Fracture blisters occur on skin overlying a fractured bone, and fractures complicated by the development of overlying blisters remain a clinical dilemma in orthopedics. : 43 Fracture blisters are tense vesicles or bullae that arise on markedly swollen skin directly overlying a fracture. Fracture blisters pop up in trauma patients occasionally. A fracture blister typically occurs near fractures where the skin has little subcutaneous tissue between it and bone. These include elbows, knees, ankles, and wrists. They tend to complicate fracture management because they interfere with splinting, casting, and incision planning for open reduction procedures. They can appear anytime within a few hours of injury to 2–3 weeks later. These blisters are thought to be caused by shearing forces applied at the time of injury. There are two types described, based on their color: clear fluid and hemorrhagic. The difference lies in the level of the shear. Clear fluid blisters have separated within the epidermis, and hemorrhagic blisters separate at the dermal-epidermal junction. The clinical difference is healing time; clear blisters take about 12 days and hemorrhagic blisters heal in about 16 days. The decision to pop the blisters in order to treat the fracture, or wait for them to heal first usually hinges on the preferences of the orthopaedic surgeon as there is a lack of data on what treatment is ideal. Waiting delays care an average of 7 days, and longer for tibial plateau and calcaneal fractures. Operating immediately anecdotally increases wound infection rates. Additional images


== References ==
In the last half-century, however, a focus on behavioral and genetic testing of mammals has accumulated extensive evidence of at least dichromatic color vision in a number of mammalian orders. Mammals are now usually assumed to be dichromats (possessing S- and L-cones), with monochromats viewed as the exceptions. Two mammalian orders containing marine mammals exhibit monochromatic vision:

Pinnipeds (including seals, sea lions and walruses)
Cetaceans (including dolphins and whales)Unlike the trichromacy exhibited in most primates, Owl monkeys (genus Aotus) are also monochromats. Several members of the family Procyonidae (raccoon, crab-eating raccoon and kinkajou) and a few rodents have been demonstrated as cone monochromats, having lost functionality of the S-cone (retaining the L-cone).The light available in an animals habitat is a significant determiner of a mammals color vision. Marine, Nocturnal or Burrowing mammals, which experience less light, have less evolutionary pressure to preserve dichromacy, so often evolve monochromacy.A recent study using through PCR analysis of genes OPN1SW, OPN1LW, and PDE6C determined that all mammals in the cohort Xenarthra (representing sloths, anteaters and armadillos) developed rod monochromacy through a stem ancestor. See also
Achromatopsia
Blue cone monochromacy
Cone dystrophy
Dichromacy
Trichromacy
Tetrachromacy

References
External links
Rossi, Ethan (February 2013). "Visual Function and Cortical Organization in Carriers of Blue Cone Monochromacy". PLOS ONE. 8 (2): e57956. Bibcode:2013PLoSO...857956R. doi:10.1371/journal.pone.0057956. PMC 3585243. PMID 23469117. Weleber, Richard (June 2002). "Infantile and childhood retinal blindness: A molecular perspective (TheFranceschetti Lecture)". Ophthalmic Genetics. 23 (2): 71–98. doi:10.1076/opge.23.2.71.2214. PMID 12187427. S2CID 30741530.