In epidural lumbar puncture, all structure are pierced except -
Structure pierced during lumbar puncture (from outside in) are :-

Skin → Subcutaneous tissue → Supraspinous & interspinous ligament → Ligament flavum → Dura matter → Arachnoid matter.
Posterior longitudinal ligament
Ligamentum flavum
Interspinous ligament
Supraspinous ligament