The thoracic wall consists of skin, fascia, muscles, and bones including 12 pairs of ribs, 12 thoracic vertebrae, and the sternum. It provides protection for thoracic viscera and enables breathing movements. The ribs are of three types and have characteristic features including heads, necks, tubercles, angles, and costal grooves. Cervical ribs can cause pressure on nerves and arteries in the neck. Rib fractures commonly occur at the angle and may cause pneumothorax. The thoracic vertebrae have distinguishing transverse processes. Openings of the thoracic wall are bounded by bones and costal cartilages. Intercostal muscles cover the spaces between ribs and enable

1. The Thoracic Wall:
Bony Thoracic Cage

2. Thoracic Wall
• Structure:
skin  fascia  muscle  bone
blood vessels & nerves
• Functions:
1. protection of thoracic
viscera
2. provides the mechanical
function of breathing

3. Thoracic Cage
The bony part of thoracic wall
- 12 pairs of ribs & CC
- 12 thoracic vertebrae
- Sternum

4. Ribs
- Flat curved bones with high
resilience
- Form most of the thoracic cage
-3 types:
1. True (1 st – 7 th )
2. False (8 th – 10 th )
3. Floating (11 th & 12 th )

5. Features of Typical Ribs
1. Head: wedge-shaped with 2 articular facets
2. Neck: connects the head with the body
3. Tubercle: articular &
non-articular parts
4. Shaft (Body): angle &
costal groove

6. Typical Ribs
3 rd – 9 th ribs are considered
typical
1. Articular facets
2. Crest of Head
3. Neck
4+5. Tubercle
6. Angle
7. Costal groove
8. shaft

7. Atypical Ribs
• 1st rib
Flat, scalene tubercle & grooves for subclavian v.
• 2nd rib
rough tuberosity for serratus anterior m.
• 10th rib
one facet on the head
• 11th & 12th
one facet on the head & no neck or tubercle

8. 1st Rib
1. Flat rib
2. Scalene Tubercle
3. Grooves for
subclavian vessels
4. One Facet on the
head

9. Clinical: Cervical Rib
• Extra rib arise from C7 vertebra
• Present in ∼1% of people
• Complications:
Causes pressure on nerves & arteries supplying the
upper limb
Tingling & numbness  Partial paralysis
ischemic muscle pain (due to?)

10. Cervical Rib

11. Rib Fractures
• Common chest injuries (middle ribs, 5-10)
• Mostly in weakest part (the angle)
• Present as a sever localized pain
• Complications: inj. to underlying structures
pneumothorax (air in pleural cavity)

12. Structure of Vertebrae
Body
Vertebral arch
(P & L)
7 processes

13. Distinguishing Features of Thoracic
Vertebrae

14. Sternum
( G, Sternon: chest bone )
Flat, vertically elongated bone
that forms the middle anterior
part of the thoracic cage
3 parts:
Manubrium
Body
Xiphoid process

15. Manubrium
Shaped
(L, Handle)
* Several notches:
Jugular  Clavicular 
Costal
* Manubriosternal Joint:
2 o fibrocartilaginous
Sternal angle

16. Sternal Angle
Angle of louis
Manubriosternal
joint
Easily palpated
Opposite to T4-T5
disc
2nd costal cartilage:
Counting the ribs & intercostal spaces

17. Body: T5 – T9, costal notches 3 rd – 7 th
Xiphoid process: T10, hyaline cartilage 
ossified

18. Openings of Thoracic Wall
Boundaries of superior
thoracic opening:
T1,
1 st rib,
manubrium
Boundaries of inferior
thoracic opening:
T12,
11 th & 12 th ribs,
7-10 CC,
xiphisternal joint

19. Thoracic Outlet Syndrome
• On the superior thoracic opening (anatomical inlet)
• Compression of subclavian art. between the clavicle & 1st rib
(Costoclavicular syndrome)
• Pale color & coldness on the skin of upper limb
• Diminished radial pulse

20. Joints of Thoracic Cage
Posteriorly:
1. Intervertebral joints 1
(2 o cartilaginous)
2
2. Costovertebral joints
(synovial plane)
3. Costotransverse joints
3
(synovial plane)

21. Joints of Thoracic Cage
Anteriorly:
1. Costochondral joints
(1 o cartilaginous)
2. Sternocostal joints
(synovial plane,
except 1 st CC )
3. Manubriosternal joint
(2 o cartilaginous)
4. Xiphisternal joint
(1 o cartilaginous)

22. Intercostal Muscles
3 layers of m. that cover intercostal spaces
From outside to inside:
1. External intercostal m.:
runs downward toward sternum (your ant. pockets)
replaced anteriorly by membrane
2. Internal intercostal m.:
runs downward toward VC (your post. pockets)
replaced posteriorly by membrane

23. 3. Innermost intercostal & Transversus
Thoracic
IIm:
on lateral sides only
TTm:
4-5 slips of muscles
From post. surface of sternum
To 2 nd -6 th costal cartilages
Bld. Vessels & nerves run between:
Internal & innermost IMs