JACOBS LOCKING HOOK - Thick, threaded rods for fixation of various spinal deformities.

JARCHO-LEVIN SYNDROME - Extensive defects of the spine with associated defects in the ribs leading to a small, stiff thorax and pulmonary compromise.

JOINT - The junction or articulation of two or more bones that permits varying degrees of motion between the bones.

JOINTS of LUSCHKA (uncovertebral joints) - Unique to the cervical spine, these jointlike structures are formed by the apposition of posterolateral portions of adjacent vertebral bodies; forms the anterior portion of the canal where nerves pass through.

JUGULAR VEIN - The major vein on each side of the neck draining blood from the head towards the heart. Large obvious vein in the neck.

JUVENILE RHEUMATOID ARTHRITIS - generalized inflammatory joint disease in children.

JUVENILE SCOLIOSIS - Begins between the ages of 3 and 10 years of age.