naming facial expression, head, neck

• Prime movers


  Provide the major force for producing a specific movement
• Antagonists


  Oppose or reverse a particular movement
• Synergists


  Add force to a movement<|>Reduce undesirable or unnecessary movement
• Fixators


  Synergists that immobilize a bone or muscle's origin
• Factors used in naming skeletal muscles

  • Location
  • Shape
  • Relative size
  • Direction of fibers or fascicles
  • Number of origins
  • Location of attachments
  • Action
• Muscle shapes


  • Circular (orbicularis oris)
  • Convergent (pectoralis major)
  • Parallel (sartorius)
  • Unipennate (extensor digitorum longus)
  • Fusiform (biceps brachii)
  • Bipennate (rectus femoris)
  • Multipennate (deltoid)
• Muscle mechanics: Arrangement of fascicles

  • Circular
  • Convergent
  • Parallel
  • Fusiform
  • Pennate
• Three main functions of the muscular system

  • Movement
  • Posture maintenance
  • Homeostasis
• Muscles of the head

  • Muscles of facial expression
  • Muscles of mastication and tongue movement
• Muscles of facial expression

  Insert into the skin<|>Important in nonverbal communication<|>All innervated by cranial nerve VII (facial nerve)
• Epicranius (occipitofrontalis) – covers the upper part of the cranium and consists of two muscular parts: Frontalis – lies over the frontal bone, Occipitalis – lies over the occipital bone
• Galea aponeurotica — cranial aponeurosis, broad, tendinous band connecting above muscles and extends over the cranium like a cap
• Orbicularis oculi – a ring-like band of muscle, called a sphincter muscle, that surrounds the eye
• Orbicularis oris – a sphincter muscle that encircles the mouth
• Buccinator muscle – located in the wall of the cheek; fibers directed forward from the bones of the jaws to the angle of the mouth
• Zygomaticus (major and minor) – extend from the zygomatic arch downward to ward the corner of the mouth
• Platysma - thin, sheetlike muscle whose fibers extend from the chest upward over the neck to the face
• Muscles of mastication and tongue movement

  • Temporalis
  • Masseter
  • Medial pterygoid
  • Lateral pterygoid
  • Styloglossus
  • Hyoglossus
  • Genioglossus
• Masseter – thick, flattened muscle that can be felt just in front of the ear when the teeth are clenched; fibers extend from the zygomatic arch to the mandible
• Temporalis – a fan-shaped muscle located on the side of the skull above and in front of the ear
• Medial pterygoid- extends back and downward from the sphenoid, palatine and maxillary bones to the ramus of the mandible
• Lateral pterygoid – fibers extend forward from the region just below the mandibular condyle to the sphenoid bone
• Muscles that move the head and vertebral column

  • Sternocleidomastoid
  • Splenius capitis
  • Semispinalis capitis
  • Erector spinae
• Sternocleidomastoid – a long muscle in the side of the neck that extends upwards from the thorax to the base of the skull behind the ear
• Splenius capitis – a broad, straplike muscle in the back of the neck; connects the base of the skull to the vertebrae in the neck and upper thorax
• Semispinalis capitis – a broad, sheetlike muscle extending upward from the vertebrae in the neck and thorax to the occipital bone
• Erector spinae – run longitudinally along the back, with origins and insertions in many places on the axial skeleton; can be subdivided into lateral, intermediate and medial groups
• What students must be able to do for major skeletal muscles

  • Identify
  • Describe
  • Provide the action (movement)
  • Identify the origin and insertion bones