[ANAT]_LEC_006_HEAD-AND-NECK.pdf

(006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 OUTLINE I. THE SKULL (CRANIUM AND FACIAL BONES) I...

(006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 OUTLINE I. THE SKULL (CRANIUM AND FACIAL BONES) II. THE MANDIBLE III. TEMPOROMANDIBULAR JOINT IV. THE SCALP V. THE FACE VI. THE NECK I. THE SKULL The head and neck region of the body contains many important structures compressed into a relatively small area.  composed of several separate bones united at immobile joints called sutures  Sutural Ligament: connective tissue between the bones  mandible is an exception, for it is united to the skull by the mobile temporomandibular joint  Can be divided into those of the cranium and those of the face. o Cranium: upper portion o Face: lower portion Figure I.A anterior view of the skull A. CRANIUM C. FACIAL BONES The cranium consists of the following bones, two of which are paired: The frontal bone, or forehead bone, curves downward to make the 1. Frontal bone: 1 upper margins of the orbits. 2. Parietal bones: 2 3. Occipital bone: 1 The superciliary arches can be seen on both side, and the 4. Temporal bones: 2 supraorbital notch, or foramen, can be recognized. Medially, the 5. Sphenoid bone: 1 frontal bone articulates with the frontal processes of the maxillae and 6. Ethmoid bone: 1 with the nasal bones. Laterally, the frontal bone articulates with the zygomatic bone. B. FACIAL BONES The orbital margins are bounded by the frontal bone superiorly, the zygomatic bone laterally, the maxilla inferiorly, and the processes of the maxilla and frontal bone medially. The facial bones consist of the following, two of which are single: Within the frontal bone, just above the orbital margins, are two hollow 1. Zygomatic bones: 2 spaces lined with mucous membrane called the frontal air sinuses. 2. Maxillae: 2 These communicate with the nose and serve as voice resonators. 3. Nasal bones: 2 4. Lacrimal bones: 2 The two nasal bones form the bridge of the nose. Their lower 5. Vomer:1 borders, with the maxillae, make the anterior nasal aperture. The 6. Palatine bones: 2 nasal cavity is divided into two by the bony nasal septum, which is 7. Inferior conchae: 2 largely formed by the vomer. The superior and middle conchae are 8. Mandible: 1 shelves of bone that project into the nasal cavity from the ethmoid on each side; the inferior conchae are separate bones. The two maxillae form the upper jaw, the anterior part of the hard palate, part of the lateral walls of the nasal cavities, and part of the floors of the orbital cavities. The two bones meet in the midline at the intermaxillary suture and form the lower margin of the nasal aperture. Below the orbit, the maxilla is perforated by the infraorbital foramen. The alveolar process projects downward and, together with the fellow Page 1 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 of the opposite side, forms the alveolar arch, which carries the upper external auditory meatus. The ramus and body of the mandible lie teeth. Within each maxilla is a large, pyramid-shaped cavity lined inferiorly. with mucous membrane called the maxillary sinus. This communicates with the nasal cavity and serves as a voice resonator. Note that the thinnest part of the lateral wall of the skull is where the anteroinferior corner of the parietal bone articulates with the greater wing of the sphenoid; this point is referred to as the pterion. Clinically, the pterion is an important area because it overlies the The zygomatic bone forms the prominence of the cheek and part of anterior division of the middle meningeal artery and vein. the lateral wall and floor of the orbital cavity. Medially, it articulates with the maxilla and laterally it articulates with the zygomatic process Identify the superior and inferior temporal lines, which begin as a of the temporal bone to form the zygomatic arch. The zygomatic single line from the posterior margin of the zygomatic process of the bone is perforated by two foramina for the zygomaticofacial and frontal bone and diverge as they arch backward. The temporal fossa zygomaticotemporal nerves. lies below the inferior temporal line. The mandible, or lower jaw, consists of a horizontal body and two The infratemporal fossa lies below the infratemporal crest on the vertical rami. greater wing of the sphenoid. The pterygomaxillary fissure is a vertical fissure that lies within the fossa between the pterygoid process of the sphenoid bone and back of the maxilla. It leads D. LATERAL VIEW OF THE SKULL medially into the pterygopalatine fossa. The inferior orbital fissure is a horizontal fissure between the greater wing of the sphenoid bone and the maxilla. It leads forward into the orbit. The pterygopalatine fossa is a small space behind and below the orbital cavity. It communicates laterally with the infratemporal fossa through the pterygomaxillary fissure, medially with the nasal cavity through the sphenopalatine foramen, superiorly with the skull through the foramen rotundum, and anteriorly with the orbit through the inferior orbital fissure. E. POSTERIOR VIEW OF THE SKULL Figure I.B Lateral view of the skull The frontal bone forms the anterior part of the side of the skull and articulates with the parietal bone at the coronal suture. The parietal Figure I.C Posterior view of the skull bones form the sides and roof of the cranium and articulate with each The posterior parts of the two parietal bones with the intervening other in the midline at the sagittal suture. They articulate with the sagittal suture are seen above. Below, the parietal bones articulate occipital bone behind, at the lambdoid suture. with the squamous part of the occipital bone at the lambdoid suture. The skull is completed at the side by the squamous part of the On each side the occipital bone articulates with the temporal bone. In occipital bone; parts of the temporal bone, namely, the squamous, the midline of the occipital bone is a roughened elevation called the tympanic, mastoid process, styloid process, and zygomatic process; external occipital protuberance, which gives attachment to muscles and the greater wing of the sphenoid. Note the position of the and the ligamentum nuchae. On either side of the protuberance the superior nuchal lines extend laterally toward the temporal bone. Page 2 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 F. SUPERIOR VIEW OF THE SKULL Figure I.D superior view of the skull Anteriorly, the frontal bone articulates with the two parietal bones at the coronal suture. Occasionally, the two halves of the frontal bone fail to fuse, leaving a midline metopic suture. Behind, the two Figure I.E Inferior view of the skull parietal bones articulate in the midline at the sagittal suture. The mandibular fossa of the temporal bone and the articular tubercle form the upper articular surfaces for the temporomandibular joint. G. INFERIOR VIEW OF THE SKULL Separating the mandibular fossa from the tympanic plate posteriorly is the squamotympanic fissure, through the medial end of which the chorda tympani nerve exits from the tympanic cavity. If the mandible is discarded, the anterior part of this aspect of the skull is seen to be formed by the hard palate. The palatal processes The styloid process of the temporal bone projects downward and of the maxillae and the horizontal plates of the palatine bones can be forward from its inferior aspect. The opening of the carotid canal can identified. In the midline anteriorly is the incisive fossa and foramen. be seen on the inferior surface of the petrous part of the temporal Posterolaterally are the greater and lesser palatine foramina. bone. Above the posterior edge of the hard palate are the choanae The medial end of the petrous part of the temporal bone is irregular (posterior nasal apertures). These are separated from each other by and, together with the basilar part of the occipital bone and the the posterior margin of the vomer and are bounded laterally by the greater wing of the sphenoid, forms the foramen lacerum. During life, medial pterygoid plates of the sphenoid bone. The inferior end of the the foramen lacerum is closed with fibrous tissue, and only a few medial pterygoid plate is prolonged as a curved spike of bone, the small vessels pass through this foramen from the cavity of the skull pterygoid hamulus. to the exterior. Posterolateral to the lateral pterygoid plate, the greater wing of the The tympanic plate, which forms part of the temporal bone, is C sphenoid is pierced by the large foramen ovale and the small shaped on section and forms the bony part of the external auditory foramen spinosum. Posterolateral to the foramen spinosum is the meatus. While examining this region, identify the suprameatal crest spine of the sphenoid. on the lateral surface of the squamous part of the temporal bone, the suprameatal triangle, and the suprameatal spine. Behind the spine of the sphenoid, in the interval between the greater wing of the sphenoid and the petrous part of the temporal bone, is a In the interval between the styloid and mastoid processes, the groove for the cartilaginous part of the auditory tube. The opening of stylomastoid foramen can be seen. Medial to the styloid process, the the bony part of the tube can be identified. petrous part of the temporal bone has a deep notch, which, together Page 3 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 with a shallower notch on the occipital bone, forms the jugular below and behind the third molar tooth. anatomically foramen. described as the division between the body of your mandible and the angle of the mandible, these are surgical Behind the posterior apertures of the nose and in front of the foramen delineations magnum are the sphenoid bone and the basilar part of the occipital - submandibular fossa – superficial part of the bone. The pharyngeal tubercle is a small prominence on the submandibular salivary gland, lies below the posterior part undersurface of the basilar part of the occipital bone in the midline. of the mylohyoid line. - sublingual fossa, sublingual gland, lies above the anterior The occipital condyles should be identified; they articulate with the part of the mylohyoid line superior aspect of the lateral mass of the first cervical vertebra, the  upper border of the body of the mandible – alveolar part; in the atlas. Superior to the occipital condyle is the hypoglossal canal for adult, it contains 16 sockets for the roots of the teeth (your teeth transmission of the hypoglossal nerve. Posterior to the foramen are not directly connected to the body or to the bone of your magnum in the midline is the external occipital protuberance. The mandible) superior nuchal lines should be identified as they curve laterally on  lower border of the body of the mandible – base. - digastric fossa on either side of the symphysis menti – each side. anterior bellies of the digastric muscles are attached.  ramus of the mandible is vertically placed and has H. THE CRANIAL CAVITY - - an anterior coronoid process a posterior condyloid process, or head - the two processes are separated by the mandibular notch The cranial cavity contains the brain and its surrounding meninges, - lateral surface of the ramus attachment of the masseter portions of the cranial nerves, arteries, veins, and venous sinuses. muscle. - medial surface mandibular foramen for the inferior alveolar nerve and vessels – continues as mandibular I. THE VAULT OF THE SKULL canal, which opens on the lateral surface of the body of the mandible at the mental foramen The internal surface of the vault shows the coronal, sagittal, and The mandibular canal would not terminate in the mental lambdoid sutures. In the midline is a shallow sagittal groove that foramen but would continue mesially or to the midline via lodges the superior sagittal sinus. On each side of the groove are - incisive canal is a continuation forward of the mandibular several small pits, called granular pits, which lodge the lateral canal beyond the mental foramen and below the incisor lacunae and arachnoid granulations. Several narrow grooves are teeth. You have actually a hollow canal within the body of present for the anterior and posterior divisions of the middle the mandible. meningeal vessels as they pass up the side of the skull to the vault. - projection of bone, lingual – attachment of the sphenomandibular ligament  The coronoid process receives on its medial surface the J. THE BASE OF THE SKULL attachment of the temporalis muscle. Below the condyloid process, or head, is a short neck The interior of the base of the skull is divided into three cranial fossae: anterior, middle, and posterior. The anterior cranial fossa is separated from the middle cranial fossa by the lesser wing of the sphenoid, and the middle cranial fossa is separated from the posterior cranial fossa by the petrous part of the temporal bone. II. THE MANDIBLE  largest and strongest bone of the face, and it articulates with the skull at the temporomandibular joint  consists of a horse-shoe shaped body and a pair of rami (the body and the rami are joined at an angle which you called the angle of the mandible)  symphysis menti (anteriorly) – faint line of the fusion of the two halves of the mandible during formation when you’re still an Figure II.A Mandible embryo  The mental foramen (posterior) – below the second premolar !!!!! CLINICAL NOTES !!!!! tooth – transmits the terminal branches of the inferior alveolar nerve and vessels FRACTURE OF THE MANDIBLE  medial surface of the body - in the median plane are seen the mental spines – origin to The mandible is horseshoe shaped and forms part of a bony ring with the genioglossus muscle above and the geniohyoid the two temporomandibular joints and the base of the skull. muscles below Traumatic impact is transmitted around the ring, causing a single - mylohyoid line – oblique ridge that runs backward and fracture or multiple fractures of the mandible, often far removed from laterally from the area of the mental spines to an area the point of impact. Page 4 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 III. TEMPOROMANDIBULAR JOINT B. ARTICULAR DISC  It is a fibrocartilage that intervenes between the bony surfaces and divides the TMJ into upper and lower compartments.  It is an oval plate that attaches: o circumferentially to the capsule o in front to the tendon of the lateral pterygoid muscle and o by fibrous bands to the head of the mandible.  The fibrous bands ensure that the disc moves forward and backward with the head of the mandible during protraction and retraction of the mandible. Figure II.A The temporomandibular joint  The upper surface of the disc is concavo convex from anterior to posterior to fit the shape of the articular tubercle The temporomandibular joint (TMJ) is the synovial articulation and the mandibular fossa. between the articular tubercle and the anterior portion of the mandibular fossa of the temporal bone above and the head  The lower surface is concave to fit the head of the (condyloid process) of the mandible below. mandible.  The synovial membrane lines the capsule in both the upper The capsule surrounds the joint and is attached above to the articular and lower cavities of the joint. tubercle and the margins of the mandibular fossa and below to the neck of the mandible. C. NERVE SUPPLY Auriculotemporal and masseteric branches of the mandibular nerve A. LIGAMENTS 1. Lateral temporomandibular ligament D. MOVEMENTS a. Its fibers run downward and backward from the tubercle on the root of the zygoma to the lateral surface of the neck of the mandible b. It strengthens the lateral aspect of the capsule c. It limits the movement of the mandible in a posterior direction thus protecting the external auditory meatus 2. Sphenomandibular ligament a. It is the thin band that is attached above to the spine of the sphenoid bone and below to the lingula of the mandibular foramen. b. It lies on the medial side of the joint c. It represents the remains of the first pharyngeal arch in this region. 3. Stylomandibular ligament a. It is a band of thickened deep cervical fascia that extends from the apex of the styloid process to the angle of the mandible. b. It lies behind and medial to the joint and some distance Figure II.C Movements of the TMJ from it. a. Mandible Depression i. The head of the mandible rotates on the undersurface of the articular disc around a horizontal axis and the mandible is pulled forward (protracted). ii. Muscles under action: Contraction of the digastrics, the geniohyoids, and the mylohyoids. Figure II.B ligaments of the TMJ Page 5 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 Forward pulling of the mandible by Lateral b. Posteriorly: Tympanic plate of the external auditory meatus pterygoid muscle. and the glenoid process of the parotid gland iii. The forward movement of the disc is limited by the c. Laterally: Parotid gland, fascia, and skin tension of the fibroelastic tissue, which tethers the disc to d. Medially: Maxillary artery and vein and auriculotemporal the temporal bone posteriorly. nerve b. Mandible Elevation F. CLINICAL SIGNIFICANCE OF THE TMJ i. The movements in depression of the mandible are reversed. a. The great strength of the lateral temporomandibular ii. First, the head of the mandible and the disc move ligament prevents the head of the mandible from passing backward, and then the head rotates on the lower surface backward and fracturing the tympanic plate when a severe of the disc. blow falls on the chin. b. The articular disc of the temporomandibular joint may iii. Muscles under action: become partially detached from the capsule, and this Contraction of the temporalis, the masseter, and results in its movement becoming noisy and producing an the medial pterygoids audible click during movements at the joint. The head of the mandible is pulled backward by c. Temporomandibular Joint Dislocation the posterior fibers of the temporalis. i. When the mandible is depressed the head of the mandible and the articular disc both move forward until they The articular disc is pulled backward by the reach the summit of the articular tubercle. In this position, fibroelastic tissue, which tethers the disc to the the joint is unstable, and a minor blow on the chin or a temporal bone posteriorly. sudden contraction of the lateral pterygoid muscles, as in c. Mandible Protrusion yawning, may be sufficient to pull the disc forward beyond i. The articular disc is pulled forward onto the anterior the summit. tubercle, carrying the head of the mandible with it. ii. In bilateral cases, the mouth is fixed in an open position, ii. All movement takes place in the upper cavity of the joint. and both heads of the mandible lie in front of the articular tubercles. Pressing the gloved thumbs downward on the iii. In protrusion, the lower teeth are drawn forward over the lower molar teeth and pushing the jaw backward easily upper teeth. achieve reduction of the dislocation. The downward iv. Muscles under action: pressure overcomes the tension of the temporalis and masseter muscles, and the backward pressure overcomes Contraction of the lateral pterygoid muscles of the spasm of the lateral pterygoid muscles. This process is both sides, assisted by both medial pterygoids. called reduction. d. Mandible Retraction The articular disc and the head of the mandible are pulled backward into the mandibular fossa. Retraction is brought about by contraction of the posterior fibers of the temporalis. e. Rotation occurs in chewing f. At position of rest, the teeth of the upper and lower jaws are slightly apart. g. On closure of the jaws, the teeth come into contact (occlusion). h. Lateral Chewing Movements Figure II.D Comparison between a normal and a dislocated TMJ i. Alternately protruding and retracting the mandible on each side produces lateral motions. ii. Muscles responsible for movement work alternatively not in unison. E. IMPORTANT TEMPOROMANDIBULAR JOINT RELATIONS a. Anteriorly: Mandibular notch and the masseteric nerve and artery Figure II.E Illustration of dislocation, reduction and normal TMJ Page 6 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 IV. THE SCALP 2. SUPRAORBITAL NERVE  branch of the ophthalmic division of the trigeminal nerve  winds around the superior orbital margin and ascends over the forehead. It supplies the scalp as far backward as the vertex. 3. ZYGOMATICOTEMPORAL NERVE  branch of the maxillary division of the trigeminal nerve, supplies the scalp over the temple. CERVICAL SPINAL NERVE BRANCHES: 1. AURICULOTEMPORAL NERVE  branch of the mandibular division of the trigeminal nerve  ascends over the side of the head from in front of the auricle  supply the skin over the temporal region. 2. LESSER OCCIPITAL NERVE  branch of the cervical plexus (C2)  supplies the scalp over the lateral part of the occipital region and the skin over the medial surface of the auricle 3. GREATER OCCIPITAL NERVE Figure IV.A Layers of the scalp  branch of the posterior ramus of the 2nd cervical nerve  ascends over the back of the scalp Skin, which is thick and hair bearing and contains numerous  supplies the skin as far forward as the vertex of the skull sebaceous glands  Connective tissue – fibrofatty, the fibrous septa uniting the skin C. ARTERIAL SUPPLY OF THE SCALP to the Underlying aponeurosis of the occipitofrontalis muscle  Aponeurosis (epicranial) – thin, tendinous sheet that unites the Occipital and frontal bellies of the occipitofrontalis muscle  Loose areolar tissue – occupies the subaponeurotic space and loosely Connects the epicranial aponeurosis to the periosteum of the skull (the pericranium)  Pericranium – periosteum covering the outer surface of the skull bones A. MUSCLES OF THE SCALP OCCIPITOFRONTALIS (main muscle of the scalp)  moves the first three layers of the scalp move forward or backward, the loose areolar tissue of the fourth layer of the scalp allowing the aponeurosis to move on the pericranium  can raise the eyebrows in expressions of surprise or horror. B. SENSORY NERVE OF THE SCALP Figure IV.B Blood supply of the scalp TRIGEMINAL BRANCHES: 1. SUPRATROCHLEAR and the SUPRAORBITAL ARTERIES  Branches of the ophthalmic artery 1. SUPRATROCHLEAR NERVE  ascend over the forehead in company with the  branch of the ophthalmic division of the trigeminal nerve supratrochlear supraorbital nerves 2. SUPERFICIAL TEMPORAL ARTERY  winds around the superior orbital margin and supplies the scalp  smaller terminal branch of the external carotid artery Page 7 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021  ascends in front of the auricle in company with the auriculotempora nerve ( the pulse that you can feel in front B. SENSORY NERVES OF THE FACE of your ear)  Divides into anterior and posterior branches, which supply  It is supplied by branches of three divisions of the trigeminal the skin over the frontal and temporal regions. nerve (Ophthalmic, maxillary, mandibular), except for the small 3. POSTERIOR AURICULAR ARTERY area over the angle of the mandible and the parotid gland(which is supplied by great auricular nerve)  a branch of the external carotid artery 1. Ophthalmic nerve (CN V1) – supplies the region  ascends behind the auricle to supply the scalp above and developed from the frontonasal process. behind the auricle 2. Maxillary nerve (CN V2) – serves the region developed 4. OCCIPITAL ARTERY from the maxillary process of the first pharyngeal arch.  a branch of the external carotid artery 3. Mandibular nerve (CN V3) – serves the region developed  ascends from the apex of the posterior triangle from the mandibular process of the first pharyngeal arch.  Supplies the skin over the back of the scalp and reaches as  Also supply proprioceptive fibers to the underlying muscles of high as the vertex of the skull. facial expression.  They are the sensory nerve supply to the mouth, teeth, nasal D. VENOUS DRAINAGE OF THE SCALP cavities and paranasal air sinuses.  supratrochlear and supraorbital veins unite at the medial  Ophthalmic nerve (CN V1) – supplies the skin of the forehead, margin of the orbit to form the facial vein the upper eyelid, the conjunctiva, and the side of the nose down to and including the tip.  superficial temporal vein unites with the maxillary vein in the o Lacrimal nerve – skin and conjunctiva of the lateral part of substance of the parotid gland to form the retromandibular vein the eyelid. o Supraorbital nerve – skin and conjunctiva on the central  posterior auricular vein unites with the posterior division of the part of the upper eyelid; it also supplies the skin of the retromandibular vein, just below the parotid gland, to form the forehead. external jugular vein o Supratrochlear nerve – skin and conjunctiva on the medial part of the upper eyelid and the skin over the lower part of  occipital vein drains into the suboccipital venous plexus, which the forehead, close to the median plane. lies beneath the floor of the upper part of the posterior triangle; o Infratrochlear nerve – skin and conjunctiva on the medial the plexus in turn drains into the vertebral veins or the internal part of the upper eyelid and the adjoining part of the side of jugular vein. the nose. o External nasal nerve – skin on the side of the nose down as far as the tip. E. LYPHATIC DRAINAGE OF THE SCALP  Maxillary nerve (CN V2) – supplies the skin on the posterior part of the side of the nose, the lower eyelid, the cheek, the  anterior part of the scalp and forehead drain into the upper lip, and the lateral side of the orbital opening. submandibular lymph nodes o Infraorbital nerve – skin of the lower eyelid and cheek, the  lateral part of the scalp above the ear is into the superficial side of the nose, and the upper lip. parotid (preauricular) nodes o Zygomaticofacial nerve – skin over the prominence of the  part of the scalp above and behind the ear drain into the mastoid cheek. nodes o Zygomaticotemporal nerve – skin over the temporal  back of the scalp drain into the occipital nodes bone. V. THE FACE  Mandibular nerve (CN V3) – supplies the skin of the lower lip, the lower part of the face, the temporal region, and part of the auricle. A. SKIN OF THE FACE o Mental nerve – supplies the skin of the lower lip and chin. o Buccal nerve – skin over a small area of the cheek. o Auriculotemporal nerve – skin of the auricle, the external  It possesses numerous sweat and sebaceous glands, which auditory meatus, the outer surface of the tympanic tries to protect your skin. membrane, and the skin of the scalp above the auricle.  They are connected to the underlying bones by loose connective tissue in which embedded are the facial expression.  Note: It’s not just the auriculotemporal nerve that serves the  No deep fascia is present in the face, making your face very skin, also the branches of vagus nerve which supplies posterior thin so you can easily palpate the bones because these are the portion of the external auditory meatus. fascia that is really not a thick muscle on the face. Page 8 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021  It descends behind the facial artery to the lower margin of the body of the mandible – crosses superficial to the submandibular gland and is joined by the anterior division of the retro mandibular vein – drains into the internal jugular vein. E. TRIBUTARIES  Facial vein receives tributaries that correspond to the branches of the facial artery.  It joins, o the pterygoid venous plexus by the deep facial vein. o the cavernous sinus by the superior ophthalmic vein.  Transverse facial vein joins the superficial temporal vein within the parotid gland. Figure V.A Left: Sensory nerve supply to the skin of the face Right: branches of the facial nerve to muscles of facial expression C. ARTERIAL SUPPLY OF THE FACE The face receives a rich blood supply from two main vessels, the facial and superficial temporal arteries.  Facial artery – arises from the external carotid artery in the upper neck.  Journey of facial artery – It Arches upward and over the submandibular salivary gland – curves around the inferior margin of the body of the mandible at the anterior border of the masseter muscle – runs upward in a tortuous course toward the angle of the mouth covered by platysma and risorius muscle – ascends deep to the zygomaticus muscles and the levator labii Figure V.B Left: arterial supply of the face; Right: venous superioris muscle and runs along the side of the nose to the drainage of the face medial angle of the eye – anastomoses with the terminal branches of the ophthalmic artery. F. LYMPHATIC DRAINAGE OF THE FACE It’s pulse can be easily felt in anterior border of masseter muscle.  Lymph from the forehead and the anterior part of the face drains  Branches into – submandibular nodes. o Submental artery – supplies skin of chin and lower lip. o Inferior labial artery – runs medially in lower lip and  Lateral part of the face, including the lateral parts of the eyelids drains into – parotid lymph nodes. anastomoses with it’s fellow of the opposite side. o Superior labial artery – runs medially in upper lip and  Central part of the lower lip and the skin of the chin drains into - gives branches to the septum and ala of the nose. submental lymph nodes. o Lateral nasal artery – supplies skin on the side and dorsum of nose. o Angular artery – terminal part of facial artery D. VENOUS DRAINAGE OF THE FACE  Facial vein – formed at the medial angle of the eye by the union of the supraorbital and supratrochlear veins.  Journey of facial vein – Connects to the superior ophthalmic vein directly through the supraorbital vein and through the superior ophthalmic vein, the facial vein is connected to the cavernous sinus. Page 9 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021  Eyelid muscles o Orbicularis oculi – sphincter muscle of eyelid. o Occipitofrontalis – dilator muscle. o Corrugator and procerus – acts on orbit. o Levator palpebrae superioris – elevates upper eyelids.  Nostril muscles o Nasalis and depressor septi – sphincter muscles. o Dilator naris and levator labii superioris alaeque nasi – dilator muscles.  Lip and cheek muscles o Orbicularis oris – primary sphincter muscle of lips. o Buccinator – significant in food processing. H. FACIAL NERVES Figure V.C left: bones of the skull; Right: lymph drainage of the face G. MUSCLES OF THE FACE Figure V.E Lateral view of the head illustrating the facial nerves  As it runs forward within the substance of the parotid salivary gland it divides into its five terminal branches. o Temporal branch o Zygomatic branch o Buccal branch o Mandibular branch o Cervical branch Figure V.D Lateral view of the headillustrating the muscles of the face  It is the nerve of the second pharyngeal arch and supplies all the muscles of facial expression.  Facial muscles are integumentary muscles  It does not supply the skin, but its branches communicate with  Embedded in the superficial fascia, and most arise from the the branches of trigeminal nerve. bones of the skull and are inserted into the skin.  Primary function of the facial muscles is to serve as sphincters or dilators of the orifices of the face (orbits, mouth, eyes and nose)  Secondary function of the facial muscles is to modify the expression of the face.  All facial muscles develop from the second pharyngeal arch and are supplied by the facial nerve. Page 10 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 VI. THE NECK 1. GREATER OCCIPITAL NERVE - is a branch of the posterior ramus of the 2nd cervical nerve. The 1st cervical nerve has no  The neck is the region of the body that lies between the lower cutaneous branch. margin of the mandible above and the suprasternal notch and the upper border of the clavicle below. 2. LESSER OCCIPITAL NERVE (C2) - hooks around the  It is strengthened by the cervical part of the vertebral column, accessory nerve and ascends along the posterior border of the which is convex forward and supports the skull. sternocleidomastoid muscle to supply the skin over the lateral  Behind the vertebrae is a mass of extensor muscles and in front part of the occipital region and the medial surface of the auricle. is a smaller group of flexor muscles.  In the central region of the neck are parts of the respiratory 3. GREAT AURICULAR NERVE (C2 AND 3) - ascends across the system, namely, the larynx and the trachea, and behind are sternocleidomastoid muscle and divides into branches that parts of the alimentary system, the pharynx and the esophagus. supply the skin over the angle of the mandible, the parotid  At the sides of these structures are the vertically running carotid gland, and on both surfaces of the auricle. arteries, internal jugular veins, the vagus nerve, and the deep cervical lymph nodes. 4. TRANSVERSE CUTANEOUS NERVE (C2 AND 3) - emerges from behind the middle of the posterior border of the sternocleidomastoid muscle. It passes forward across that A. SKIN OF THE NECK muscle and divides into branches that supply the skin on the anterior and lateral surfaces of the neck, from the body of the  The natural lines of cleavage of the skin are constant and run mandible to the sternum. almost horizontally around the neck. 5. SUPRACLAVICULAR NERVES (C3 AND 4) - emerge from  This is important clinically because an incision along a cleavage beneath the posterior border of the sternocleidomastoid muscle line will heal as a narrow scar, whereas one that crosses the and descend across the side of the neck. They pass onto the lines will heal as a wide or heaped-up scar. chest wall and shoulder region, down to the level of the second rib. B. CUTANEOUS NERVES i. MEDIAL SUPRACLAVICULAR NERVE crosses the medial end of the clavicle and supplies the skin as far as the median plane. ii. INTERMEDIATE SUPRACLAVICULAR NERVE crosses the middle of the clavicle and supplies the skin of the chest wall. iii. LATERAL SUPRACLAVICULAR NERVE crosses the lateral end of the clavicle and supplies the skin over the shoulder and the upper half of the deltoid muscle and posterior aspect of the shoulder as far down as the spine of the scapula. C. SUPERFICIAL FASCIA  The superficial fascia of the neck forms a thin layer that encloses the platysma muscle.  Also embedded in it are the cutaneous nerves referred to in the previous section, the superficial veins, and the superficial lymph nodes. Figure VI.A  Superficial Veins Sensory nerve supply to the skin of the head and neck 1. External Jugular Vein  Begins behind the angle of the mandible by the union of the posterior auricular vein with the posterior  The skin overlying the trapezius muscle on the back of the neck division of the retromandibular vein and on the back of the scalp as high as the vertex is supplied  Descends obliquely across the sternocleidomastoid segmentally by posterior rami of cervical nerves 2 to 5. muscle and above the clavicle in the posterior triangle,  The skin of the front and sides of the neck is supplied by anterior pierces deep the fascia and drains into the subclavian rami of cervical nerves 2 to 4 through branches of the cervical vein plexus. The branches emerge from beneath the posterior border 2. Tributaries of the sternocleidomastoid muscle.  External jugular vein has the following tributaries: Page 11 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 o Posterior auricular vein o Posterior division of the retromandibular vein E. MUSCLES OF THE NECK o Posterior external jugular vein o Transverse cervical vein o Suprascapular vein o Anterior jugular vein 3. Anterior Jugular Vein  Begins below the chin, by the union of several small veins  Runs down he neck close to the midline, just above the suprasternal notch  Veins of two sides are united by a transverse trunk called the jugular arch  veins turn laterally and passes deep to sternocleidomastoid muscle to drain into the external jugular vein  Superficial lymph nodes- o lie along the external jugular vein superficial to the sternocleidomastoid muscle. o Receive lymph vessels from the occipital and mastoid lymph nodes and drain into the deep cervical lymph nodes D. BONES OF THE NECK  CERVICAL SPINE/VERTEBRAE  HYOID BONE - a mobile single bone found in the midline of the neck below the mandible and abides the larynx. It does not articulate with any other bones. o The hyoid bone is U shaped and consists of a body and two greater and two lesser cornua. It is attached to the skull Figure VI.C Muscles of the neck by the stylohyoid ligament and to the thyroid cartilage by STERNOCLEIDOMASTOID MUSCLE the thyrohyoid membrane. o The hyoid bone forms a base for the tongue and is  When the sternocleidomastoid muscle contracts, it appears suspended in position by muscles that connect it to the as an oblique band crossing the side of the neck from the mandible, to the styloid process of the temporal bone, to sternoclavicular joint to the mastoid process of the skull. the thyroid cartilage, to the sternum, and to the scapula.  It divides the neck into anterior and posterior triangles.  It is the articulation of several muscles which are  The anterior border covers the carotid arteries, the internal sternohyoid, omohyoid, mylohyoid, geniohyoid, hyoglossus, jugular vein, and the deep cervical lymph nodes; it also thyrohoid, digastric and stylohyoid. overlaps the thyroid gland.  The muscle is covered superficially by skin, fascia, the platysma muscle, and the external jugular vein.  The deep surface of the posterior border is related to the cervical plexus of nerves, the phrenic nerve, and the upper part of the brachial plexus. Scalenus Anterior Muscle  The scalenus anterior muscle is a key muscle in understanding the root of the neck.  It is deeply placed and it descends almost vertically from the vertebral column to the 1st rib. IMPORTANT RELATIONS Anteriorly: Related to the carotid arteries, the vagus nerve, the Figure VI.B The hyoid bone internal jugular vein, and the deep cervical lymph nodes. The transverse cervical and suprascapular arteries and the prevertebral layer of deep cervical fascia bind the phrenic nerve to the muscle. Page 12 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 Posteriorly: Related to the pleura, the origin of the brachial plexus, o Stylohyoid ligament: connects the styloid process to the lesser and the second part of the subclavian artery. The scalenus medius cornu of the hyoid bone muscle lies behind the scalenus anterior muscle. o Stylomandibular ligament: connects the styloid process to the Medially: Related to the vertebral artery and vein and the angle of the mandible sympathetic trunk. On the left side, the medial border is related to the thoracic duct. o Sphenomandibular ligament: connects the spine of the sphenoid bone to the lingulingualhe mandible Laterally: Related to the emerging branches of the cervical plexus, the roots of the brachial plexus, and the third part of the subclavian o Pterygomandibular ligament: connects the hamular process of artery. the medial pterygoid plate to the posterior end of the myolohyoid line of the mandible. It gives attachment to the superior F. DEEP CERVICAL FASCIA constrictor and the buccinator muscles  Investing layer o Layer that encircles the neck o It splits to enclose the trapezius and the H. MUSCLE TRIANGLES OF THE NECK sternocleidomastoid muscles  Pretracheal Layer Called as triangles because they are formed by the border of the o A thin layer that is attached above the laryngeal cartilages muscles o Surrounds the thyroid and the parathyroid glands, forming 1. ANTERIOR TRIANGLE the sheath for them, and encloses the infrahyoid muscle  The anterior triangle is bounded above the body of the  Prevertebral layer mandible, posteriorly by the sternocleidomastoid muscle o A thick layer that passes like a septum across the neck and anteriorly by the midline behind the pharynx and the esophagus and in front of the prevertebral muscles and the vertebral column  It is further subdivided into the carotid triangle, the digastric triangle, the submental triangle and the muscular o Forms the fascial floor of the posterior triangle and it extends laterally over the first rib into the axilla to form the triangle important axillary sheath 2. POSTERIOR TRIANGLE  Carotid Sheath  Bounded posteriorly by the trapezius muscle, anteriorly by the sternocleidomastoid muscles and the inferiorly by the o Not a separate sheath but A local condensation of the clavicle prevertebral, the pretracheal and the investing layers of the  The posterior triangle of the neck is further subdivided by deep fascia that surround the common and internal carotid the inferior belly of the omohyoid muscle into a large arteries, the internal jugular vein, the vagus nerve and the occipital triangle above and a small supraclavicular o deep cervical lymph nodes triangle Surgically, anatomically, these are arbitrary triangles. They are not distinct structures. They are used surgically to identify structure on what we really want to operate on instead of G. CERVICAL LIGAMENTS opening the whole neck VII. TEST YOUR KNOWLEDGE DIRECTION: choose the best answer 1. The skull bones are made up of external and internal tables of compact bones separated by a layer of spongy bone called A. Dimple B. Diploe C. Dipole D. Dilpoe E. None of the above 2. Paired facial bones, except A. Maxillae B. Mandible C. Zygomatic D. Inferior conchae Figure VI.D Cross section of the neck at the level of the 6th E. All of the above cervical vertebra Page 13 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 3. Mandible, except ANSWERS: 1.B 2.B 3.C 4.A 5.D 6.D 7.D 8.B 9.C 10.A A. Horseshoe-shaped body B. Articulates with the skull at the TMJ VIII. REFERENCE C. Mental foramen above the second premolar tooth Snell, R.S., (2012). CLINICAL ANATOMY By Regions. 9 th edition. D. Has a pair of rami Philadelphia, PA: Lippincott Williams & Wilkins E. All of the above 4. An oval plate of fibrocartilage that divides the TMJ to upper and lower cavities IX. APPENDIX A. Articular disc B. Stylomandibular ligament C. Sphenomandibular ligament D. Lateral temporomandibular ligament E. None of the above 5. Muscles of mastication, except A. Temporalis B. Masseter C. Paired Lateral Pterygoid D. Unpaired Medial Pterygoid E. All of the above 6. Scalp, except A. Thick skin with numerous sebaceous glands B. Arteries and veins found in the connective tissue layer C. Thin, tendinous sheet of epicranial aponeurosis D. Loose adipose tissue E. Pericranium, which is the periosteum covering the outer surface of the skull bones 7. Face, except A. No deep fascia is present B. Skin of the face is supplied by branches of the three divisions of the trigeminal nerve C. Blood supply from the facial and superficial temporal arteries D. Facial bones consist of 8 bones, two of which are paired E. All of the above 8. The superficial layer of the neck forms a thin layer that encloses what muscle A. SCM B. Platysma C. Scalene D. Digastric E. None of the above 9. Hyoid bone, except A. U-shaped B. Mobile, single bone C. Articulates with other bones D. Forms a base for the tongue E. All of the above 10. Anterior triangle of the neck, except A. Occipital triangle B. Carotid triangle C. Submental triangle D. Digastric triangle Page 14 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 Page 15 of 16 PREPARED BY: CMED 1A  (006) THE HEAD AND NECK DR. N. LACUESTA JR | 02/21/2021 Page 16 of 16 PREPARED BY: CMED 1A