Depictions of Underarm Phalanxes

[Macedon]

I also think that most people misunderstand underarm fighting. In a phalanx you would never try to fight underarm against the enemy's torso (would be protected by his shield) or head (the angle would be too weird). Underarm fighting while in phalanx would aim at the enemy legs and feet, so you would keep your spear well under your shield too. Such harassment can be a real problem, especially if you are not fully armored on the leg area and makes you wanna bend down...