Thoracic cage anatomy

Question 1

Component of thoracic cage

Answer 1

1. 12 ribs

2. Sternum (manubrium, body and xiphoid)

Question 2

Significant parts of sternum

Answer 2

1. Jugular notch at top of manubrium
2. Manubrium: articular site: clavical and 1st rib
3. Sternal angle (between manubrium and body): where the 2nd rib is joint onto
4. xiphoid process: xiphisternal joint: 7th rib join there

Question 3

the joint type and names of the joint

Answer 3

Joint name: costosternal joints (between ribs and stermun)

via costal cartilages

rib 1: cartliagenous joint
rest: synovial joint

Question 4

blood supply of thoracic cage - ARTERY

Answer 4

1. POSTERIOR (BACK)
2. Aorta - subclavian artery - costocervical trunk - SUPERIOR INTERCOSTAL ARTERY (1, 2nd space)
3. DIRECT branches of the descending thoracic aorta
4. SUBCOSTAL artery (12th space and below)
5. ANTERIOR (FRONT)
6. subclavian artery - INTERNAL THORACIC ARTERY - branches off (1-6th space)
7. split: MUSCULOPHRENIC artery: 7-9th space and diaphragm
   superior epigastric artery: rectus abdominus

Question 5

blood supply to the ribs: VEINS

Answer 5

POSTERIOR (BACK)
Right side: drains into AZYGOUS VEIN
Left side: SUPERIOR intercostal veins into ACCESSORY HEMIAZYGOUS vein; the rest into hemiazygous vein
=> eventually into azygous vein

then into SUPERIOR VENA CAVA

2. ANTERIOR (front, also follows the branches of arteries)
   drains into internal thoracic vein
   eventually into BRACHIOCEPHALIC VEIN

Question 6

the classification of ribs according to: their attachment to sternum; their characteristic

Answer 6

1. True ribs: have articular site on the vertebrae AND sternum (via costal cartilages)
2. False ribs: have articular site on vertebrae, but attaches to the costal cartilage of 7th rib
3. Floating ribs: have articular site on vertebrae column, but no attachment at sternum

Atypical vs typical ribs

Question 7

Typical ribs characteristics and the joint names with vertebrae

Answer 7

Head (posterior): articular site x2: top and bottom vertebrae body

Neck
Tubercle: 1x articular site to the transverse process of vertebrae, 1x muscle attachment site
Angle
Body, ends with costal cartilages

Joint names:
costovertebral, costotransverse joint, these are synovial joints (free movement)

Question 8

The bucket handle and pump handle movement describe

Answer 8

Bucket handle movement: increases transverse diameter (7-10th ribs)

Pump handle movement: AnteroPosterior diameter (ribs 1-6)`

Question 9

content of the intercostal space

Answer 9

1. intercostal muscles: external (V), interna, innermost
2. Vessels: intercostal arteries and veins
3. Nerves: intercostal nerves (1-11th spinal nerve)
   VAN in this order

muscles that transverse different levels:
subcostal muscle and sternocostalis (originates from body and xiphoid process of sternum, attachment onto the inferior side of ribs (under) 2-6th ribs’ costal cartilage). UPWARD AND LATERAL direction)

Question 10

external intercostal membrane where is it

Answer 10

at the anterior (remember dissection class)
originates from the posterior and goes around to anterior where it becomes muscle membrane

opposite for internal intercostal muscle