CHEST W ALL
Extrinsic muscles of the chest wall:
Pectoralis major Accessory
muscles of
Serratus anterior (attach to ribs) inspiration
External oblique abdominis
Expiration by
Rectus abdominis
depressing rib
cage
Intrinsic muscles of the chest wall:
external intercostal- \\\\
Intercostal
internal intercostal- //// neurovascular
innermost intercostal bundle VAN
between them
Inside the ribs, there is a layer
of fascia called the
sitting under
endothoracic fascia. This fascia groove of each rib
acts like a glue to adhere to a
serous membrane called
parietal pleura
The Sternum:
Manubrium
Sternal angle(louis)- 2o cartilaginous joint
Body of sternum
Xiphisternum (xiphoid process)
Rib classification:
True ribs (1-7)
False ribs (8-10) -costal margin
Free floating ribs (11-12)-no posterior attachment
*Attached posteriorly to the 12 thoracic vertebrae
The Thoracic cage joints:
1st sternocostal joint – 10 cartilaginous
2nd -7th sternocostal joint – synovial
8th -10th chondrochondral joint -synovial
Ribcage support:
Sternocleidomastoid muscle
Mastoid process of skull to
clavicle and sternum
Scalenus anterior, Medius and posterior
from transverse process of cervical
vertebrae to 1st and 2nd rib
,Babies’ vs adults:
Babies have more horizontal ribs meaning costal margin is wider
Babies have more flexible ribs less likely to fracture
Usually both heal rapidly
, Osteology of Typical rib:
3rd – 9th/10th rib
Head – superior demi-facet
Interarticular crest
(back)
Posterior
Inferior demi-facet
Neck
Tubercle – articular part (facet)
Non articular part (ligamentous)
Shaft Anterior (front)
Angle of the rib
Subcostal groove
For nerves arteries veins to be supported
Osteology of Atypical Rib:
1st Rib – boomerang
Scalene tubercle (for anterior scalenus)
Single facet
Grooves for subclavian vessels
2 rib – tubercle for scalenus posterior
nd
Tubercle for serratus anterior
(10 ) – Sometimes Atypical
th
May articulate with t10 vertebrae only
11 + 12 – do not have tubercles and don’t attach anteriorly
th th
Inly have single facet on heads
Articular Facets on vertebrae:
Superior facet (head of rib)
Inferior facet (rib below)
Facet for rib tubercle
Typical vs Atypical thoracic vertebrae:
Atypical are 1 10 11 and 12
*2 is not Atypical and 10 is always Atypical
Costovertebral Joints:
Facilitate movement of ribs
Upper ribs outwards and forwards – pump handle (true ribs)
Lower ribs to side – bucket handle (false ribs)
e
Anastomos
Vasculature of the chest wall:
1)branches of axillary artery to pectoral region
2)thoracic aorta forms posterior intercostal arteries 3)
3) internal thoracic arteries form anterior intercostal arteries
breathing
depends on pressure of
Valveless- movement
*Subclavian arteries give rise to the internal thoracic arteries on each side
Extrinsic muscles of the chest wall:
Pectoralis major Accessory
muscles of
Serratus anterior (attach to ribs) inspiration
External oblique abdominis
Expiration by
Rectus abdominis
depressing rib
cage
Intrinsic muscles of the chest wall:
external intercostal- \\\\
Intercostal
internal intercostal- //// neurovascular
innermost intercostal bundle VAN
between them
Inside the ribs, there is a layer
of fascia called the
sitting under
endothoracic fascia. This fascia groove of each rib
acts like a glue to adhere to a
serous membrane called
parietal pleura
The Sternum:
Manubrium
Sternal angle(louis)- 2o cartilaginous joint
Body of sternum
Xiphisternum (xiphoid process)
Rib classification:
True ribs (1-7)
False ribs (8-10) -costal margin
Free floating ribs (11-12)-no posterior attachment
*Attached posteriorly to the 12 thoracic vertebrae
The Thoracic cage joints:
1st sternocostal joint – 10 cartilaginous
2nd -7th sternocostal joint – synovial
8th -10th chondrochondral joint -synovial
Ribcage support:
Sternocleidomastoid muscle
Mastoid process of skull to
clavicle and sternum
Scalenus anterior, Medius and posterior
from transverse process of cervical
vertebrae to 1st and 2nd rib
,Babies’ vs adults:
Babies have more horizontal ribs meaning costal margin is wider
Babies have more flexible ribs less likely to fracture
Usually both heal rapidly
, Osteology of Typical rib:
3rd – 9th/10th rib
Head – superior demi-facet
Interarticular crest
(back)
Posterior
Inferior demi-facet
Neck
Tubercle – articular part (facet)
Non articular part (ligamentous)
Shaft Anterior (front)
Angle of the rib
Subcostal groove
For nerves arteries veins to be supported
Osteology of Atypical Rib:
1st Rib – boomerang
Scalene tubercle (for anterior scalenus)
Single facet
Grooves for subclavian vessels
2 rib – tubercle for scalenus posterior
nd
Tubercle for serratus anterior
(10 ) – Sometimes Atypical
th
May articulate with t10 vertebrae only
11 + 12 – do not have tubercles and don’t attach anteriorly
th th
Inly have single facet on heads
Articular Facets on vertebrae:
Superior facet (head of rib)
Inferior facet (rib below)
Facet for rib tubercle
Typical vs Atypical thoracic vertebrae:
Atypical are 1 10 11 and 12
*2 is not Atypical and 10 is always Atypical
Costovertebral Joints:
Facilitate movement of ribs
Upper ribs outwards and forwards – pump handle (true ribs)
Lower ribs to side – bucket handle (false ribs)
e
Anastomos
Vasculature of the chest wall:
1)branches of axillary artery to pectoral region
2)thoracic aorta forms posterior intercostal arteries 3)
3) internal thoracic arteries form anterior intercostal arteries
breathing
depends on pressure of
Valveless- movement
*Subclavian arteries give rise to the internal thoracic arteries on each side
