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Thorax and Respiratory system


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Thorax and thoracic cavity location
superior portion of the trunk
located between the neck and abdomen
Thoracic Cage Constituents
12 prs. Ribs (true, false, floating)
Costal Cartilages
12 Thoracic Vertebrae
Thoracic Wall
...and a few nerves...
Muscles of Respiration
Internal/external intercostals
External Intercostal muscles
-located between ribs, intercostal space
-run inferomedially
-function to elevate ribs, increasing lateral and anteroposterior spaces of thoracic cavity to accomodate air.
-Nerve: intercostal nerves
Internal intercostal muscles
-Location: intercostal space
-Function: Depress ribs, thereby decreasing thoracic cavity space, for forced expiration of air.
-Nerve: intercostal
Origin: xiphoid process, lower 6 ribs, upper two lumbar vertebra
Insertion: Central tendon, forms a wide musculofibrous sheet btwn thoracic and abdominal cavities.
Innervation: phrenic, some intercostals.
Function: aids in inspiration of air
Accessory respiratory muscles
Inspiration: Scalene, Sternocleidomast, pectoralis minor.

Expiration: abdominal muscles
Blood Supply/return from thorax
-Anterior intercostal artery
-Posterior thoracic artery
-Posterior intercostal vein
-Anterior intercostal vein
Anterior Intercostal artery
-Supplies blood to anterior thoracic wall.

-Branches from Internal Thoracic Artery
Posterior Thoracic Artery
Direct branch of aorta
-supplies blood to posterior thoracic wall.
Posterior intercostal vein
Drains blood from posterior rib musc.
-Joins azygous vein system, drains to Superior Vena Cava.
Anterior intercostal veins
Drain blood from anterior rib muscles
-Join the internal thoracic vein, then the brachiocephalic vein or SVC.
Innervation of Thoracic walls/floor
Walls: T1-T12 (subcostal nerve)

Diaphragm: Phrenic Nerve (C3-C5)and peripheral intercostals.

Deck Info