Download Thorax

Objectives
Axial Skeleton 3
Thorax
THORAX (Chest Region)
• Bony cage formed by the
sternum, costal cartilage, ribs
& body of thoracic vertebrae
• Cone shaped ; superior end
is narrow while inferior end is
broad ; cage flattens toward
the back
• Functions:
– Encloses & protects
organs of thoracic cavity
– Supports bones of
shoulder girdle & upper
extremities
FEATURES OF MANUBRIUM
• Jugular or
suprasternal notch –
depression on
superior surface
• Clavicular notch –
lateral to jugular notch
& articulates with
clavicle
1.
2.
3.
4.
Identify the bones of the thorax
List the functions of the thorax
Identify the three regions of the sternum
Discuss the articulation of the sternum
and ribs
5. Differentiate between the types of ribs
STERNUM
(hyaline cartilage until age 40)
1. Manubrium –
triangular, superior
portion
2. Body –
intermediate, largest
portion
3. Xiphoid Process –
inferior, smallest
portion
ARTICULATION WITH RIBS
• Ribs 1 & 2 articulate
with manubrium
• Ribs 3 – 10 articulate
with the body of the
sternum
• No ribs articulate with
xiphoid processes
1
RIBS
• 12 pairs
• Increase in length from 1 – 7
• Decrease in length from 8 - 12
2. False ribs
– Ribs 8 – 12
– Vertebrochondrol –
ribs 8, 9, 10 ;
attached to each
other & then to rib
7
– Indirect attachment
– Floating ribs – ribs
11 & 12; only
attached posteriorly
to the vertebrae
TYPES OF RIBS
1. True or
vertebrosternal ribs
– ribs 1 – 7
– directly attached
to sternum by
strips of hyaline
cartilage called
costal cartilage
Between the Ribs
• Intercostal space – between ribs; filled with
intercostal muscle which aids in expansion &
contraction of rib cage when breathing
http://mywebpages.comcast.net/wnor/respiratorymovements.htm
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