500.A 25-year-old woman is brought to the emergency room by her
roommate because she has a fever of 102°F, stiff neck, and the “worst
headache of her life.” You check the fundus of her eyes for any evidence of
papilledema and there is none. In addition to collecting blood to be sent to
the lab for evidence of sepsis, the attending recommends you perform a
spinal tap to obtain CSF for evidence of infection. What landmarks and lig-
aments do you need to remember when performing a spinal tap?
a. The umbilicus, which tells you where dermatome T10 is, and the sacrococ-
cygeal ligament, which you must penetrate
b. The posterior superior iliac crest, which are parallel with spinous process of L4,
and supraspinous, intraspinous, ligamentum flavum, which you must pene-
trate prior to piercing the dura and arachnoid membranes
c. The anterior superior iliac crest, which are parallel with spinous process of L2,
and supraspinous, intraspinous, ligamentum flavum, which you must pene-
trate prior to piercing the dura and arachnoid membranes
d. The sacral cornu, which demarcate the sacral hiatus, and the sacrococcygeal lig-
ament, which you must penetrate to get access to the extradural space
e. The posterior superior iliac crest, which are parallel with spinous process of S2,
and supraspinous, interspinous, ligamentum flavum, which you must pene-
trate prior to piercing the dura and arachnoid membranes
Extremities and Spine 587