## **Core Concept**
Frozen pelvis refers to a condition where there is a significant reduction in the mobility of the pelvic joints, often due to severe inflammation, fibrosis, or neoplastic infiltration. This condition can lead to pelvic pain and limited range of motion. It is commonly associated with advanced pelvic malignancies.

## **Why the Correct Answer is Right**
The correct answer, **C. Carcinoma cervix**, is right because carcinoma of the cervix, when advanced, can infiltrate the surrounding tissues and cause extensive fibrosis. This process can lead to the obliteration of the normal tissue planes within the pelvis, resulting in a "frozen pelvis." The tumor can invade the pelvic sidewalls, parametria, and uterosacral ligaments, causing severe pelvic pain and immobility.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While endometriosis can cause pelvic pain and adhesions, it typically does not result in the extensive fibrosis and immobility characteristic of a frozen pelvis.
- **Option B:** Pelvic inflammatory disease (PID) can cause pelvic pain and adhesions due to inflammation, but it usually does not lead to the severe, irreversible changes seen in a frozen pelvis.
- **Option D:** Ovarian tumor, unless it is a very advanced and aggressive malignancy, is less commonly associated with the extensive pelvic infiltration and fibrosis that characterizes a frozen pelvis.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that a frozen pelvis is often a sign of advanced pelvic malignancy, most commonly cervical cancer. The clinical presentation can include severe pelvic pain, urinary retention, and difficulty with defecation, in addition to reduced mobility of the pelvic structures on examination.

## **Correct Answer:** . Carcinoma cervix