Ans. b (Herniation of synovium of knee joint) (Ref. Maheshwari orthopedics 3rd/pg. 276)Baker's cyst is formed when synovial fluid (fluid that is produced by the joint lining to lubricate and protect the joints) escapes from the knee joint capsule (also called the synovial sac or synovium) and forms a new sac outside the joint at the back of the knee.Common Lower Limb orthopedic injuries and lesionsInjuryDescriptionTreatmentLisfranc fracture# Fracture through base of second metatarsal# The second metatarsal is the stabilizing force of the tarsometatarsal joint# Surgical fixation (can be open or closed)Maisonneuve fracture# Malleolar (ankle) and proximal fibula fracture with disruption of the medial deltoid ligament# Long leg cast for 6-12 weeks# Surgical fixation for:# Medial malleolar fracture# Widened medial joint spaceBaker's cyst# cyst in the medial popliteal fossa# Associated with arthritis and joint trauma# Rupture of cyst can mimic symptoms of deep vein thrombosis# Treat underlying cause (adults)# Symptomatic relief with NSAIDsCalcaneal fracture# Most frequently injured foot bone# Usually occurs due to fall from a height with patient landing on his feet# posterior splint for nondisplaced fractures# Surgical repair for displaced fracturesJones fracture# Fracture of diaphysis of fifth metatarsal# Usually occurs due to force applied to ball of foot, as in pivoting or dancing# Often complicated by nonunion# Shkort leg cast for nondisplaced fractures# Surgical repair for displaced fractures