Download Thoracic cage Diaphragm

Thoracic cage, diaphragm
Mark Kozsurek, M.D., Ph.D.
ED I., 15/11/2011
Questions to be answered
How are the bones of the thorax connected together?
→ the joints of the thoracic cage
Which muscles act upon these joints?
→ the muscles of the thoracic cage
How does the thoracic cage move?
→ the mechanism of breathing
How are the ribs connected to the vertebrae?
How do the ribs attach to the sternum?
How are the ribs connected to the vertebrae?
COSTOVERTEBRAL JOINTS:
2. JOINT OF HEAD OF RIB
- costal facet of the vertebra
- articular facet of the head of the rib
1. COSTOTRANSVERSE JOINT
- costal fovea of the transverse process
- articular facet of the the costal tubercle
Articular surfaces of vertebrae
TYPICAL
„TYPICAL VERTEBRAE”
- TII-IX present a superior and an inferior
costal demifacet.
„ATYPICAL VERTEBRAE”
- TI bears a complete superior costal facet
for the head of the first rib and an inferior
costal demifacet for the head of the second
rib.
- TX only has a superior costal demifacet.
- TXI-XII express complete costal facets for
the ribs with the same number. They have
no costal facets on their transverse
processes.
Articular surfaces of the ribs
Ribs II-X
Rib I
Ribs XI-XII
Ribs I, XI-XII have continuous facets on their heads, the articular surfaces of
the heads of ribs II-X are divided into two by a crest, ribs XI-XII have no
tubercle and do not articulate with transverse processes.
Joint of the head of the rib
Costotransverse joint
Radiate ligament of the head
of the rib (not shown)
Joint of the head of the rib
Costotransverse joint
lateral
costotransverse lig.
superior
costotransverse lig.
radiate lig. of the
head of the rib
Costotransverse ligament attaches the neck of the rib
to the transverse process. Lateral costotransverse
ligament connects the tip of the transverse process to
the roughened nonarticular part of the tubercle of the
rib. Superior costotransverse ligament attaches the
neck of the rib to the transverse process of the vertebra
above.
Intra-articular ligament connects the crest of the
head of the rib to the intervertebral disc. Radiate
ligament of the head of the rib reinforces the capsule
of the joint of the head of the rib.
How are the ribs connected to the sternum?
Manubriosternal and
xiphisternal joints:
synchondroses, with
age they become
ossified.
Sternocostal joints:
Rib I: synchondrosis
Ribs II-VII: synovial
joints
Intercostal joints:
Ribs VI-X
synovial joints
radiate
sternocostal
ligament
Thoracic muscles – the intercostal ones
external intercostal m.
vertebra
rib
internal intercostal membrane
internal intercostal m.
innermost intercostal m.
transversus thoracis m.
external intercostal membrane
sternum
Blood supply and innervation of the thoracic wall
Posterior intercostal arteries are direct branches of the
thoracic aorta, while the anterior intercostal arteries
arise from the internal thoracic artery, a branch of the
subclavian artery. Supreme intercostal arteries of the two
upper intercostal spaces also come from the subclavian
artery.
Posterior intercostal veins drain into the azygos vein (on
the right) or into the hemiazygos/ accessory hemiazygos
veins (on the left). Anterior intercostal veins open into
the internal thoracic vein, which empties into the
brachiocephalic vein.
Intercostal nerves exit from the spinal cord and leave the
vertebral canal through the intervertebral foramina.
Intercostal vessels and nerves give off posterior, lateral
and anterior branches to supply the external layers of
the thoracic wall.
1.
4.
2.
3.
5.
1. Pectoralis major (and minor)
2. Serratus anterior
3. Abdominal muscles
4. Trapezius (Levator scapulae,
Rhomboids, Serratus posterior)
5. Latissimus dorsi
Diaphragm
Central tendon with the opening
for the inferior vena cava
a
b
b
According to the site of
origin muscle fibres
constitute the:
IVC
a, sternal part
c
b, costal part
c, lumbar part
superior aspect
esophagus
aorta
c
inferior view
sternal part
costal part
lumbar part
sternocostal triangle
(of LARREY)
lumbocostal triangle
(of BOCHDALEK)
Blackboard!
L1
L2
L3
lateral, medial, median
arcuate ligaments
Caval opening: IVC,
right phrenic nerve,
central tendon, T8
Esophageal opening:
esophagus, ant. et post.
vagal trunk, T10
Aortic hiatus: aorta,
thoracic duct (the greatest
lymph vessel), L1
Sternocostal triangle of Larrey:
internal thoracic artery and vein *
* they are called superior epigastric a. et v. bellow the diaphragm
Between the medial and lateral parts (variable!!!):
greater splanchnic nerve, azygos/hemiazygos veins,
lesser splanchnic nerve and sympathetic trunk
Innervation, blood supply of the diaphragm
Internal thoracic artery (ITA) is one of the first branches
of the subclavian artery. ITA gives off the
pericardiacophrenic artery first which descends together
with the phrenic nerve between the pleura and the
pericardium. Before reaching the trigone of Larrey, ITA
gives off the musculophrenic artery contributing to the
blood supply of the diaphragm.
Already from the abdominal aorta the inferior phrenic
arteries ascend to the inferior surface of the diaphragm.
Phrenic nerve arises mainly from the C4 segment, this is
why injuries of the neck around or above this level may
cause sudden death due to the palsy of the diaphragm.
Respiratory movements
Ribs rotate around an axis defined by the two costovertebral joints.
During inspiration both the anteroposterior and lateral diameters of the chest increase!
Quiet breathing
Inspiration (active)
Expiration (passive)
Note:
The position of the central tendon
and the heart resting on it is not
changing during quiet breathing!!!
In midposition (green) the right
dome of the diaphragm reaches
the level of the 5th rib,
while on the left it is in the 5th
intercostal space.
90°
External and internal intercostal muscles are perpendicular to each other!
external intercostal
internal intercostal
Take a deep breath and relax!
It’s over!