It seems that they were permanent.

1. Rashi in Zevachim (35a, DH a'Itzabi) writes that they were stone. In addition, I saw that the Sefer Nesivos ha'Kodesh (written by Rav Salman of Charkov and printed in Yerushalayim in 1955) on Zevachim (35a, DH vela'Avodah) writes that one must say that when the Gemara in Zevachim (24a) states that David ha'Melech sanctified the floor of the courtyard of the Beis ha'Mikdash, it means that he also sanctified the Itztava'os. The Nesivos ha'Kodesh writes that as soon as the courtyard was built, the Itztava'os were also built along with it.

2. I assume that the reason why they do not appear on the drawings is that they are a part of the floor and this is a detail one would not expect to find on the drawings.

3. However, it still is rather perplexing that the Rambam seems to make no reference to the Itzava'os. (See Sefas Emes to Zevachim 35a who points this out.)

Kesivah v'Chasimah Tovah,

Dovid Bloom

I found something written by Rav Moshe Feinstein zt'l in Igros Moshe (CM II 61:4) which may help us understand why the Itztava'os do not appear in the drawings of the Beis ha'Mikdash.

1. Rav Moshe was asked why the Rambam did not mention in his Yad ha'Chazakah what the Gemara teaches on 65b -- that on Erev Pesach the holes of the courtyard were plugged up. He answered that the Rambam maintains that there is no Mitzvah to plug up the holes. Therefore, if it was difficult for the Kohanim to walk on the Itztava'os, they did not block up the holes.

2. It seems that when Rav Moshe says that it is not a Mitzvah to plug up the holes, he means that this is not obligatory (even though it is praiseworthy to do so). I would suggest that there is a source for this from the phrase used by the Gemara, "It is a praise for the sons of Aharon that they should walk up to their knees in blood." This suggests that while it was praiseworthy to do so, it was not obligatory.

3. Accordingly, it would appear that the entire concept of the Itztava'os is not actually obligatory but merely optional. If one would build the floor of the courtyard without them, there would be nothing invalid about this. This may be the reason why they do not appear in the drawings of the Beis ha'Mikdash.

1) I saw in the notes of Rav Elyashiv zt'l (in He'oros b'Maseches Pesachim) in our Sugya that he asks why the Itztavei are not mentioned in the Mishnayos where the building of the Beis ha'Mikdash is described. He does not give an answer to this question.

2) However, I would like to remain with my suggestion in the previous answer that the sources describing the way the Beis ha'Mikdash was built mention only things which were obligatory, while the Itztavei were not obligatory because if the Kohanim do not want to walk on them they are not obligated to plug up the Azarah, as Rav Moshe Feinstein writes.

3) I would like to suggest that on the basis of the above idea another question may be answered. This is a question asked by the Rosh Yeshiva of Brisk in Yerushalayim, Rav Meshulam David Solovetchik shlit'a, in his Sefer on Zevachim 35a (where our Sugya also appears). He asks that since the Gemara says here that it is a praiseworthy thing that the sons of Aharon should walk up to their knees in blood, why did they not plug up the Azarah every day, or at least they should have done so on Yom Tov, when there were a lot of Korbanos?

4) It seems that we may answer this question based on the words of Rav Moshe as follows. Since it was not obligatory to plug up the Azarah, we may say that the reason why they did this only on Erev Pesach was that this was the day in the year when the most people were in the Beis ha'Mikdash and the most Korbanos were offered, and consequently there was more blood in the Azarah than on any other day in the year. Therefore, the Azarah was plugged up on the day of the year when it had the most spectacular effect.

5) I found a similar idea to what Rav Moshe writes (that the Rambam records only laws which are obligatory). This is in the writings of the Chafetz Chaim, in Likutei Halachos to Menachos 62a. The Gemara there states that the Korban is waved by three Kohanim because of the principle, "The honor of the king is through many people." The Rambam, however, does not mention that it should be done with three Kohanim. The Chafetz Chaim writes that the reason why he does not mention it is that it is a "Hidur Mitzvah," it is done merely to make the Mitzvah more beautiful, but it is not an essential part of the Mitzvah of waving the Korban.

6) One of my sons had an ingenious suggestion to solve the problem of why the Itztavei are not mentioned anywhere, other than in our Gemara.

(a) Before I continue further, I should say that I have since posed this question to two Gedolei Torah. The first Gadol gave an answer which was unclear and which I was unable to understand. The second Gadol initially answered that the Itztavei were temporary and used only on Erev Pesach. However, when I asked him that, if so, the Itztavei would be a Chatzitzah between the feet of the Kohanim and the floor of the Azarah, he retracted from his Peshat and said that this is indeed a strong question and "Tzarich Iyun."

(b) I also found (via an Otzar ha'Chochmah search) that in Sha'arei Torah (7:109), which was a periodical published in Warsaw before the Holocaust, somebody asked that there are two items mentioned in the Gemara which do not appear on the diagrams of the Beis ha'Mikdash. The first is our Itztavei. The second is the "Lishkah she'Einan Mevukarim" mentioned in Sukah 42a just before the Mishnah there. I did not find in Sha'arei Torah that anyone provided a solution to these problems.

(c) Our suggestion is as follows. First, we have to answer another question in the Sugya, namely, why did the Rambam omit the law that the Azarah was plugged up on Erev Pesach? (We mentioned this question above in the name of Rav Moshe Feinstein, and I have also found that Rav Yaakov Kaminetsky asked this in Emes l'Yaakov here.)

(d) Our thesis is as follows. The Rambam (Hilchos Beis ha'Bechirah 6:1) writes that the Beis ha'Mikdash was not built on flat land but was in fact on a slope. The Mishnah in Midos (2:6) tells us that according to Rebbi Eliezer ben Yakov, there were stairs between the Ezras Yisrael and the Ezras Kohanim. The Ezras Kohanim (which was closer to the holiest part) was 2 1/2 Amos higher than the Ezras Yisrael.

(e) It is reasonable to assume that the Korban Pesach was slaughtered primarily in the Ezras Kohanim. (The Mishnah in Midos 3:5 says that there were rings adjacent to the Mizbe'ach on which the Korbanos were slaughtered. These were in the Ezras Kohanim.)

(e) We come to the conclusion that according to Rebbi Eliezer ben Yakov, if the Azarah would be stopped up, this would mean that all of the blood from the Korbanos would flow straight down into the Ezras Yisrael, which would then become impossible for use. Therefore, it must be that when the Gemara in Pesachim (65b) tells us that the Azarah was plugged up, it does not follow the opinion of Rebbi Eliezer ben Yakov.

(f) Rather, the Gemara there in Pesachim follows the opinion of the Rabanan in Yoma (16a), who disagree with Rebbi Eliezer ben Yakov and maintain that the Ezras Kohanim and Ezras Yisrael were on the same level. According to this, the blood of the thousands of Korbenos Pesach that were slaughtered had more space to spread out. They would be at an equal level both in the Ezras Kohanim and in the Ezras Yisrael and would not reach higher than knee level in either place. Therefore, matters would be slightly more manageable.

(g) However, the Rambam (6:1) rules according to Rebbi Eliezer ben Yakov, because the Gemara in Yevamos (49b) states that "the Mishnah of Rebbi Eliezer ben Yakov is 'Kav v'Naki.'" Rashi there (DH v'Naki_ writes that this means that wherever Rebbi Eliezer ben Yakov is mentioned, the Halachah follows his view. Since the Rambam rules like Rebbi Eliezer, it follows that he rules that one does not plug up the Azarah. If so, it follows automatically from our Sugya that the Itztavei are unnecesary, which is why the Rambam makes no mention of them!

Kol Tuv,

Dovid Bloom