Applied anatomical concepts

Question 1

Quiet inspiration and muscles involved.

Answer 1

Movement of air into the lungs, less effort.

Scalene muscles- contract and pull on the first two ribs.

Diaphragm- contracts and flattens, increases thoracic volume.

External intercostal muscles- contract and pull ribs in a superolateral direction.

Question 2

Scalene muscle innervation, attachment and action.

Answer 2

Insertion: Ribs I and II.

Origin: cervical vertebrae II-VII

Innervation: C3-C6

Action: Elevates first two ribs during quiet and forced expiration.
Flexes neck laterally.

Question 3

Origin of the diaphragm

Answer 3

3 origins:

Sternal- 2 muscular slips attached to sternum

Costal- attaches to inferior 6 costal cartilages

Lumbar- medial and lateral arcuate ligaments on L1-L3.

Question 4

Innervation of the diaphragm

Answer 4

Motor- phrenic nerve

Sensory- Lower intercostal nerves and phrenic nerves (centrally)

Question 5

Action of the diaphragm

Answer 5

Actions: Increase/decrease pressure in thorax and abdomen.

Aids: coughing, laughing, urination, defecation and lifting heavy objects.

Question 6

What structure anchors the medial and lateral arcuate ligaments in the diaphragm

Answer 6

The right and left Crura

Question 7

Blood supply of the diaphragm

Answer 7

Superior and inferior phrenic arteries

Question 8

Venous drainage of the diaphragm

Answer 8

Internal thoracic veins

Inferior vena cava

Azygous vein

Question 9

Origin of phrenic nerve

Answer 9

Ventral rami C3-C5

Question 10

Supply of phrenic nerve

Answer 10

Motor- the sole supply of the diaphragm

Sensory:

• Central region of the diaphragm.
• Pericardium
• Mediastinal pleura

Question 11

Course of right phrenic nerve

Answer 11

Origin: ventral rami C3-5

Enters superior mediastinum, lateral to the Vagus nerve.

Passes the right wall of the SVC, right wall of pericardium.

Passes of right atrium and descends to diaphragm, near IVC orifice

Question 12

Course of left phrenic nerve

Answer 12

Phrenic nerve enters the superior mediastinum, lateral to the vagus nerve.

Runs over aortic arch and pulmonary trunk.

Descends on pericardium over left ventricle—-> to the diaphragm region near the cardiac apex.

Also passes anterior to main bronchi

Question 13

Effects of trauma on the phrenic nerve

Answer 13

Breathing deficit

Sensory deficit

Referred pain- C3-C5

Question 14

Recurrent laryngeal nerve compression

Answer 14

Can cause vocal cord paralysis, as the nerve supplies the larynx.

Can be caused by cancer of the upper lobe in each lung or of the left main bronchus.

Question 15

Area supplied by the posterior interventricular branch of the right coronary artery.

Answer 15

Interventricular septum

Portions of the ventricles- the adjacent portions

Question 16

Area supplied by the left anterior descending artery/ left anterior interventricular artery.

Answer 16

Anterolateral myocardium

Cardiac apex

Interventricular septum

Part of the left ventricle

Question 17

Area of the heart supplied by the circumflex branch of the left coronary artery.

Answer 17

Posterolateral left ventricle,

Anterolateral papillary muscle.

Question 18

Muscles involved in forced expiration

Answer 18

Internal intercostal muscles

Oblique and transverse abdominal muscles

Quadratus lumborum

Question 19

Muscles involved in forced inspiration

Answer 19

Pectoral muscles

Sternocleidomastoid

Latissimus dorsi

Question 20

What dimaters increase during respiration?

Answer 20

Anterior-posterior

Vertical

Transverse/ Lateral