Download thorax_diaphragm-1

Thorax and Diaphragm
OBJECTIVES:
Thursday March 30th 2017
- List the parts of the sternum.
- Name the different types of ribs and their parts.
- Name and describe the importance of the inter‐costal
muscles.
- Name and describe the location of the inter‐costal nerves,
arteries and veins.
- Describe the innervation and vascularization of the
diaphragm.
-List the three major hiatuses and the vessels that go
through each.
Christopher Ramnanan, Ph.D.
[email protected]
PLEASE NOTE:
These objectives will
be tested on final
practical but not
next week’s
midterm.
(You’re welcome)
Thoracic Cage: Sternum, 12 pairs of Ribs, 12 Thoracic Vertebrae
Focus on The Sternum
Jugular
Notch
Sternum:
Manubrium
Body
Xiphoid
Process
Sum of 2 Costal Margins:
Subcostal/Infrasternal Angle
Note: Sternum articulates with ribs (via costal
cartilages, sternocostal joints); manubrium
makes up one boundary of the superior
thoracic aperture
Sternal Angle:
2nd Costal CartiIage
T4/T5 IV Disc
Bifurcation of Trachea
Azygos Arch
Aortic Arch (Lig. Arteriosum, L.
Recurrent Laryngeal N.)
The Thorax of
Infants
Before birth, the liver is a
major hematopoetic organ.
The liver is enlarged (relative
to the anatomy of the adult),
pushing the diaphragm up,
and therefore making the
thoracic cavity relatively
small
• Especially the pulmonary
cavities/space occupied by
the lungs
Thoracic Cage: Focus on Ribs
True Ribs (1-7): articulate w/ sternum via own costal cartilage
False Ribs (8-10): articulate w/ sternum via costal cartilage of rib above it
Floating Ribs (11-12): no articulation with sternum
All ribs articulate with thoracic vertebrae posteriorly
Features of a Typical Rib (3rd-9th ribs typical)
Typical Ribs:
-Head (2 articular facets to form joints with 2 thoracic vertebrae bodies)
-Tubercle (1 articular site to form joint with thoracic vertebra transverse
process)
-Costal groove to convey intercostal neurovascular bundle
Atypical Ribs
(Superior Views)
1st rib: shortest;
broadest; most sharply
curved; grooves for
subclavian vessels; one
articular facet on head
(T1 vertebrae)
2nd rib: short and
broad; rough superior
tuberosity
Ribs 10-12: only one
articular facet on
head
Ribs 11 and 12:
short; no articulation
with sternum
Thoracic Cage: Focus on Vertebrae
Costovertebral Joints (Example here: 7th rib)
Intercostal Muscles
Transversus
Thoracis
Innermost
Intercostal
M. ‘hands on
chest’
External
Intercostal
M. ‘hands
in pocket’
Internal
Intercostal
M. ‘hands
on chest’
Note: These muscles are supplied by intercostal
nerves, arteries, and drained by intercostal veins
Inspiration
Secondary
SCM
Scalenes
Primary
External
intercostals
Internal
intercostals
(interchondral
part)
Diaphragm
Expiration
Quiet
breathing
Passive recoil
of lungs, rib
cage
Active
breathing
Internal
intercostals
(interosseous
part)
Abdominal
muscles
Intercostal Arteries and Veins
Posterior Body Wall: Generally, Posterior
Intercostal arteries supplied by thoracic aorta;
Posterior intercostal veins drain to azygos
system
Anterior Thoracic Wall: Anterior intercostal
arteries supplied by internal thoracic a.;
Anterior intercostal vein drain to internal
thoracic v.
Posterior View, Ant. Body Wall
Intercostal Nerves
Anterior Rami of T1T11
Motor and Sensory
supply to body wall
(also supplies
sympathetics)
Courses laterally
from sympathetic
trunk
Intercostal
Nerve
Intercostal Nerve Dermatomes
Segmental Organization in Thorax
T4
T5
T6
T7
T8
T9
T10
T11
T12
L1
Note: T4 and T10 landmarks
The Diaphragm
Central
tendon
Central
tendon
Diaphragm consists of central
tendon (derived from cervical
region in development) and lateral
components (derived from body
wall).
Motor: supplied by C3-C5
Sensory: centrally C3-C5;
peripherally T6-T12
The Diaphragm
Diaphragm consists of central
tendon (derived from cervical
region in development, supplied by
C3-C5) and lateral components
(derived from body wall, supplied
by T5-T12)
Central
tendon
Central
tendon
Caval opening (T8) in central tendon:
transmits IVC, right phrenic n., liver
lymphatics
Esophageal hiatus (T10): transmits
esophagus and ant/post vagal trunks
Aortic hiatus (T12): transmits aorta,
thoracic duct, and azygos vein
Origin: Ribs/Costal Cartilages, Sternum, Lumbar Vertebrae
Insertion: Central Tendon
Esophageal
Hiatus
Medial Arcuate
Ligament: arc over
psoas major (bilateral);
sympathetic chains pass
posterior to this ligament
Lateral Arcuate
Ligament: arc over
quadratus lumborum
(bilateral)
Median Arcuate
Ligament: arc over
aorta (unpaired)
R and L Diaphragmatic Crus: both crura
form aortic hiatus and median arcuate lig.;
right crus forms esophageal hiatus
Blood Supply
Pericardiacophrenic a/v (courses with
phrenic nerves)
Musculophrenic a/v (one terminal branch of
the internal thoracic a/v)
Superior and inferior phrenic arteries (off
the aorta either above or below the
diaphragm)
LAB 5 CHECKLIST – THORAX AND DIAPHRAGM
NB: Items italicized are conceptual, those denoted with a * are FYI
THORAX
-
-
Sternum
Jugular notch
Manubrium
Body
Xiphoid process
Subcostal angle
Sternocostal joints
Superior thoracic aperture
Sternal angle
- 2nd costal cartilage
- T4/T5 IV disc
- Bifurcation of the trachea
- Azygos arch
- Aortic arch
- Lig. Arteriosum
- L. recurrent laryngeal n.
MUSCLES
Transversus thoracis m.
External intercostal m.
Internal intercostal m.
Innermost ntercostal m.
Diaphragm
- Caval opening
- Esophageal hiatus
- Aortic hiatus
- Medial arcuate ligament
- Lateral arcuate ligament
- Median arcuate ligament
- R and L diaphragmatic crus
-
-
BONES AND JOINTS
True ribs (1-7)
False ribs (8-10)
Floating ribs (11-12)
Head of rib
Neck of rib
Tubercle
Costal angle
Body
Costal groove
Typical rib
Atypical rib
Vertebrae
- Superior costal facet
- Inferior costal facet
- Facet for tubercle
- Spinous process
- Transverse process
- Lamina
- Body
- Vertebral foramen
Costovertebral joint
Costotransverse joint
INNERVATION
- Intercostal n.
- Phrenic n.
- Motor and sensory supply to the
diaphragm
-
ARTERIAL SUPPLY
Anterior and posterior intercostal a.
Internal thoracic a.
Thoracic aorta
Pericardiacophrenic a.
Musculophrenic a.
Superior phrenic a.
Inferior phrenic a.
-
VENOUS DRAINAGE
Anterior and posterior Intercostal v.
Azygos system
Internal thoracic v.
Pericardiacophrenic v.
Musculophrenic v.