Most doctors have received the following page at some point in their career: “Patient having abdominal pain, please come assess.” Carnett’s sign (described by British surgeon J.B. Carnett in 1926) is a physical exam finding that helps differentiate abdominal wall from intra-abdominal sources of pain. Once the tender spot is located, the test is considered positive when the patient’s pain increases upon tensing of the abdominal wall muscles– such as by raising both legs with straight knees or lifting the head and shoulders from the bed. Conversely, if the pain decreases with this maneuver, an intra-abdominal source is more likely1,2.
A positive Carnett’s sign should broaden the differential of abdominal pain to include: hernias, irritation of intercostal nerve roots, rectus sheath hematomas, myofascial pain, anterior cutaneous nerve entrapment (latter discussed in another pearl). In the appropriate clinical setting, local corticosteroids or anesthetic injections, or the application of hot or cold packs may be therapeutic2,3.
- Carnett JB. Intercostal neuralgia as a cause of abdominal pain and tenderness. J Surg Gynecol Obstet 1926; 42:625-632.
- Bundrick JB, Litin SC. Clinical pearls in general internal medicine. Mayo Clin Proceedings 2011;86: 70–74.
- Suleiman S , Johnston DE. The abdominal wall: an overlooked source of pain. Am Fam Physician 2001; 64: 431-8.
Contributed by Brad Lander MD, Mass General Hospital, Boston, MA.