*ep/op meaning "back"

From: Andrew Jarrette
Message: 37135
Date: 2005-04-12

Has anyone ever commented on the fortuity whereby Greek epi "on" (Sanskrit api of similar meaning) and Hittite appa "back(wards)" can be united by the common idea of "back" (containing the backbone)?  epi was presumably "on the back of (an animal)" while appa was "towards the back".  From "towards the back" can be derived the meaning "later, latter" of Sanskrit aparam, the meaning "last" of Hittite apecis, and the meaning of English after and its Germanic cognates.  So is there any IE word *op- or *ep- that means "back" (of a human or an animal)? Can Latin ob, Oscan/Umbrian op "near, with, at", Venetic op "at", Latvian ap(-) "round, about, on", Lithuanian apie, api, ap- "round" and Mycenaean opi "at" be related to these words, perhaps from the original sense "on, upon"?  And is there any possibility that Greek apo "away, off, from" (Sanskrit apa of similar meaning) can be connected with this common idea of "back"?  Perhaps apo meant originally "off" = "from on", especially "off the back of (an animal)"?  Or is that grasping at straws?  I'm aware that the initial a- suggests an initial laryngeal which epi and its kin do not share, but perhaps there is some deeper connection, i.e. the commonality of V + p + V with optional initial laryngeal.
Just wondering if any connection has been made regarding these words.
 
Andrew