Patients with MALS reportedly experience abdominal pain, particularly in the epigastrium, which may be associated with eating and which may result in anorexia and weight loss.The pain can be in the left or right side, but usually where the ribs meet. Other signs are persistent nausea, lassitude (especially after a heavy meal) and exercise intolerance. Diarrhea is a common symptom, some experience constipation. While some experience vomiting, not everyone does. Exercise or certain postures can aggravate the symptoms. Occasionally, physical examination reveals an abdominal bruit in the mid-epigastrium.

Complications of MALS result from chronic compression of the celiac artery. They include gastroparesis and aneurysm of the pancreaticoduodenal arteries.

The patient presents with a protrusion near the neck or between the ribs. The mass becomes prominent when the patient is straining or coughing. In asymptomatic individuals, lung hernia is incidentally detected in a chest X-ray taken for another reason. On physical examination, a prominence or mass is seen during Valsalva maneuver.

In medicine, the median arcuate ligament syndrome (MALS, also known as celiac artery compression syndrome, celiac axis syndrome, celiac trunk compression syndrome or Dunbar syndrome) is a condition characterized by abdominal pain attributed to compression of the celiac artery and possibly the celiac ganglia by the median arcuate ligament. The abdominal pain may be related to meals, may be accompanied by weight loss, and may be associated with an abdominal bruit heard by a clinician.

The diagnosis of MALS is one of exclusion, as many healthy patients demonstrate some degree of celiac artery compression in the absence of symptoms. Consequently, a diagnosis of MALS is typically only entertained after more common conditions have been ruled out. Once suspected, screening for MALS can be done with ultrasonography and confirmed with computed tomography (CT) or magnetic resonance (MR) angiography.

Treatment is generally surgical, the mainstay being open division, or separation, of the median arcuate ligament combined with removal of the celiac ganglia. The majority of patients benefit from surgical intervention. Poorer responses to treatment tend to occur in patients of older age, those with a psychiatric condition or who use alcohol, have abdominal pain unrelated to meals, or who have not experienced weight loss.

Breath sounds on the side of the rupture may be diminished, respiratory distress may be present, and the chest or abdomen may be painful. Orthopnea, dyspnea which occurs when lying flat, may also occur, and coughing is another sign. In people with herniation of abdominal organs, signs of intestinal blockage or sepsis in the abdomen may be present. Bowel sounds may be heard in the chest, and shoulder or epigastric pain may be present. When the injury is not noticed right away, the main symptoms are those that indicate bowel obstruction.

The mediastinum (from Medieval Latin "mediastinus", "midway") is the central compartment of the thoracic cavity surrounded by loose connective tissue, as an undelineated region that contains a group of structures within the thorax. The mediastinum contains the heart and its vessels, the esophagus, trachea, phrenic and cardiac nerves, the thoracic duct, thymus and lymph nodes of the central chest.

Lung hernia (Sibson hernia) is a protrusion of lung outside of thoracic wall. In 20% patients with lung hernia, the incidence is congenital. In 80% of the cases, the hernia is noted after chest trauma, thoracic surgery or certain pulmonary diseases. Congenital hernia occurs because of the weakness of the suprapleural membrane or neck muscles. In pulmonary diseases such as asthma, frequent coughing can lead to high intra thoracic pressure, causing the lung to herniate out. Lung hernia may occur near the neck (cervical), between the ribs (intercostal), near the vertebrae (paravertebral) or near the sternum (parasternal).

Diaphragmatic rupture (also called diaphragmatic injury or tear) is a tear of the diaphragm, the muscle across the bottom of the ribcage that plays a crucial role in respiration. Most commonly, acquired diaphragmatic tears result from physical trauma. Diaphragmatic rupture can result from blunt or penetrating trauma and occurs in about 5% of cases of severe blunt trauma to the trunk.

Diagnostic techniques include X-ray, computed tomography, and surgical techniques such as laparotomy. Diagnosis is often difficult because signs may not show up on X-ray, or signs that do show up appear similar to other conditions. Signs and symptoms included chest and abdominal pain, difficulty breathing, and decreased lung sounds. When a tear is discovered, surgery is needed to repair it.

Injuries to the diaphragm are usually accompanied by other injuries, and they indicate that more severe injury may have occurred. The outcome often depends more on associated injuries than on the diaphragmatic injury itself. Since the pressure is higher in the abdominal cavity than the chest cavity, rupture of the diaphragm is almost always associated with herniation of abdominal organs into the chest cavity, which is called a traumatic diaphragmatic hernia. This herniation can interfere with breathing, and blood supply can be cut off to organs that herniate through the diaphragm, damaging them.

The thoracic spine begins at the base of the neck and extends to the middle of the trunk. Any pain in this area is considered "middle back pain".

The exact symptoms associated with middle back pain will depend upon the underlying cause. Most middle back pain is not serious in nature. However, it does tend to have more serious pathology associated with it than pain in the neck or low back. Symptoms can include pain, either locally near the spine or referred along area the corresponding nerve dermatome. Symptoms can also include numbness or pins and needles when nerve irritation or compression is involved. Weakness in the legs or loss of bowel or bladder control in the presence of thoracic spine pain can indicate spinal cord compression and should be investigated.

Thoracic spinal pain was significantly associated with: concurrent musculoskeletal pain; growth and physical; lifestyle and social; backpack; postural; psychological; and environmental factors. Specific risk factors identified in adolescents included age (being older) and poorer mental health.

Flail chest is a life-threatening medical condition that occurs when a segment of the rib cage breaks due to trauma and becomes detached from the rest of the chest wall. Two of the symptoms of flail chest are chest pain and shortness of breath.

It occurs when multiple adjacent ribs are broken in multiple places, separating a segment, so a part of the chest wall moves independently. The number of ribs that must be broken varies by differing definitions: some sources say at least two adjacent ribs are broken in at least two places, some require three or more ribs in two or more places. The flail segment moves in the opposite direction to the rest of the chest wall: because of the ambient pressure in comparison to the pressure inside the lungs, it goes in while the rest of the chest is moving out, and vice versa. This so-called "paradoxical breathing" is painful and increases the work involved in breathing.

Flail chest is usually accompanied by a pulmonary contusion, a bruise of the lung tissue that can interfere with blood oxygenation. Often, it is the contusion, not the flail segment, that is the main cause of respiratory problems in people with both injuries.

Surgery to fix the fractures appears to result in better outcomes.

Familial thoracic aortic aneurysm is an autosomal dominant disorder of large arteries.

There is an association between familial thoracic aortic aneurysm, Marfan syndrome and massive baclofen overdose as well as other hereditary connective tissue disorders.

Numerous associated abnormalities of other organ systems may be present. This heterogeneity requires comprehensive evaluation of all patients and treatment regimes that can vary from modification of activities to extensive spinal surgeries. Furthermore, it is unclear whether Klippel–Feil syndrome is a unique disease, or if it is one part of a spectrum of congenital spinal deformities. Klippel–Feil syndrome is usually diagnosed after birth.

The most common sign of the disorder is restricted mobility of the neck and upper spine. A short neck and low hairline at the back of the head may occur in some patients.

Associated abnormalities may include:

- scoliosis (side-to-side curvature of the spine), which is abnormal curving of the spine. The spine sometimes appears as a "C" or an "S"

- spina bifida, when the spinal canal and the back bone do not close completely during birth

- anomalies of the kidneys and the ribs

- cleft palate (hole in the roof of the mouth)

- dental problems (late dentition, high-risk of caries, oligo- and hypodontia)

- respiratory problems

- heart malformations

- short stature

- Duane syndrome

- Approximately 35% of patients with Klippel–Feil syndrome will also have a congenital elevation of the scapula known as Sprengel's deformity

The disorder also may be associated with abnormalities of the head and face, skeleton, sex organs, muscles, brain and spinal cord, arms, legs, fingers and heart defects. These heart defects often lead to a shortened life expectancy, the average being 35–45 years of age among males and 40–50 among females. This condition is similar to the heart failure seen in gigantism.

In 2011, a study identifying the occurrence of symptoms of 100 patients was published.

Thoracic endometriosis is characterised by onset of the following clinical situations within 24 hours prior to and 72 hours after onset of menses.

- Catamenial pneumothorax: this is the most common clinical manifestation, present in 80% of cases. Catamenial pneumothorax is defined as a recurrent pneumothorax that occurs within the first 72 hours after menstruation. It may not necessarily occur with every menstrual cycle and in most cases is one-sided and right side. There are particular cases of catamenial pneumothorax on the left side, and on very rare occasions there may be a bilateral catamenial pneumothorax. Symptoms are the same as for any other pneumothorax: chest pain, cough and breathlessness. Symptoms are usually mild but there may be severe presentations.

- Catamenial hemothorax: this is a rare manifestation of thoracic endometriosis, occurring in 14% of cases. Almost always, the right side is involved but has reported one case of a bilateral catamenial hemothorax. The most common presenting symptoms are nonspecific and include cough, chest pain and shortness of breath. In some cases, signs may mimic pulmonary embolism. The quantity of blood loss varies, but severe anemia is possible. In almost all cases, chest x-ray shows the presence of pleural effusion without specific characteristics. A CT scan may show additional features such as nodular lesions of the pleura, multiloculated effusions, or bulky pleural masses.

- Cyclic haemoptysis: haemoptysis during menstruation is extremely rare, with about 30 case reports in medical literature. Currently, there have been no reports of massive haemoptysis or death. Cyclic haemoptysis is a sign of pulmonary parenchymal endometriosis; ectopic endometrial tissue in the lung responds to cyclical hormonal variation, bleeding along with the normal endometrium located in the uterus.

- Pulmonary nodules: nodules are common radiological features in patients with thoracic endometriosis; most cases are associated with catamenial haemoptysis.

Apart from the previously mentioned clinical manifestations, the patient may suffer from dysmenorrhoea and irregular menses.

"Widened mediastinum/mediastinal widening" is where the mediastinum has a width greater than 6 cm on an upright PA chest X-ray or 8 cm on supine AP chest film.

A widened mediastinum can be indicative of several pathologies:

- aortic aneurysm

- aortic dissection

- aortic unfolding

- aortic rupture

- hilar lymphadenopathy

- anthrax inhalation - a widened mediastinum was found in 7 of the first 10 victims infected by anthrax ("Bacillus anthracis") in 2001.

- esophageal rupture - presents usually with pneumomediastinum and pleural effusion. It is diagnosed with water-soluble swallowed contrast.

- mediastinal mass

- mediastinitis

- cardiac tamponade

- pericardial effusion

- thoracic vertebrae fractures in trauma patients.

A cervical rib in humans is an extra rib which arises from the seventh cervical vertebra. Sometimes known as "neck ribs", their presence is a congenital abnormality located above the normal first rib. A cervical rib is estimated to occur in 0.2% (1 in 500 people) to 0.5% of the population. People may have a cervical rib on the right, left or both sides.

Most cases of cervical ribs are not clinically relevant and do not have symptoms; cervical ribs are generally discovered incidentally. However, they vary widely in size and shape, and in rare cases, they may cause problems such as contributing to thoracic outlet syndrome, because of pressure on the nerves that may be caused by the presence of the rib.

A cervical rib represents a persistent ossification of the C7 lateral costal element. During early development, this ossified costal element typically becomes re-absorbed. Failure of this process results in a variably elongated transverse process or complete rib that can be anteriorly fused with the T1 first rib below.

On imaging, cervical ribs can be distinguished because their transverse processes are directed inferolaterally, whereas those of the adjacent thoracic spine are directed anterolaterally.

The presence of a cervical rib can cause a form of thoracic outlet syndrome due to compression of the lower trunk of the brachial plexus or subclavian artery. These structures become encroached upon by the cervical rib and scalene muscles.

Compression of the brachial plexus may be identified by weakness of the muscles around the muscles in the hand, near the base of the thumb. Compression of the subclavian artery is often diagnosed by finding a positive Adson's sign on examination, where the radial pulse in the arm is lost during abduction and external rotation of the shoulder. A positive Adson's sign is non-specific for the presence of a cervical rib however, as many individuals without a cervical rib will have a positive test.

Pneumothorax and haemothorax are discussed above, and are rarely life-threatening. Otherwise, the most common complication is progressive tissue damage or scarring related to inflammation, and in extremely rare cases malignant transformation of the endometrial tissue.

Tumor-like disorders of the lung pleura are a group of conditions that on initial radiological studies might be confused with malignant lesions. Radiologists must be aware of these conditions in order to avoid misdiagnosing patients. Examples of such lesions are: pleural plaques, thoracic splenosis, catamenial pneumothorax, pleural pseudotumor, diffuse pleural thickening, diffuse pulmonary lymphangiomatosis and Erdheim-Chester Disease.

Traumatic asphyxia occurs when a powerful compressive force is applied to the thoracic cavity. This is most often seen in motor vehicle accidents, as well as industrial and farming accidents. However, it can present anytime a significant pressure is applied to the thorax.

Klippel–Feil syndrome is a rare disease, initially reported in 1884 by Maurice Klippel and André Feil from France, characterized by the congenital fusion of any two of the seven cervical vertebrae.

The syndrome occurs in a heterogeneous group of patients unified only by the presence of a congenital defect in the formation or segmentation of the cervical spine. Klippel-Feil results in limited movement of the neck. Klippel–Feil syndrome is sometimes identified by shortness of the neck, but not all people with this disorder have a visibly shortened neck. Some people with the syndrome have a very low hairline.

In 1919, in his PhD thesis, André Feil suggested another classification of the syndrome encompassing not only deformation of the cervical spine but also deformation of the lumbar and thoracic spine.

Traumatic asphyxia, or Perthes' syndrome, is a medical emergency caused by an intense compression of the thoracic cavity, causing venous back-flow from the right side of the heart into the veins of the neck and the brain.

A chylothorax (or chyle leak) is a type of pleural effusion. It results from lymph formed in the digestive system called chyle accumulating in the pleural cavity due to either disruption or obstruction of the thoracic duct.

In people on a normal diet, this effusion can be identified by its turbid, milky white appearance, since chyle contains high levels of triglycerides. It is important to distinguish chylothorax from pseudochylothorax (pleural effusions high in cholesterol), which has a similar appearance, but is caused by more chronic inflammatory processes, and has a different treatment.

Two of the symptoms of flail chest are chest pain and shortness of breath.

The characteristic paradoxical motion of the flail segment occurs due to pressure changes associated with respiration that the rib cage normally resists:

- During normal inspiration, the diaphragm contracts and intercostal muscles pull the rib cage out. Pressure in the thorax decreases below atmospheric pressure, and air rushes in through the trachea. The flail segment will be pulled in with the decrease in pressure while the rest of the rib cage expands.

- During normal expiration, the diaphragm and intercostal muscles relax increasing internal pressure, allowing the abdominal organs to push air upwards and out of the thorax. However, a flail segment will also be pushed out while the rest of the rib cage contracts.

The constant motion of the ribs in the flail segment at the site of the fracture is extremely painful, and, untreated, the sharp broken edges of the ribs are likely to eventually puncture the pleural sac and lung, possibly causing a pneumothorax. The concern about "mediastinal flutter" (the shift of the mediastinum with paradoxical diaphragm movement) does not appear to be merited. Pulmonary contusions are commonly associated with flail chest and that can lead to respiratory failure. This is due to the paradoxical motions of the chest wall from the fragments interrupting normal breathing and chest movement. Typical paradoxical motion is associated with stiff lungs, which requires extra work for normal breathing, and increased lung resistance, which makes air flow difficult. The respiratory failure from the flail chest requires mechanical ventilation and a longer stay in an intensive care unit. It is the damage to the lungs from the flail segment that is life-threatening.

Paget–Schroetter disease, also known as Paget–von Schrötter disease, is a form of upper extremity deep vein thrombosis (DVT), a medical condition in which blood clots form in the deep veins of the arms. These DVTs typically occur in the axillary or subclavian veins.

About 96% of individuals with aortic dissection present with severe pain that had a sudden onset. The pain may be described as a tearing, stabbing, or sharp sensation; 17% of individuals feel the pain migrate as the dissection extends down the aorta. The location of pain is associated with the location of the dissection. Anterior chest pain is associated with dissections involving the ascending aorta, while interscapular (back) pain is associated with descending aortic dissections. If the pain is pleuritic in nature, it may suggest acute pericarditis caused by bleeding into the pericardial sac. This is a particularly dangerous eventuality, suggesting that acute pericardial tamponade may be imminent. Pericardial tamponade is the most common cause of death from aortic dissection.

While the pain may be confused with the pain of a myocardial infarction (heart attack), aortic dissection is usually not associated with the other signs that suggest myocardial infarction, including heart failure and ECG changes.

Individuals with aortic dissection who do not present with pain have a chronic dissection.

Less common symptoms that may be seen in the setting of aortic dissection include congestive heart failure (7%), fainting (9%), stroke (6%), ischemic peripheral neuropathy, paraplegia, and cardiac arrest. If the individual had a fainting episode, about half the time it is due to bleeding into the pericardium leading to pericardial tamponade.

Neurological complications of aortic dissection (i.e., stroke and paralysis) are due to the involvement of one or more arteries supplying portions of the central nervous system.

If the aortic dissection involves the abdominal aorta, compromise of the branches of the abdominal aorta is possible. In abdominal aortic dissections, compromise of one or both renal arteries occurs in 5–8% of cases, while mesenteric ischemia (ischemia of the large intestines) occurs 3–5% of the time.