Thorax 1: Thoracic Wall

Question 1

what is the thorax?

Answer 1

cranial trunk between neck and abdomen

Question 2

what is the thoracic cavity?

Answer 2

protected by the rib cage and limited caudally by the diaphragm

Question 3

what is the rib cage?

Answer 3

bony structure formed by the ribs, thoracic vertebrae and sternum

protects the thoracic cavity and part of the abdominal one

Question 4

what is the origin of the levatores costarum?

Answer 4

transverse process of the thoracic vertebrae

Question 5

what is the insertion of the levatores costarum?

Answer 5

lateral surfaces and cranial borders of the dorsal ends of the ribs located caudal to the vertebral origin

Question 6

what is the innervation of the levatores costarum?

Answer 6

intercostal nerves

Question 7

what is the action of the levatores costarum?

Answer 7

to draw the ribs cranially in inspiration and/or to produce rotation and lateral flexion of the vertebral column

Question 8

what is the origin of the intercostales externi?

Answer 8

caudal borders of the ribs

Question 9

what is the insertion of the intercostales externi?

Answer 9

cranial borders and lateral surfaces of the caudal rib

Question 10

what is the innervation of the intercostales externi?

Answer 10

intercostal ribs

Question 11

what is the action of the intercostales externi?

Answer 11

to draw the ribs cranially in inspiration

Question 12

how do the fibers extend in the intercostales externi?

Answer 12

CAUDOventrally

Question 13

what is the origin of the intercostales interni?

Answer 13

cranial borders of the ribs

Question 14

what is the insertion of the intercostales interni?

Answer 14

caudal borders of the preceding ribs

Question 15

what is the innervation of the intercostales interni?

Answer 15

intercostal nerves

Question 16

what is the action of the intercostales interni?

Answer 16

to pull the ribs caudally during expiration

Question 17

how do the fibers extend in the intercostales interni?

Answer 17

CRANIOventrally

Question 18

what is the origin of the retractor costae?

Answer 18

transverse processes of the first 3 or 4 lumbar vertebrae

Question 19

what is the insertion of the retractor costae?

Answer 19

caudal borders of the last rib

Question 20

what is the innervation of the retractor costae?

Answer 20

lumbar nerves

Question 21

what is the action of the retractor costae?

Answer 21

to retract the last rib during expiration

Question 22

what is the origin of the transversus thoracis?

Answer 22

the sternal ligament at the midline

Question 23

what is the insertion of the transversus thoracis?

Answer 23

cartilages of the ribs from 2nd to 8th

Question 24

what is the innervation of the transversus thoracis?

Answer 24

spinal nerves

Question 25

what is the action of the transversus thoracis?

Answer 25

it draws the ribs caudomedially, assisting in expiration

Question 26

what is the origin of the rectus thoracis?

Answer 26

ventral region of the 1st rib

Question 27

what is the insertion of the rectus thoracis?

Answer 27

by an aponeurosis to the origin of rectus abdominis

Question 28

what is the innervation of the rectus thoracis?

Answer 28

intercostal nerves

Question 29

what is the action of the rectus thoracis?

Answer 29

to advance the ribs cranially during inspiration

Question 30

what are the origins of the diaphragm?

Answer 30

-costal regions --> costal arch -sternal region --> xiphoid cartilage -lumbar region --> ventral surface of the lumbar vertebrae by two crura

Question 31

what is the insertion of the diaphragm?

Answer 31

central tendon --> radiated fibers

Question 32

what is the innervation of the diaphragm?

Answer 32

PHRENIC NERVE

Question 33

what is the action of the diaphragm?

Answer 33

increases the volume of the thoracic cavity during inspiration

Question 34

what happens during inspiration of the diaphragm?

Answer 34

central portion moves caudally during contraction volume of the thoracic cavity increases ribs move dorsally and cranially to expand ribcage, cranial lift of sternum

Question 35

what happens during expiration of the diaphragm?

Answer 35

central portion moves cranially with relaxation decrease the volume of thorax, elastic recoil of lungs expel air ribs move ventrally and caudally to compress ribcage, sternum compresses caudally and dorsally

Question 36

what is the dorsal blood supply of the thoracic wall?

Answer 36

dorsal intercostal branches off aorta

Question 37

what is the ventral blood supply of the thoracic wall?

Answer 37

ventral intercostal branches off internal thoracic