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Muscle OIA and Actions in Anatomy & Physiology

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Terms in this set (31)

  • What does OIA stand for in muscle anatomy?
    Origin, Insertion, and Action.
  • Define the Origin of a muscle.
    The relatively fixed end of a muscle; usually the proximal attachment.
  • Define the Insertion of a muscle.
    The movable end of a muscle; usually the distal attachment.
  • What is the Action of a muscle?
    The movement produced when a muscle contracts.
  • Buccinator muscle OIA and action
    Origin: Alveolar processes of maxilla and mandible. Insertion: Lips (blends with orbicularis oris). Action: Compresses cheeks; keeps food between teeth.
  • Orbicularis oris muscle OIA and action
    Origin: Maxilla and mandible indirectly. Insertion: Lips. Action: Compresses and purses lips.
  • Risorius muscle OIA and action
    Origin: Connective tissue covering the cheek. Insertion: Angle of mouth. Action: Draws corners of mouth laterally.
  • Zygomaticus major muscle OIA and action
    Origin: Zygomatic bone. Insertion: Angle of mouth. Action: Elevates and retracts corner of mouth.
  • Zygomaticus minor muscle OIA and action
    Origin: Zygomatic bone. Insertion: Upper lip. Action: Elevates the upper lip.
  • Orbicularis oculi muscle OIA and action
    Origin: Orbital margin. Insertion: Eyelid. Action: Closes eyelid.
  • Frontalis muscle OIA and action
    Origin: Epicranial aponeurosis. Insertion: Skin of eyebrows and forehead. Action: Elevates eyebrows and wrinkles forehead.
  • Occipitalis muscle OIA and action
    Origin: Occipital bone and mastoid process of temporal bone. Insertion: Epicranial aponeurosis. Action: Tenses and retracts scalp.
  • Platysma muscle OIA and action
    Origin: Between 2nd costal cartilage and acromion region. Insertion: Mandible and skin of cheek/lower face. Action: Depresses mandible and lower lip; tenses skin of neck.
  • Superior rectus muscle OIA and action
    Origin: Common tendinous ring around optic canal/superior orbital fissure. Insertion: Superior surface of eyeball. Action: Elevates the eye (looks up).
  • Inferior rectus muscle OIA and action
    Origin: Common tendinous ring around optic canal/superior orbital fissure. Insertion: Inferior surface of eyeball. Action: Depresses the eye (looks down).
  • Lateral rectus muscle OIA and action
    Origin: Common tendinous ring around optic canal/superior orbital fissure. Insertion: Lateral surface of eyeball. Action: Abducts the eye (looks laterally).
  • Medial rectus muscle OIA and action
    Origin: Common tendinous ring around optic canal/superior orbital fissure. Insertion: Medial surface of eyeball. Action: Adducts the eye (looks medially).
  • Superior oblique muscle OIA and action
    Origin: Common tendinous ring around optic canal/superior orbital fissure. Insertion: Posterior to superior rectus on eyeball. Action: Depresses and abducts eye; rotates it medially.
  • Inferior oblique muscle OIA and action
    Origin: Floor of orbit on maxilla. Insertion: Posterior, lateral surface of eyeball. Action: Elevates and abducts eye; rotates it laterally.
  • General OIA for extrinsic eye muscles
    Origin: Around optic canal and superior orbital fissure; inferior oblique originates on maxilla. Insertion: Surface of eyeball. Action: Position and move the eye.
  • Masseter muscle OIA and action
    Origin: Zygomatic arch. Insertion: Lateral surface of mandibular ramus. Action: Elevates mandible and closes jaw.
  • Temporalis muscle OIA and action
    Origin: Temporal lines/temporal fossa. Insertion: Coronoid process and lateral surface of mandibular ramus. Action: Elevates and retracts mandible.
  • Medial pterygoid muscle OIA and action
    Origin: Medial surface of lateral pterygoid plate. Insertion: Medial surface of mandibular ramus. Action: Elevates mandible and helps move it side-to-side.
  • Lateral pterygoid muscle OIA and action
    Origin: Superior head: greater wing of sphenoid; inferior head: lateral surface of lateral pterygoid plate. Insertion: Mandible at condylar process. Action: Opens jaw and moves mandible side-to-side.
  • Sternocleidomastoid (SCM) muscle OIA and action
    Origin: Manubrium of sternum and medial clavicle. Insertion: Mastoid process of temporal bone. Action: Both sides contract: flex neck; one side contracts: rotates head opposite side and tilts head same side.
  • Scalenes muscle OIA and action
    Origin: Transverse processes of cervical vertebrae. Insertion: Superior surfaces of ribs 1 and 2. Action: Flex neck bilaterally; laterally flex neck unilaterally; elevate ribs during inhalation.
  • Iliocostalis muscle OIA and action
    Origin: Iliac crest, sacral crest, lumbar spinous processes. Insertion: Transverse processes of middle/inferior cervical vertebrae and ribs. Action: Extends spine bilaterally; laterally flexes spine same side unilaterally.
  • Longissimus muscle OIA and action
    Origin: Transverse processes of lower thoracic and upper lumbar vertebrae. Insertion: Along spine and mastoid process. Action: Extends spine; helps extend head and neck.
  • Spinalis muscle OIA and action
    Origin: Spinous processes of inferior thoracic and superior lumbar vertebrae. Insertion: Spinous process of axis (C2) and other upper vertebrae. Action: Extends the spine.
  • What are the three muscles of the erector spinae group?
    Iliocostalis (lateral), longissimus (middle), and spinalis (medial). Main action: extending the spine.
  • Quadratus lumborum muscle OIA and action
    Origin: Iliac crest. Insertion: Inferior margin of rib 12 and transverse processes of lumbar vertebrae L1–L4. Action: Depresses ribs bilaterally; laterally flexes spine same side unilaterally.