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10-1
Muscular System II:Head, Neck and Trunk Muscles
Lecture 10
10-2
Muscles of the Neck
Fig. 11.8
Anterolateral Neck Muscles• Sternocleidomastoid
• One or both may contract
Posterior Neck Muscles• Semispinalis capitis, Splenius capitis, Trapezius
Fig. 11.10
MylohyoidDigastric
Anterior bellyPosterior belly
Sternocleidomastoid
Trapezius
GeniohyoidHyoid bone
Clavicle
Superficial Deep
Semispinalis capitis (cut)Splenius capitis (cut)
Semispinalis capitisSternocleidomastoid
Splenius capitis
Levator scapulae
Deep Deeper
10-3
Muscles of Facial Expression
Fig. 11.2Elevators• Levator labii superioris, Occipitofrontalis, ZygomaticusDepressors• Depressor labii inferioris, Platysma
Other actions• Buccinator, Orbicularis oculi, Orbicularis oris
Superficial Deep
Frontal belly of occipitofrontalis
Orbicularis oculi
Levator labii superiorisZygomaticus
Depressor labii inferioris
PlatysmaPlatysma
Depressor labii inferioris
Orbicularis oris
ZygomaticusLevator labii superioris
Orbicularis oculi
Temporalis
Masseter
Orbicularis orisBuccinator
10-4
Muscles of Facial Expression
Elevators• Levator labii superioris, Occipitofrontalis, ZygomaticusDepressors• Depressor labii inferioris, Platysma
Other actions• Buccinator, Orbicularis oculi, Orbicularis oris
10-5
Muscles of Facial Expression
Fig. 11.3
10-6
Muscles of Mastication
Major Muscles• Temporalis and Masseter
Temporalis:Origin - temporal lines of parietalInsertion - coronoid processMasseter:Origin - zygomatic archInsertion - lateral side of mandible
Fig. 11.5
10-7
Hyoid Muscles
Actions of hyoid muscles• move mandible and hyoid
Fig. 11.8
MylohyoidDigastric
Anterior bellyPosterior belly
GeniohyoidHyoid bone
Clavicle
Superficial Deep MylohyoidDigastricAnterior bellyPosterior belly
10-8
Trunk Muscles - Muscles of Vertebral Column
Fig. 11.11
Superficial:• Erector spinae (Iliocostalis, Longissimus, Spinalis), Semispinalis, and MultifidusDeep:• InterspinalisActions:• Extension, rotation, lateral flexion of the back
Multifidus
IliocostalisLongissimus
Spinalis Erector spinae
Deep Deeper
Semispinalis
10-9
Muscles of Respiration
Fig. 11.13
Inspiration:• Diaphragm is primary muscle of inspiration (depresses floor of thoracic cavity)• External intercostals elevate ribs
Expiration:• Internal intercostals depress ribs
10-10
Review Question
Axial muscles of the spine control the position of the(a) Head, neck, and pectoral girdle(b)Head, neck, and vertebral column(c) Vertebral column only(d)Vertebral column and pectoral and pelvic girdles
10-11
Points to Remember• Muscles of the face move the skin rather than a
joint allowing a vast range of facial expressions• Muscles that move the mandible are also known as
muscles of mastication because they provide the chewing action
• Complexity of muscles of the vertebral column required for flexibility and maintaining posture
10-12
Questions?
