Facet Joints. Search. Also known as zygapophyseal or apopphyseal joint, is a synovial joint between the superior articular process of one vertebra and the inferior articular process of the vertebra directly above it. There are two facet joints in each spinal motion segment.
Generally speaking, the ectoderm differentiates to form the nervous system (spine, peripheral nerves and brain), tooth enamel and the epidermis (the outer part of integument).enerally speaking, the ectoderm differentiates to form the nervous system (spine, peripheral nerves and brain), tooth enamel and the epidermis (the outer part of integument).
Medical Definition of ectoderm. 1  1: the outermost of the three primary germ layers of an embryo. 2  2: a tissue (as neural tissue) derived from ectoderm.