Thorax

Question 1

Describe In brief the thorax.

Answer 1

Cavity between superior and inferior thoracic apertures.
Cone shaped, narrow superiorly.
Upper protects heart, lungs large vessels.
Lower protects some abdominal viscera.

Question 2

What are the functions of the thoracic cage.

Answer 2

Protect vital thoracic and abdominal organs.
Resists negative and positive intrathroracic pressure.
Provides attachment for upper limb and support weight of upper limb.
Provide attachment to intrinsic and extrinsic muscles of thorax.

Question 3

Describe the structures of the thoracic cage.

Answer 3

Sternum, 12 thoracic vertebrae, 12 ribs and cartilage.
Cartilage allows ribs to move.
11th and 12th rib have no connection to sternum, ‘floating ribs’.
Ribs are oblique.

Question 4

Explain the two anterior joints of the ribs.

Answer 4

Cartilaginous joints: 1st sternocostal and all the costochondral joints, manubriosteral joint.
Synovial joints: 2-7 sternocostal joints, chondro-chondral joints between costal cartilages of ribs 7 -10.

Question 5

Describe a typical rib.

Answer 5

Head articulates with thoracic vertebrae - costovertabral.
Neck extends laterally.
Tubercle, (posterior) articulates with transverse process. Costotransverse joint.
Costal groove is between ridge of internal surface of the rib and inferior border.

Question 6

Describe the sternum.

Answer 6

Manubrium - thickest, strongest part, makes slight angle with sternal body.
Body - Anterior surface nearly flat, posterior surface slightly concave.
Xiphoid - Upper end forms cartilaginous joint with lower end of sternum, lower end attaches to linea alba.

Question 7

Explain what passes through the thoracic aperture.

Answer 7

Common carotid artery
Trachea 
Oesophagus
Internal Jugular Vein
Upper portion of lungs
Subclavian Artery and vein
Brachiocephalic artery.
Superior Vena cava.

Question 8

What are the sympathetic trunks.

Answer 8

Paired bundles of nerves and ganglia that run parallel, length of the spine.

Question 9

Describe the phrenic nerve.

Answer 9

Mainly C4, also C3 and C5.

Keeps the diaphragm alive.

Question 10

Describe the Vagus nerve, cranial nerve VX.

Answer 10

Contributes to heart and abdominal organs and conveys sensory information from organs.

Question 11

What is the purpose of the thoracic duct.

Answer 11

Returns the lymph to the circulatory system from the body.

Question 12

Describe the nerves in the posterior thorax.

Answer 12

12 pairs.
Dorsal (posterior) Rami pass posteriorly and supply bones, joints, muscles, skin of back.
Ventral (anterior) rami of T1-11 are ‘Intercostal nerves’
(T12 - called subcostal)
Supply abdominal and thoracic wall.

Question 13

Describe the major veins of the thorax.

Answer 13

Vena Cavae
Internal thoracic veins
Azygos System: veins on each side of vertebral column, drain back and walls of thorax and abdomen.
Empty into vena cava.
Hemiazygos and accessory hemiazygos drains left side Azygos drains right.

Question 14

Describe the Thoracic duct.

Answer 14

Largest lymphatic duct.
Lies posterior and between the aorta and oesophagus.
Lies both superior and inferior mediastinum.
Drains to venous system at junction between internal and left subclavian veins.

Question 15

Describe the main arteries of the thorax.

Answer 15

Anteriorly internal thoracic artery (and vein) descends from subclavian artery, on the back of the ribs.
Posteriorly thoracic aorta, posterior and anterior Intercostal arteries. (and veins.)

Question 16

Describe the Diaphragm.

Answer 16

Origin: Sternal - Inner part of ziphoid process. Coastal-inner surface of lower 6 ribs.
Lumbar - Upper 2 - 3 lumbar vertebrae.
Insertion: Central tendon - Itself.
Action: Draws central tendon down during inspiration, increases volume of thoracic cavity.
Nerve Supply: Phrenic (C3,4,5)

Question 17

List the major structures that pass through the diaphragm.

Answer 17

Inferior Vena Cava.
Descending Aorta.
Oesophagus.
Throacic Duct.
Azygos Vein
Sympathetic Chains

Question 18

Describe the external Intercostal Muscles.

Answer 18

Origin: Inferior border of ribs.
Insertion: Superior border of ribs below, run obliquely down and forward.
Action: Helps to expand thoracic cavity during inspiration by elevating ribs.
Nerve Supply: Intercostal.

Question 19

Describe the internal intercostal muscles.

Answer 19

Origin: Inferior border of ribs.
Insertion: Inner lip of the superior border of ribs below, run obliquely down and back.
Action: Fix intercostal spaces during exhalation. Aid forced expiration by depressing ribs.
Nerve Supply: Intercostal.

Question 20

List the accessory muscles of respiration.

Answer 20

Sternocleidomastoid.
Scalenes.
Serratus anterior.
Pectoralis Major and minor.

Question 21

Describe the trachea and bronchi.

Answer 21

Continues from the larynx
Descends anteriorly to the Oesophagus.
Follows the curvature of the spine.
Bifurcates into right and left main bronchi at level of T4/5.

Question 22

Describe the lungs.

Answer 22

Spongy organs.
Pulmonary cavities contains lungs and pleurae.
Apex, Base, Surfaces, Borders.
Left and right lung lobes.
Cardiac notch on anterior border of left lung.

Question 23

Describe the Pleurae.

Answer 23

Serous membrane arranged as a closed invaginated sac.

Visceral and Parietal.

Question 24

Describe the Hilum.

Answer 24

Depression on the medial aspect of the lung.

Structures enter and leave the lung here.

Question 25

Briefly describe the heart.

Answer 25

Hollow muscular organ which receives blood from  veins and propels it our in arteries.
Venous and Arterial chambers.
Obliquity. 
Aortic Arch - level with T4
Heart Between T5 and T9

Question 26

Explain the external feature of the heart.

Answer 26

Surfaces, apex and borders.
Superior Left Atrium
Inferior Right ventricle.
Left - left ventricle 
Right - Right Atrium
Intrerventricular grooves (anterior and posterior)
Base - Forms posterior surface.

Question 27

Describe the pericardium.

Answer 27

Fibroserous membrane covering heart and begging of major thoracic blood vessels.

Question 28

Describe the pericarial cavity.

Answer 28

Closed sac, containing pericarial fluid, lies between parietal and visceral pericarial layers.

Question 29

List the Vessels that supply the heart.

Answer 29

Right and left coronary arteries.

Coronary sinus, drains blood into right atrium.

Question 30

Where are the valves in the heart.

Answer 30

Between Right atrium and right ventricle.
Between right atrium and pulmonary trunk.
Between left atrium ad left ventricle.
Between left ventricle and aorta.