Orofacial musculature(muscles of mastication and facial expression) 7/20/20151

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Muscles of the face develop from the second pharyngeal arch and are innervated by branches of the facial nerve. 7/20/20154

Facial muscles and expression 7/20/20155

Muscle of scalp Occipitofrontalis 7/20/20156

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MUSCLE OF AURICLE Auricularis anterior Auricularis superior Auricularis posterior 7/20/20159

Muscles of orbit Orbicularis oculi Corrugator supercilii 7/20/201510

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7/20/ Corrugator supercilliFrowning

Muscles of nose Procerus Nasalis Depressor septi 7/20/201513

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7/20/ Frowning- procerus

7/20/ Anger- Depressor septi

Muscles around the mouth Orbicularis oris Levator labii superioris alaeque nasi Zygomaticus major Levator anguli oris Zygomaticus minor Depressor anguli oris Depressor labii inferioris Mentalis Risorius buccinator 7/20/201517

7/20/ ■■ Closes the mouth. ■■ Protracts the lips. ■■ Expressions: puckering, whistling

7/20/ Expressions: anger, smugness, contempt

7/20/ Expressions: smile, smugness

7/20/ Smiling and laughing

7/20/ Grinning - Risorius Expressions: smile, sneer (“Dracula” expression) Expressions: grin, smile, laugh

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7/20/ Expressions: pucker, exertion, sighExpressions: sadness, uncertainty, dislike

7/20/ Grief- Depressor anguli oris Whistling – Buccinator

7/20/ Expressions: sorrow, doubt, ironyExpressions: doubt, pout, disdain

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Muscle of the neck 7/20/ Horror, Terror and fright - Platysma

Clinically the facial nerve is examined by testing the followinhg facial muscles Frontalis Corrugator supercilli Orbicularis oculi Orbicularis oris Buccinator Platysma 7/20/201529

Muscles of mastication Muscles are organs of motion. They move various parts of the body by their contractions. Muscles of mastication originate on the upper 2/3 rd of the skull and insert on the mandible. These muscles work in group with each other and with other muscles as well. 7/20/201530

EMBRYOLOGY 7/20/201531

ARCHES DERIVATIVES 1st Arch (Mandibular) - Trigeminal nerve - Muscles of mastication - Mylohyoid - Ant. Belly of digastric 2 nd Arch (Hyoid) - Facial nerve - Facial muscles - Stylohyoid muscle - Post.belly of digastric 3 rd Arch - Glossopharyngeal nerve - Stylopharyngeal muscle 4 th Arch - Vagus nerve - Intrinsic muscles of pharynx 7/20/201532

Muscles develop from condensation of mesenchyme……….. MYOBLASTS Myoblasts continue division till late fetal life. In late fetal life muscle growth decreases in size. 7/20/201533

Muscles of mastication Primary muscles Masseter Temporalis Lateral pterygoid Medial pterygoid Secondary or accessory muscles Digastric Mylohyoid Geniohyoid 7/20/201534

MASSETER 7/20/201535

1)Superficial layer : Origin: Anterior two third of inferior surface of zygomatic arch & zygomatic process. Insertion: lower part of lateral surface of ramus of mandible. 2)Deep layer : Origin: Deep surface of zygomatic arch. Insertion: Upper part of ramus & coronoid process of mandible. 7/20/201536

RELATIONS 7/20/ Superficial : skin, platysma, branches of facial nerve and transverse facial branches of the superficial temporal vessels Deep: temporalis and ramus Posterior margin Overlapped by parotid gland Anterior margin: Projects over the buccinator and is crossed below by facial vein

NERVE SUPPLY: masseteric N. branch of ant. Div.of mandibular N. BLOOD SUPPLY: Massetreic artery, a branch of Maxillary A. ACTIONS:1)Elevation of jaw 2)Retraction 7/20/201538

TEMPORALIS 7/20/201539

RELATION Superficial  Skin  Temporal fascia  Superficial temporal vessels  The zygomatic arch  Masseter 7/20/201540

DEEP SURFACE  Temporal fossa  Lateral pterygoid  Superficial head of medial pterygoid  Maxillary artery and its deep temporal branches  Deep temporal nerves Anterior border  seperated from the zygomatic bone by a mass of fat Posterior border  massetric nerves and arteries 7/20/201541

BLOOD SUPPLY: Deep temporal part of maxillary artery Anterior deep temporal artery Posterior deep temporal artery Middle deep temporal artery NERVE SUPPLY:Deep temporal branches of ant. trunk of mand. N 7/20/201542

ACTIONS elevates the mandible - upward pull of anterior fibres and the backwards pull of the middle fibers, Retraction of mandible - backward pull of posterior fibres It also contributes to side to side grinding movements. 7/20/201543

Palpation 7/20/201544

LATERAL PTERYGOID 7/20/201545

ORIGIN UPPER HEAD –SMALL  Infra temporal surface and Infra temporal crest of greater wing of the sphenoid bone. LOWER HEAD -LARGE  Lateral surface of lateral pterygoid plate (opposite to the origin of the medial pterygoid). 7/20/201546

RELATIONS SUPERFICIAL SURFACE (LATERALLY)  Ramus of the mandible  Maxillary artery  Tendon of the temporalis and  Masseter DEEP SURFACE (MEDIALLY)  Upper part of the medial pterygoid  Spheno mandibular ligament  Middle meningeal artery and  Mandibular nerve 7/20/201547

UPPER BORDER (SUPERIORLY) Temporal and massetric branches of mandibular nerve LOWER BORDER (INFERIORLY) Lingual nerve Inferior alveolar nerve 7/20/201548

NERVE SUPPLY The lateral pterygoid is supplied by a branch of anterior division of the mandibular nerve. BLOOD SUPPLY Pterygoid branch of 2nd part of maxillary artery Upper head and lateral part of lower head  branch of buccal nerve Medial part of lower head  anterior trunk of the mandibular nerve 7/20/201549

ACTIONS 1)Depresses the mandible to open the mouth 2)Lateral & Medial pterygoid act together for protrusion 3)Both act alternatively for side to side movement (chewing) 7/20/201550

MEDIAL PTERYGOID 7/20/201551

ORIGIN: A)SUPERFICIAL HEAD-From tuberosity & palatine process of maxilla B)DEEP HEAD- Medial surface Of lateral pterygoid plate INSERTION - Fibres inserted into medial surface of angle & ramus of mandible 7/20/201552

RELATIONS SUPERFICIAL / LATERAL SURFACE  Mandibular ramus  Spheno mandibular ligament  Maxillary artery  Inferior alveolar nerves and vessels  Lingual nerve DEEP /MEDIAL SURFACE  Tensor veli palatini  Styloglossus  Stylopharyngeus 7/20/201553

NERVE SUPPLY Branch of the main trunk of the mandibular nerve. Pterygoid branch of 2nd part of maxillary artery BLOOD SUPPLY Elevates the mandible. With lateral pterygoid these muscles helps in protruding the mandible. ACTIONS 7/20/201554

Palpation 7/20/201555

SECONDARY MUSCLES OF MASTICATION 7/20/

Mylohyoid Origin- 3 fibres ant, middle, post. which originates from mylohyoid line of mandible. Insertion- Post. Fibres-into body of hyoid Ant & middle-into median raphae uniting left & right muscles 7/20/201557

NERVE SUPPLY Mylohyoid nerve a branch of mandibular nerve branch of inferior alveolar nerve. Aids in opening action of the mandible Assist in act of swallowing by raising the tongue and floor of mouth by elevating the hyoid bone ACTIONS 7/20/201558

DIGASTRIC Posterior belly origin  mastoid notch medial to mastoid process Anterior belly origin  digastric fossa of mandible Insertion- body & greater cornu of hyoid bone 7/20/201559

ACTIONS Pulls mandible back & down Retrusive and opening movements Elevation of hyoid bone NERVE SUPPLY Anterior belly  branch of mylohyoid nerve Posterior belly  branch of facial nerve 7/20/201560

Geniohyoid Strap shaped muscle ORIGIN inferior genial tubercle INSERTION Fibers run backward and downward and inserted into the anterior surface of body of the hyoid bone. 7/20/201561

ACTIONS It stabilizes the mandible along with digastric by pulling hyoid up Help depress the mandible NERVE SUPPLY Ventral rami of the first and second cervical nerves 7/20/201562

Disorders of muscles 1. TRISMUS The term trismus denotes a motor distribution of the trigeminal nerve, especially spasm of the masticatory muscle, with difficulty in opening the mouth. 7/20/ IJDA, 2(3), July-September, 2010Trismus

Etiology 1.Masticatory muscle disorders 2.Odontogenic infections 3.Multiple intra oral L.A injections 4.Trauma with mand. Frac. 5.Neuromuscular tetanus(lock jaw) 6.Radiation therapy 7.Tumors of nasopharynx, tongue, saliv. glands 8.Third molar surgery 7/20/201564

Treatment Heat therapy Analgesics Soft diet Muscle relaxants. 7/20/201565

2. Muscle pain (myalgia) Most frequent causes of discomfort around head & neck Any pain must first be assumed to be dental in origin then only go for muscle pain Palpable muscle tenderness, pain decreases muscle strength by 33-50% Pain can be non pulsatile, aching sensation,sometimes more sharper & lancinating 7/20/201566

Etiology 1.Emotional stress 2.Placement of high crown 3.Any source of deep pain Clinical features 1.Muscle weakness 2.No pain when muscle is at rest 3.Limited mouth opening but can achieve full mouth opening Treatment 1.Remove the cause & set muscle at rest 2.No therapy other than muscle relaxants 7/20/201567

3. Myofascial pain(trigger point Myalgia) First given by TRAVELL & RINZLER in 1952 Regional myogenous pain condition charac. by local areas of firm hypersensitive bands of muscle tissue known as trigger pts. They elicit pain on palpation. Certain nerve endings in muscle tissues may become sensitized. 7/20/201568

Etiology Local-trauma fatigue Systemic- Hypovitaminosis poor physical condition viral infections, stress Clinical features 1.Local muscle sensitivity 2.Various trigger pts. 3.Sometimes can tell only about referred pain 7/20/201569

4. M yospasms (tonic contraction myalgia) It is a sudden violent involuntary contraction of a muscle or a group that is attended by pain & interfere with function. Clinical features a. Major jaw positional changes occur because muscle in spasm is contracted b. Sudden change in occlusal condition occurs called as ACUTE MALOCCLUSION mainly by inferior head of lateral pterygoid c. Very firm muscles on palpation 7/20/201570

5. M yositis (inflammatory myalgia) Longer the pt. complains of muscle pain more chances of myositis Not common Prolonged &constant muscle pain and not periodic episodes Clinical features a.Constant aching pain b.Pain present during rest & inc. during function c.Muscles very tender to palpation 7/20/201571

Treatment 1.Until acute symptoms subside restricted use within painless limits No exercises,massage or injection Anti inflammatory therapy 2.When acute symptoms subside Stop anti inflammatory therapy Active exercises 7/20/201572

References GRAY’S ANATOMY 39 th EDITION Trismus INDIAN JOURNAL OF DENTAL ADVANCEMENTS Human anatomy- BD Chaurasia’s 7/20/201573