**Core Concept**
Posterior dislocation of the hip joint is a type of traumatic injury where the femoral head is displaced out of the acetabulum in a posterior direction. This typically occurs due to high-energy trauma, such as a car accident or a fall from a height, which can cause the femur to be driven posteriorly out of the acetabulum.

**Why the Correct Answer is Right**
In a posterior dislocation of the hip, the affected limb will be in a position of flexion, internal rotation, and adduction, often described as the "frog-leg" position. This position is due to the shortening of the limb and the tension in the posterior capsule and the sciatic nerve. The patient may also experience pain, limited range of motion, and difficulty bearing weight on the affected limb.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because posterior dislocation of the hip typically results in flexion, internal rotation, and adduction of the affected limb, not extension, external rotation, and abduction.

**Option B:** This option is incorrect because posterior dislocation of the hip is characterized by a shortened limb and a decrease in range of motion, not an increased range of motion.

**Option C:** This option is incorrect because posterior dislocation of the hip typically results in a decrease in hip joint space on the affected side, not an increase.

**Clinical Pearl / High-Yield Fact**
In cases of suspected posterior hip dislocation, it is essential to perform a thorough neurovascular examination to assess for potential sciatic nerve injury and to rule out other associated injuries.

**Correct Answer: C.**