The active player may play any number of item cards during his turn. To play an item card, the player places it faceup in his play area. The item is now being carried by the player’s wizard. The text on the item card indicates when the carried item can be used.
While a temporary or permanent spell remains active, its caster must maintain the spell. To do so, the casting player simply leaves the card faceup in his play area. Maintained spells count against the caster’s maximum hand size, so there is a practical limit to how many spells can be maintained at once. Thus, if a player has six cards in hand and one maintained spell, he has a total of seven cards and is at his normal maximum hand size.
Carried items count toward a player’s hand size. If a wizard picks up an object that would take the player above his maximum hand size, then he must first discard a card, end a maintained spell, or drop a carried item to make room for the object. A wizard can carry any number of items as long as his player does not exceed his maximum hand size.
So an Item card counts as a card in your hand, as you have to put it in play like any other Permanent. Then the item itself counts as a card in your hand, as per the rules for carried items. The net total is that summoning an item counts as 2 cards to your hand.