The authors agree that this surname has as its base the Latin term spina ("thorn", "sharpened point"). S. Vannozzi specifies that this root goes back to the Indo-European radical spin-, with the general sense of "pointed projection", and notes that the variants La Spina, Spinella and Spinosa share that same origin.

The authors also agree that the surname admits several semantic motivations. E. De Felice distinguishes three paths of formation: the nickname in the figurative sense of "affliction, moral pain"; the religious reference to the spina Christi, that is, the thorn of the crown of Christ; and the abbreviated hypocoristic of the medieval surname Malaspina ("bad thorn, painful thorn"). F. Miranda adds that the first bearers may have lived in localities with abundant thorny vegetation, or may have been devotees of the thorns of the passion of Christ. Miranda further notes that the surname could be an aphaeretic form —through the fall of the initial syllable— of the personal name Crispino, derived from the Latin crispus ("curly, crimped").

As for the toponymic origin, De Felice points out that, especially in the centre-north of Italy, the surname may reflect the place names Spina or Spino, frequent in that area. Miranda specifically mentions Spina di Gualdo, in the Macerata area, and Spina, in the Perugia area, as examples of that connection.

Regarding geographical distribution, the authors agree that it is a pan-Italian surname. E. Rossoni confirms that both Spina and its variant Spinelli are diffused throughout Italy. De Felice observes a high frequency in the south and in Sardinia —where it coexists with the variant in -s, Spinas, typical of Sardinian—, while in the centre-north the forms Spino and Spini appear more sporadically. Miranda highlights an especially marked presence in Sicily, Campania, Calabria, Lazio, Apulia, Piedmont and Sardinia, among other regions.

On specific variants, Rossoni provides more detailed distribution data: Spinella is typically Sicilian, with a greater concentration in the Palermo, Messina and Catania areas, besides the Reggio Calabria area. Spinello has an area in the Turin area —possibly due to internal migrations—, another in Veneto in the Padua, Venice and Rovigo areas, and a third in Sicily, in the Caltanissetta, Ragusa, Syracuse and Catania areas. Spinetta, on the other hand, is located in the Genoa, La Spezia and Massa areas.