The normal structure of axonal terminals in lamina V of cervical spinal cordof the adult rat was examined with EM.Among 4039 various types of terminals inlamina V,the terminals with clear round synaptic vesicles(R)and the terminalswith clear flat synaptic vesicles(F)constitute about 40% each,the terminals withlarge granular vesicles(LG)about 16% and the central terminals of syntapticglomeruli about 3%.In addition,about 3.2% of the various types of terminalscontain neurofilaments,about 0.9% exhibit low electron dense axoplasm and thevesicles are partly lost or clumping.The synapses of the terminals in lamina V aremainly axodendritic,a small number of them are axoaxonal.There are more F,fewer R and LG in lamina V than those in lamina Ⅱ;thesynapses between the terminals and proximal dendrites,and axosomatic synapses aremore commonly seen in lamina V than in Ⅱ.