Muscular System

• Types of Muscle & Functions:

  • Skeletal
  • Cardiac
  • Visceral
• Skeletal - voluntary
• Cardiac & Visceral - involuntary
• Skeletal


  Mostly movement of bones and body parts and stabilizing body positions.
• Cardiac 


  HEART only and develops pressure for arterial blood flow.
• Visceral


  This term will be used instead of smooth in terms of location.
• Visceral


  Grouped in walls of hollow organs.
• Visceral


  Sphincters regulate flow in tubes.
• Visceral


  Maintain the diameter of tubes and move material in GI tract and reproductive organs.
• Skeletal Muscle Functions:

  • Produce movement
  • Maintain posture
  • Stabilize joints
  • Generate heat
• Parts of a Skeletal Muscle:

  • Origin
  • Insertion
  • Belly
• Origin - most stationary end, and it is located where the tendon attaches.
• Insertion - the most mobile end, and it is located where the tendons insert.
• Belly - middle fleshy part.
• Action - the motion or function of the muscle.
• Flexors — extensors
• Abductors — adductors
• Prime mover or agonist - major actor and the action of a single muscle or group of muscles.
• Antagonist - the one with opposing effect.
• Synergists - help prime mover or agonist.
• Fixators - stabilize the origin of prime mover or agonist.
• Direction of muscle fibers relative to the middle of the body / Y axis:

  • rectus
  • oblique
  • transverse
• rectus - straight / parallel to the midline of the body.
• oblique - diagonal to the midline
• transverse - perpendicular to the midline
• Specific location in the body:

  • abdominis
  • brachii
  • femoris
  • digitorum
  • hallucis
  • spinalis
  • oris
  • oculi
  • palmaris
  • pollicis
  • carpi
  • scapularis
• • abdominis = abdomen
  • brachii = arms
  • femoris = femur
  • digitorum = finger/toe
  • hallucis = great toe
  • spinalis = spine
  • oris = mouth
  • oculi = ocular/eye
  • palmaris = palm
  • pollicis = thumb
  • carpi = carpal/wrist
  • scapularis = scapula
• Number of attachments:

  • 2 attachments
  • 3 attachments
  • 4 attachments
• • 2 attachments = biceps
  • 3 attachments = triceps
  • 4 attachments = quadriceps
• Origin and insertion:

  • Sternocleidomastoid
• Sternocleidomastoid:

  • Origin = sternum and clavicle
  • Insertion = mastoid process
• Shape:

  • deltoid
  • orbicularis
  • serratus
  • trapezius
• • deltoid = triangular
  • orbicularis = circlular
  • serratus = saw-toothed
  • trapezius = trapezoid
• Size:

  • longus
  • brevis
  • minimus
  • medius
  • maximus
  • major
  • minor
• • longus = long
  • brevis = short
  • minimus = smallest/least
  • medius = medium
  • maximus = largest/greatest
  • major = larger
  • minor = smaller
• Type of action:

  • abductor
  • adductor
  • flexor
  • extensor
  • levator
  • depressor
• • abductor = pulls the limb away from the midline
  • adductor = pulls the limb closer to the midline
  • flexor = decreases the angle at a joint (bend)
  • extensor = increases the angle at a joint (straighten)
  • levator = raises a part
  • depressor = lowers a part
• In relation to the muscle to the bone or body part:

  • supra
  • infra
  • lateralis
  • medialis
  • internal
  • external
  • superior
  • inferior
  • dorsi
  • anterior
• • supra = above or over
  • infra = below
  • lateralis = at the side
  • medialis = in the middle
  • internal = inside
  • external = outside
  • superior = above or over
  • inferior = below
  • dorsi = the back
  • anterior = the front
• smallest muscle = Stapedius