Muscular System

• Frontalis:

  • Draws scalp anteriorly
  • Raises eyebrows
  • Wrinkles forehead
• Occipitalis:

  • Draws scalp posteriorly
• Temporalis:

  • For mastication
  • Elevates mandible and closes jaw
• Orbicularis oculi:

  • Closes eye
• Orbicularis oris:

  • Closes mouth
  • Puckers the lips
• Buccinator:

  • For mastication
  • Compresses cheeks (as in blowing or whistling)
• Masseter:

  • For mastication
  • Raises jaw
• Sternocleidomastoid:

  • Flex head
  • Rotates head toward opposite shoulder
  • Allows bending of the neck and turning or tilting the head
• Levator labii superioris:

  • Elevates upper lip
• Trapezius:

  • Extends head
  • Rotates scapula
• Zygomaticus major:

  • Raises angle of mouth (as in smiling)
• Zygomaticus minor:

  • Elevates upper lip
  • Exposes maxillary teeth
• Depressor anguli oris:

  • Depresses angle of mouth
• Medial pterygoid:

  • Raises jaw
• Lateral pterygoid:

  • Lowers jaw
• Platysma:

  • Depresses mandible
• Levator scapula:

  • Raises scapula
• Rhomboideus:

  • Retracts scapula
• Erector spinae (Iliocostalis, Longissimus, Spinalis):

  • Maintains erect posture of vertebral column
• Latissimus dorsi:

  • Extends shoulders
  • Adducts arm
• Gluteus medius:

  • Abducts thigh
  • Medially rotates thigh
• Gluteus maximus:

  • Extension at hip joint
• Infraspinatus:

  • Extends and rotates arm
• Teres major:

  • Extends shoulders
• Supraspinatus:

  • Abducts arm
• Scalenes (Scalenus anterior, Scalenus medius, Scalenus posterior):

  • Raise the ribs
  • Expand thorax
• External intercostals:

  • Expand thorax
• Internal intercostals:

  • Compress thorax
• Pectoralis major:

  • Controls movement of the arm
  • Adducts and medially rotates arm
• Pectoralis minor:

  • Depresses scapula
• Serratus anterior:

  • Protracts scapula
• External abdominal obliques:

  • Compresses abdomen
• Internal abdominal obliques:

  • Compresses abdomen
• Rectus abdominis:

  • Flexes vertebral column
  • Increases pressure of abdomen
• Transverse abdominal:

  • Compresses abdomen
• Deltoid:

  • Abducts the arm
  • Flexes and extends shoulders
• Biceps brachii:

  • Flexes elbow
  • Supinates arm
• Brachialis:

  • Flexes arm
• Brachioradialis:

  • Flexes forearm (synergist of brachialis)
• Extensor carpi radialis longus:

  • Extends and abducts wrist