Anatomy of breathing

Question 1

Effect of posture on breathing

Answer 1

Standing=easy inhalation (gravity) but hard exhalation because liver in way
Lying down=easy exhalation but harder inhalation (spine curvature makes diaphragm contraction more difficult)

Question 2

Intrinsic muscle of chest wall

Answer 2

external intercostal, internal intercostal, subcostal, transversus thoracis

Question 3

Sternocleidomastoid function+innervation

Answer 3

extend head, flexes neck, turns head, inspiratory muscles (keeps chest wall upwards, tonic). Innervated by spinal accessory CNXI

Question 4

Scalene muscle function+innervation

Answer 4

lateral flexion neck, flexion neck, inspiratory muscle. Innervated by cervical plexus

Question 5

Flail chest what

Answer 5

Bit of chest wall isolated by rib fracture. segment free to bellow in and out

Question 6

Accessory muscles and function

Answer 6

pec minor elevates rib 3-5 helping inspiration
serratus anterior-attaches to scapula, pulls lower part
pec major-attaches to rib 6-8 and sternum. Lower part anchored to humerus

Question 7

Muscles in quiet and forced inspiration

Answer 7

quiet-diaphragm, scalene (hold 1st rib stable), intercostal
forced-scalene, sternocleidomastoid, intercostal, pec muscle, serratus anterior, erector spinae (straighten back for efficient elevation), quadratus lumborum (floating rib stabilisation)

Question 8

Muscles in quiet and forced expiration

Answer 8

quiet-elastic recoil of lung+gravity, intercostal, diaphragm relaxation
forced-abdominal muscle depress ribs+compress abdomen+elevate diaphragm, intercostal, latissimus dorsi