Intercostal space

Question 1

Intercostal space

Answer 1

• Space between adjacent ribs
  > Occupied by three intercostal muscles and membranes
  > as well as Neurovascular structures (VAN)

Question 2

Neurovascular structures (VAN)

Answer 2

– in costal groove deep in-between internal intercostals and innermost intercostal muscles – inferior border of rib

Sup: Vein (intercostal)
Artery (intercostal)
Inf: Nerve (intercostal)

• Each intercostal space contains 3 arteries: 1 posterior and 2x
  anterior
• Except 10 and 11- no anterior

Question 3

Arteries:

Answer 3

• Arteries enter intercostal spaces at the back and front
• Ant. intercostal a. has two branches – one below margin upper rib, other above margin lower rib and meets collateral branch of post. intercostal artery
• Ant. & post. intercostal aa. supply intercostal muscles, parietal pleura and overlying skin

Question 4

Question 5

Vein:

Answer 5

• In each space are one post. and two ant. intercostal veins accompanying the arteries of the same names
• Ant. and post. intercostal veins normally drain in opposite directions
• Most post. intercostals veins end in azygos/hemiazygos venous system.
• Internal thoracic veins accompany internal thoracic arteries
• Veins largely correspond to aa.

Question 6

Nerves of thoracic wall:

Answer 6

12 pairs – they run in intercostal space and supply the structures in that space and the overlying skin in that area

• Ant. rami of nerves T1 – T11 form intercostal nerves.
• Ant. ramus T12 is subcostal nerve.
  ( no rib below it – so no intercostal space)
• Atypical intercostal nerves:
  o 1st joins brachial plexus (axilla and arm)
  o 2nd – intercostobrachial n.
  o from 7th – 11th nerve (thoracoabdominal nerves).
• Typical intercostal nerves: 3rd – 6th.

Question 7

Branches of typical intercostal nerves: 3rd – 6th

Answer 7

• Ant. Rami communicantes which splits into:
  ( connection with sympathetic trunk)
• Lat. cutaneous branches
• Ant. cutaneous branches
• Collateral branches
• Muscular branches
• Dermatome – strip of skin supplied by a nerve

Question 8

Surface anatomical landmarks

Answer 8

•	Ribs & intercostal spaces 
•	 Clavicles 
•	Sternum 
•	Costal margin 
•	 Infrasternal / subcostal angle 
•	Ant. & post. axillary fold 
•	 Nipple 
•	Vertebral column 
•	Scapula 
•	Jugular notch 
                >Inferior border of body of T2
•	Manubrium
     >Level of T3 and T4
•	Sternal angle / Manubriosternal joint 
     >Intervertebral disc T4 & 5
     >2nd costal cartilage attachment
•	Body of sternum
    >Anterior to R border of heart 
    >T5-T9
•	Xiphisternal joint 
    >Inferior border T9

Question 9

Vertical lines of thoracic wall

Answer 9

• Midsternal line
• Midclavicular
• Anterior & posterior axillary lines
• Midaxillary
• Posterior median (midvertebral) line
• Scapular line