BDS1041 Facial Expression PDF, NGU School of Dentistry

BDS1041 Facial expression Date : 21 / 12 / 2021 Objectives List the main muscles of facial expression and describe the movements they produce Describe the layout of the main branches of the facial nerve on the face Understand the anatomical basis for clinical tests of the integrity...

BDS1041 Facial expression Date : 21 / 12 / 2021 Objectives List the main muscles of facial expression and describe the movements they produce Describe the layout of the main branches of the facial nerve on the face Understand the anatomical basis for clinical tests of the integrity of the facial nerve Describe the relationship of the facial nerve to the parotid gland  Visceral or Facial Skull Follows a musculoskeletal growth trajectory (face growth observed at least until 18 years of age) Bone elements involved: Sphenoid Temporal (zygomatic process) Maxilla Zygomatic Palatine Mandible Hyoid Facial Muscles – Terminology “Levator...” - Raises “Depressor...” - lowers “Major” – the larger “Minor” – the smaller “Superioris” – superior “Inferiorioris” – inferior “Orbicularis” - encircles  Facial Muscles of Expression Some of the muscles of facial expression also have a role in chewing : Orbicularis oris keeps the lips closed Buccinator in the cheek helps to move food around within the mouth so that it engages with the teeth  Facial Muscles – Surprise epicranial aponeurosis Occipitofrontalis: This muscle has two parts, one on the forehead and one on the back of the head, both of which are joined by an aponeurosis. Facial Muscles – Surprise Epicranial frontalis: occipitofrontalis. Raises forehead & eye brows, pulls scalp backward  Facial Muscles – Closing Eyelid Orbicularis oculi: Closes eyelids Circular fibers around the orbit Facial Muscles – Frowning Corrugator supercilii: Draws eyebrow medially  Facial Muscles – Closing Lips Orbicularis oris: Closes or purses lips  Facial Muscles – Assist Chewing Buccinator: Moves “bolus” of food Buccina= Trumpet It squeezes food from cheek between the teeth into the mouth again for more chewing before swallowing It prevents food debris & air from being squeezed back into the parotid duct Facial Muscles – Opening Risorius: Smile widely Risorius  Facial Muscles – Raising Upper Lip Levator labii superioris: Raises upper lip Facial Muscles – Raising Upper Lip Levator labii superioris alaeque nasi: Raises upper lip and widens nostril Facial Muscles – Smiling Zygomaticus major: Draws cheek back and corner of mouth open Facial Muscles – Raising Upper Lip Zygomaticus minor: Raises upper lip Zygomaticus minor Facial Muscles – Smiling Levator anguli oris: Raises angle of mouth Levator anguli oris Facial Muscles – Frowning Depressor anguli oris: Lowers angle of mouth Facial Muscles – Lowering Lower Lip Depressor labii inferioris: Lowers lower lip Facial Muscles – Raising Chin Mentalis: Raises chin, protrudes lower lip, and Decreases depth of lower vestibule. Facial Muscles – Grimacing Platysma: Raises skin of neck and lowers corner of mouth.  Facial Nerve (VII) – Motor Branches Motor fibres leave the posterior cranial fossa via the stylomastoid foramen Gives posterior auricular to stylohyoid & post. Belly of digastric Travel within the parotid gland superficial to ECA & retromandibular vein Supply the facial expression musculature Facial nerve (VII) T Motor distribution of facial nerve 1. Temporal Z 2. Zygomatic 3. Buccal B 4. Mandibular 5. Cervical (to platysma) M C Facial Nerve (VII) – Motor Branches Lower motor neuron lesion: Facial palsy (Bell’s palsy), e.g.: following inflammation of the facial nerve while in the facial canal in petrous bone… Picture: left facial nerve palsy  Upper motor neuron lesion: All motor nuclei of cranial nerves receive bilateral cortico-nuclear fibers except the part of facial nucleus that innervates muscles of the lower part of the face (& part of XII nucleus) which receives contralateral cortico-nuclear fibers only R L R L Upper motor neuron lesion (e.g.: Stroke on the opposite side), lower part of the face is affected while upper part of the face is unaffected R L R L  Sensory and Motor Distribution of Trigeminal Nerve (V) on the Face Sensory supply of the face is provided by the trigeminal nerve (Vi, Vii, and Viii) Motor supply: Muscles of mastication are supplied by the mandibular division of the trigeminal nerve (Viii) The muscles of facial expression are supplied by the facial nerve (VII) Trigeminal herpes Herpes Zoster virus Affects the trigeminal ganglion Presents as vesicular rash in the exact distribution of the dermatome involved  Vasculature of the Face Facial artery (branch of the external carotid): Over the ramus of the mandible, along the lateral aspect of the nose Anastomoses with orbital and scalp vessels and the superficial temporal artery Facial vein: Runs along the facial artery Communicates with orbital veins and intracranial venous sinuses, drains to the internal jugular vein directly (and via the retromandibular vein)  Orbital vessels Superficial temporal Maxillary Internal carotid facial External Common carotid carotid Dr. Shahira Samir  *Facial artery: From ECA Tortuous (free movement) Enters face anterior to masseter, angle of mouth, side of nose At side of nose, it is called Angular artery Ends by anastomosing with orbital vessels Gives labial & nasal branches & anastomoses with transverse facial of superficial temporal artery *Superficial temporal artery Gives transverse facial artery Veins of the face: Superficial temporal vein + maxillary vein→ Retromandibular v. (inside parotid gland)→ divides into: i. Anterior division: Sup. temporal Unites with facial vein→ common Retromand. Max. facial→ internal jugular vein Post. Auricular ii. Posterior division: Facial Unites with posterior auricular→ CommonFacial External jugular v. (descends in the EJV neck superficial to sternomastoid IJV m.)→ Subclavian vein Subclavian Veins Communications to cavernous sinus Dangerous area of the face Objectives List the main muscles of facial expression and describe the movements they produce Describe the layout of the main branches of the facial nerve on the face Understand the anatomical basis for clinical tests of the integrity of the facial nerve Describe the relationship of the facial nerve to the parotid gland Thank you