Muscles Of Facial Expression


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Muscles of facial expression - its nerve innervation & aplllied anatomy

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Muscles Of Facial Expression

  1. 1. NERVE INNERVATIONS & ITS APPLIED ANATOMY Seminar By, Dr. Jacob Abraham Dept. Of Orthodontics S.R.M. Dental College, Chennai, India
  2. 2. The face is the mirror of the mind, and eyes without speaking confess the secrets of the heart. St. Jerome
  3. 3. MUSCLES OF FACIAL EXPRESSION  Generally from skull to skin  Innervated by facial nerve (CN VII)  Sphincters and dilators around mouth (lips), eyes, nostrils  Wrinkle lines perpendicular to muscle fibres
  4. 4.  There are 17 Muscles 2. Frontal Belly Of Occipitofrontalis 3. Corrugator Super cilia 4. Orbicularis Occuli 5. Compressor Naris 6. Dilator Naris 7. Procerus 8. Depressor Septi 9. Nasalis 10. Buccinator 11. Zygomaticus Major and Minor 12. Levator labii Superioris alaeque nasi 13. Depressor anguli oris 14. Levator Anguli Superioris 15. Depressor Labii Inferioris 16. Orbicularis Oris 17. Risorius 18. Mentalis
  5. 5. MUSCLES OF FACIAL EXPRESSION  Frontal Belly of Ocipito frontalis:  Orgin : Galea Aponeurotica  Insertion: Orbicularis oculi and adjacent skin  Action: Draws scalp forward and raises eyebrows
  6. 6. MUSCLES AROUND THE EYE  Sphincter: Orbicularis oculi (Orbital, palpebral and lacrimal parts)  Blink (spread tears across cornea) and close eyes tightly  Note: elevators of upper lid innervated by CN III, sympathetics
  7. 7. MUSCLES OF EYE  Orbicularis oculi  Sphincter muscle of eyelid  O: frontal & maxillary bones  I: tissue of eyelid  Action: closes eye  Nerve: facial / CN VII
  8. 8. MUSCLES AROUND THE NOSE  Procerus - wrinkles skin of nose  Compressor nares – lateral to bridge of nose compresses nasal cartilage.  Dilator nares - lateral to nostrils – dilates
  9. 9. MUSCLES OF FACIAL EXPRESSION  Zygomaticus Major an d Minor  Orgin: zygomatic bone  Insertion: corners of mouth  Action: smiling  Nerve: facial / CN VII
  10. 10. MUSCLES AROUND THE MOUTH  Numerous dilators (levators/depressors of upper/lower lip and angle of mouth)  Buccinator  Sphincter: Orbicularis oris Surrounds/closes mouth
  11. 11. MUSCLES OF MOUTH Modiolus –Knitting of muscle fibers
  12. 12. MUSCLES OF FACIAL EXPRESSION  Buccinator Orgin: Maxilla and Mandible Insertion: Angle of the mouth Action: Retracts angle of mouth
  13. 13. Buccinator Muscle  Superior Pharyngeal Constrictor (SC)  Pterygomandibular raphe (PR)  Middle Pharyngeal Constrictor (MC)  Tonsillar Branch Of Facial Artery (1)  Glossopharyngeal nerve (2)  Stylohyoid ligament (3)  The pterygomandibular raphe serves as an insertion point for two muscles:  Superior constrictor and Buccinator
  14. 14. Common Facial Expressions  Smiling & Laughing: Zygomatics Major  Sadness: Levator Labii Superioris and Levator Anguli Oris  Grief: Depressor Anguli Oris  Anger: Dilator Naris & Depressor Septi  Frowning: Corrugator Supercilii & Procerus  Horror, Terror & Fight: Platysma  Surprise: Frontalis  Doubt: Mentalis  Grinning: Risorius  Contempt: Zygomatic Minor
  15. 15. SMILING MUSCLES FROWNING MUSCLES  Orbicularis Oculi: close  Frontalis: elevate eyelid eyebrows  Nasalis: compress/dilate  Orbicularis Oris: closes nasal openings mouth  Levator Labii Superioris:  Depressor Anguli Oris: raise upper lip draw angle of mouth  Levator Anguli Superioris: downward raise angle of mouth  Depressor Labii Inferioris: upward lowers lower lip  Zygomaticus: draw angle  Mentalis: draws chin up of mouth upward  Platysma: draws lower lip  Risorius: draw angle of down & back mouth laterally
  16. 16. CUTANEOUS INNERVATION OF FACE  Branches of trigeminal nerve (CN V):  Ophthalmic (V1)  Maxillary (V2)  Mandibular (V3)  Cervical plexus branches (C2)  Lesser occipital  Great auricular  Greater occipital nerve (dorsal ramus of C2)
  17. 17. MUSCLES & NERVE SUPPLY  Orbicularis oculi Temporal and zygomatic branches  Muscles of Upper Lip and Buccal Branch Buccinator, Levator Anguli Oris  Risorius and Mandibular Branch muscles of lower lip  Platysma Cervical Branch
  18. 18. FACIAL NERVE  It has both Efferent component and Afferent component  Efferent component supplies all the muscles and the glands such as the  Lacrimal gland  Submandibular gland  Sublingual gland  Afferent component supplies the  Taste sensation of the Ant.2/3rd of the tongue
  19. 19. Innervation Of Muscles Of Facial Expression: Facial N. (VII)  LMNs in facial nucleus is in inferior pons  Fibres course around abducens nucleus - internal genu  Exits brainstem at cerebellopontine angle with CN VIII
  20. 20. Course of facial nerve (CN VII)  Through the petrous part of the temporal bone:  Through internal acoustic meatus with CN VIII  Into facial canal, along walls of the tympanic cavity (external genu of facial nerve, geniculate ganglion)  Exits skull via stylomastoid foramen, most branches go through parotid gland  Temporal  Zygomatic  Buccal  Marginal mandibular  Cervical  Posterior auricular
  21. 21. Damage to UMNs, LMNs, or facial nerve  Clinical testing: raise eyebrows, close eyes tightly, smile  Unilateral UMN: contralateral lower 1/2-2/3 of face paralysed  Unilateral LMN or CN VII: entire ipsilateral face paralysed (Bell’s palsy)  Lack of blinking  Leaky mouth  Speech difficulties  (other CN VII functions)
  22. 22.  A lesion involving the nuclear or infranuclear portion of the facial nerve will produce a peripheral facial palsy.  If all motor components are involved, there is complete paralysis of all facial muscles on the involved side. The brow is smooth, the eye does not close, the nasolabial fold is flat, and that side of the mouth droops. There is no movement at all. The paradigm of this type of involvement is Bell's palsy.  Idiopathic: Bell's palsy may strike at any age, often after a mild viral illness. Recovery is over a period of weeks to months and is variable. The cause of the idiopathic variety is unknown.
  23. 23. Applied Anatomy For Orbicularis Oculi  If any injury to the nerve which supplies that muscle, it will lead to paralyses of that muscle. This causes the dropping of lower eyelid , called as “Ectropion’’ and  Spilling of tears , called as “Epiphora”.  Some times there will be radiating wrinkles at the angle of the eye during strong closure. This called as “Crow’s Feet”
  24. 24.  Risorisus Sardonicus:  Smile in tetanus  It is the smile like feature in agony due to pulling of the muscles of the angle
  25. 25. References  Cunningham’s Manual of Practical Anatomy  B.D. Chaurasia  Gray’s Anatomy  Internet