ventral

Adjective

• nearest to or facing toward the axis of an organ or organism
  • the upper side of a leaf is known as the adaxial surface
    

• toward or on or near the belly (front of a primate or lower surface of a lower animal)
  • the ventral aspect of the human body
    
  • the liver is somewhat ventral in position
    
  • ventral (or pelvic) fins correspond to the hind limbs of a quadruped
    

Related words

• Antonyms: 
  abaxial , dorsal