**Core Concept**
Congenital torticollis is a condition where a baby's head is tilted to one side due to a shortening of the sternocleidomastoid muscle, usually caused by trauma during birth or a congenital abnormality. This condition can lead to a permanent deformation of the neck if not treated promptly.

**Why the Correct Answer is Right**
The sternocleidomastoid muscle plays a crucial role in rotating the head and flexing the neck. In congenital torticollis, the shortening of this muscle leads to a restricted range of motion, causing the head to tilt towards the affected side. This is often accompanied by a palpable mass or nodule in the muscle, which is a result of fibrosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** This statement is true as congenital torticollis is often associated with a palpable mass or nodule in the sternocleidomastoid muscle.
* **Option B:** This statement is also true as congenital torticollis can lead to a restricted range of motion in the neck, causing the head to tilt towards the affected side.
* **Option C:** This statement is true as the exact cause of congenital torticollis is often unknown, but it is believed to be related to trauma during birth or a congenital abnormality.

**Clinical Pearl / High-Yield Fact**
One important clinical correlation to remember is that congenital torticollis is often associated with other congenital anomalies, such as omphalocele, gastroschisis, and clubfoot. A high index of suspicion is essential in diagnosing this condition early on to prevent long-term deformities.

**Correct Answer: D.