Long and sho arm of chromosome are called respectively:

Sho arm of a chromosome- 'p' (for petit) and long arm is referred to as 'q' In a banded karyotype, each arm of the chromosome is divided into two or more regions by prominent bands. Note- Regions are numbered in direction away from centromere. Each region is fuher subdivided into bands and sub bands and are numbered in numerical fashion as well. Example- the notation Xp 22.2 refers to a chromosomal segment located on the sho arm of the 'x' chromosome, in region 2, band 2 and sub band 2.