splenius
noun
sple·ni·us ˈsplē-nē-əs 
plural splenii ˈsplē-nē-ˌī
: either of two flat oblique muscles on each side of the back of the neck and upper thoracic region
Word History
Etymology
New Latin, from Latin splenium plaster, compress, from Greek splēnion, from splēn
First Known Use
1732, in the meaning defined above
Medical Definition
splenius
noun
sple·ni·us -nē-əs
plural splenii -nē-ˌī
: either of two flat oblique muscles on each side of the back of the neck and upper thoracic region:
a
: splenius capitis
b
: splenius cervicis