A physician orders a lumbar puncture (spinal tap) for his 43…

A physician orders a lumbar puncture (spinal tap) for his 43-year-old female patient in order to obtain a sample of cerebrospinal fluid (CSF) to diagnose bacterial versus viral meningitis. He explains to her that this procedure will be done in the lower back, between the spinous processes of the L3 and L4 vertebrae. What is the anatomical basis for performing the lumbar puncture at this location?

Following an injury suffered in a soccer match, a 32-year-ol…

Following an injury suffered in a soccer match, a 32-year-old female is examined in a seated position in the clinic. As the clinician holds the right tibia with both hands and pulls the tibial forward under the distal part of the femur, there is gapping at the joint where the tibia is excessively translated anteriorly. The left tibia cannot be displaced in this way. Which structure is most likely damaged in the right knee?