What are some motifs of imprisonment in Henrik Ibsen's A Doll's House ?

One motif of imprisonment is
the loan Nora withdrew from Krogstad several years ago. At
the time, Nora thought she was taking out the loan in order to liberate herself and her
husband by rescuing his health. While rescuing her husband's health certainly did
provide for her more security than she would have had otherwise, the loan has also been
a point of imprisonment for her. For years she has had to save every penny she could
from her housekeeping money, especially money for her clothing. Having to save money on
clothing has been a source of emotional imprisonment for her because, as she explains to
Christine, "[I]t was often very hard on me, Christine--because it is delightful to be
really well dressed, isn't it?" (I). In addition, she had to earn money by finding any
work she could do behind Torvald's back. One winter she "was lucky enough to get a lot
of copying to do" and locked herself up in her room working until late at night
(I).

Another motif of imprisonment is of
course the signature Nora forged on the bond for the loan.
At the time, Nora did not consider it to be a serious matter and did it to save her
husband. However, now Krogstad is blackmailing her with her forged signature as a threat
against her reputation and her husband's reputation in order to try and secure his job
at the bank thereby imprisoning her with the forged signature.

A third
motif of imprisonment we see is Dr. Rank's
illness. Dr. Rank has what Nora refers to as "consumption of the spine,"
otherwise called Pott disease, and claims that his illness is due to Dr. Rank's father's
immoral, overly indulgent character. As Nora explains to Christine, "His father was a
horrible man who committed all sorts of excesses; and that is why his son was sickly
from childhood" (II). As Dr. Rank explains, "My poor innocent spine has to suffer for my
father's youthful amusements," such as his father's indulgences in "asparagus," "pâté de
foie gras," "and heaps of port and champagne" (II). According to Dr. Rank, all of his
father's indulgences wreaked havoc on his own immune system. Dr. Rank is therefore
imprisoned by his father's own sins. He is paying the consequences for his father's sins
by having to die young. Dr. Rank considers his upcoming premature death as an unfair
imprisonment.