Skeletal muscles part 2

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Skeletal muscles part 2
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A few review questions

• Muscles of the face originate in the skull. Where
  do they insert?
• The skin
• What is the strongest muscle associated with
  chewing?
• Masseter
• What muscle action allows you to whistle?
• Buccinator
• What muscle closes the eye?
• Orbicularis oculi

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Muscles of the spine

• Covered by superfical back muscles
• Erector spinae is chief extensor of vertebral
  column
• Opposed by quadratus lumborum and various
  abdominal muscles

Iliocostalis, spinalis, longissimus
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Muscles of the trunk

• Protect abdominal viscera
• Move vertebral column
• Assist in breathing (expiration)
• Assist in urination and defection
• Assist in childbirth

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Muscles of trunk, continued

• Muscles associated with breathing
• Diaphragm
• External and internal intercostals
• Other muscles become involved with forced
  breathing

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Diaphragm separates thorax and abdomen

• Important for breathing
• Returning venous blood to the heart
• Three major openings
• Aortic hiatus
• Esophageal hiatus
• Caval opening

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Perineum floor of pelvic cavity

• Levator ani
• Pubococcygeis, iliococcygeus
• Coccygeus
• Support organs in pelvic cavity
• Resist pressure from coughing, urination, etc.
• Sphincters

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Female and male perimeum
Deep muscles are the same
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Appendicular muscles

• Shoulders and upper limbs
• Pectoral girdle anterior and posterior thoracic
  muscles
• Pelvic girdle and lower limbs

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Muscles of the neck, shoulder, and back
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Muscles that position the pectoral girdle
Muscles originate on axial skeleton and insert on
clavicle or scapula
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Muscles that move the arm

• Anterior

• Posterior

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Range of movement at shoulder

• Elevation of scapula- shrugging
• Depression- pull-up
• Abduction-push-up
• Adduction- pulling something toward you
• Upward rotation- lifting arm past horizontal
• Downward rotation- supporting weight with hands
• Deep muscles (rotator cuff) stabilize shoulder

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Muscles that move the arm

• Deltoid, supraspinatus-abduction
• Rotator cuff-subscapularis, teres major (medial)
  infraspinatus, teres minor (lateral)
• Latissimus dorsi-extension, adduction
• Pectoralis major- flexion, adduction

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Muscles of the upper limb

• Most muscles that insert on the forearm and wrist
  originate on the humerus
• Biceps brachii and triceps brachii originate on
  scapula
• Brachoradialis is opposed on triceps brachii
• Flexors of wrist are on anterior and medial
  surfaces of forearm extensors are on posterior
  and lateral surface
• Flexor digitorum and extensor digitorum muscles
  perform flexion and extension of fingers

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Muscles that move arm and hand

• Arm

• Forearm

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Trunk and proximal limbs
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Muscles of the hip and lower limb

• Muscles that move the thigh (p. 298)
• Gluteal group
• Lateral rotator group
• Adductor group
• Iliopsoas group
• Muscles that move the leg (p. 303)(flexors,
  extensors)
• Muscles that affect the ankles and feet (p. 312)
  (flexors, extensors, intrinsic)

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Muscles that move the thigh
Gluteus maximus Extends hip
Gluteus minimus Abducts thigh
Adductors Adduct thigh and flex hip
Gracilis Adducts thigh and flexes knee
Iliopsoas Flexes hip
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Muscles that move the leg (anterior)
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Muscles that move the leg (posterior)
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Muscles that move the leg (lateral)

• lateral

• Major groups

• Flexors of knee
• Biceps femoris, semimembranosus, semitendinosus,
  sartorius, popliteus
• Extensors of knee
• Quadriceps (rectus femoris, vastus intermedius,
  vastus lateralis, vastus medialis)

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Muscles that move the leg
Hamstring muscles (biceps femoris, semimembranosus, semitendinosus) Flex knee
Sartorius Flexes hip and knee
Quadriceps muscles (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius) Extensors of knee
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Muscles that move the foot and toes
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Organization of leg muscles

• Muscles are in compartments, superificial and
  deep
• Anterior- extension
• Posterior- flexion
• Medial- adductor
• Lateral- eversion of foot, flexion (ankle)

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Compartments

• Formed by fascia allow independent movement

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Review compartments of upper limb (p. 314, 315)

• arm

• forearm

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Review compartments of lower limb (p. 316)
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Summary

• Extrinsic and intrinsic muscles in hand are
  important for fine motor skills
• Muscles that move spine are complex in
  organization
• Muscles that move femur and large and powerful
• Compartments are associated with types of
  movement
• Intrinsic muscles of foot are limited to support
  and movement