module 5 part 1

• Muscles


  Organs that contract to produce movement
• Muscular system


  • Includes all the skeletal or striated muscles within the body
• Classifications of muscles


  • Skeletal muscle
  • Smooth and cardiac muscle
• Skeletal muscle


  • Composed of organization of structures: Epimysium, Perimysium, Endomysium
• Epimysium


  Connective tissue around an entire muscle and the deep fascia of the muscle
• Perimysium


  Shift surrounding the bundles of muscle fiber
• Endomysium


  Connective tissue between individual muscle fibers
• Belly


  Thick fleshy central part of the muscle tissue
• Origin


  The less movable; in the limbs, it is the proximal attachment
• Insertion


  The more movable part; in the limb, it is the more distal attachment
• Fleshy attachment


  The apparent direct attachment of muscle to bone
• Tendinous attachment


  The dense connective tissue connecting the spindle or pennate muscle to bone
• Aponeurotic attachment


  The flat, tendinous sheet associated with flat muscles such as those of the abdominal wall
• Extrinsic muscles


  Run from one region of the body to another and alter the position of the whole part
• Intrinsic muscles


  Lie completely within one region of the body where they have their origin and insertion
• Extensor


  Muscles that straighten a limb or increase the joint angle
• Azygous muscles are not paired
• Braciocephalicus (3 muscles)


  • Action: to advance the limb; to extend the shoulder and draw the neck and head to the side
  • Innervation: accessory nerve, and ventral branches of cervical nerves
• Sternocephalicus (4 muscles)


  • Origin: the first sternebrae or manubrium
  • Insertion: the mastoid part of the temporal bone and the nuchal crest of the occipital bone
  • Action: to draw head and neck to the side
  • Innervation: accessory nerve and the ventral branches of cervical nerves
• Omotransversarius


  • Attachment: the distal end of the spine of scapula; cranially, the wing of the atlas
  • Action: to advance the limb or flex the neck laterally
  • Innervation: accessory nerve
• Trapezius (divided into 2 muscles)

  • Origin: the median raphe of the neck and the supraspinous ligament from the level of the third cervical vertebra to the level of the ninth thoracic vertebra
  • Insertion: the spine of the scapula
  • Action: to elevate and abduct the forelimb
  • Innervation: accessory nerve
• Latissimus dorsi


  • Origin: the thoracolumbar fascia from the spinous processes of the lumbar and the last seven or eight thoracic vertebrae; a muscular attachment to the last two or three ribs
  • Insertion: the teres major tuberosity of the humerus and the teres major tendon
  • Action: to draw the free limb caudally as in digging; to flex the shoulder
  • Innervation: thoracodorsal nerve (C7, C8, T1)
• Serratus ventralis


  • Origin: the transverse processes of the last of the five cervical vertebrae and the first seven or eight ribs ventral to their middle
  • Insertion: the dorsomedial third of the scapula (serrated face)
  • Action: to support the trunk and depress the scapula
  • Innervation: ventral branches of the cervical nerve and the long thoracic nerves
• Rhomboideus (3 muscles)


  • Origin: the nuchal crest of the occipital bone; the median fibrous raphe of the neck; the spinous processes of the first seven thoracic vertebrae
  • Insertion: the dorsal border and adjacent surfaces of the scapula
  • Action: to elevate the forelimb and draw the scapula against the trunk
  • Innervation: ventral branches of cervical and thoracic nerves
• Abductor


   muscles that moves a part of the body from midline
• Adductor


  muscles that moves a part toward the midline
• Flexor


  muscles that bends a limb at its joint or decreases the joint angle
• Epimysium


  Connective tissue around an entire muscle and the deep fascia of the muscle