This is a dream about diminished capacity or ability. Our limbs are what give us mobility and the dexterity with which to create, both of which are impacted in some way when we lose a limb. Whether it is as significant as an entire arm or leg or just the smallest finger or toe, the appearance of a missing limb or amputation in a dream is reflecting some sort of invasion of your ability to navigate through life. Consider the use of the limb that is missing and you will have more information to interpret.... Complete Dictionary of Dreams
A missing article, such as a set of keys, denotes a sense of being out of control.
A missed plane, bus, train, appointment, or time commitment can symbolize a missed opportunity, and the frustration of being behind and unorganized is also suggested. (See also Loss of Something).... Dream Symbols in The Dream Encyclopedia