B6 - The v. cava cranialis and the venous blood supply of the thorax

Question 1

Draw vena cava cranialis (dog)

Answer 1

• Vena cava crainialis arise from the craniodorsal part of the sinus venosus of the right atrium
• Vena cava cranialis runs towards the thoracic inlet in the cranial mediastinum to the right of the midline and ventral to the trachea.
• At first, vena cava crianialis is situated left to tr. brachiocephlaicus, but by the thoracic inlet is reached, it has become ventral to it
• V. azygous dextra (ø sus)
  
  • Arises from v. cava cranialis
  • V. hemiazygous sinistra (not always)
  • V. broncho-esophagea
• V. azygous sinistra (ru, sus)
  
  • Arises from sinus coronarius of the heart
  • V. hemiazygous dextra???
• V. intercostales dorsales and v. costoabdominalis dorsalis
  
  • ​Each vein gives off r. dorsales
• V. costocervicalis
  
  • ​Dextra et sinistra
  • Arises from vena cava cranialis
    
    • ​Ca: sinistra arises from v. brachiocephalica
  • V. vertebralis​
  • V. cervicalis profunda
  • V. scapularis dorsalis
  • V. intercostalis suprema
  • V. intercostalis I (ca), v. intercostalis II (sus)
• V. thoracica interna
  
  • ​Arises at the level of the 1^st to 2^nd intercostal space
  • Arise by common stem in ca
  • Vv. intercostalis ventralis
  • Vv. perforantes
    
    • ​Rr. sternalis
    • Rr. mammarii (ca, sus)
  • Vv. mediastinales
  • Vv. thymichi (young animals)
  • V. pericardiophrenica
  • Divides when it reaches the diaphragm:
    
    • V. musculophrenica
      
      • ​Vv. intercostales ventrales
    • V. epigastrica craniales
      
      • ​V. epigastrica cranialis superficialis (ø eq)
        
        • Rr. mammarii (ca, sus)
        • Anastomoses with V. epigastrica caudalis superficiales
• V. brachiocephalica
  
  • ​V. brachiocephalica dextra (ca, sus)
  • V. brachiocephalica sinistra
    
    • ​V. costocervicalis sinistra
    • V. thoracica interna sinistra
    • V. thyroidea caudalis (car)
    • V. subclavia sinistra et dextra
      
      • ​Ca, sus: arises from division of tr. brachiocephalica division
      • Ru, eq: arises from vena cava caudalis at the thoracic inlet
      • Sus: doubel
    • V. jugularis externa sinistra et dextra
      
      • ​V. jugularis interna sinistra et dextra (ø eq)
      • V. cephalica sinistra et dextra
      • V. cervicalis superficialis sinistra et dextra

Question 2

Give the interspecies differences in vena cava cranialis

Answer 2