**Core Concept**
Phantom limb is a condition characterized by the sensation of pain, numbness, or movement in a limb that is no longer present. This phenomenon occurs due to the reorganization of the brain's somatosensory cortex, which is responsible for processing sensory information from the body.

**Why the Correct Answer is Right**
Phantom limb is a classic example of a disorder of the central nervous system, specifically the brain's ability to process and interpret sensory information. The condition arises from the brain's attempt to reorganize itself after a limb is lost, resulting in the misinterpretation of neural signals as sensations from the missing limb. This phenomenon is often seen in individuals who have undergone amputations, but it can also occur in individuals with neurological disorders such as stroke or spinal cord injury.

**Why Each Wrong Option is Incorrect**
* **Option A:** Phantom limb is not a disorder of the peripheral nervous system, which is responsible for transmitting sensory information from the body to the central nervous system.
* **Option B:** Phantom limb is not a disorder of the musculoskeletal system, which is responsible for the structure and movement of the body's muscles and bones.
* **Option C:** Phantom limb is not a disorder of the integumentary system, which is responsible for the body's skin and associated structures.

**Clinical Pearl / High-Yield Fact**
Phantom limb is a common phenomenon that affects up to 80% of individuals who have undergone amputations. It is often managed with a combination of pharmacological and non-pharmacological interventions, including pain management medications and physical therapy.

**Correct Answer: D. Disorder of the central nervous system.