Lymphatic drainage of glans penis is by
**Core Concept**
The lymphatic drainage of the glans penis is a critical aspect of understanding the anatomy and potential pathways for the spread of diseases such as penile cancer. The glans penis is a highly vascularized and sensitive area, and its lymphatic drainage is primarily through the deep inguinal lymph nodes.
**Why the Correct Answer is Right**
The lymphatic drainage of the glans penis is primarily through the deep inguinal lymph nodes due to the absence of lymphatic vessels in the skin of the glans penis. The lymphatic vessels of the glans penis drain into the corpora cavernosa, which then drain into the deep inguinal lymph nodes. This is in contrast to the shaft of the penis, which drains into the superficial inguinal lymph nodes. The deep inguinal lymph nodes are located along the femoral vein and play a crucial role in the lymphatic drainage of the lower limb, including the glans penis.
**Why Each Wrong Option is Incorrect**
* **Option A:** The superficial inguinal lymph nodes are responsible for the lymphatic drainage of the shaft of the penis, not the glans penis.
* **Option B:** The internal iliac lymph nodes are responsible for the lymphatic drainage of the pelvic organs, but not the glans penis.
* **Option C:** The para-aortic lymph nodes are responsible for the lymphatic drainage of the abdominal organs, but not the glans penis.
**Clinical Pearl / High-Yield Fact**
It is essential to note that the lymphatic drainage of the glans penis is primarily through the deep inguinal lymph nodes, and this knowledge is critical for the proper staging and treatment of penile cancer.
**Correct Answer: A. Deep inguinal lymph nodes.**