Undarum in Ulnis.

Ing. He has his hands full
Ing. He is up to the elbows in business

Persons were said to be up to the elbows in the sea and striving with them against the waves, who were contending with difficulties which threatened to overwhelm them. A similar phrase is used by us, speaking of persons who have more than sufficient employment, he has his hands full, we say, or he is up to the elbows in business.

Fuente: Erasmo, 3539.