Dimerization of Immunoglobulin G
For human IgG1 and 4, the only inter-heavy chain disulfide bonds are the two in the hinge region. IgG2 has 4 disulfides in the hinge, and IgG3 has 11:



There are intra-heavy chain disulfides in the Fc region, and of course there are non-covalent bonds between the two heavy chains (as well as the light chains) to maintain structure, but aside from the hinge region the only other inter-chain disulfides are between heavy and light.

Here is an interesting review of classical (determined in the 1960s) and non-classical (more recently discovered) disulfide bond formation and structure in human IgGs.