Sthula-Sarira (Sanskrit) [from sthula coarse, gross, not refined, heavy, bulky and differentiated matter + sarira (shelter) A gross body, impermanent because of its wholly compounded character; the physical. The sthula-sarira; material shelter is the vehicle or carrier on this plane of the Linga Sarira. (Jeeva)
Strictly speaking the physical body is a shelter, a house, man's 'carrier' in another sense; and no more is an essential part of him than are the clothes in which his body is garmented. Man really is a complete human being without the Sthula-sarira. The human constitution can be a complete human entity even when the physical body is discarded, but the Sthula-sarira is needed for evolution and active work on this sub-plane of the solar kosmos.
The soul is like an immaterial copy, a twin of the material body which shape it takes on, being its spiritual inhabitant, not the other way around. The body is not formed or produced by the soul, but by mixing genetic properties of two other material beings; the father and the mother. This enables the inhabiting entity to discover new ways of experiencing life, experiencing new talents and circumstances that hopefully lead to enlightenment. Reincarnation is about getting an other chance and this is how it is done.