**Core Concept**
During a radical hysterectomy for stage Ib cervical cancer, the primary goal is to remove the cancerous cervix, uterus, and a portion of the vagina. The procedure involves the removal of the parametria, upper vagina, and part of the ureters. The structures to be removed are carefully selected to ensure the removal of all cancerous tissue while preserving surrounding vital organs.

**Why the Correct Answer is Right**
The correct answer is the structure that is not typically removed during a radical hysterectomy. The parametria, which are the connective tissue surrounding the cervix and uterus, are often removed to ensure the removal of all cancerous tissue. The paracolpium, which is the connective tissue surrounding the vagina, is also removed. However, the round ligament of the uterus is not typically removed during a radical hysterectomy.

*Option A: Parametria* - The parametria are often removed during a radical hysterectomy to ensure the removal of all cancerous tissue.

*Option B: Round ligament of the uterus* - The round ligament of the uterus is not typically removed during a radical hysterectomy.

*Option C: Paracolpium* - The paracolpium is often removed during a radical hysterectomy to ensure the removal of all cancerous tissue.

*Option D: Ureter* - The upper ureters are often ligated and removed during a radical hysterectomy to ensure the removal of all cancerous tissue.

**Clinical Pearl / High-Yield Fact**
When performing a radical hysterectomy, it is essential to carefully identify and preserve the ureters, as injury to these structures can lead to significant morbidity.

**Correct Answer:** B. Round ligament of the uterus.