Isaiah explains this metaphor in verse 15. The "head," the part of an animal a person would want to be, is "the leader and the noble man," and the "tail," the dirty part of the animal, is "the prophet who teaches lies." (See: [[rc://en/ta/man/jit/figs-metaphor]])
The "palm branch" grows high on the tree and is a metaphor for people who are important and rule others. The "reed" grows in shallow water and is a metaphor for people who are poor and unimportant and are ruled by others. (See: [[rc://en/ta/man/jit/figs-metaphor]])