Muscles Of Breathing

Question 1

Diaphragm

Answer 1

Origin: cartilage of ribs 7-12, xiphoid process, lumbar vertebrae
Insertion: anterior longitudinal ligament (vertebral column)
Action: expands thoracic cavity, compresses abdominal cavity
Innervation: phrenic nerve (c3-5)

Question 2

Internal intercostals

Answer 2

Origin: superior border of ribs 2-12
Insertion: inferior of ribs above (1-11)
Action: depresses ribs (forced expiration)
Innervation: intercostal nerves

Question 3

External intercostals

Answer 3

Origin: lower border of ribs 1-11
Insertion: upper border of ribs below (2-12)
Action: elevates ribs (normal inspiration)
Innervation: intercostal nerves