lecture 9

Question 1

Occipitofrontalis or epicranius muscle

Answer 1

• Frontal belly.
• Occipital belly.
• Anterior, superior and posterior auricularis

Question 2

Periorbital muscles

Answer 2

orbicularis oculi (orbital, palpebral and lacrimal parts).
corrugator supercilli.

Question 3

Perinasal muscles

Answer 3

Nasalis (transverse and alar parts).
Procerus.
Depressor septi

Question 4

Peribucalis or perioralis muscles

Answer 4

Orbicularis oris.
Levator labii superioris aleaque naris.
Levator labii superioris.
Zygomaticus minor.
Zygomaticus major.
Rizorius.
Levator anguli oris.
Buccinator.
Depressor labii inferioris.
Depressor anguli oris.
Mentalis.

Question 5

Masticatory or chewing muscles

Answer 5

• Masseter muscle
• Temporalis muscle
• Medial pterygoid muscle
• Lateral pterygoid muscle

Question 6

a broad musculofibrous layer covers the dome of the skull, from the nuchal lines to the eyebrows. The fibrous part between the muscular bellies is the galea aponeurotica or epicranial aponeurosis.

Answer 6

Occipitofrontalis or epicranius muscle:

Question 7

surround the natural orifices and act as sphincters and dilators, which close and open the orifices respectively.

Answer 7

Muscles of the facial expression.

Question 8

Masseter (O, IN, inn, M/A)

Answer 8

o: Inferior zygomatic arch
IN: ramus mandible angle.
INN: CN V3
M/A: Elevates and protrudes mandible, closed the jaw

Question 9

Temporalis (O, IN, inn, M/A)

Answer 9

O: Temporal fossa and the deep surface of the temporal fascia
IN: coronoid process and ramus of mandible
INN: CN V3
M/A: Elevates mandible closing jaws;

Question 10

Medial pterygoid (O, IN, inn, M/A)

Answer 10

O: Deep head: lateral pterygoid plate and palatine bones.
Superficial head: tuberosity of maxilla.
IN: Medial surface of ramus of mandible, inferior to Mandibular foramen
INN: CN V3
M/A: Acting together, they help to elevate mandible, closing jaws; they help to protrude mandible; acting alone they protrude side of jaw; acting alternately they produce a grinding motion.

Question 11

Lateral pterygoid (O, IN, inn, M/A)

Answer 11

O:  greater wing of sphenoid bone
Inferior head: lateral pterygoid plate.
IN: Neck of mandible (pterygoid fossa)
INN: CN V3
M/A:  they produce side-to- side movement of mandible.