Tretten is a village in Øyer Municipality in Innlandet county, Norway. The village is located on the Losna lake, which is part of the Gudbrandsdalslågen river. Tretten is located in the Gudbrandsdal valley, along the Gudbrandsdalslågen river in the southern part of the municipality. It is located along the European route E6 highway, about 25 kilometres (16 mi) north of the town of Lillehammer. The municipal center of Tingberg lies about 5 kilometres (3.1 mi) to the southeast of Tretten. The 1.22-square-kilometre (300-acre) village has a population (2021) of 860 and a population density of 707 inhabitants per square kilometre (1,830/sq mi).The village had its own sports team Tretten IL until 1990, when a merger created Øyer-Tretten IF. The village is also the site of Tretten Church which serves the northern part of the municipality. Tretten was the location of the biggest train disaster in Norways history. The Tretten train disaster occurred on 22 February 1975 when two passenger trains collided head on. The tragedy resulted in 27 people being killed. On 15 August 2022, the Tretten Bridge over the Gudbrandsdalslågen river completely collapsed; it had beams of glued laminated timber and others of weathering steel. There were no fatalities. One vehicle driver was rescued by helicopter and the driver of a car escaped by himself. Name
The village (and church parish) is named after the old Tretten farm (Old Norse: Þrœttin or Þróttvin) since the first church was built there. This farm is now named Prestgarden which means the vicarage.
ulnar nerve, 2 cases) or median nerve, 1 case), hip/lower limb (i.e. sciatic nerve, 1 case), and lumbar spine/pelvis/thigh (i.e. the obturator nerve, 1 case). Individual cases of NF have been reported to occur in the lower female genital tract, bladder, prostate, tongue, and parotid gland. In some cases, NF tumors have  regressed after incisional biopsy, i.e. a biopsy that takes a small part of the diseased tissue.The cranial fasciitis variant of NF occurs in the soft and hard cranial tissues of the outer layers of the skull. Patients with this variant are more commonly males than females and almost exclusively between 3 weeks and 6 years of age. They typically present with a tumor in areas of the head that lay directly over the temporal or parietal bones. Individual cases have been reported to occur in the lower jaw, frontonasal region, anterior nasal spine (i.e. nasal process of the maxilla), and the orbit (i.e. eye socket)-maxilla area. Characteristically, the tumor is rapidly enlarging, non-painful, rarely regressing without treatment, and potentially expanding into the skulls interior.In a review of 50 cases, the intravascular fasciitis variant of NF occurred in individuals aged 6 months to 66 years (median age 27 years) with male and females being equally affected (52%:48%). Individuals with this variant commonly presented with a blood vessel-localized tumor of the head and neck area (34% of cases), lower extremity (32% of cases), upper extremity (20% of cases), or trunk (14% of cases).