Antarctic expeditions are exceptional challenges for the human body, and medical issues such as nutritional deficiencies, polar anemia, cold injuries, and even death have been reported. We prospectively investigated medical issues encountered by a 33-year-old female adventurer completing the longest solo unsupported one-way polar ski expedition in Antarctica, covering 1484.53 km in 70 days and 16 h from Hercules Inlet to the Ross Ice Shelf, in temperatures estimated from -12 to -50°C and wind speeds of up to 60 mi/h. The adventurer developed a debilitating overuse musculoskeletal neck injury due to poor environmental conditions (ie, poor visibility, wind, and soft snow) while pulling a heavy sled and continuously holding the neck in a flexed position for checking directions on a mounted compass. The adventurer further developed a cold injury on the left calf (polar thigh) that gradually worsened and became ulcerated and more painful throughout the expedition. Potential risk factors included cold ambient temperatures, exposure to windy conditions, and clothing. After the expedition, this injury was treated with a skin graft. Important changes in body mass were observed (ie, reduction of body mass by 26.7% after the expedition) as well as general fatigue, muscle soreness, and sleep deterioration. This case study contributes to the body of knowledge of medical issues during Antarctic expeditions and provides the first scientific account of an adventurer with polar thigh. Further research into this condition is recommended.