Which statement best describes the sub-classes of synarthrodial joints?

The correct choice accurately defines the sub-classes of synarthrodial joints as comprising cartilaginous, fibrous, and ligamentous types. Synarthrodial joints are characterized by their lack of joint cavity and a high degree of stability, allowing little to no movement.

Fibrous structures, such as sutures found in the skull, provide firm connections between bones without allowing any movement. Cartilaginous connections, such as those found at the growth plates or the pubic symphysis, allow for slight movement while providing structure and strength. Additionally, certain ligamentous joints, which are less commonly classified under synarthroses, can also fall within this category by connecting bones with dense connective tissue that restricts motion.

Other options do not encompass the full classification of synarthrodial joints, thereby overlooking the comprehensive nature of these joint types.