A Diver Experienced Arm Swelling 10 Days Postdive


  • Father and son divers were vacationing in the Caribbean for 12 days, completing around 20 dives.
  • One week after returning home, the son noticed his shoulder was hurting, thought it was muscle soreness and continued with his day.
  • One day later his arm was very swollen. His father took him to the doctor where a CT scan was ordered.

Reported Story

Two divers — father and son — dove in the Caribbean for 12 days, completing about 20 dives. 

One week after returning home, on a Saturday, the younger diver noticed his shoulder was hurting. He thought he’d slept wrong and proceeded to work all weekend. On Monday when he was stowing gear in his studio, he needed help, as it turned out his right arm was very swollen.

When the diver’s father saw it, he assumed a spider bite and took his son to the doctor because he was unable to drive. 

The doctor called in two other doctors, and they ordered a CT scan. At that point they suspected a blood clot. The imaging prompted the treating physician to send the diver to the emergency department, where additional tests were done, and the diver was admitted to the hospital. While the doctors had not found a blood clot, a clot was strongly suspected, so they put him on a blood thinner via IV and ran more tests. 

Things got worse the next day, and doctors finally diagnosed a compressed artery in the diver’s right shoulder. That diagnosis was soon amended to include the vein.

Further imaging got to the root cause: thoracic outlet syndrome (TOS). TOS occurs when the gap between the clavicle and first rib doesn’t have the normal opening that would accommodate the neural-vascular bundle. In this diver’s case, the developed circulatory network made it clear this had been present since birth and a recent event had finally gotten kinked enough to restrict the flow.

The diver underwent surgery to remove his first rib, and everything went well.


Thoracic outlet syndrome refers to a group of conditions in which there is compression of the nerves, arteries or veins in the passageway from the lower neck to the armpit, between the collarbone and the first rib. TOS may result from trauma, repetitive arm movements, tumors, pregnancy or anatomical variations such as a cervical rib. Depending on what structure is affected, the symptoms may appear as neurogenic, vascular or nonspecific.

In the majority of cases, the symptoms are neurogenic and affect the brachial plexus, a bundle of nerves that control movements of the shoulder, arm and hand. Symptoms may include numbness and tingling in the arm and fingers, pain or aches in the shoulder, arm and hand, weakening of hand grip and a decrease in muscle mass, especially around the thumb.

In case of vascular thoracic outlet syndrome, signs and symptoms may include bluish coloration in the hand, pain and swelling in the arm, a blood clot in veins or arteries, pale and cold fingers or hand, weak or absent pulse in the affected arm, weakness and fatigue of the arm.


Discussion among a team of thoracic surgeons pinned the probable cause on the 20 dives with a tank and weights over two weeks. They figured it would’ve happened eventually, but this sped it up. As it had been more than 10 days since his last dive before symptoms appeared, decompression sickness (DCS) was promptly ruled out. 

Possible causes are anatomical defects, poor posture, trauma or pregnancy. Trauma may occur acutely, such as in a car accident, or chronically due to repeated activity such as pitching in baseball, swimming, stocking shelves or even typing on a computer. Carrying a heavy backpack or scuba equipment may contribute to it. Usually, there is a delay between the trauma and the symptom onset.

Women and adults 20 to 40 years old are more commonly affected than the rest of the population.