Thoracic cage

Question 1

What is the Thoracic Cage made up of, and its functions

Answer 1

Vertebrae and Intervertebral disc
Ribs
Sternum
Costal Cartilages
Function:
Protection of viscera
Muscle attachment 
note: relation to pectoral gridle

Question 2

Describe the different types of ribs

Answer 2

Costal Element 12 pairs of ribs; described as:
True
False
Floating

Ribs also classified as:
Typical Ribs 3-9
Atypical 1,2,10th-12th

Question 3

Features of a rib (3-9)

Answer 3

• Head with 2 facets
• Neck
• Tubercle
• Body (shaft) with costal grove

Question 4

Thoracic Vertebrae

Answer 4

• Heart shaped body with two facets
• Costal facet on Transverse process
• Inferior pointing spinous process

Question 5

Joints of the rib cage

Answer 5

Intervertebral
Costovertebral
Costotransverse
Costochondral
Interchondral
Sternochondral
Sternoclavicular

Question 6

Costovertebral and Costotransverse joints

Answer 6

• Costovertebral: Head of rib articulates with costal (demifacet) on two adjacent vertebrae and the associated IV disc. Exceptions 1st, 11th and 12th which only articulate with one vertebrae.
• Costotransverse: Tubercle of rib articulates with transverse process of vertebrae

Question 7

Pectoralis major

• Origin
• Insertion
• Function
• Innervation

Answer 7

• Origin or Proximal attachment: Clavicle and sternum
• Insertion or distal attachment: Humerus
• Function: Adducts and medially rotates humerus
• Innervation: Lateral and Medial Pectoral nerves

Question 8

Pectoralis minor

• Origin
• Insertion
• Function
• Innervation

Answer 8

• Origin or Proximal attachment: 3-5th rib.
• Insertion or Distal attachment: coracoid process of scapula.
• Function: Stabilizers scapula
• Innervation: Medial pectoral nerve

Question 9

Intercostal muscles

• Three layers
• Vascularity

Answer 9

• External Intercostals –anterior inferior direction
• Internal Intercostals – posterior inferior direction
• Innermost Intercostals
• Supplied by intercostal artery, vein and nerve which runs in subcostal groove.
• Crosses over to allow expansion and contraction of the rib cage

Question 10

Serratus anterior

• Origin
• Insertion
• Function
• Innervation

Answer 10

• Origin or Proximal attachment: 1-8th rib.
• Insertion or Distal attachment: medial border of scapula.
• Function: Protracts scapula
• Innervation: Long Thoracic Nerve
• teeth like projections spread over 1-8th ribs

Question 11

Arterial supply of the thoracic cage

Answer 11

Blood supply to the thoracic wall derived from:
- Thoracic aorta-Posterior Intercostal arteries
- Subclavian artery- Anterior Intercostal arteries
Venous drainage via azygos and hemiazygos- 103