Implantable medical leads that are flexible and extensible in a controllable manner to facilitate subject body movements and that are bundled to create a branched lead to permit lead body ends on one or both ends of the lead to be movable relative to one another so as to be positionable in different locations. Implantable medical leads advantageously include individual lead portions, sub-bundles, and bundles that are able to be selectively positioned and implanted within a subject body and that are useful, in particular, for use in the neck region of a subject body and other regions of any subject's body that may benefit from increased flexibility, extensibility and positionability.