Superficial and Deep Face

Question 1

Neurocranium (Cranial Vault)

Answer 1

1) Parietal (2)
2) Temporal (2)
3) Frontal (1)
4) Occipital (1)
5) Sphenoid (1)
6) Ethmoid (1)

Question 2

Viscerocranium

Answer 2

Makes up the face.

1. Mandible (1)
2. Maxilla (2)
3. Palatine (2)
4. Zygomatic (2)
5. Lacrimal (2)
6. Vomer (1)
7. Nasal (2)
8. Inferior nasal concha (2)

Question 3

Muscles of Facial Expression

Answer 3

• Origninate from bones of the facial skeleton and insert onto the skin of the face.
• All are innervated by the Facial Nerve (CN VII)
• Muscles of facial expression act together in groups

Question 4

Superficial Muscles of Facial Expression

Answer 4

1. Frontalis part, Occipitofrontalis muscle
2. Orbicularis oculi muscle (orbital part)
3. Orbicularis oculi muscle (palpebral part)
4. Procerus muscle
5. Levator labii superioris alaeque nasi muscle
6. Nasalis muscle
7. levator labii superioris muscle
8. zygomaticus minor muscle
9. orbicularis oris muscle
10. zygomaticus major muscle
11. Depressor labii inferioris muscle
12. Mentalis muscle
13. Depressor anguli oris muscle
14. Risorius muscle
15. Platysma muscle

ALL INNERVATED BY FACIAL NERVE (CN VII)

Question 5

Deep muscles of facial expression

Answer 5

1. Corrugator supercilii muscle
2. Levator anguli oris muscle
3. Occipitalis belly, occipitofrontalis muscle
4. Buccinator muscle

ALL INNERVATED BY FACIAL NERVE

Question 6

Motor innervation of muscles of facial expression

Answer 6

Facial Nerve (Cranial Nerve VII)

Question 7

Sensory innervation of face

Answer 7

Trigeminal Nerve (Cranial Nerve V)

Question 8

Facial Nerve (Cranial Nerve VII)

Answer 8

• It exits the skull via the stylomastoid foramen, pierces the parotid gland, and as it passes through, divides into 5 major branches:

1. Temporal (Ten)
2. Zygomatic (Zebras)
3. Buccal (Bit)
4. Marginal/Mandibular (My)
5. Cervical (Cannoli)

Question 9

Bell’s Palsy

Answer 9

Results from laceration of the facial nerve or cranial nerve VII. This then causes paralysis of one side of the face, causes it to droop.

Question 10

Branches of the Trigeminal Nerve (Cranial Nerve V)

Answer 10

1. Ophthalmic Division (CN V1) “LaSSIE”
   
   1. Supraorbital
   2. Supratrochlear
   3. Infratrochlear
   4. External Nasal
   5. Lacrimal
2. Maxillary Division (CN V2):
   
   1. Zygomaticotemporal
   2. Zygomaticofacial
   3. Infraorbital
3. Mandibular Division (CN V3):
   
   1. Ariculotemporal
   2. Buccal
   3. Mental

Question 11

Parotid Gland

Answer 11

• Secretes serous fluid via stenson’s duct, which pierces the buccinator muscle and enters the oral cavity adjacent to the upper second molar.
• Innervated by parasympathetic fibers from the glossopharyngeal nerve (IX) which synapse in the otic ganglion (behind V3 as it exits the foramen ovale) and then travels in the auriculotemporal nerve as it passes through the parotid gland
• Facial Nerve (CN VII) ​passes through it

Question 12

12 Arteries of the face

Answer 12

1. Superficial Temporal Artery
2. Facial Artery
3. Mental Artery
4. Superior labial Artery
5. Inferior labial Artery
6. Posterior Auricular Artery
7. Occipital Artery
8. Transverse Facial Artery
9. Angular Artery
10. Lateral Nasal Artery
11. Supraorbital Artery
12. Supratrochlear Artery

Question 13

Venous Drainage

Answer 13

1. Facial Vein: Largest and most important
2. Superficial temporal vein
3. maxillary vein
4. retromandibular vein
5. pterygoid venous plexus
6. cavernous sinus
7. superior and inferior ophthalmic veins
8. supraorbital vein
9. supratrochlear vein
10. Angular vein
11. Deep facial vein

Question 14

“Danger Triangle”

Answer 14

If an infection occurs in the upper face (“danger triangle”) potentially the bacteria can migrate from this region via the deep facial vein into the cranium.

Facial vein infection then can spread by its interconnections (ophthalmic & infraorbital veins) to the pterygoid plexus and into the cavernous sinus and thus reach the brain causing meningitis or encephalitis.

Question 15

Layers of the Scalp

Answer 15

1. Skin
2. Connective Tissue
3. Aponeurosis
4. Loose connective tissue
5. Pericranium

Question 16

Temporal Fossa

Answer 16

Borders:

• Superior and Posterior: Superior temporal line
• Anterior: Frontal and Zygomatic bones
• Inferior: Zygomatic arch and infratemporal crest
• Medial (floor): pterion (frontal, parietal, temporal, and sphenoid bones)
• Lateral: Zygomatic arch

Bones of the temporal Fossa:

• Parietal
• Temporal
• Sphenoid
• Frontal
• Pterion: This is not a bone but it is the result of joining and it a weak spot in the temple because the middle meningeal artery runs deep to it. Rupture leads to epidural hematoma

Contents of Temporal Fossa:

1. ​Skin
2. Subcutaneous fascia
3. superficial temporal artery and vein, auriculotemporal nerve, and temporal branch of facial nerve
4. Temporal fascia (dense fascia) boundaries:
   
   1. Superior: superior temporal line
   2. Inferior: Zygomatic arch
5. Temporalis muscle
6. Anterior and posterion deep temporal vein, artery and nerve.
7. Masseter Muscle?

Question 17

Infratemporal fossa

Answer 17

A wedge-shaped area located inferior to the temporal fossa.

Bony Landmarks:

1. Articular Tubercle
2. Mandibular Fossa
3. Postglenoid Tubercle
4. Condyloid Process
5. Ramus and Angle
6. Coronoid Process
7. Maxillary Tuberosity
8. Pterygomaxillary fissue
9. Foramen Ovale and Foramen Spinosum
10. Spine of the Sphenoid bone

Question 18

Contents of the Infratemporal Fossa

Answer 18

• the inferior portion of the temporalis muscle;
• the medial and lateral pterygoid muscles;
• These muscles, along with the masseter, comprise the muscles of mastication;
• the temporomandibular joint (TMJ);
• the sphenomandibular & stylomandibular ligaments;
• the maxillary artery and its branches (3 segments);
• the mandibular division of the trigeminal nerve [CN V3] & its branches;
• sensory and motor branches of the facial nerve [CN VII] - chorda tympani;
• branches of the glossopharyngeal nerve [CN IX];
• the pterygoid plexus of veins;
• the otic ganglion (parasympathetics for parotid gland from CN IX).

Question 19

Muscles of Mastication

Answer 19

1. Lateral Pterygoid muscle
2. Medial Pterygoid muscle
3. Sphenomandibular ligament

All muscles of mastication are innervated by the mandibular nerve or branches of V3.

Question 20

4 Movements of the Jaw

Answer 20

1. Protraction: Anterior movement. Uses lateral pterygoid (most important muscle), assisted by medial pterygoid, some limited contribution from the masseter muscle
2. Retraction: Posterior movement. Posterior fibers of temporalis and Deep fibers of masseter
3. Elevation: Closing. Temporalis, masseter, medial pterygoid
4. Depression: opening. lateral pterygoid, digastric (primary anterior belly), mylohyoid, geniohyoid, infrahyoid, and GRAVITY (very important)

Question 21

Temporomadibular Joint (TMJ)

Answer 21

• It is a synovial (diarthrodial) joint, but unlike other synovial joints it does not contain the usual hyaline cartilage, rather it has a dense irregular connective tissue articular disc.
• It is a “modified” hinge joint

Components:

1. Articular tubercle
2. Madibular fossa
3. Condyle of the mandible
4. articular disc
5. postglenoid tubercle

Two Movements:

1. First movement: lower compartment. Hinge movement (rotational); it occurs first and opens the jaw 1 finger breadth
2. Second movement: upper compartment: Only acts after the hinge movement has completed. sliding/gliding movement along the eminence, leading to full opening (3 finger breadth) and protrusion (sliding forward) of the madible. The articular disc moves with the head of mandible

Ligaments of TMJ:

1. Temporomandibular (lateral) ligament
2. Sphenomandibular ligament
3. Stylomandibular ligament

The superior head of the lateral pterygoid muscle also attaches to the articular disc to aid in its displacement during jaw opening and closing.

Question 22

Maxillary Artery

Answer 22

Question 23

The Mandibular Division of Trigeminal Nerve (V3)

Answer 23

This nerve is a “mixed” nerve carrying both motor and sensory fibers. The mandibular division of CN V exits the middle cranial fossa by passing through the foramen ovale and enters the infratemporal fossa. After giving off small branches, the majority of the mandibular division of the Trigeminal nerve is divided into Anterior and Posterior Divisions, with anterior being primarily motor and posterior being primarily sensory.

Question 24

Anterior Division (Primary Motor Division)

Answer 24

1. Buccal Nerve (Aka Long Buccal Nerve)
   
   1. Exception is that it is sensory to the external cheek and oral cavity.
2. Anterior and Posterior Deep Temporal Nerves. Provide innervation to the temporalis muscle
3. Nerve to the lateral pterygoid muscle
4. Nerve to the masseter muscle

Question 25

Posterior Division (Primary SENSORY Division)

Answer 25

1. Auriculotemporal Nerve: Sensory to the anterior ear and temporal region.
   
   1. Special #1: Lesser petrosal nerve (preganglionic parasympathetic) is derived from the glossopharyngeal nerve (CN IX) and runs to the otic ganglion where it synapses. The postganglionic fibers leabing the otic ganglion join (run with) the auriculotemporal nerve to supply secromotor fibers to the parotid gland. GLOAP
   2. Special #2: The auriculotemporal nerve splits to encircle the middle meningeal artery (before it passes through the foramen spinosum) and then reunites to continue along its course in front of the ear.
2. Lingual Nerve: V3 general sensory innervation from the anterior 2/3rds of the tongue (pain, temp, and touch) travel in the lingual nerve.
   
   1. Special #1: Receives the chorda tympani nerve (CN VII) which exits the petrotympanic fissure to enter the infratemporal fossa and join with the lingual nerve.
      
      1. Chorda tympani supplies special viseral afferent (SVA) fibers for taste from the anterior two-thirds of the tongue
      2. Chorda tympani fibers traveling in he lingual berve also carry preganglionic parasympathetics (GVE) which run to the submandibular ganglion (located immediately adjacent to submandibular gland) to synapse.
      3. Postganglionic fibers from the submandibular ganglion provide the secretomotor innervation to the submandibular and sublingual glands.
3. Inferior Alveolar Nerve: Passes through the mandibular foramen, enters the mandibular canal, and supplies sensory innervation to the mandibular (lower) teeth. It then continues anteriorly and exits the mental foramen at which point it becomes known as the mental nerve.
   
   1. Special #1: Before entering the mandibular foramen, the inferior alveolar nerve gives off a nerve known as the nerve to the mylohyoid. The nerve to the mylohyoid runs anteriorly and inferiorly to supply motor innervation to the anterior belly of th edigastric and mylohyoid muscles.