L3 Muscles Of Respiration

Question 1

What are the true , false, floating, typical and atypical ribs

Answer 1

True .. 1-7
False .. 8-10
Floating ..11-12

Typical.. 3-9
Atypical .. 1+2 / 10+11+12

Question 2

What are the components of I.C space ?

Answer 2

1. I.C. Muscles
2. Neurovascular bundle ( between internal and innermost )
3. Fascia ( we are concerned with the internal fascia )

Question 3

What is the origin and insertion of intercostal muscles ?

Answer 3

External starts posteriorly and replaced by external i.c. membrane at the region of costal cartilage

Internal starts anteriorly and replaced by membrane as you are going posteriorly

Innermost layer presents as discontinuous laterally (most lateral parts )

Question 4

What is the transversus thoracis muscle ?

Answer 4

consists of four or five slips that run from the posterior surface of the xiphoid process and body of the sternum to 3 rd – 4 th costal cartilages
It is a type of innermost layer

Question 5

What is the subcostal muscle ?

Answer 5

Subcostal muscles are variable; these are posterior muscles usually present in the lower intercostal spaces extending from the angle of one rib to the internal surface of second or third rib inferior to it, crossing two intercostal spaces

Question 6

What are levator costarum muscles ?

Answer 6

Levator costarum muscles extend from the transverse processes of c7 to T11 and attach to ribs 1-12 close to their tubercles. These muscles are innervated by dorsal rami of spinal nerves C8 – T11

Question 7

What is the function of Serratus posterior superior and inferior muscle?

Answer 7

It has limited role in the movement of thoracic cage however They mainly help in Proprioception (They Provide the brain with the position of the ribs in association to the vertebrae.

Question 8

What is the nerve supply to the thoracic wall ?

Answer 8

Whole thoracic wall is innervated by ( thoracic spinal nerves )

DORSAL RAMUS
- for the back

VENTRAL RAMUS
- will form intercostal nerves giving lateral and anterior cutaneous branches

Question 9

What is the blood supply to the thoracic wall ?

Answer 9

POSTERIORLY
- it is from the thoracic aorta

ANTERIORLY
- internal thoracic artery that will give 2 intercostal arteries

Both will anastomoses forming a circle

Question 10

What are the venous drainage of the diaphragm ?

Answer 10

• internal thoracic veins ( musclophrenic vein )

- inferior vena cava

Question 11

What is the blood supply to the diaphragm ?

Answer 11

Superiorly:
- The musculophrenic artery and vein from the internal thoracic artery and vein

Inferiorly :
-The inferior phrenic artery ( first pair of arteries that arises from the abdominal aorta )

Question 12

What are the branches of the phrenic nerves ?

Answer 12

1. Right and left phrenic nerves
2. Pericardio-phrenic branches
3. Phrenico-abdominal branches

Question 13

What is the MOVEMENTS OF RIBS ?

Answer 13

COSTOTRANSVERSE as the ribs will articulate with transverse process

Upper ribs … rotation

Lower ribs … gliding

Question 14

The most important muscles that take part in the movement of ribs is ?

Answer 14

Levator costarum muscles ( 12 pairs )

Question 15

What are the accessory muscle ?

Answer 15

1. Levator costarum
2. Scalene muscles ( anterior, middle, posterior )
3. Pectoralis ( major , minor )
4. Serratus posterior ( sup. and inf. )