Table 2.

Symphyseal classes by Scapino (5).

Symphyseal classes (5)	Symphyseal plates	Symphyseal space	Fibrocartilagineuos pad	Soft tissues	Symphyseal flexibility
Class I	Flat or with few, low interdigitating irregularities (ridges and valleys); a smooth, conspicuous craniodorsal area	Wider caudally than rostrally	Cuneiform shape, wider dorsally than ventrally on transverse section and wider rostrally than caudally in coronal section	Threewalled fibrous capsule, deep dense fibrous ligaments [dorsal transverse, ventral transverse, ventral oblique (external) and internal cruciate (central area)]; a central and aboundant venous plexus, wider caudally than rostrally	Maximum flexibility: basic movements visible to the naked eye and manually easy to produce
Class II	Ridges and valleys more numerous and intimately related than in class I; presence of a smooth craniodorsal area	Narrower as compared to class I, with approximately the same width all along the symphysis	Thinner as compared to class I	Thick and short fibrocartilagineus and fibrous ligament fibers running nearly transversely across the joint; venous plexus less abundant rostrally than caudally	Limited flexibility: visible movements, but manually more difficult to produce
Class III	Plates irregularities taller and interdigitating more that in class II; absent or small smooth craniodorsal area	Narrower space as compared to class II, wth approximately the same width all along the symphysis	Smaller as compared to class II, irregular in shape	Ligaments fibers mostly transverse and caudally irradiated in all directions; reduced or nearly absent venous plexus as compared to class II	Stiff: minute amounts of visible movements under forceful manipulation
Class IV	Bony fusion	Not present	Not present	Absent, with non-lamellar bone obliterating the joint space	Rigid: no visible movements