#muscle actions

[drawittoknowitmedical]

Gross Anatomy Glossary: Muscle Actions

Flexor or Extension? Adduction or Abduction? Use this flashcard for a quick review, or watch the full tutorial to learn more about muscle actions and nomenclature! 

[nursingthehudson]

Quick Guide: Muscles of Respiration

Muscle

Action

Origin

Insertion

Innervation

Serratus posterior superior

Elevates ribs during forced inspiration

O: Spinous processes of C7–T3 vertebrae

I: Lateral borders of ribs 2–5

Thoracic spinal nerves

Serratus posterior inferior

Depresses ribs during forced expiration

O: Spinous processes of T11–L3 vertebrae

I: Inferior borders of ribs 8–12

Thoracic spinal nerves

Scalene muscles

Elevate 1st and 2nd ribs during forced inspiration when neck is fixed

O: Transverse processes of cervical vertebrae

I: Superior surface of 1st and 2nd ribs

Cervical spinal nerves

External intercostals

Elevate ribs during quiet and forced inspiration

O: Inferior border of superior rib

I: Superior border of inferior rib

Thoracic spinal nerves

Internal intercostals

Depresses ribs during forced expiration

O: Superior border of inferior rib

I: Inferior border to superior rib

Thoracic spinal nerves

Transversus thoracis

Depresses ribs during forced expiration

O: Posterior surface of xiphoid process and inferior region of sternum

I: Costal cartilages 2–6

Thoracic spinal nerves

Diaphragm

Contraction causes flattening of diaphragm (moves inferiorly) during inspiration and thus expands thoracic cavity; increases pressure in abdominopelvic cavity

O: Inferior internal surface of ribs 7–12; xiphoid process of sternum and costal cartilages of inferior 6 ribs; lumbar vertebrae

I: Central tendon

Phrenic nerves (C3–C5)