Sternocleidomastoid

Cards (5)

  • O (origin):
    • Sternal head: upper surface manubrium
    • Clavicular head: upper surface medial 1/3 clavicle
    A) sternocleidomastoid
  • R (direction):
    • Upwards
    A) sternocleidomastoid
  • I (insertions):
    • Mastoid process of skull
    A) sternocleidomastoid
  • A (actions):
    • Assists with respiration
    • Bilateral action: neck flexion (posterior fibres may also extend head on neck at atlantooccipital joint)
    • Unilateral action: ipsilateral lateral flexion and contralateral rotation
    A) sternocleidomastoid
  • NS (nerve supply):
    • Motor: Spinal part of accessory nerve (cranial nerve 11)
    • Sensory: Ventral rami C2, C3
    A) sternocleidomastoid