Anatomy Block 3 Lecture 22 Scalp, Face and Parotid Region

5 layers of Scalp

1. Skin-Contains sweat and sebaceous glands, hair follicles and is well-vascularized. 2. Connective Tissue- Dense, well vascularized and innervated 3. Aponeurosis of occipitofrontalis muscle 4. Loose connective tissue (spongy layer that collects fluid from injury or infection) 5. Periosteum of skull- external periosteum of calvaria/skullcap

What is the otic ganglion?

A small parasympathetic ganglion that sits in the infra temporal fossa, medial to the mandibular nerve. It is functionally associated with the glossopharyngeal nerve and innervates the parotid gland for salvation.

Superficial Temporal Artery

A smaller terminal branch of the external carotid. This artery emerges on the face between the TMJ and the ear from where it splits into frontal and parietal branches. The superficial temporal artery also gives off a branch called the transverse facial artery which arises in the parotid gland and divides into numerous branches that supply the parotid gland and duct, massete and the skin of the face. It anatomies with branches of the facial artery.

Muscles of Face

AKA Muscles of Facial Expression. they are located in the subcutaneous tissue of the anterior and posterior scalp, face and neck. most of these muscles attach to bone or fascia and produce their effects by pulling/tugging on the skin. Also Play Roles as Sphincters and Dilators that close and open orifices: Muscles of facial expressions also surround the orifices of the eyes, nose and mouth and act as sphincters and dilators that close and open the orifices.

Orbicularis Oculi (Muscles of Facial Expression- Eyes)

AKA orbital sphincter Origin: Palpebral Part: medial palpebral ligament Orbital part: Nasal part of frontal bone, nasal part of frontal bone, medial palpebral ligament. Insertion: Palpebral part: Lateral palpebral raphe Orbital part: Fibers from uninterrupted eclipse around orbit. Innervation: Facial Nerve Action: Closes eyelids. Palpebral part does so lightly as in blinking while the orbital part does so tightly or forcefully as if winking/squinting.

Buccinator (Muscle of facial expression-mouth)

Aka cheek muscle Origin: Mandible Alveolar process of maxilla and mandible (posterior parts of maxilla and mandible) Pterygomandibular raphe Insertion: Angle of mouth, blends with orbiculares iris and lips. Action: Presses check against molar teeth (like when making a duck face), also resists distention when blowing, Works with tongue to keep food between teeth. Thus, developmentally it is a facial muscle but functionally it works to keep food between teeth during mastication. It is pierced by the parotid duct.

Infra temporal fossa

An irregularly shaped space deep and inferior to the zygomatic arch, deep to ramus of mandible and posterior to maxilla. Boundaries of the infratemporal fossa are: Laterally: ramus of mandible Medially: Laterl ptyregoid plate Anteriorly: posterior aspect of maxilla Posteriorly: tympanic plate, mastoid and styloid process of temporal bone Superiorly: inferior surface of great wing of sphenoid bone Inferiorly: where medial ptyregoid attaches to mandible near its angle.

Branches of the trigeminal nerve

As mentioned, trigeminal nerve supplies cutaneous (sensory) innervation to the muscles of facial expression and has a motor branch for the muscles of mastication. It can be further divided into 3 parts: 1. Ophthalmic V1- completely sensory 2. Maxillary V2- completely sensory 3.Mandibular V3- mostly sensory but receives motor fibers from facial nerve thus it supplies motor branches to the muscles of mastication.

Depressor Septi (Muscle of facial expression-nose)

As shown in the diagram, this muscle lies deep to the obicularis oris muscle. Origin: Maxilla above medial incisor. Insertion: Mobile part of nasal septum. Innervation: facial nerve Action: Pulls knows inferiorly.

Blood or infections can occur where in the scalp?

Blood or pus from an infection collects in the loose connective tissue and can spread easily. It is prevented from passing into the neck or sub-temporal regions because of attachments of the epicranial aponeurosis. Infection and bleeding can also become intracranial via emissary veins.

Botox is injected into which muscle to treat migraines?

Corrugator supercilli muscle is injected with botox for the treatment of migraines. The procedure is as follows: 1. Botox is injected into the corrugator supercilli. This causes the muscle to freeze, releasing pressure on migraine causing nerves especially the supraorbital nerve. 2. Patient is sedated and a small cut is made into the muscle and part of it is removed. 3. The gap from the cut is filled with fat from upper eyelid easing migraine and smoothing frown lines.

Which nerve is most likely to be damaged if the parotid gland is damaged?

Facial Nerve CN VII exits the skull at the stylomastoid foramen and ramifies through the parotid gland. Thus injury or damage to parotid gland will sever the facial nerve and its branches depending on the extent of the injury.

Nasalis (Muscle of facial expression-nose)

Nasalis muscle is a muscle of facial expression of the nose. It has 2 parts: the transverse part and the alar part. Origin: Transverse part: Maxilla, just lateral to nose. Alar Part: Maxilla over lateral incisor Insertion: Transverse part: aponeurosis across dorsal of nose with muscle fibers from other side Alar part: alar cartilage of nose Innervation: Facial nerve Action: compresses nasal aperture, draws cartilage downward and laterally opens nostril.

Risorius (Muscle of facial expression-mouth)

Superficial to the buccinator Origin: Fascia over masseter muscle Insertion: Skin at the corner of the mouth Innervation: Facial Nerve Action: Retracts corners of mouth as when smiling with lips sealed.

Eminectomy for TMJ Displacement

Surgery is considered necessary where there is severe displacement of the cartilage in the joint, resulting in pain and limited function, which cannot be repositioned by other means. The most common form of surgery is an eminectomy. This involves removal of that part of the jaw joint (the eminence) which is causing obstruction of the forward movement of the cartilage. A general anaesthetic is administered to ensure that no movement occurs during the procedure. A small incision is made in front of the ear (the same incision is used in face-lift procedures) and the eminence of the bone removed. This surgery is considered relatively minor and is normally day case surgery.

TMJ Dislocation

TMJ dislocation is almost always anterior and when mouth is open, locks in front of articular eminence.

Function of the TMJ Normal Vs. Abnormal

Normal Closed Position: The structures that makes it possible for you to open and close your mouth include the bones, joints and muscles. When functioning correctly, your jaw bone or mandible is separated from your skull by a soft disc that acts as a cushion when you chew, speak or swallow. This soft cushion is the articular disc. In closed position it sits normally separating your jaw from skull. Normal Open Position: When joint is functioning properly, the disc stays in place (horizontally) when the jaw is in use, preventing bony structures from coming in contact with each other. Dysfunctioning Open Position: When not functioning properly and jaw is opened, the disc is commonly pulled forward when the jaw is in use causing the bone of the mandible and skull to come in contact with each other, thus grinding together.

Which muscles resists distention when blowing up of cheeks?

Orbiculares oris as it acts as a sphincter in this case.

Sphincter of Eyes

Orbicularis occult closes the eyelids and assists the flow of lacrimal fluid (tears). It has 3 parts: 1. Palpebral Part- which gently closes eyelids 2. Lacrimal Part- which passes posterior to the lacrimal sac, aiding draining of tears 3. Orbital Part- tightly closes eyelids to protect eyeballs against glare and dust.

Which muscle/muscles prevent distention of mouth when blowing?

Orbicularis oris and buccinator

Which muscle is responsible for kissing?

Orbicularis oris as it causes phasic contractions that compress and protrude the lips

Sphincter of mouth

Orbicularis oris is the sphincter of the mouth and is the first in the series of sphincters associated with alimentary (digestive) tract.

Damage to which muscle can cause drooling?

Orbicularisoiris.

Which muscle is responsible for winking/tightly closing eyes?

Orbital part of orbicularis oris

Depressor Labi Inferioris (Muscle of facial expression-mouth)

Origin: Anterior part of oblique line of mandible Insertion: Lower lip at midline, blends with muscles from opposite sides. Innervation: Facial Nerve Action: Draws lip downward and laterally.

Zygomaticus minor (Muscle of facial expression-mouth)

Origin: Anterior portion of zygomatic bone Insertion: Upper lip just medial to the corner of the mouth Innervation: Facial nerve Action: Draws upper lip upward.

Masseter

Origin: Inferior border and medial aspect of zygomatic arch Insertion: Lateral surface of frames of mandible Innervation: Innervated by mandibular division V3 of trigeminal nerve Action: elevation of mandible (closes mouth)

Levator Labi Superioris (Muscle of facial expression-mouth)

Origin: Infraorbital margin of maxilla Insertion: Skin of upper lateral half of lip Innervation: Facial nerve Action: Raises upper lip, helps from nasolabial furrow.

Corrugator supercilli

Origin: Medial end of superciliary arch Insertion: Skin on medial half of eyebrow Innervation: Facial Nerve Action: Draws eyebrows medially and downward.

Orbicularis Oris (Muscle of facial expression-mouth)

Origin: Midline of maxilla and mandible and muscles in the area. Insertion: Mucous membrane of lips. Forms ellipse around mouth. Innervation: Facial Nerve Action: Closes mouth, phasic contraction compresses and protrudes lips (as if kissing) or resists did tension (like when blowing up cheeks and preventing mouth from opening).

Procerus (Muscle of facial expression-nose)

Origin: Nasal bone and upper part of lateral nasal cartilage Insertion: Skin of lower forehead between eyebrows. Innervation: Facial nerve Action: Draws down medial angle of eyebrows, producing transverse wrinkles over bridge of nose.

Depressor Anguli Oris (Muscle of facial expression-mouth)

Origin: Oblique line of mandible below canine, pre-molar and first molar teeth. Insertion: Skin at the corner of mouth and blending with orbiculares oris. Innervation: Facial Nerve Action: Draws corners of mouth and downward laterally (pouting)

Zygomaticus major (Muscle of facial expression-mouth)

Origin: Posterior part of lateral surface of zygomatic bone. Insertion: Skin at the corner of mouth Innervation: Facial nerve Action: Draws corners of mouth upward and laterally as when smiling with teeth showing.

When an individual is asked to raise eyebrows and wrinkle the forehead, what is that assessing?

That is assessing the facial nerve by testing the strength of the frontalis muscle.

Lateral Ptyregoids

Origin: Sphenoid bone Insertion: anterior surface of mandibular condyle (joint area) Action: opens jaw, allows grinding action from side to side and protrudes mandible. Innervation:the medial ptyregoid is innervated by the main trunk of mandibular nerve V of the trigeminal nerve before it divides to supply all other muscles of mastication. All other muscles of mastication get innervation from the mandibular branch V3 of trigeminal nerve.

Medial Pterygoid

Origin: Sphenoid, palatine and maxillary bones Insertion: medial (inner) aspect of ramus Action: Closes jaw, parallels masseter muscle since it lies deep to the master Innervation; since it is a muscle of mastication, it is innervated by the mandibular branch V3 of trigeminal nerve.

Platysma

Origin: Subcutaneous tissue of infraclavicular and supraclavicular regions Insertion: Base of mandible, skin of cheek and lower lip, angle of mouth, orbicularis iris. Action: Depresses mandible (against resistance), tenses skin of inferior face and neck (conveying tension and stress).

Temporalis

Origin:Temporal fossa and temporal fascia Insertion:coronoid process (a flattened angled projection at the corner of the jaw). Innervation: Third mandibular branch of trigeminal nerve Action: Elevates and retracts posterior fibers of mandible (closes the mouth)

What are some symptoms of a blowout fracture to the orbit?

Pain Diplopia Epistaxis- bleeding from nostril Restricted vertical eye movements Sub-conjutival hemorrhage Swollen eye lid Loss of sensation due to bruising

What is the importance of buccinator and orbicularis oris working together?

The buccinator and orbiculares iris work together with the tongue to keep the food between the teeth during mastication (chewing). The buccinator contracts to keep food centered on molar teeth and the orbicularis oris maintains dam of oral vestibule at lower lip. If paralyzed, drooling occurs.

Importance of buccinator muscle

The buccinator is active in smiling and also holds the cheek taut to prevent it from folding in and being injured while chewing. The buccinator is also active during sucking, whistling, blowing (when playing a wind instrument like trumpet).

The parotid duct turns medially after leaving the parotid gland and traveling anterior across the master enters the oral cavity by piercing which muscle?

The buccinator muscle.

What is the chorda tympani nerve?

The chords tympani nerve is a branch of the facial nerve. it originates from the taste buds in the anterior two-thirds of the tongue and carries sensation via the lingual nerve to the facial nerve which carries messages to the brain.

Contents of infra temporal fossa

The contents of the infra temporal fossa re: Inferior part of temporals muscle Lateral and medial ptyregoid muscles Maxillary artery Pterygoid venous plexus Mandibular, inferior alveolar, lingua, buccal and chorda tympani nerves and the otic ganglion.

Emissary Veins

The emissary veins connect the extracranial venous system with the intracranial venous sinuses. They connect the veins outside the cranium to the venous sinuses inside the cranium. They drain from the scalp, through the skull, into the larger meningeal veins and dural venous sinuses.

Where does ethmoid bone sit?

The ethmoid is a bone of the cranium and is seen through the orbit, lateral to the lacrimal bone.

Describe Parotid Gland

Parotid gland is the largest salivary gland. It receives both sensory and autonomic innervation. Sensory innervation is by auriculotemoral and greater auricular nerve whereas the autonomic innervation is by glossopharyngeal nerve CN IX. Autonomic (parasympathetic) innervation controls saliva production. An increase in parasympathetic activity increases salivary production. (Note: the facial nerve passes through the parotid gland and gives rise to 5 branches that supply muscles of facial expression. It does not innervate the parotid gland which receives its innervation from the glossopharyngeal nerve.) The parotid gland is located anteroinferiorly to the ear, between mandibular rams and mastoid process. The parotid duct leaves the gland, passes anteriorly across master and turns medially to pierce buccinator muscle. Enters the oral cavity at the level of the second upper molar.

How can you test the facial nerve?

Raise eyebrows Frown Smile Show teeth Puff up cheeks Keep eyes closed Against resistance

Sensory and motor innervation of the face is given by which nerves?

Sensory (cutaneous) innervation is given by the trigeminal nerve which has 3 divisions: 1. Ophthalmic- V1 2. Maxillary 3. mandibular These nerves further have branches: Supratrochlear, infratrochlear, supra-orbital, lacrimal, external nasal nerves(all from ophthalmic branch V1) Infra-orbital, Zygomaticotemporal, Zygomaticofacial nerves (all from maxillary branch V2). Auriculotemporal, buccal and mental nerves (all from mandibular branch V3) Motor Innervation to the face is supplied by Facial nerve which exits the cranium through the stylomastoid foramen and transfuses through the parotid gland to give rise to 5 branches which innervate the following muscles: Temporal- orbicularis oculi, frontalis, corrugator supercilii Zygomatic- orbicular oculi Buccinator branch- innervates buccinator, zygomaticus, orbicularis oris Marginal Mandibular- mentalis Cervical-platysma

Superficial Vasculature of Face (Facial Artery)

The face is richly supplied with superficial arteries and drained by external veins. Most arteries supplying the face are branches of the external carotid arteries. The facial artery supplies the major arterial supply to the superficial face. It arises from the external carotid artery and winds its way to the inferior border of the mandible, anterior to the masseter. It then courses its way to the canthus 9medial angle of the eye). This facial artery sends branches to upper and lower lips (the superior and inferior labial arteries). It also sends branches to the sides of the nose (lateral nasal artery). It then terminates as the angular artery.

Nerves of the Face

The face receives both cutaneous (sensory) and motor innervation. The trigeminal nerve provides cutaneous (sensory) innervation to the face. However, this nerve has a motor root known as the mandibular nerve V3 which gives motor innervation to the muscles of mastication. The facial nerve is the nerve that provides motor innervation to the muscles of facial expression. Note: remember physical exam for ICM and cranial nerve tests.

What are the branches of the facial nerve?

The facial nerve has 5 branches. The Zebra Bit My Cookie Temporal branch- Innervates the frontalis, orbicualris oculi and corrugator supercilli. Zygomatic branch- innervates orbicularis oculi. Buccinator branch- innervates the orbicularis iris, buccinator and zygomaticus. Marginal Mandibular branch- innervates the mentalis. Cervical branches-innervate the platysma.

Which nerve damage can cause dry eyes

The facial nerve supplies motor innervation to the muscles of facial expression. This nerve supplies the orbicularis oculi which is responsible for closing the eye and blinking via the action of palpebral part. Thus, damage to facial nerve will not allow the eyes to close properly and thus the tears or lacrimal lubrication is not allowed to spread evenly across the cornea causing dry eyes.

If the force of blow to the orbit causes backward displacement of the eyeball, which sinus can be affected?

The force of blow backward can cause the eyeball to displace downward and thus injure the maxillary sinus.

If a person experience a blow to the orbit and can no longer perform vertical eye movements, which muscle or muscles are most likely affected?

The inferior and superior rectus muscles are responsible for vertical eye movements. Thus, in case of a blow entraps either of these muscles, vertical eye movement will be severed. (Inferior rectus muscle limits upward gaze while superior rectus muscle limits downward gaze).

Which muscle/muscles of mouth help prevent nasolabial furrow?

The levator labii superioris and the levator anguli oris both assist in preventing nasolabial furrow. Keep in mind that the levator labii superioris raises upper lip and levator anguli oris raises corners of the mouth (from an angle).

Levator labii superioris alaeque nasi (Muscle of facial expression- mouth and nose)

The lifter of the upper lip and the wing of the nose. Origin: Frontal process of maxilla Insertion: Alar cartilage of nose and upper lip Innervation: Facial Nerve Action: Raises upper lip and opens nostril and enables the expression we call snarl.

Levator labii superioris alaeque nasi (mouth and nose muscle)

The lifter of the upper lip and the wing of the nose. Origin: Frontal process of maxilla Insertion: Alar cartilage of nose and upper lip Innervation: Facial Nerve Action: Raises upper lip and opens nostril and enables the expression we call snarl. Elvis Presly face

Describe mandibular nerve block

The mandibular nerve V3 is a branch of the trigeminal nerve that has both motor and sensory innervations. In terms of motor, it supplies the muscles of mastication. In terms of sensory, it supplies auriculotemporal, lingual, inferior alveolar, buccal, and mental nerves. It is divided into anterior and posterior trunks. Anterior trunk: Buccal, mental nerves and muscles of mastication. Posterior trunk: Auriculotemporal, lingual, and inferior alveolar (inferior dental) nerves. When a mandibular nerve block is performed, it anesthetizes auriculotemporal, inferior alveolar, lingual and buccal branches of mandibular nerve.

Maxillary Artery (needs more work)

The maxillary artery is the bigger terminal branch of the external carotid artery, the other small one being the superficial temporal artery. It is found in the infra temporal fossa. It has 17 branches! It supplies blood to the maxilla and mandible, deep facial areas, cerebral duramater and nasal cavity. Hence it supports both hard and soft tissues in the maxillofacial region. It is further divided into 3 parts: 1. Mandibular/Retromandibular part- The first part is the mandibular part and is called so because it winds around the neck of the mandible. It gives off the following branches: Deep auricular, anterior tympanic, middle meningeal (passes through the spinosum foramen and splits into anterior and posterior parts), accessory meningeal(passes through foramen ovule), inferior alveolar (splits to give off a branch to mylohyoid and dental branches which terminate at the mental foramen as mental branches). 2. Pterygoid Part- 2nd part of maxillary artery, called so because it passes through the 2 heads of the later ptyergoid muscles. Branches of this part are the mesenteric branch, pterygoid branch, deep temporal branches and buccal branch. 3. Pterygopalatine fossa- 3rd part of the maxillary artery. It is the terminal portion and enters the pterygopalatine fossa. It gives off the following branches: Descending Palatine: supplies mucous membrane, glands of the palate (roof of mouth) and palatine gingiva. Posterior superior alveolar: called posterior as it is behind the maxilla. Supplies maxillary molar and pre-molar teeth, buccal gingiva and lining of maxillary sinus. Infra-orbital: supplies upper lip, side of nose, infra-orbital region, inferior eyelid, lacrimal sac Pharyngeal artery: supplies roof of pharynx, inferior part of pharyngotympanic tube, sphenoidal sinus Artery of pterygoid canal: supplies superior part of pharynx, pharyngotympanic (auditory tube) and tympanic cavity Sphenopalatine: the maxillary artery terminates here which supplies nasal cavity (lateral nasal wall, nasal septum and adjacent paranasal sinuses).

Mental Nerve Block

The mental nerve can be blocked with local anesthesia, a procedure used in surgery of the chin, lower lip and buccal mucosa from midline to the second premolar. In this technique, local anesthetic is infiltrated in the soft tissue surrounding the mental foramen.

Mentalis (Muscle of facial expression-mouth)

The mentalis muscle lies deep to the depressor lab inferioris. Origin: Mandible inferior to incisor teeth. Insertion: Skin of chin Innervation: Facial Nerve Action: Raises and protrudes lower lip as it wrinkles skin on chin.

Occipital-frontalis

The occipital-frontalis has a frontal belly and an occipital belly Frontal Belly Origin: Epicranial aponeurosis Insertion: Skin and sub-cutaneous tissue of eyebrows and forehead Actions: Elevates eyebrows and wrinkles skin of forehead, protracts scalp indicating surprise or curiosity. Occipital Belly Origin: Lateral 2/3 of superior nuchal line Insertion: epicranial aponeurosis Action: Retracts scalp, increasing effectiveness of frontal belly.

Bones of the orbit

The orbit is made up of the frontal bone, lacrimal, ethmoid and sphenoid bones, palatine and zygomatic bones.

Pterygoid Venous Plexus

The pterygoid venous plexus occupies most of the space in the infra temporal fossa. It is located partly between the temporals and pterygoid muscles. It drains anteriorly from the facial vein via the deep facial vein but mainly drains posteriorly via the maxillary vein and then the retromandibular veins.

Bones of Face and Skull

The skull is made up of the face and cranium. The cranium is made up of 8 bones: Occipital 2 Parietal Frontal 2 Temporal Spehnoid Ethmoid The Face is made up of 14 facial bones: Mandible Maxilla (2) Vomer Conchae (Inferior nasal conchae- 2) Nasal (2) Zygomatic (2) Lacrimal (2) Palatine bones (2) Note: for face, only vomer and mandible are 1 bone, everything else is paired. Muffins Make Very Cute Nurses Ziplock Leftover Portions

Which nerve supplies the corrugator supercilli?

The supraorbital nerve supplies the corrugator supercili which is the nerve that will be affected in case of migraines.

TMJ

The temporomandibular joint or TMJ contains a fibrocartilaginous disc. The heads of the Lateral pterygoids insert into the TMJ. Superior head inserts into the capsule and disc. Inferior head inserts into the pterygoid fovea. This joint is moved by the muscles of mastication. The articular disc divides the joint into superior and inferior compartments. The superior compartment has gliding movements and inferior compartment acts as a true hinge joint.

Muscles of mastication

There are 4 muscles of mastication all fed by the mandibular branch V3 of the trigeminal nerve. This branch is both sensory and motor. The following are muscles of mastication and are primarily involved in chewing: temporalis masseter medial pterygoids (deep to masseter) Lateral pterygoids (deep to masseter)

Nasal septum is made up of

Vomer and perpendicular plate of ethmoid bone. This nasal septum divides the nasal cavity into right and left parts.

Bell's phenomenon

When a patient suffering from facial nerve palsy is asked to close his/her eyes, the eyes appear to move upward and outward due to the inability of the orbicularis oculi to properly close the eyelid.

Blowout Fracture

When blows are powerful enough and the impact is directly on the bony rim, the resulting fractures usually occur at the sutures between the bones forming the orbital margin (weakest point of orbital wall). When an indirect traumatic injury displaces the orbital wall, it is called a "Blowout Fracture". Fractures of the medial wall may involve the ethmoidal and sphenoidal sinuses, whereas fractures of the inferior wall may involve the maxillary sinuses and may entrap the inferior rectus muscle limiting upward gaze. Orbital fractures often result in intra-orbital bleeding, causing pressure in the eye to increase leading to exophthalmos (protrusion of the eyeball).

When the upper lip and wings of the nose are lifted bilaterally, what is that a sign of?

When both the upper lip and the wing of the nose is lifted bilaterally as a result of the action of the levator labi superioris alaeque nasi, it is a sign of respiratory distress "fighting for air". This is seen in emphysema, bronchiolitis, Chronic Obstructive Pulmonary Disease (COPD).

Causes of TMJ Dislocation

Yawning, large bite, excessive contraction of lateral pterygoids, blow to chin when mouth is open, fracture of mandible.

Levator anguli oris (Muscle of facial expression-mouth)

Is a muscle that lies deep to the levator anguli superioris and shows up on the lateral sides of the superioris. Origin: Maxilla below Infraorbital foramen. Insertion: Skin at the corner of the mouth. Innervation: Facial nerve. Action: Raises corner of mouth, helps from nasolabial furrow.

Complications of TMJ Dislocation

It can cause damage to neighboring nerves. Example: auriculotemporal nerve, a branch of mandibular nerve V3.

Which facial muscle is both a mouth muscle and a nose muscle?

Levator labii superioris alaeque nasi

Which muscle is responsible for the snarl expression?

Levator labii superioris alaeque nasi.

Trigeminal Nerve

Major SENSORY nerve of the head and innervates the muscles that move the lower jaw (the masseter and temporals both elevate the lower jaw or mandible thus closing the mouth). It is the motor nerve for the muscles of mastication. Divisions of trigeminal nerve: 1. Ophthalmic nerve CN V1 (fully sensory)- has the following branches of cutaneous nerves: lacrimal, supra-orbital, supra-trochlear, infratrochlear and external nasal nerves 2. Maxillary nerve CN V2 (fully sensory)- has the following branches of cutaneous nerves: infra-orbital, zygomaticotemporal and zygomaticofacial nerves 3. Mandibular nerve CN V3 (it has both sensory and motor function. It receives motor fibers from facial nerve and thus motor portion supplies muscles of mastication). Has the following branches: Anterior trunk which gives sensory branches such as buccal nerve, mental nerve and motor branches to the muscles of mastication. Posterior trunk: gives off the following sensory branches: auriculotemporal nerve, inferior alveolar nerve, lingual nerve. These nerves are named according to their main regions of termination (eye, maxilla and mandible).

Middle Meningeal Artery

Middle meningeal artery comes off the first part of the maxillary artery and passes through the foramen spinosum to supply the duramater and calvaria (scalp). It splits into anterior and posterior branches. The anterior branch runs below the pterion (area where frontal, parietal, temporal and sphenoid join together. It is located on the side of the skull just behind the temple), it is vulnerable to injury here since the are is thin and injury can result in an epidural hematoma. Posterior meningeal is the largest branch that supplies the dural region in the posterior fossa.

Innervation of the scalp anterior to the auricles is by which nerve? Posterior to the auricles?

Innervation of the scalp anterior to the auricles is by all divisions of the trigeminal nerve, V1, V2, V3. The scalp posterior to the auricle sis innervated by spinal cutaneous nerves C2 and C3 of the cervical plexus.

Bones of the Face Explanation

Frontal Bone- forms skeleton of forehead, articulating inferiorly with nasal and zygomatic bones. Also articulates with lacrimal, ethmoids and sphenoid bones by forming the roof of the orbit. Supra-orbital margin of frontal bone has a supra-orbital foramen or notch. Superior to supra-orbital margin is a ridge known as superciliary arch. Zygomatic bone that form the prominences of the cheek, lie in the inferolateral sides of the orbit and rest on the maxilla. A small zygomaticofacial formamen pierces the lateral aspect of each bone. Inferior to nasal bone if the piriform (pear shaped aperture through which you can see the middle ad inferior conchae, vomer and perpendicular plate of ethmoid). On the lateral walls of each nasal cavity are curved bony plates, the nasal conchae. Maxilla forms upper jaw and is joined by the inter maxillary suture in the median plane. It has an alveolar process that supports maxillary teeth. They connect with zygomatic bones laterally and have infra-orbital foramen. Mandible is a U-shaped bone forming the lower jaw. It has an alveolar process that supports mandibular teeth. It has a horizontal part-the body and a vertical part- the rams. Inferior to second pre-molar teeth are mental foramina. Forming the prominence of the chin is the mental protuberance which is inferior to the mental symphysis (region where the halves of the mandible fuse).

Facial Nerve Palsy

Injury to facial nerve or its branches produces paralysis of some or all the facial muscles on the affected side. This is known also called Bell's Palsy. The affected areas sag and facial expressions are distorted. The loss of tonus of orbicularis oculi causes the inferior eyelid to evert away from the eyeball. As a result, the lacrimal fluid is not spread evenly over the cornea, preventing lubrication, hydration and flushing of the cornea thus causing dryness and making the cornea more vulnerable to ulceration. If injury paralyzes the orbiculares iris and buccinator, food will begin to accumulate in the oral vestibule and the person will have to stick their finger in their mouth t get the food out. When sphincters or dilators of the mouth are affected, the sides of the mouth droop due to gravity and unopposed force of the facial muscles resulting in drooling and food dripping out the corners of the mouth. Weakened lip muscles affect speech. Affected people cannot whistle or blow a wind instrument efficiently. They frequently dab their eyes and corners of mouth with a handkerchief to wipe the tears and saliva.