland, reaching the same through the otie ganglion, inferior maxillary division of the trigeminus, and the auriculo- ‘ ral nerve, external petrosal nerve joins the sympathetic plexus on the middle , near the foramen spinosum, and is distributed with this artery. 28 A MANUAL OF DISSECTION. 4, The tympanic branch to the stapedius, the smallest muscle of the body, pierces the pyramid on the inner surface of the tympanum. 5. The chorda tympani is a sensory nerve, and, while given in anatomies as a branch of the seventh nerve, is in reality functionally not so. It accompanies the seventh nerve in the same manner as the descendens hypoglossi—a deep cervical nerve—accompanies, in a part of its course, the hypoglossal nerve, and appears to be a branch thereof. The chorda tympani is an aberrant branch of the glossopharyngeal nerve. It originates in the nucleus of the glossopharyngeal nerve, and, as the pars inter- media, passes with the seventh nerve in the facial canal to the iter chords pos- terior, whence it traverses the middle ear and reaches the tongue through the lingual branch of the inferior maxillary division of the trifacial under the name of the chorda tympani. It supplies the submaxillary and sublingual glands, and confers the sense of taste on the anterior two-thirds of the tongue. (See Gerrish.) 6. A branch is given off two lines above the stylomastoid foramen to the auricular branch of the vagus nerve. Branches at the Stylomastoid Foramen. 1. To the stylohyvid and posterior belly of the digastric (digastric branch). 2. To the attollens aurem, retrahens aurem, and posterior belly of the occipitofrontalis muscle (posterior auricular nerve). Branches on the Face and Neck. Subdivisions, two: cervicofacial (or lower) and temporofacial (or upper). The cervicofacial division is distributed, as its name implies, to the neck and lower parts of the face. Branches: Inframandibular, supramandibular, buccal. (a) The inframandibular branch skirts the angle of the mandible, is distributed to the platysma, and communicates with the superficial cervical nerve, a branch of the cervical plexus. (6) The supramandibular branch crosses the masseter muscle, lies on the body of the mandible, communicates with the mental branch of the mandibular nerve at the mental foramen, and supplies the inferior segment of the orbicularis oris and muscles inserted into the same. (c) The buccal branch crosses the masseter muscle below Stenson’s duct, enters a quantity of fat in front of the masseter muscle, and supplies the buccinator muscle. This nerve communicates with the long buccal branch of the inferior maxillary division of the fifth nerve. The buccal branches from the fifth and seventh nerves unite to form a plexus, from which the buccinator muscle is sup- plied with motion, and the skin, glands, and mucous membrane of the cheek with sensation. The temporofacial or upper division of the facial nerve is larger than the cervicofacial. It crosses the neck of the mandible and external carotid artery. It receives communicating branches from the auriculotemporal, and divicles into the temporal, malar, and infra-orbital branches. (a) The temporal branches cross the zygomatic and supply the anterior part of the occipitofrontalis, corrugator supercilii, tensor tarsi, and upper segment of the orbicularis palpebrarum. They communicate with the supra-orbital, temporal, lacrymal, and auriculotemporal nerves. (6) The malar branches cross the malar bone and supply the orbicularis_palpe- brarum. They pass beneath the zygomatic muscles and communicate with the infra-orbital, lacrymal, and malar branches of the superior maxillary. (c) The infra-orbital branches cross the masseter, pass beneath, and supply the zygomatic muscles, and are distributed to the muscles of the nose, upper lip, and orbicularis palpebrarum. They communicate with the nasal and infratrochles branches of the ophthalmic, the buccal branches of the facial, and the infra- orbital branches of the superior maxillary. THE FACE. 29 MUSCLES OF MASTICATION. Dissection and Identification. Temporal Fascia. Identify (1) by its origin from the temporal ridge, its insertion into the upper border of the zygomatic arch, and its location on the temporal muscle; (2) by the dense fibrous structure. Dissection: Cut at several attachments; remove and expose the sub- jacent temporal muscle. Temporal Muscle. Identify (1) by its origin from the temporal ridge and deep part of the temporal fascia; (2) by its insertion into the coronoid process. Dissection: Saw through the ends of the zygomatic arch and turn same down with the attached masseter muacle. ris Fascia, Identify (1) by its location on the outer surface of the masseter mugcle; (2) by its continuity with the parotid and temporal fascie. Masseter Muscle. Identify (1) by its origin from the zygomatic arch and its insertio: into the outer surface of the ramus; (2) by its superficial relation to the pes anserinus. Dis- section: Turn down with the zygomatic arch previously sawn through and find its nerve pass- ing through the sigmoid notch, Fig. 9, ‘The temporal muscle, the zygoma and masseter having been removed. (GRAY.) External Pterygoid Muscle. Identify (1) by its origin from the greater wing of the sphenoid and pterygoid plate ; (2) by its insertion into the condylar process and interarticular brocartilage. Internal Pterygold Muscle. Identify (1) by its origin from the external pterygoid plate; (2) by its insertion into the inner surface of the ramus. Dissection: These muscles cannot be dissected until the mandible has been sawn through at the symphysis menti and the tongue split. Then work from the inner surface. Buccinator. Depress the jaw and put the muscle on the stretch ; then identify by its loca- tion opposite the molar teeth and its attachment to the alveolar processes. The muscles of mastication derive their nerve-supply from the fifth ; their blood-supply from the internal maxillary artery. They are inserted into and move the mandible on the upper jaw for triturative purposes. The buccinator is also a muscle of facial expression, and is further innervated by the seventh nerve. Their collective use is the mastication of solid food ; hence the collective name, muscles of mastication The Temporal Fascia. ‘The temporal fascia covers the greater part of the tem- musele. It arises from the temporal ridge. It is inserted into both the borders of the superior part of the zygomatic arch, and is con- ith the masseteric Tisoin. It is in relation superficially with the 30 A MANUAL OF DISSECTION. temporal vessels, the auriculotempora!l nerve, and the temporal branches of the facial nerve. The Temporal Muscle. Origin: (1) The temporal ridge ; (2) the temporal fascia ; (3) the greater part of the temporal fossa. Insertion: Corouoid process of the mandible. Action: To close and retract the jaw. Synergists: The masseter and internal pterygoid. Antagonists: Digastric, platysma, hyoid depressors, and gravity. Nerve-supply : ‘The temporal branches ‘of the inferior maxillary division of the trigeminus. Blood-supply: The muscular branches from the second stage of the internal maxillary artery. The Masseteric Fascia covers the masseter muscle. It is attached above to the zygomatic arch ; below to the posterior and inferior borders of the ramus. It is continuous above with the temporal, posteriorly with the parotid fascia, and is in relation superficially with the pes anserinus, part of the parotid salivary gland, and Stenson’s duct. The Masseter Muscle. Divisions: Superficial and deep layers. Origin: (1) The lower border of the malar bone and anterior two-thirds of the lower border of the Fis. 10. The pterygoid muscler, the zygomatic arch, and a portion of the ramus of the Jaw having been removed. (GRAY.) zygomatic arch ; @) the inner surface of the zygomatic arch and the posterior third of the lower border of the zygomatic arch. Insertion: The outer surface of the ramus. Action: