HUMAN ANATOMY
Dr. Sarwar Hossain Khan
THORAX
• HUMAN BODY
1.Head & neck
2.Upper extremity
3.Thorax
4.Abdomen
5.Lower extremity
Thorax
-upper part of the trunk
-supported by a skeletal
framework (thoracic cage)
-contains the lungs & heart
Thoracic cage /skeleton
of thorax
-an osseo-cartilaginous, elastic
& conical cavity
-the upper opening /inlet is
narrower than the outlet
-flattened antero-posteriorly
BOUNDARIES
Ant.- Sternum
Post.- Bodies of
12 thoracic
vertebrae with their
intervertebral disc
Side - 12 ribs with their
cartilages
SHAPE – Conical
Difference bet. Adult & infant
thoracic cage
In transverse section:
Adult-kidney/oval/bean shaped( transverse diameter
>ant. Post. Diameter)
Infant(<2yrs)-circular
In ribs placement:
Adult -obliquely placed
-so their movement help in respiration
alternatively up & down
- this present the thoracic-abdomen
respiration in adult
Infant – ribs are horizontally placed
- respiration movement is abdominal
APPLIED ANATOMY
1.Fractures of ribs are rare in child ,
the chest wall is highly elastic in
children.
2.In adults it usually occurs at the
weak point of ribs (angle of ribs)
3.The upper 2 ribs & the lower 2 ribs
are rarely injured
INLET OF THORAX
Def.-the narrow upper end of thorax
which is continous with the neck is
called the inlet of thorax
Shape :- reniform in shape
-ant.post diameter -5cm
-transverse diameter – 10cm
-slopes downwards & forwards
-sternal end of 1st rib lies about
3-4cm lower than the vertebrae end
BOUDARIES
Front –upper border of manubrium
Behind- superior surface of the body of
T1
Sides-1st ribs with its cartilage
Partition of inlet/ Sibson’s
fascia
-placed bet.the neck & thorax
-partly seperates them so incomplete
-has two halves –rt. & Lt.
-triangular in shape
-apex is attached to the tip of the
transverse process of C7 vertebrae
-base to the inner border of 1st rib &
its cartilage
-it is also called Sibson’s fascia or
suprapleural membrane
Importance
It provides rigidity to the thoracic inlet
The root of the neck cannot be puffed of &
down during respiration
Structures passing
through inlet
Viscera-1.trachea
2.oesophagus
3.apices of lungs
with pleura
Vessels-1.brachiocephalic
artery (rt.)
2.left common
carotid artery
3.left subclavian
artery
4.rt. & Lt.
brachiocephalic veins
5.rt. & Lt. internal
thoracic artery
Muscles- 1.sternothyroid
2.sternohyoid
Nerves-1.rt. & Lt. phrenic nerve
2.rt. & Lt. vagus nerve
3.rt. & Lt. sympathetic
nerve
4.rt. & Lt. first thoracic
nerve
OUTLET OF THORAX
Def.-the broad lower end of thorax
which is continuous with the
abdominal cavity is called the outlet
of thorax
BOUNDARIES :
In front-by the xiphoid process & 710th costal cartilage forming an
intrasternal angle
Behind-inf.surface of body of T12
Sides-11th & 12th ribs
Partition of outlet/
diaphragm
-complete ( covers
whole the
circumference)
-separates thorax
from abdomen
-it is
musculotendinous
-called the
diaphragm
Structures passing through
the outlet
Major openings in diaphragm:
1.Venacaval opening
-lies opposite to disc bet. T8 & T9 vertebrae
-transmits: IVC & few branch of rt. phrenic
nerve
2.Oesophageal opening
-lies at the level of T10 vertebrae
-transmits: oesophagus,rt.& Lt. vagus
nerve,Lt. gastric artery, Lt.gastric vein
3.Aortic opening
-lies behind the diaphragm at the level of
lower border of T12
-transmits: aorta,thoracic duct
Minor openings
1.Foramen of Morgan’s/Larry’s space
-sup. epigastric vein
2.Greater & lesser splenic nerve
3.Sympathetic chain
4.Subcostal nerve & vessels
5.Musculophrenic nerve
WALLS OF THE THORAX
Coverings(outwards to inwards):
1.Skin
2.Superficial fascia
3.Deep fascia
4.Muscles
5.Ribs & intercostal spaces
6.Endothoracic fascia
7.Parietal pleura
INTERCOSTAL SPACES:
-the spaces bet.the ribs
-11 in no.on eachside
-last 2 spaces are open in front
BOUNDARIES
ABOVE-sharp lower margin of upper rib & its cartilage
BELOW-blunt upper margin of lower rib & its cartilage
IN FRONT-lateral border of sternum
BEHIND-body of corresponding thoracic vertebrae
CONTENTS:
1.Muscles
2.Blood vessels
3.Nerves
INTERCOSTAL MUSCLES
-3 in no.
-from outward to inward
1.external intercostal muscle
2.internal intercostal muscle
3.transverse thoracic
1.EXT.INTERCOSTAL MUSCLE
-forms most superficial layer
Extension:-extends forward from the rib
tubercle behind to the costochondral
junction in front then through an
aponeuorosis upto the sternum
ATTACHMENT
Origin-lower border of upper rib
Insertion-upper border of lower rib
DIRECTION
-fibres are directed downwards & forwards
2.INT.INTERCOSTAL MUSCLE
-forms the middle layer of muscles
Extension:-extends backward from the sternum in
front to the post.angle of ribs behind then by an
aponunosis upto the vertebrae
ATTACHMENT
Origin-costal groove of upper rib
Insertion-upper border of lower rib
DIRECTION
Downwards & backwards
3.TRANSVERSUS THORACIC
-forms depest layer
-direction is same to int.intercostal muscle
-has 3 portion: subcostalis,intercostal
intimi,sternocostalis
NEUROVASCULAR BUNDLE
Intercostal nerves & vessels run bet.the middle &
innermost layer of muscles
-they are arranged in above downwards:
1.Intercostal vein(v)
2.Intercostal artery(a)
3.Intercostal nerves(n)
-lies in the costal groove
FUNCTION OF MUSCLES:
1.ext.intercostal muscle-help in inspiration
2.int.intercostal muscle-help in expiration
3.Prevent blowing out or sucking in of the intercostal
spaces as well as the tissues with change in
internal thoracic process of respiration
INTERCOSTAL VESSELS
ARTERIES:
Each intercostal space contains –
One post.intercostal artery
Two ant.intercostal arteries
POST.INTERCOSTAL ARTERY:
-one in each spece
-11 in no. on each side
-1st & 2nd arteries are branches of
sup.intercostal artery-subclavian artery
-3rd to 11th are branches of descending
thoracic aorta
Ant.intercostal arteries:
-2 in each space
-10th & 11th spaces do not have
-upper 6 spaces are branches of
internal thoracic artery
-lower spaces are branches of
musculophrenic artery
-ant.& post.intercostal arteries
meet each other at
costochondral juction
VEINS
-correspond to the arteries
ANT.INTERCOSTAL VEINS:
-2 in eacs space
-1st -6th drain into internal thoracic vein
-7th – 9th drain into musculophrenic vein
POST.INTERCOSTAL VEIN:
-1 in each spce
-on right side drain into azygous vein
-on left side drain into –
1st to 4th :lt.brachiocephalic vein
5th to 11th :hemiazygous vein
:
INTERCOSTAL NERVES
-11 in no.on each side
-each is the ant.rami of the first 11 thoracic
nerves
APPLIED ANATOMY
INTERCOSTAL NEURAGLIA:
-sharp burning pain in the area
supplied by intercostal nerves
e.g.rib & herpes zoster
Thank you