A.T. Robertson Commentary Matthew 26:7

"there came unto him a woman having an alabaster cruse of exceeding precious ointment, and she poured it upon his head, as he sat at meat." — Matthew 26:7 (ASV)

An alabaster cruse of exceeding precious ointment (αλαβαστρον μυρου βαρυτιμου). The flask was of alabaster, a carbonate of lime or sulphate of lime, white or yellow stone, named alabaster from the town in Egypt where it was chiefly found. It was used for a phial employed for precious ointments in ancient writers, inscriptions and papyri just as we speak of a glass for the vessel made of glass. It had a cylindrical form at the top, as a rule, like a closed rosebud (Pliny). Matthew does not say what the ointment (μυρου) was, only saying that it was "exceeding precious" (βαρυτιμου), of weighty value, selling at a great price. Here only in the N.T. "An alabaster of nard (μυρου) was a present for a king" (Bruce). It was one of five presents sent by Cambyses to the King of Ethiopia (Herodotus, iii. 20).

She poured it upon his head (κατεχεεν επ της κεφαλης αυτου). So Mark , while John (John 12:3) says that she "anointed the feet of Jesus." Why not both? The verb κατεχεεν is literally to pour down. It is the first aorist active indicative, unusual form.