Thorax 1: Thoracic Wall Flashcards
what is the thorax?
cranial trunk between neck and abdomen
what is the thoracic cavity?
protected by the rib cage and limited caudally by the diaphragm
what is the rib cage?
bony structure formed by the ribs, thoracic vertebrae and sternum
protects the thoracic cavity and part of the abdominal one
what is the origin of the levatores costarum?
transverse process of the thoracic vertebrae
what is the insertion of the levatores costarum?
lateral surfaces and cranial borders of the dorsal ends of the ribs located caudal to the vertebral origin
what is the innervation of the levatores costarum?
intercostal nerves
what is the action of the levatores costarum?
to draw the ribs cranially in inspiration and/or to produce rotation and lateral flexion of the vertebral column
what is the origin of the intercostales externi?
caudal borders of the ribs
what is the insertion of the intercostales externi?
cranial borders and lateral surfaces of the caudal rib
what is the innervation of the intercostales externi?
intercostal ribs
what is the action of the intercostales externi?
to draw the ribs cranially in inspiration
how do the fibers extend in the intercostales externi?
CAUDOventrally
what is the origin of the intercostales interni?
cranial borders of the ribs
what is the insertion of the intercostales interni?
caudal borders of the preceding ribs
what is the innervation of the intercostales interni?
intercostal nerves
what is the action of the intercostales interni?
to pull the ribs caudally during expiration
how do the fibers extend in the intercostales interni?
CRANIOventrally
what is the origin of the retractor costae?
transverse processes of the first 3 or 4 lumbar vertebrae
what is the insertion of the retractor costae?
caudal borders of the last rib
what is the innervation of the retractor costae?
lumbar nerves
what is the action of the retractor costae?
to retract the last rib during expiration
what is the origin of the transversus thoracis?
the sternal ligament at the midline
what is the insertion of the transversus thoracis?
cartilages of the ribs from 2nd to 8th
what is the innervation of the transversus thoracis?
spinal nerves
what is the action of the transversus thoracis?
it draws the ribs caudomedially, assisting in expiration
what is the origin of the rectus thoracis?
ventral region of the 1st rib
what is the insertion of the rectus thoracis?
by an aponeurosis to the origin of rectus abdominis
what is the innervation of the rectus thoracis?
intercostal nerves
what is the action of the rectus thoracis?
to advance the ribs cranially during inspiration
what are the origins of the diaphragm?
-costal regions –> costal arch
-sternal region –> xiphoid cartilage
-lumbar region –> ventral surface of the lumbar vertebrae by two crura
what is the insertion of the diaphragm?
central tendon –> radiated fibers
what is the innervation of the diaphragm?
PHRENIC NERVE
what is the action of the diaphragm?
increases the volume of the thoracic cavity during inspiration
what happens during inspiration of the diaphragm?
central portion moves caudally during contraction
volume of the thoracic cavity increases
ribs move dorsally and cranially to expand ribcage, cranial lift of sternum
what happens during expiration of the diaphragm?
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
what is the dorsal blood supply of the thoracic wall?
dorsal intercostal branches off aorta
what is the ventral blood supply of the thoracic wall?
ventral intercostal branches off internal thoracic
