Test for abdominal pain involving tensing of abdominal muscles while palpating a tender spot to differentiate between local abdominal wall pain or pain of intraabdominal causes.
Carnett’s sign is a finding on clinical examination in which acute abdominal pain remains unchanged or increases when the muscles of the abdominal wall are tensed.
The patient is asked to lift the head and shoulders from the examination table to tense the abdominal muscles.
Alternatively the patient is asked to raise both legs with straight knees.
A positive test increases the likelihood that the abdominal wall and not the abdominal cavity is the source of the pain.
A negative Carnett’s sign is said to occur when the abdominal pain decreases when the patient is asked to lift the head; this points to an intra-abdominal cause of the pain.
The differential diagnosis of a positive test includes hernias, nerve entrapment syndrome, irritation of intercostal nerve roots, anterior cutaneous nerve entrapment, rib-tip syndrome, myofascial pain, trigger points and rectus sheath hematomas.
All abdominal wall hernias may be associated with pain and the test may be useful in their evaluation.
The hernias of the anterior abdominal wall include: epigastric hernias, umbilical hernias, spigelian hernias and incisional hernias.
Those of the groin include: direct inguinal hernia, indirect inguinal hernia, and femoral hernia.
Those of the pelvic wall include: sciatic hernia, obturator hernia and perineal hernia.