Going up to the Bimah for an Aliyah:
One who is called up to the Torah for an Aliyah is to walk towards the Bimah in the shortest path available. [This applies whether the shortest path to the Bimah is on one’s right side or left side. One is to quickly walk to the Bimah upon being called.]
Two paths of equal distance: If there are two available routes of equal distance, he is to ascend through the path which is towards his right.
Returning from the Bimah after an Aliyah:
At the conclusion of one’s Aliyah he is to descend from the Bimah and return to his place in a different and longer path than the path used to ascend to the Bimah.
Two paths of equal distance: If upon ascending there were two available routes of equal distance, and he ascended through the path which is towards his right, he is to descend from the opposite path.
 Michaber 141/7
 Literally “One who goes up to the Bima is to ascend through the closest available opening from where he is currently situated”
The reason: This is to be done out of respect towards the congregation in order that they do not delay in order for him to arrive. Likewise, it is done out of respect to the Torah, in order to show that the Torah is beloved to him and he rushing to read it. [M”B 141/22 in name of Levush and P”M]
 Chasam Sofer 187; Kaf Hachaim 141/38
Other opinions: Some Poskim rule one is to always follow his right side. [Biur HaGr”a 141]
 Elya Raba 141; M”B 141/25; Kaf Hachaim 141/39
 The reason: As the Sages taught that whenever one turns, he is to turn to his right. [M”B 141/22 in name of Levush and P”M]
 Michaber 141/7
 The reason: This is to be done out of respect to the Torah, in order to show that the reading of the Torah is not a burden upon him. [M”B 141/24 in name of Levush]
 The reason: This is based on a verse in Yechezkal that states “Do not return through the gate which you entered.” [M”B 141/25 in name of Levush and Gr”a]