===Posts that Don't Reach the Ceiling===
# If there are doorposts which are ten tefachim but they don't reach the ceiling and there is a wall which reaches the ceiling the mezuzah should be placed on the doorposts and not the wall (spot ב in the picture).<ref>Derech Hachaim
280:8, Pitchei Teshuva 286:10, Kitzur Shulchan Aruch 11:12, Chovat Hadar 8:2:2. *Derech Hachayim 280:8 writes that if a doorpost doesn't reach the ceiling the mezuzah should be placed on that doorpost as long as it is ten tefachim tall. The Mikdash Me'at 286:36 establishes the case of the Derech Hachaim to only when the door reaches within a third of the entire doorway. However, the Keviyut Mezuzah Khilchata p. 389 points out that this Mikdash Me'at is a very difficult explanation of the Derech Hachaim. He agrees with the Derech Hachaim. Also, Chovat Hadar 8:2:2 p. 73 writes that if there are doorposts which are ten tefachim they are considered the right place for the mezuzah even if there is a wall which does reach the ceiling. Sechel Tov 289:73 quotes others who agree with the Chovat Hadar. However, [http://www.yutorah.org/sidebar/lecture.cfm/839765/rabbi-baruch-simon/%D7%91%D7%A2%D7%A0%D7%99%D7%9F-%D7%9E%D7%A7%D7%95%D7%9D-%D7%A7%D7%91%D7%99%D7%A2%D7%AA-%D7%94%D7%9E%D7%96%D7%95%D7%96%D7%94/] discusses this case at length and comes to the conclusion that it should be placed on the wall if the doorposts aren't shoulder height (spot א in the picture).
* In theory, Keviyut Mezuzah Khilchata 9:4 writes that there's two reasons why such a doorway would require a mezuzah. 1) The ten tefach posts are viewed as though they are extended up to the ceiling based on '''gud asik''' (Meiri Eruvin 11b, Sh"t Rav Eliyahu Mizrachi 2:26). 2) The posts don't need to touch the roof (Chesed Lavraham 16, Chazon Ish 170:3). Seemingly according to the first approach the mezuzah would be placed a third of the way to the ceiling, whereas the second approach would say to put it a third of the way up the post itself. He points out that another factor to consider is whether the mezuzah needs to be within a third of the height of the post or the doorway.</ref>