Presentation on theme: "Skin innervation of the face"— Presentation transcript:
1Skin innervation of the face Skin of the face is supplied by branches of trigeminal nerve except the area over the angle of mandible & parotid gland, which is supplied by great auricular nerve..Ophthalmic nerve supplies the region developed from the frontonasal process.The maxillary nerve supplies the region developed from the maxillary process of 1st pharyngeal arch.The mandibular nerve supplies the region developed from the mandibular process of 1st pharyngeal arch.Skin of face has numerous sweat & sebaceous glands. It is connected to underlying bones by loose C.T, in which are embedded the muscles of facial expression.No deep fascia is present in the face.
2Ophthalmic NerveIt supplies skin of forehead, upper eyelid, conjunctiva, & side of the nose, it has 5 branches :1-Lacrimal N. : supplies skin & conjunctiva of lateral part of upper eyelid.2-Supraorbital N.: winds at supraorbital notch,it supplies skin & conjunctiva on the central part of upper eyelid + skin of forehead.3-Supratrochlear N. : it lies medial to supraorbital N. it supplies skin & conjunctiva on medial part of upper eyelid + skin of forehead.4-Infratrochlear N. : leaves orbit to supply skin & conjunctiva on the medial part of upper eyelid + skin of adjoining part of the side of the nose.5-External nasal N. : leaves nose to supply skin on the side of the nose down as far as the tip.
3Maxillary NerveIt supplies the skin of posterior part of the side of nose, lower eyelid, cheek, upper lip, lateral side of the orbit It has 3 branches :1-Infraorbital N. : is a direct continuation of maxillary N. it leveas orbit via infraorbital foramen. It gives numerous small branches to supply skin of lower eyelid & cheek, side of nose, & the upper lip.2-Zygomaticofacial N. : passes onto face via a small foramen on lateral side of zygomatic bone to supply skin over the cheek.3-Zygomaticotemporal N. : passes through a small foramen on the posterior part of zygomatic bone to supply skin of temple.
4Mandibular NerveIt supplies skin of lower lip, lower part of face, temporal region & part of the auricle + side of scalp. It has 3 branches1-Mental N. : emerges from the mental foramen of mandible to supply skin of lower lip & chin.2-Buccal N. : enters the face from under cover of the masseter. It passes over the buccinator. It supplies skin & m.m of cheek.3-Auriculotemporal N. : leaves upper border of parotid gland , between superficial temporal vessels & auricle to supply skin of auricle, external auditory meatus, outer surface of tympanic membrane & skin of scalp above auricle.
5Arterial Supply of the Face Facial artery : arises from external carotid artery it reaches face by piercing deep fascia at the lower border of the mandible and then curving up to the face close to anteroior border of masseter, here its pulse can be easily felt it then passes upwards in a tortuous course over the mandible and buccinator towards the angle of mouth it then ascends along side of nose to the medial angle of eye, where it anastomoses with the terminal branches of the ophthalmic artery.Superficial temporal artery : the smaller terminal branch of external carotid artery within the parotid gland.It ascends in front of auricle to supply the scalp.
6Arterial Supply of the Face Transverse facial artery : a branch of superficial temporal artery of external carotid artery, within the parotid gland.It runs forward across the cheek just above parotid duct.Infraorbital artery : it is the terminal part of maxillary artery (one of terminal branches of external carotisd artery), it enters face via infraorbital foramen.Mental artery : branch of inferior alveolar from maxillary from ext.c.artery, ,it enters face via mental foramen of mandible.Zygomaticofacial & zygomaticotemporal arteries, from superficial temporal artery.Lacrimal artery : from ophthalmic artery, of internal carotid artery.Supraorbital & Supratrochlear arteries : branches of ophthalmic artery, of internal carotid artery , supply skin of forehead.
7Branches of Facial artery 1- Submental artery : arises at the lower border of the body of mandible to supply skin of chin + lowe lip Inferior labial artery : arises near angle of mouth to run medially in the lower lip and anastomoses with its fellow of opposite side Superior labial artery : runs medially in the upper lip and gives branches to the septum + ala of nose. 4- Lateral nasal artery : supplies skin on the side & dorsum of nose.
8Venous Drainage of Face Facial vein : is formed at the medial angle of eye by union of supraorbital & supratrochlear veins it is connected to cavernous sinus through superior ophthalmic vein. This connection is of great clinical importance because it provides a pathway for spread of infection from face to cavernous sinus It descends behind the facial artery to the lower border of body of mandible It crosses with the facial artery superficial to submandibular gland –It is joined by anterior division of retromandibular vein to form common facial vein to end into the internal jugular vein.
9Tributaries of Facial vein It recevies tributaries that correspond to the branches of facial artery.It is joined to pterygoid venous plexus ( a venous network lying around pterygoid muscles) by deep facial vein and to the cavernous sinus by superior ophthalmic vein.Transverse facial vein joins superficial temporal vein within the parotid gland.
10Lymph Drainage of the Face Lymph from forehead + anterior part of face drains into submandibular L.Ns., a few buccal lymph nodes may be present along course of these lymph vessels.Lateral part of face + lateral parts of eyelids drin into parotid L.Ns.Lower lip + chin are drained into submental L.Ns.
11Facial NerveIt emerges from stylomastoid foramen to enter the parotid gland , it supplies all muscles of facial expression. it does not supply the skin ,It runs within substance of parotid gland, it divides into 5 terminal branches : Temporal branch : emerges from upper border of gland to supply anterior + superior auricular muscles, frontal belly of occipitofrontalis, orbicularis oculi and corrugator supercillii Zygomatic branch : emerges from anterior border of parotid gland to supply orbicularis oculi.
12Facial Nerve3- Buccal branch : emerges from anterior border of parotid gland below parotid duct to supply buccinator +ms.of upper lip & nostril.4- Mandibular branch : emerges from anterior border of parotid gland to supply ms. of lower lip Cervical branch : emerges from lower border of parotid gland , it descends in the neck to supply platysma muscle + depressor anguli oris muscle.
14Skin & Fascia of the Face Skin of face has numerous sweat & sebaceous glands.It is connected to the underlying bones by loose connective tissue (superficial fascia), in which are embedded muscles of facial expression.No deep fascia in the face.
15Muscles of Face (muscles of facial expression) They are called ms. Of expression because they pull skin of face to produce various expressions.They are arranged in groups around the eye, nose & mouth.They have bony origin.They are inserted into skin of face (no deep fascia in face).They are supplied by branches of facial N., Except levator P.S. by occulomotor N. (striated ms.) + sympathetic N. (smooth ms.).
16Muscles of Face A) Muscles of eyelids : B) Muscles of Nose : 1- levator palpebrae superioris (the dilator ms. of eyelids, lying in the orbital cavity).2-Orbicularis oculi (the sphincter ms of eyelids).3-Corrugator supercilii (deep to orbicularis oculi) Occipitofrontalis (ms. of scalp).B) Muscles of Nose :1-Procerus.2-Compressor & dilator naris.
17Muscles of Face C) Muscles of Lips : D) Muscles of Cheek : Sphincter muscle of the lips :“ Orbicularis Oris”.Dilator muscles of the lips :1-Levator labii superioris alaeque nasi Levator labii superioris Depressor labii inferioris Zygomaticus minor Zygomaticus major Levator anguli Oris (deep to zygomatic ms.) Depressor anguli Oris Risorius Mentalis.D) Muscles of Cheek :“Buccinator”
18Muscles of Face (muscles of facial expression) 3 large muscles : Buccinator m. (ms. of cheek) Orbicularis oculi m Orbicularis oris m.Many small muscles : Dilator ms. of lips (separate lips) : Levator labii superioris alaeque nasi, levator labii superioris Zygomaticus minor & major Levator anguli oris, risorius & depressor anguli oris Depressor labii inferioris & mentalis origin : bones & fascia around oral aperature Insertion : into substance of lips.
192- Corrugator supercilli : -It lies deep to orbicularis oculi 2- Corrugator supercilli : It lies deep to orbicularis oculi. origin : superciliary arch (bone) Insertion : skin of eyebrow Action : vertical wrinkles of forehead, as in frowning Compressor naris & dilator naris : origin : maxilla. Insertion : the fibres are continuous with those of opposite side in front of the bridge of nose to form aponeurosis of bridge of nose Action : compesses & widens nasal cartilages and aperature Procerus : It is continuous with the medial part of occipito-frontalis ms Origin : nasal bone Insertion : medial part of skin of eyebrow. Action : wrinkles skin of nose.
20Orbicularis oculi : Orbital part : Origin : medial palpebral ligament + adjoining bone Insertion :The fibres have no lateral attachment, it loops return to origin Action : closes eyelids by throwing skin around orbit into folds to protect eyeball Palpebral part : Origin : medial palpebral ligament Insertion : lateral palpebral raphe & skin of eyelids Action : closes palpebral fissure of eyelids gently (sleep) and dilates lacrimal sac.
21Orbicularis oris : Origin : maxilla, mandible & deep skin Orbicularis oris : Origin : maxilla, mandible & deep skin Insertion : encircles oral orifice to be inserted to the m.m lining the inner surface of lips Action : compresses the lips together to close the mouth (sphincter muscle of lips).
22Muscle of Cheek : Buccinator Muscle : Origin : from outer surface of maxilla & mandible opposite the molar teeth + from pterygomandibular ligament.Insertion : upper fibres : into upper lip lower fibres : into lower lip middle fibres : decussate at the angle of mouth.N.supply : buccal branch of facial N.Action : it compresses the cheeks & lips against the teeth to prevent accumulation of food in vestibule of mouth it is used in wistling, when cheeks are distended with air.
23Muscle of Cheek : Buccinator Muscle : It is covered on outside by buccopharyngeal fascia & buccal pad of fat.Its deep surface is lined by buccal mucosa.It is pierced by : parotid duct , opposite upper 2nd molar tooth Buccal branch of mandibular nerve (sensory) to supply m.m of cheek on the inner surface of buccinator muscle.
24Facial muscle Paralysis The facial ms. Are innervated by facial N.Cause : Damage to facial N. (by a tumor in internal acoustic meatus or parotid galnd) /or operation or infection in middle ear / or perineuritis, Bell’s palsy in facial nerve canal.Results : Lower motor neuron lesion which involves distortion of face+ drooping of lower eyelid + angle of mouth will sag on the affected side. /But Upper motor neuron lesion is due to lesion of pyramidal tract and here the upper face is normal because the neurons supplying this part receive corticobulbar fibres from both cerebral cortices.
26The Cranial CavityContents of cranial cavity the brain meninges of brain (dura, arachnoid & pia mater) from outside inwards blood vessels of brain & meninges parts of cranial nerves Blood venous sinuses Hypophysis cerebri (pituitary gland).
27Dura Mater of BrainIt is a thick dense membrane which consists of 2 layers (outer & inner).The 2 layers are attached together except at blood venous sinuses.Outer endosteal layer : it covers inner surface of bones of skull it is firmily attached to sutures of skull and to foramen magnum, it does not extend through foramen magnum .Inner meningeal layer : it covers brain and continuous with dura mater of spinal cord through foramen magnum it sends tubular sheaths around cranial nerves as they pass through foramina in skull it sends 4 septa into cranial cavity to divide cavity into spaces, these septa stabilize the brain within the cavity during movement of head.
28Dural Septa : 1- Falx Cerebri It is a sickle-shaped fold of dura that descends in the midline between 2 cerebral hemispheres.Attachment : its narrow anterior end is attached to internal frontal crest & crista galli its wide posterior end is attached to upper surface of tentorium cerebelli venous sinuses in falx cerebri : superior sagittal sinus : lies in its upper convex fixed border inferior sagittal sinus : lies in its lower concave free margin straight sinus : lies at line of attachment of posterior end of falax with tentorium cerebelli.
292- Tentorium cerebelliIt is a crescentic fold of dura that roofs posterior cranial fossa.It separates the occipital lobe of cerebrum above from cerebellum below.Its free border : is concave and forms a gap called, tentorial notch, for passage of midbrain –it crosses above the attached border of tentorium to be fixed at the 2 anterior clinoid processes at the point of crossing of the free & attached borders : the trochlear & oculomotor Ns. Pierce the tentorium to enter lateral wall of cavernus sinus at the apex of petrous temporal bone : the inferior layer of tentorium is invaginated anteriorly beneath the sup. Petrosal sinus to form a recess called trigeminal cave which contains the trigeminal ganglion.
302- Tentorium cerebelliAttached border : it is convex and directed peripherally its posterior part is attached to the lips of transverse sulcus its anterolateral part is attached to the lips of groove for superior petrosal sinus (at the upper border of petrous temporal bone) Its anterior end crosses below the free border and is attached to the 2 posterior clinoid processes.In the median plane : the superior layer of tentorium cerebelli is attached to falx cerebri the inferior layer of tentorium cerebelli is attached to falx cerebelli.
312- Tentorium cerebelliVenous sinuses in the tentorium cerebelli : straight sinus : at the line of attachment of posterior end of falx cerebri with tentorium cerebelli transverse sinus : in the posterior part of the attached border superior petrosal sinus : in the anterolateral part of attached border.
323-Falx Cerebelli :It is a small sickle-shaped fold of dura placed in median plane below tentorium cerebelli.Its free anterior border projects forwards between the 2 cerebellar hemispheres.Its posterior border is attached to the internal occipital crest.It contains the occipital sinus in its posterior fixed border.
334-diaphragma sellae : It is a small circular fold of dura. It forms the roof of sella turcica.It has a centeral opening for passage of the stalk of hypophysis cerebri (pituitary stalk).
34Dural Nerve Supply Trigeminal N. Vagus N. First 3 cervical nerves. Sympathetic fibres around the meningeal arteries.
35Dural Arterial Supply Internal carotid artery. Maxillary artery…. Middle meningeal artery, it is the most important branch.Ascending pharyngeal artery.Occipital artery.Vertebral artery.Meningeal VeinsMiddle meningeal vein follows the branches of middle meningeal artery and drains into the pterygoid venous plexus or sphenoparietal sinus.
36Middle meningeal artery It is a branch of 1st part of maxillary artery.It reaches middle cranial fossa through foramen spinosum to lie between the meningeal & endosteal layers of dura.It passes forwards and laterally grooving the squamous part of temporal bone. Then it divides into : large anterior (frontal) branch. & small posterior (parietal) branch.It divides into anterior & posterior branches opposite a point 20mm above center of zygomatic arch.
37Extradural hemorrhage This is intracranial hemorrhage outside the dura mater.It results mostly from injury of middle meningeal artery, usually occuring in the region of the pterion (at anteroinferior part of the parietal bone) as a result of a blow over the side of the head.A collection of blood, (extradural hematoma) occurs between the dura and the skull bones, stripping off the periosteum of inner table of the bone.The intracranial pressure rises producing local pressure on the motor area of brain.Blood may pass out through the fracture to form a soft swelling under the temporalis ms
38Arachnoid materIt is a delicate, impermeable membrane covering the brain, lying between pia mater & dura mater.It is separated from the dura by subdural space, and from the pia by subarachnoid space, which is filled with cerebro-spinal fluid.The arachnoid projects into the venous sinuses to form arachnoid villi, they are most numerous at superior sagittal sinus, aggregations of arachnoid villi are called arachnoid granulations, where C.S.F diffuses into bloodstream.Cerebral arteries &veins & cranial nerves lie in subarachnoid space.
39Cerebrospinal fluidIt is produced by the choroid plexuses within lateral, 3rd & 4th ventricles of brain.It passes via 3 foramina in roof of 4th ventricle to circulate in subarachnoid space, upward over surfaces of cerebral hemispheres and downward around spinal cord.The spinal subarachnoid space extends down as far as 2nd sacral vertebra.The fluid enters bloodstream by passing into arachnoid villi and diffuses into venous sinuses.
40Pia materIt is a thin vascular membrane that closely covering the brain.It extends over the cranial nerves and fuses with their epineurium.The cerebral arteries enter the brain carrying a sheath of pia mater.
42Venous SinusesThey are blood channels between the endosteal & meningeal layers of dura mater.The walls of sinuses are lined by endothelium.They receive tributaries from : the brain, the diploe of skull, the orbit, & the internal ear.They differ from the veins in having no valves, or muscles in their walls. So they do not contract when they are ruptured and bleeding is controlled only by pressure.Single sinuses are : superior sagittal, 2-inferior sagittal, 3-straight sinus & 4-intercavernus sinus Occipital sinus.Paired sinuses are : transverse sinuses sigmoid sinuses cavernus sinuses superior & inferior petrosal sinuses sphenoparietal sinuses.
43Superior Sagittal Sinus It lies in the upper fixed border of falx cerebri.It begins in front at frontal crest & foramen cecum, where it receives : vein from nasal cavity, then runs backward grooving vault of skull.At the internal occipital protuberance, it is dilated to form the confluence of the sinuses, here it deviates to one side (usually the right) to become the right transverse sinus.It is connected to the opposite transverse sinus and it receives the occipital sinus.
44Tributaries and communications of the Superior Sagittal Sinus The sinus communicates with 2-3 venous lacunae on each side.Numerous arachnoid villi & granulations project into the lacunae, which also receive the diploic & meningeal veins.It receives also the cerebral veins.It communicates with veins of scalp by emissary veins passing through the parietal foramina.
45Inferior Sagittal Sinus It lies in the free lower border of falx cerebri.It runs backward to join great cerebral vein at free border of tentorium cerebelli to form straight sinus.Straight SinusIt lies at the junction of falx cerebri with tentorium cerebelli.It is formed by union of inferior sagittal sinus & great cerebral vein.It ends by turning to left to form the left transverse sinus.
46Transverse SinusesAre paired sinuses, begin at the internal occipital protuberance.Right sinus is usually continuous with the superior sagittal sinus, and left sinus is continuous with the straight sinus.Each sinus occupies the attached margin of tentorium cerebelli, grooving the occipital bone.They receive the superior petrosal sinuses, cerebral & cerebellar veins, & diploic veins.They end by turning downward as sigmoid sinuses.
47Sigmoid Sinuses Are direct continuation of transverse sinuses. Each sinus turns downward and medially and grooves the mastoid part of temporal bone, here it lies behind mastoid antrum.Finally, it passes through jugular foramen to join the internal jugular vein.
48Occipital sinusIt is a small sinus occupying the attached border of falax cerebelli.It begins near foramen magnum, where it communicates with vertebral veins and drains into the confluence of the sinuses.It connects the beginning of transverse sinus with the end of sigmoid sinus.May be single or paired.
49Cavernus sinusesAre lie in middle cranial fossa on each side of body of sphenoid bone ( hypophyseal fossa).Each sinus extends from superior orbital fissure anteriorly, to apex of petrous temporal bone posteriorly.Inside the sinus : internal carotid artery surrounded by sympathetic plexus abducent nerve.In the lateral wall of cavernus sinus : oculomotor nerve trochlear nerve ophthalmic nerve of trigeminal N maxillary nerve of trigeminal N.
50Cavernus sinusesTributaries : superior & inferior ophthalmic veins cerebral veins sphenoparietal sinus, along posterior margin of lesser wing of sphenoid central vein of retina.Each sinus drains posteriorly into : superior & inferior petrosal sinuses and inferiorly into : pterygoid venous plexus.The 2 sinuses communicate with each other by anterior & posterior intercavernous sinuses, which run in diaphragma sellae.Each sinus has important communication with facial vein through superior ophthalmic vein.
51Superior & inferior Petrosal sinuses Are small sinuses lying on the superior & inferior borders of petrous part of temporal bone.The superior sinus drains the cavernus sinus into transverse sinus.The inferior sinus drains the cavernus sinus into internal jugular vein.
52Hypophysis Cerebri (Pituitary gland) : It is the master endocrine gland, which attached to brain by the infundibulum.Site : sella turcica of sphenoid bone (hypophyseal fossa).It has 2 lobes, anterior lobe or adenohhypophysis and posterior lobe or neuro-hypophysis.Superiorly : diaphragma sellae, which has a central aperature to allow passage of infundibulum.Inferiorly : body of sphenoid+ sphenoid air sinuses.Laterally : cavernus sinus.Posteriorly : dorsum sellae, basilar artery, & pons.Blood supply : superior & inferior hypophyseal branches of internal carotid artery / veins drains into intercavernous sinuses.
53Diploic VeinsThey are thin- walled, valveless veins lying in the diploe of skull (between the inner & outer tables of the bones of skull).They communicate with the meningeal veins & dural venous sinuses.They include : frontal, temporal & occipital diploic veins.
54Emissary VeinsThey are small valveless veins, pass via foramina in the skull and connect the dural venous sinuses with veins outside the skull.Function : they help to equalize the pressure in veins outside the skull and in the dural venous sinuses.Their danger : infection outside the skull may spread along the emissary veins to reach the dural venous sinuses and produce septic thrombi.
55Intracranial part of Internal Carotid Artery : It enters the cranial cavity through the carotid canal in petrous part of temporal bone.It passes into foramen lacerum to enter the cavernus sinus.It lies with the abducent nerve on the floor of cavernus sinus.It pierces the roof of cavernus sinus to lie on the medial side of anterior clinoid process and divide into anterior & middle cerebral arteries.Branches : superior & inferior hypophyseal arteries to pituitary gland meningeal branches.