In health care, plantar fasciitis is "inflammation of the thick tissue on the bottom of the foot (plantar fascia) causing heel pain. The plantar fascia (also called plantar aponeurosis) are bands of fibrous tissue extending from the calcaneal tuberosity to the toes. The etiology of plantar fasciitis remains controversial but is likely to involve a biomechanical imbalance. Though often presenting along with heel spur, they do not appear to be causally related.".
"A single ultrasound guided dexamethasone injection is a safe and effective short term treatment for plantar fasciitis". However, "significant pain relief did not continue beyond four weeks." 
- Anonymous (2015), Plantar fasciitis (English). Medical Subject Headings. U.S. National Library of Medicine.
- McMillan AM, Landorf KB, Gilheany MF, Bird AR, Morrow AD, Menz HB (2012). "Ultrasound guided corticosteroid injection for plantar fasciitis: randomised controlled trial.". BMJ 344: e3260. DOI:10.1136/bmj.e3260. PMID 22619193. Research Blogging.