| Sg | Pl | |
| Nom | brjóst | brjóst (rule) |
| Acc | brjóst (rule) | brjóst (rule) |
| Dat | brjósti (rule) | brjóstum (rule) |
| Gen | brjósts (rule) | brjósta (rule) |
| Sg | Pl | |
| Nom | brjóstit (rule) | brjóstin (rule) |
| Acc | brjóstit (rule) | brjóstin (rule) |
| Dat | brjóstinu (rule) | brjóstunum (rule) |
| Gen | brjóstsins (rule) | brjóstanna (rule) |