Carnett's sign
Encyclopedia
In medicine
, Carnett's sign is an eponymous finding on clinical examination in which (acute
) abdominal pain
remains unchanged or increases when the muscles of the abdominal wall are tensed. For this part of the abdominal examination
, the patient can be asked to lift the head and shoulders from the examination table to tense the abdominal muscles. An alternative is to ask the patient 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 (for example, due to rectus sheath hematoma
instead of appendicitis
). 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.
s, nerve entrapment syndrome, irritation of intercostal nerve roots, anterior cutaneous nerve
entrapment, rib
-tip syndrome, myofascial pain, trigger points and rectus sheath hematoma
s.
All abdominal wall hernias may be associated with pain and Carnett's 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, femoral hernia and sports hernia. Those of the pelvic wall include: sciatic hernia, obturator hernia and perineal hernia. The support hernias include: vault prolapse, enterocele
, cystocele, rectocele and uterine decensus. Although most hernias can be detected clinically with the presence of a lump with an expansile cough impulse some may be difficult to detect either because they are small or because the patient is obese. In cases where the diagnosis is suspected but clinically unconfirmed, additional investigation using radiography or ultrasonography may be helpful. Herniography, in which contrast medium is introduced into the peritoneal cavity, has been successfully used to reveal previously unsuspected inguinal hernias in patients with groin pain of uncertain origin and to detect impalpable interparietal lesions such as Spigelian hernias.
Rib tip syndrome is characterized by pain along the costal margin and is caused by hypermobility of the eighth, ninth and tenth ribs. These ribs do not articulate with the sternum but instead are bound to each other by a thin band of fibrous tissue. If this fibrous attachment becomes divided, the rib(s) may ride up and irritate the intercostal nerve(s) causing pain. Clinically the patient may be aware of a snapping or clicking sensation as the ribs move relative to one another. The clinician can reproduce the symptoms by hooking his or her fingers under the costal margin and pulling upwards. Relief can be provided by anesthetizing the relevant intercostal nerve with local anesthetic. If symptoms persist, rib tip resection may be necessary.
Spontaneous rectus sheath hematoma arises from rupture of the epigastric vessels. The patient usually presents with a sudden well-localized abdominal pain associated with a tender nonpulsatile abdominal mass, usually in the lower abdomen. There is frequently a plausible precipitating factor such as local trauma, a bout of coughing or anticoagulant therapy. The diagnosis can be confirmed on ultrasound examination and a conservative approach to treatment can be adopted provided that the hematoma does not enlarge. Carnett's test may be diagnostic in this setting.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, Carnett's sign is an eponymous finding on clinical examination in which (acute
Acute abdomen
The term acute abdomen refers to a sudden, severe abdominal pain of unclear etiology that is less than 24 hours in duration. It is in many cases a medical emergency, requiring urgent and specific diagnosis...
) abdominal pain
Abdominal pain
Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem...
remains unchanged or increases when the muscles of the abdominal wall are tensed. For this part of the abdominal examination
Abdominal examination
The abdominal exam, in medicine, is performed as part of a physical examination, or when a patient presents with abdominal pain or a history that suggests an abdominal pathology.The exam includes several parts:* Setting and preparation...
, the patient can be asked to lift the head and shoulders from the examination table to tense the abdominal muscles. An alternative is to ask the patient to raise both legs with straight knees.
A positive test increases the likelihood that the abdominal wall and not the abdominal cavity
Abdominal cavity
The abdominal cavity is the body cavity of the human body that holds the bulk of the viscera. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roof is the thoracic diaphragm , and its oblique floor is the pelvic inlet...
is the source of the pain (for example, due to rectus sheath hematoma
Rectus sheath hematoma
A rectus sheath hematoma is an accumulation of blood in the sheath of the rectus abdominis muscle. It causes abdominal pain with or without a mass....
instead of appendicitis
Appendicitis
Appendicitis is a condition characterized by inflammation of the appendix. It is classified as a medical emergency and many cases require removal of the inflamed appendix, either by laparotomy or laparoscopy. Untreated, mortality is high, mainly because of the risk of rupture leading to...
). A negative
Negative test
The subject Negative Test can relate to:*A negative medical test, in which the target parameter that was evaluated was not present.*In software testing, a test designed to determine the response of the system outside of what is defined. It is designed to determine if the system doesn't crash with...
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.
History
This test was first described by John B. Carnett in 1926. The first clear description of anterior abdominal wall pain arising from structures other than the underlying viscera was Cyriax in 1919.Cyriax EF (1919) On various conditions that may stimulate the referred pains of visceral disease, and a consideration of these from the point of view of cause and effect. Practitioner 102:314-322 Cyriax considered that pain could be mimicked by lesions that arose from the vertebra, ribs or other associated structure or that they were the result of direct irritation of intercostal nerves. By identifying conditions such as alterations in the normal vertebral curves, minor subluxation of vertebral bodies and pressure on the peripheral portions of the intercostal nerves, he was able to employ various mechanical treatments to correct the abnormalities and relieve his patients’ symptoms. Despite this paper little attention was paid to this problem until Carnett developed his simple clinical test. Carnett thought that lower abdominal pain was commonly caused by the lower six thoracic nerves and wanted to be able to distinguish this origin from that arising from the viscera.Differential diagnosis
The differential diagnosis of a positive Carnett's test includes herniaHernia
A hernia is the protrusion of an organ or the fascia of an organ through the wall of the cavity that normally contains it. A hiatal hernia occurs when the stomach protrudes into the mediastinum through the esophageal opening in the diaphragm....
s, nerve entrapment syndrome, irritation of intercostal nerve roots, anterior cutaneous nerve
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...
entrapment, rib
Rib
In vertebrate anatomy, ribs are the long curved bones which form the rib cage. In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax...
-tip syndrome, myofascial pain, trigger points and rectus sheath hematoma
Hematoma
A hematoma, or haematoma, is a localized collection of blood outside the blood vessels, usually in liquid form within the tissue. This distinguishes it from an ecchymosis, which is the spread of blood under the skin in a thin layer, commonly called a bruise...
s.
All abdominal wall hernias may be associated with pain and Carnett's 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, femoral hernia and sports hernia. Those of the pelvic wall include: sciatic hernia, obturator hernia and perineal hernia. The support hernias include: vault prolapse, enterocele
Enterocele
An enterocele is a protrusion of the small intestines and peritoneum into the vaginal canal.It may be treated transvaginally or by laparoscopy....
, cystocele, rectocele and uterine decensus. Although most hernias can be detected clinically with the presence of a lump with an expansile cough impulse some may be difficult to detect either because they are small or because the patient is obese. In cases where the diagnosis is suspected but clinically unconfirmed, additional investigation using radiography or ultrasonography may be helpful. Herniography, in which contrast medium is introduced into the peritoneal cavity, has been successfully used to reveal previously unsuspected inguinal hernias in patients with groin pain of uncertain origin and to detect impalpable interparietal lesions such as Spigelian hernias.
Rib tip syndrome is characterized by pain along the costal margin and is caused by hypermobility of the eighth, ninth and tenth ribs. These ribs do not articulate with the sternum but instead are bound to each other by a thin band of fibrous tissue. If this fibrous attachment becomes divided, the rib(s) may ride up and irritate the intercostal nerve(s) causing pain. Clinically the patient may be aware of a snapping or clicking sensation as the ribs move relative to one another. The clinician can reproduce the symptoms by hooking his or her fingers under the costal margin and pulling upwards. Relief can be provided by anesthetizing the relevant intercostal nerve with local anesthetic. If symptoms persist, rib tip resection may be necessary.
Spontaneous rectus sheath hematoma arises from rupture of the epigastric vessels. The patient usually presents with a sudden well-localized abdominal pain associated with a tender nonpulsatile abdominal mass, usually in the lower abdomen. There is frequently a plausible precipitating factor such as local trauma, a bout of coughing or anticoagulant therapy. The diagnosis can be confirmed on ultrasound examination and a conservative approach to treatment can be adopted provided that the hematoma does not enlarge. Carnett's test may be diagnostic in this setting.