While bubbles can form anywhere in the body,<unk>  is most frequently observed in the shoulders, elbows, knees, and ankles. Joint pain ("the bends") accounts for about 60% to 70% of all altitude<unk>  cases, with the shoulder being the most common site for altitude and bounce diving, and the knees and hip joints for saturation and compressed air work. Neurological symptoms are present in 10% to 15% of<unk>  cases with headache and visual disturbances being the most common symptom. Skin manifestations are present in about 10% to 15% of cases. Pulmonary<unk>  ("the chokes") is very rare in divers and has been observed much less frequently in aviators since the introduction of oxygen pre-breathing protocols. The table below shows symptoms for different<unk>  types. + Signs and symptoms of<unk> <unk>  type Bubble location Signs & symptoms (clinical manifestations) Musculoskeletal Mostly large joints of the limbs (elbows, shoulders, hip, wrists, knees, ankles) * Localized deep pain, ranging from mild to excruciating. Sometimes a dull ache, more rarely a sharp pain. * Active and passive motion of the joint may aggravate the pain. * The pain may be reduced by bending the joint to find a more comfortable position. * If caused by altitude, pain can occur immediately or up to many hours later. Cutaneous Skin * Itching, usually around the ears, face, neck, arms, and upper torso * Sensation of tiny insects crawling over the skin (formication) * Mottled or marbled skin usually around the shoulders, upper chest and abdomen, with itching (cutis marmorata) * Swelling of the skin, accompanied by tiny scar-like skin depressions (pitting edema) Neurologic Brain * Altered sensation, tingling or numbness (paresthesia), increased sensitivity (hyperesthesia) * Confusion or memory loss (amnesia) * Visual abnormalities * Unexplained mood or behaviour changes * Seizures, unconsciousness Neurologic Spinal cord * Ascending weakness or paralysis in the legs * Urinary incontinence and fecal incontinence * Girdling (also referred to as girdle, banding, or tightening feeling) around the abdominal region and/or chest Constitutional Whole body * Headache * Unexplained fatigue * Generalised malaise, poorly localised aches Audiovestibular Inner ear * Loss of balance * Dizziness, vertigo, nausea, vomiting * Hearing loss Pulmonary Lungs * Dry persistent cough * Burning chest pain under the sternum, aggravated by breathing * Shortness of breath Frequency The relative frequencies of different symptoms of<unk>  observed by the U.S. Navy are as follows: + Symptoms by frequency Symptoms Frequency local joint pain 89% arm symptoms 70% leg symptoms 30% dizziness 5.3% paralysis 2.3% shortness of breath 1.6% extreme fatigue 1.3% collapse/unconsciousness 0.5% Onset Although onset of<unk>  can occur rapidly after a dive, in more than half of all cases symptoms do not begin to appear for at least an hour. In extreme cases, symptoms may occur before the dive has been completed. The U.S. Navy and Technical Diving International, a leading technical diver training organization, have published a table that documents time to onset of first symptoms. The table does not differentiate between types of<unk> , or types of symptom. + Onset of<unk>  symptoms Time to onset Percentage of cases within 1 hour 42% within 3 hours 60% within 8 hours 83% within 24 hours 98% within 48 hours 100%
Decompression sickness
Morning sickness
Ski sickness
Wooden chest syndrome
Acute HME syndrome
Simulator sickness
Chronic mountain sickness
Acute chest syndrome