Anatomy 1

Question 1

What does the diaphragm attach to?

Answer 1

• xiphoid process of the sternum;
• costal margin of the thoracic wall
• ends of ribs 11 and 12;
• ligaments that span across structures of the posterior abdominal wall; and
• bodies of lumbar vertebrae 1 and 2

Question 2

Which part of the diaphragm is the pericardium attached to?

Answer 2

The central tendon

Question 3

Describe the diaphragm in the mid saggital plane

Answer 3

In the median sagittal plane:
the diaphragm slopes inferiorly from its anterior attachment to the xiphoid, approximately at vertebral level T8/9, to its posterior attachment to the median arcuate ligament, crossing anteriorly to the aorta at approximately vertebral level T12

Question 4

Which structures pass through the diaphragm? (7) at what levels?

Answer 4

• The inferior vena cava passes through at vertebral level T8;
• The oesophagus and vagus nerve pass through the muscular part of the diaphragm, just to the left of midline, at vertebral level T10;
• The aorta and thoracic duct pass behind the posterior attachment of the diaphragm at vertebral level T12;
• The azygos and hemiazygos veins may also pass through the aortic hiatus or through the crura of the diaphragm.

Question 5

How is the diaphragm innervated?

Answer 5

The diaphragm is innervated by the phrenic nerves (C3 to C5), which penetrate the diaphragm and innervate it from its abdominal surface

Question 6

What are the parts of the parietal pleura? (4)

Answer 6

• Costal part: pleura related to the ribs and intercostal spaces.
• Diaphragmatic part: pleura covering the diaphragm.
• Mediastinal part: pleura covering the mediastinum.
• Cervical part: the dome-shaped layer of parietal pleura lining the cervical extension of the pleural cavity. (dome of pleura or pleural cupola

Question 7

What provides support for the pleural cavity in the root of the neck?

Answer 7

The suprapleural membrane

Question 8

Describe the Root of the lung and it’s vertebral level

Answer 8

Root of the lung is at level T5 to T7

The mediastinal pleura forms a sleeve-like covering for structures (i.e., airway, vessels, nerves, lymphatics) that pass between the lung and mediastinum.These structures form the root of the lung.

Here, the mediastinal pleura is continuous with the visceral pleura

Question 9

Describe the arrangement of vessels at the hilum of the RIGHT lung.

Answer 9

• The two pulmonary veins are at the base of the hilum and anterior.
• The two bronchi on each side are posterior
• The pulmonary artery is usually superior but BETWEEN the veins and bronchi/ anterior to the bronchi

Question 10

Describe the arrangement of the vessels at the hilum of the LEFT lung

Answer 10

• The two pulmonary veins are at the base of the hilum and anterior.
• The two bronchi on each side are posterior
• The pulmonary artery is the most SUPERIOR structure

Question 11

How is the parietal pleura Innervated? How is damage to the pleura therefore felt?

Answer 11

The costal pleura is innervated by the intercostal nerves so pain would be felt at the thoracic wall.

The diaphragmatic pleura and the mediastinal pleura are innervated mainly by the phrenic nerves (originating at spinal cord levels C3, C4 and C5). Pain from these areas would refer to the C3, C4 and C5 dermatomes (lateral neck and the shoulder above the clavicle)

Question 12

What is the extent of the pleural cavities?

Answer 12

• Superiorly, the pleural cavity can project as much as 3-4 cm above the first costal cartilage, but does not extend above the neck of rib I.
• Anteriorly, the pleural cavities approach each other behind the upper part of the sternum. However, behind the lower part of the sternum, the parietal pleura does not come as close to the midline on the left side because the middle mediastinum, containing the heart, bulges to the left.
• Inferiorly the pleura end above the costal margin.
• In the midclavicular line, the pleural cavity ends at approximately rib 8.
• In the midaxillary line, it extends to rib 10. From this point, the inferior margin courses somewhat horizontally, crossing ribs 11 and 12 to reach vertebra T12.

Question 13

• Describe the visceral pleura
• describe the innervation of the visceral pleura

Answer 13

• Visceral pleura is continuous with parietal pleura at the hilum of each lung where structures enter and leave the organ.
• The visceral pleura is firmly attached to the surface of the lung.
• Although the visceral pleura is innervated by visceral afferent nerves that accompany bronchial vessels, pain is generally not elicited from this tissue

Question 14

Sternocleidomastoid

• Origin:
• Insertion:
• Artery:
• Nerve:
• Action:

Answer 14

Sternocleidomastoid

• Origin: Upper part of anterior surface of manubrium of sternum
• Insertion: Lateral one-half of superior nuchal line
• Artery: occipital artery and the superior thyroid artery
• Nerve: Accessory nerve [XI] and branches from anterior rami of C2 to C3 (C4) Sensory: cervical plexus
• Action: Individually-will tilt head toward shoulder on same side rotating head to turn face to opposite side; acting together, draw head forward

Question 15

Scalenes: Anterior

• Origin:
• Insertion:
• Artery:
• Nerve:
• Action:

Answer 15

Scalenes: Anterior

• Origin: transverse processes of vertebrae C3 to C6
• Insertion: Scalene tubercle and upper surface of rib I
• Artery: Ascending cervical artery (branch of Inferior thyroid artery)
• Nerve: Anterior rami of C4 to C7
• Action: Elevation of rib I

Question 16

Scalenes: Middle

• Origin:
• Insertion:
• Artery:
• Nerve:
• Action:

Answer 16

Scalenes: Middle

• Origin: Transverse processes of vertebrae C2 to C7
• Insertion: Upper surface of rib I posterior to the groove for the subclavian artery
• Artery: Ascending cervical artery (branch of Inferior thyroid artery)
• Nerve: Anterior rami of C3 to C7
• Action: Elevation of rib I

Question 17

Scalenes: Posterior

• Origin:
• Insertion:
• Artery:
• Nerve:
• Action:

Answer 17

• Origin: Posterior tubercles of transverse processes of vertebrae C4 to C6
• Insertion: Upper surface of rib II
• Artery: Ascending cervical artery (branch of Inferior thyroid artery)
• Nerve: Anterior rami of C5 to C7
• Action: Elevation of rib II

Question 18

External Intercostals

• Origin:
• Insertion:
• Fibre Direction
• Artery:
• Nerve:
• Action:
• Antagonist:

Answer 18

External Intercostals

• Origin: lower border of ribs
• Insertion: upper border of rib below
• Fibre Direction: downward, inward fibre direction – hands in pockets
• Artery: intercostal arteries
• Nerve: intercostal nerves
• Action: Inhalation
• Antagonist: intercostales interni muscles

Question 19

Internal Intercostals

• Origin:
• Insertion:
• Fibre Direction:
• Artery:
• Nerve:
• Actions:
• Antagonist:

Answer 19

Internal Intercostals

• Origin rib: lower border of ribs
• Insertion: rib - upper border of rib below
• Fibre Direction: downward outwards fibre direction
• Artery: intercostal arteries
• Nerve: intercostal nerves
• Actions: hold ribs steady
• Antagonist: Intercostales externi muscles

Question 20

Innermost intercostal muscle

• Origin:
• Insertion:
• Fibre Direction:
• Artery:
• Nerve:
• Actions:

Answer 20

Innermost intercostal muscle

• Origin: Upper border of a rib
• Insertion: Inferior border of the rib above
• Fibre Direction: downward fibre direction
• Artery: intercostal arteries
• Nerve: intercostal nerves
• Actions: Through adduction of upper ribs to the lower ribs the muscles narrow intercostal slits and diminish thorax volume, therefore the muscles represent expiratory muscles.

Question 21

Describe the general arrangement intercostal nerves and blood vessels.

Answer 21

Intercostal nerves and associated major arteries and veins lie in the costal groove along the inferior margin of the rib and pass in between the inner two layers of muscles.

• In each space:
• The vein is the most superior structure and is therefore highest in the costal groove.
• The artery is inferior to the vein
• The nerve is inferior to the artery and often not protected by the groove. Therefore, the nerve is the structure most at risk when objects perforate the upper aspect of an intercostal space.
• Small collateral branches of the major intercostal nerves and vessels are often present superior to the inferior rib below. The order of the collateral branches is reversed: nerve on top, then artery then vein at the bottom.

Question 22

Where do the intercostal nerves originate?

Answer 22

Innervation of the thoracic wall is mainly by the intercostal nerves, which are the anterior rami of spinal nerves T1 to T11 and lie in the intercostal spaces between adjacent ribs. The anterior ramus of spinal nerve T12 (the subcostal nerve) is inferior to rib 12.

Question 23

How is the skin of the thoracic wall Innervated? (3)

Answer 23

Each intercostal Nerve has three branches which appear to Innervated the skin:

The POSTERIOR RAMUS which branches from the spinal nerve just lateral to the vertebrae. This Innervates the skin at the back.

The LATERAL CUTANEOUS BRANCH comes off the main intercostal nerve behind the midaxilliary line and splits into anterior and posterior branches to innervate skin.

The ANTERIOR CUTANEOUS BRANCH is the end of the intercostal nerve as it pokes through the intercostal musculature at the front next to the sternum. This splits into medial and lateral branches.

Question 24

Where do the intercostal arteries USUALLY originate from?

Answer 24

Vessels that supply the thoracic wall consist mainly of posterior and anterior intercostal arteries.

These arteries USUALLY originate from:

• The aorta and
• The internal thoracic arteries, which in turn arise from the subclavian arteries in the root of the neck.

Together, the intercostal arteries form a basket-like pattern of vascular supply around the thoracic wall

Question 25

What arteries do the top two intercostal arteries originate from?

Answer 25

• The upper two posterior intercostal arteries on each side are derived from:
• The supreme intercostal artery, which descends into the thorax as a branch of the costocervical trunk which is a posterior branch of the subclavian artery.

Question 26

When do anterior intercostal arteries not branch from the internal thoracic arteries?

Answer 26

upper six anterior intercostal arteries arise as lateral branches from the internal thoracic artery,
whereas those supplying the lower spaces arise from the musculophrenic artery.

Question 27

At what level do the internal thoracic arteries branch, and what are the two terminal branches?

Answer 27

• At approximately the level of the sixth intercostal space, it divides into two terminal branches:
• the superior epigastric artery, which continues inferiorly into the anterior abdominal wall
• the musculophrenic artery, which passes along the costal margin, goes through the diaphragm, and ends near the last intercostal space

Question 28

Where do intercostal veins drain to?

Answer 28

Centrally, the intercostal veins ultimately drain into the azygos system of veins or into internal thoracic veins, which both connect with the brachiocephalic veins in the neck

Question 29

Where does the thoracic wall lymph drain to?

Answer 29

• Lymphatic vessels of the thoracic wall drain mainly into parasternal nodes next to the sternum intercostal nodes in intercostal spaces just next to vertebral bodies
  diaphragmatic nodes where the diaphragm attaches to other structures
• Parasternal nodes drain into bronchomediastinal trunks.
• Intercostal nodes in the upper thorax also drain into bronchomediastinal trunks.
• Intercostal nodes in the lower thorax drain into the thoracic duct.
• Superficial regions of the thoracic wall drain mainly into axillary lymph nodes in the axilla or parasternal nodes

Question 30

Which ribs true, false and floating ribs, and what is the definition of each?

Answer 30

True: Ribs 1 - 7 are connected posteriorly with the vertebral column, and anteriorly, through the costal cartilages, with the sternum; they are called true ribs or vertebro-sternal ribs.

False: Ribs 8 – 12 which are not directly connected to the sternum are false ribs.

Floating: Ribs 11 and 12 are sometimes called floating ribs because they do not articulate with other ribs, costal cartilages, or the sternum. Their costal cartilages are small, only covering their tips.