**Core Concept**
Lymphatic spread of infection can cause multiple sinuses or fistulae, a common complication of skin infections. The lymphatic system plays a crucial role in draining the skin and underlying tissues, and disruption of this system can lead to the formation of sinuses or fistulae.

**Why the Correct Answer is Right**
The great toe is richly supplied with lymphatic vessels that drain into the inguinal lymph nodes. When an infection occurs on the great toe, the lymphatic vessels can become obstructed or damaged, leading to the formation of multiple sinuses or fistulae. This is because the lymphatic system is unable to effectively drain the infected tissue, resulting in the accumulation of pus and the formation of sinuses or fistulae.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the lymphatic system is responsible for draining the skin and underlying tissues, and obstruction or damage to this system can lead to the formation of sinuses or fistulae.
* **Option B:** This option is incorrect because the bloodstream is responsible for transporting pathogens and toxins to other parts of the body, but it is not directly responsible for the formation of sinuses or fistulae.
* **Option C:** This option is incorrect because the lymphatic system is responsible for draining the skin and underlying tissues, and obstruction or damage to this system can lead to the formation of sinuses or fistulae.

**Clinical Pearl / High-Yield Fact**
The lymphatic system plays a crucial role in draining the skin and underlying tissues, and disruption of this system can lead to the formation of sinuses or fistulae. This is a common complication of skin infections, particularly on the extremities.

**Correct Answer:** D. Staphylococcus aureus is a common cause of skin infections, and obstruction or damage to the lymphatic vessels can lead to the formation of multiple sinuses or fistulae.