A 38-year-old woman visits her gynecologist for a routine Pap smear examination. During the collection of cells from her uterine cervix she feels a mild pain. Which of the following areas is most likely to experience “referral of pain” during this procedure?
**Core Concept**
During a Pap smear examination, the cervix is stimulated, leading to the activation of nociceptors. The pain is referred to an area corresponding to the spinal segments that receive afferent input from the cervical plexus. This phenomenon is known as referred pain.
**Why the Correct Answer is Right**
The correct answer is related to the innervation of the cervix, which is primarily via the cervical plexus (C1-C3). The cervical plexus receives afferent input from the cervix and sends signals to the spinal cord, which then relays them to the brain as pain. The pain is referred to an area corresponding to the dermatome of the spinal segment that receives the input. In this case, the affected area is likely to be the shoulder and upper arm, corresponding to the C2-C3 dermatomes.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the lower back is not typically associated with referred pain from the cervix. The lower back is primarily related to the innervation of the lumbar plexus (L1-L4).
**Option B:** This option is incorrect because the groin is not typically associated with referred pain from the cervix. The groin is primarily related to the innervation of the femoral nerve (L2-L4).
**Option C:** This option is incorrect because the rectum is not typically associated with referred pain from the cervix. The rectum is primarily related to the innervation of the pudendal nerve (S2-S4).
**Clinical Pearl / High-Yield Fact**
Remember that the dermatomes corresponding to the cervical plexus (C2-C3) can experience referred pain during cervical procedures, such as a Pap smear examination.
**Correct Answer:** C.