Face & Scalp

• parotid gland

  
  

  what artery is at the parotid gland?

  External carotid divides into its terminal branches in the gland (maxillary artery and superficial temporal)
• parotid gland

  
  

  what causes saliva production from the parotid gland?


  Saliva production arises from activity of the parasympathetic fibres within the glossopharyngeal nerve (CN IX)
• parotid gland

  
  

  describe the relation between the facial nerve and the parotid gland


  The facial nerve, as it travels towards the face, actually creates a plexus that passes within the parotid gland, although - curiously - it does not innervate this gland
• parotid gland

  
  

  where is the parotid gland?

  - Parotid duct lies on masseter and pierces buccinator - opens into oral cavity on buccal side of upper left second molar

  - It is tightly enclosed in fascia (not elastic), thus swelling of this gland can become painful -"mumps"
• Innervation of the face and facial muscles - facial nerve (CN VII)

  
  

  what is the facial nerve's role?


  - motor innervation of facial muscles that are responsible for facial expression

  - parasympathetic innervation of the glands of the oral cavity and the lacrimal gland

  - sensory innervation of the anterior two-thirds of the tongue.
• Innervation of the face and facial muscles - facial nerve (CN VII)

  
  

  show the main foramina the facial nerve takes to exit the skull


  The facial nerve exits the base of the skull at the stylomastoid foramen, which is an opening in the bone located near the base of the ear.

  
• Innervation of the face and facial muscles - facial nerve (CN VII)

  
  

  some fibres of the facial nerve take the role of general somatic sensation of the skin of the concha of the auricle (ear).

  TRUE/FALSE

  TRUE
• Innervation of the face and facial muscles - facial nerve (CN VII)

  
  

  what is the special sensory role of the facial nerve?


  taste - from the anterior 2/3 of the tongue is carried by fibres of the chorda tympani, which join the lingual nerve (from CN V3)
• Innervation of the face and facial muscles - facial nerve (CN VII)

  
  

  describe the pterygopalatine ganglion of the facial nerve


  - associated with innervation of the mucous membrane of the nasopharynx as well as that of the hard and soft palate (via the maxillary or mandibular branches of the trigeminal)
• Innervation of the face and facial muscles - facial nerve (CN VII)

  
  

  describe the visceral motor of the facial nerve


  - comprised of presynaptic parasympathetic fibresto the pterygopalatine ganglion, which innervates the lacrimal glands

  as well as the submandibular and sublingual salivary glands
• Innervation of the face and facial muscles - facial nerve (CN VII)

  
  

  describe the primary motor of the facial nerve

  - the largest component

  - It supplies primarily the muscles of facial expression but also posterior belly of digastric muscle, stylohyoid and stapedius
• Innervation of the face and facial muscles - facial nerve (CN VII)

  
  

  what are the 3 components of the facial nerve?

  1. the primary motor: facial nerve proper

  
  

  2. visceral motor

  
  

  3. pterygopalatine ganglion
• Innervation of the face and facial muscles - facial nerve (CN VII)

  
  

  what are the 3 types of nerves for cutaneous innervation of the face?

  1. Ophthalmic cutaneous nerves:

  - supraorbital

  - supratrochlear

  
  

  2. Maxillary cutaneous nerves:

  - Infraorbital

  - Zygomaticofacial

  - zygomaticotemporal

  
  

  3. Mandibular cutaneous nerves:

  - mental

  - auriculotempora

  
• what is trigeminal neuralgia?

  rare episodic facial pain that is unilateral, electric shock like and provoked by light touch

  
  

  - It affect more females than males

  - The incidence increases with increasing age

  - In 95% of cases, vascular compression of the nerve root is the source of the problem

  - In the 10% of cases where the drug treatment is ineffective, surgery is suggested but it is not without risk, e.g. hearing loss

  
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  where does the mandibular division of the trigeminal nerve cross?


  This nerve exits the skull via the foramen ovale

  
  

  Main branches are:

  - auriculotemporal, supplying the skin in front of the ear

  - lingual, sensory to the anterior 2/3rds of the tongue

  - buccal, supplying the skin and lat walls/floor of oral mucosa

  - inferior alveolar, entering the mandibular bone through the

  mandibular foramen, gives rise to the inferior dental plexus and

  exits onto the face as the mental nerve

  
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  where does the maxillary division of the trigeminal nerve cross?


  this nerve crosses foramen rotundum to target several structures within the maxilla, such as the mucosa of the maxillary sinus or the posterior teeth, as well as the skin

  
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  where does the ophthalmic division of the trigeminal nerve cross?


  the sup orbital fissure to supply several structures around the eye and nose

  
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  where are the neuron cell bodies for the motor root of the trigeminal nerve?

  within the pons

  
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  what is the trigeminal ganglion?


  the sensory roots of the trigeminal nerve have their pseudounipolar neurones located within the sensory ganglion called the trigeminal ganglion

  
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  where does the minor motor contribution of the trigeminal nerve come from?

  The minor motor contribution is from fibres that target primarily the muscles of mastication
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  what are the divisions of the trigeminal nerve?

  1. Ophthalmic- around the eye- (sensory)

  2. Maxillary (sensory)

  3. Mandibular (mixed)

  
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  how many divisions does the trigeminal nerve have?

  3

  
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  which two roots come together to form the trigeminal nerve?

  sensory and motor
• Innervation of the face and facial muscles - trigeminal nerve

  
  

  where does the trigeminal nerve originate from?

  pons, at the base of the brain

  
• Innervation of the face and facial muscles

  
  

  what are the two main routes of innervation?

  1.The trigeminal nerve encodes mostly cutaneous (affecting the skin.)

  i.e. sensory (response to touch) innervation of the face (and scalp), although has a minor motor contribution

  
  

  2. The facial nerve (CN VII) provides motor (movement and function) innervation to the facial muscles
• Venous drainage of face

  
  

  what 2 veins drain the deeper tissues of the face?

  1. deep facial vein,

  which joins the facial vein

  
  

  2. retromandibular vein,

  which divides to either drain into the facial vein or a second

  branch that forms the external jugular

  
• Venous drainage of face

  
  

  describe how blood is drained from the face

  Blood is drained from a plexus of vessels at the surface that drain the anterior scalp, forehead, eyelids, nose etc.

  
  

  1. first into the facial vein as it travels from the side of the root

  of the nose to the angle of the mandible

  2. The facial vein ultimately drains into the internal jugular vein

  
• Blood supply to the face

  
  

  what are the main branches of the external carotid artery?

  - Facial branch, supplying the skin and muscles of the face

  - Transverse facial

  - Lateral nasal

  - Labial (sup and inf)

  
• Blood supply to the face

  
  

  what artery is the principle supplier of blood to the face?

  external carotid artery

  
• Muscles of the face

  
  

  What is the action of the Platysma?

  Draws mouth downward
• Muscles of the face

  
  

  describe the Platysma

  - broad, thin muscle

  - Its role is to tense the skin but also acts to depress the mandible
• Muscles of the face

  
  

  What is the origin and insertion of the Platysma?


  Origin: Fascia of chest (clavicle)

  Insertion: lower border of mandible
• Muscles of the face

  
  

  What is the action of the Zygomaticus?


  Raises corner of mouth
• Muscles of the face

  
  

  describe the Zygomaticus

  - long, cord-like muscle

  - contracting this muscle raises the angle of the mouth - Smiling, or grinning
• Muscles of the face

  
  

  What is the origin and Insertion of the Zygomaticus?

  Origin: Zygomatic bone

  Insertion: corner of lips (orbicularis and levator anguli oris muscles)
• Muscles of the face

  
  

  What is the action of the Buccinator?

  Flattens cheek against teeth
• Muscles of the face

  
  

  Describe the Buccinator

  - the 'cheek' muscle

  - Presses cheek against the teeth, so pushes food onto molars, also for suckling
• Muscles of the face

  
  

  What is the origin and insertion of the Buccinator?

  Origin: Mandible/maxilla

  Insertion: skin around mouth (orbicularis muscle at

  the angle of the mouth)
• Muscles of the face

  
  

  What is the action of Orbicularis oris?

  Closes and protrudes lips
• Muscles of the face

  
  

  Describe the Orbicularis oris

  - commonly known as the oral sphincter

  - Composed of multiple layers

  - This muscle decussates (i.e. intersects) at the corner of the mouth

  - there is no specific bony origin for this muscle.