Skeletal Muscles: Head, Neck and Trunk Muscles

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Skeletal MusclesHead, Neck and Trunk Muscles
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Muscles of the Neck
Fig. 11.8
Fig. 11.10

• Posterior Neck Muscles
• Trapezius

• Anterolateral Neck Muscles
• Sternocleidomastoid
• One or both may contract

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Muscles of Facial Expression
Frontal belly of occipitofrontalis
Temporalis
Orbicularis oculi
Levator labii superioris
Orbicularis oculi
Levator labii superioris
Zygomaticus
Zygomaticus
Masseter
Buccinator
Orbicularis oris
Orbicularis oris
Depressor labii inferioris
Depressor labii inferioris
Platysma
Platysma
Fig. 11.2

• Elevators
• Levator labii superioris, Occipitofrontalis,
  Zygomaticus
• Depressors
• Depressor labii inferioris, Platysma

• Other actions
• Buccinator, Orbicularis oculi, Orbicularis oris

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Muscles of Facial Expression

• Elevators
• Levator labii superioris, Occipitofrontalis,
  Zygomaticus
• Depressors
• Depressor labii inferioris, Platysma

• Other actions
• Buccinator, Orbicularis oculi, Orbicularis oris

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Muscles of Facial Expression
Fig. 11.3
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Muscles of Mastication
Fig. 11.5
Temporalis Origin - temporal lines of
parietal Insertion - coronoid process Masseter Or
igin - zygomatic arch Insertion - lateral side of
mandible

• Major Muscles
• Temporalis and Masseter

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Hyoid Muscles
Fig. 11.8
Actions of hyoid muscles move mandible and hyoid
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Trunk Muscles - Muscles of Vertebral Column
Fig. 11.11

• Superficial
• Erector spinae (Iliocostalis, Longissimus,
  Spinalis), Semispinalis, and Multifidus
• Deep
• Interspinalis
• Actions
• Extension, rotation, lateral flexion of the back

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Muscles of Respiration

• Inspiration
• Diaphragm is primary muscle of inspiration
  (depresses floor of thoracic cavity)
• External intercostals elevate ribs
• Expiration
• Internal intercostals depress ribs

Fig. 11.13
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Trapezius

• Extend Head, Adduct, Elevate or Depress Scapula

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Latissimus Dorsi

• Extend, Adduct Rotate Arm Medially

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Deltoid

• Abduct, Flex Extend Arm

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Pectoralis Major

• Flexes, adducts rotates arm medially

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Biceps Brachii

• Flexes Elbow Joint

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Triceps Brachii

• Extend Elbow Joint

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Rectus Abdominus

• Flexes Abdomen

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External Oblique

• Compress Abdomen

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Forearm Muscles

• Flexor carpiFlexes wrist
• Extensor carpiExtends wrist
• Flexor digitorumFlexes fingers
• Extensor digitorumExtends fingers
• PronatorPronates
• SupinatorSupinates

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Gluteus Maximus

• Extends Rotates Thigh Laterally

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Rectus Femoris

• Flexes Thigh, Extends Lower Leg

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Gracilis

• Adducts and Flexes Thigh

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Sartorius

• Flexes Thigh, Rotates Thigh Laterally

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Biceps Femoris

• Extends Thigh Flexes Lower Leg

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Tibialis Anterior

• Dorsiflexes and Inverts Foot

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Gastrocnemius

• Plantar Flexes Foot Flex Lower Leg

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Big Picture

• Function of all three major types of muscle
  (skeletal, cardiac, smooth) is integral to
  function of the entire body
• All three types of muscle tissue provide the
  movement necessary for survival
• Relative constancy of the bodys internal
  temperature is maintained by waste heat
  generated by muscle tissue