Chapter 5 The Muscular System 175
Figure 5.15 Major muscles of the head and neck. Which muscle is referred to as the “smiling” muscle?
Figure 5.16 Muscles of the Head and Neck
Muscle Location Primary Functions
Facial Muscles
Frontalis forehead; connects cranium to skin
above eyebrows
raises eyebrows, wrinkles forehead
Orbicularis oculi encircles the eyes closes eyes, enables squinting
Nasalis
nose modifi es size of nostrils
Orbicularis oris encircles mouth closes lips, produces kissing motion
Zygomaticus connects cheekbones to corners of
mouth
the “smiling” muscle
Platysma front and sides of neck pulls corners of mouth down, opens
mouth wide
Chewing Muscles
Masseter connects zygomatic bone to mandible closes the jaw
Temporalis fan-shaped muscle over temporal bone assists masseter with closing jaw
Neck Muscles
Sternocleidomastoid sides of neck fl exion of head, rotation of head toward
opposite side of contraction
Sternocleidomastoid
Frontalis
Orbicularis
oculi
Nasalis
Platysma
Zygomaticus
Orbicularis oris
Temporalis
Masseter