(i) Multinucleate muscle fiber :

Skeletal or striated muscles have many nuclei.
Skeletal muscles are attached to bones by tendons, and they produce all the movements of body parts in relation to each other.

(ii) Spindle-shaped muscle fiber :
Smooth or unstriated muscles are spindle shaped with single nucleus.
Spindle cell sarcoma is a type of connective tissue cancer in which the cells are spindle-shaped when examined under a microscope.