Download intercostal space

INTERCOSTAL
SPACE AND
THORACIC MUSCLES
AND RESPIRATORY
MOVEMENTS
DR. shazia mangi
. INTERCOSTAL SPACE :
 It means the space between two ribs.
Each space contains three muscles and
neurovascular bundle. The arrangement
of neurovascular bundle is as from above
to downward is intercostal vein,
intercostal artery, intercostal nerve.
 Intercostal nerve:
 This is a spinal nerve coming out from the
inter vertebral foramen, passes around the
neurovascular plane between internal
intercostal muscle and transverse thoracic
group of muscles. It gives of collateral
branch which supply the intercostal muscles,
the paritel pleura and periosteium of ribs (it
has no cutaneous branch).
 The main nerve gives of lateral
cutaneous branch and one terminal
branch which pierces the intercostal
muscles and overlying muscles of the
body wall along the mid axillary line and
divide in to anterior and posterior
branches to supply over the space.
Anterior cutaneous branch in upper six
space passing anterior to internal
thoracic artery by piercing the intercostal
muscles and reaches to skin. The nerve
lies below the artery and vein.
 At the back of intercostal space the nerve
crosses behind the artery where as in
front of intercostal space the nerve
crosses in front of the artery.
 1st intercostal nerve: Is the smaller
nerve beneath the flat, inferior surface of
1st rib and in contact with endothoracic
fascia and pleura. It supplies the 1st
intercostal space muscles with motor and
propioreceptive fibres and the adjacent
rib and plura with sensory fibres. It does
not supply the skin and does not have
lateral and anterior terminal cutaneous
branch.
 Subcostal nerve (12th thoracic) arising
in thorax and enters into the abdomen.
 Intercostal arteries:
 They inter in space from back to front. The upper
two spaces are supplied by superior intercostal
artery which is the branch of costocervical trunk
which is the branch of second part of subclavian
artery which is from arch of aorta /
brachiocephalic trunk.
 It enters in thorax by passing in front of neck of
1st rib having the sympathetic trunk on its medial
side. The remaining nine intercostal spaces
are a supplied each with separate branch of
descending thoracic aorta.
 On the posterior surface all these
eleven arteries supply. At front of each
inter costal space the internal thoracic
artery in upper six intercostal spaces
and musculo cutaneous branches in
lower intercostal space. It gives of two
anterior intercostal arteries which pass
back ward and make end to end
anastomosis with posterior vessels.
 Internal thoracic or the mammary
artery from the 1st part of S/C artery, it
goes down ward from the border of
sternum.
 In each intercostal space it gives two
anterior intercostal arteries.
 It divides and gives superior epigastric
and musculo phrenic artery,
pericardiophrenic and perforating
branches.
 Venous supply:
 These are two anterior intercostal veins in
each of upper nine spaces accompanying
the corresponding arteries. Upper six
veins end in internal thoracic veins and
lower end in musculophenic vein.
 There is one posterior intercostal vein in
each space and they have tributaries.
 The tributaries of veins are from vertebral
canal, vertebral venous plexus, muscles
and skin of back.
 Lower eight posterior veins drain in to
azygous vein on right side and
hemiazygous and accessory azygous on
left side.
 1st intercostal vein drain into right
brachiocephalic or vertebral vein on right
side and left brachiocephalic veins on left
side.
 On the right side second and third
intercostal vein joint to from right fourth
superior intercostal vein which drain into
azygus vein.
 Second and third intercostal veins on
the left side joint to form left superior
intercostal veins which drain into left
brachiocephalic vein.
 Lymphatics
 Anterior intercostal nodes (internal
mammary nodes).
 Posterior intercostal nodes.
RESPIRATORY
MOVEMENTS
 During the respiratory process (expiration
and inspiration) the lungs may inflate
(expand) or deflate (retract).
 Inspiration – Inflate – expand
 Expiration – deflate – retract
 These movements alter the capacity of
thoracic because of the movements of
thoracic wall.
 These movements are carried out at
different joints of thoracic cavity i.e.
vertebrosternal and vertebrochondral.
 Increase in the volume of thoracic cavity
creates the intrathoracic pressure with sucks
air into the lung.
 These movements occur at costovertebral
(all joints of thorax) and manibrosternal
joints.
 Thoracic wall expels air from lungs during
expiration.
 Pump handle movement:
 In this movement A/P diameter of thorax is
increased.
 This occurs at vertebrosternal ribs (1-7)
ribs.
 Body of sternum moves up and down
showing the pump handle movement.
 Buket handle movement:
 The middle of shaft of rib lies on sternum
causes increase in transverse diameter at
vertebrocondral ribs.
 Ap. Diameter increase in pump handle
movement at 2 – 6 ribs.
 Transverse diameter increase at 7 – 10 ribs.
Bucket handle movement.
 Contraction of diaphragm causes the
increase in vertical diameter.
 Respiratory muscles:
 Diaphragm and intercostal muscles
(Inspiration)
 Elastic recoil of lungs (Expiration)
 In forced breathing (Inspiration) Diaphragm,
intercostal muscles St. Cl. Mastoid. Pectoral
is minor and serratus anterior and alaque
nasi (Expiration) muscles of abdominal wall
and latismus dorsi.