Category: B

The preferred term for a thin layer of delicate noncellular material of a fine filamentous texture underlying the epithelium. Its principal component is collagen.  

The basal plate of the embryonic nervous system, which later develops into the ventral horns of the gray matter of the spinal cord.  

Plates of collagen fibers, 3 to 7 μm thick, found in secondary (mature, adult) bone and surrounded by cementing substance, the mineralized bone matrix. Some lamellae are parallel to each other. Other lamellae are aligned concentrically around a vascular canal — a structure known as a haversian system or osteon.  

Labor involving malposition of the fetal head with the occiput opposing the mother’s sacrum. The laboring woman experiences severe back pain.  

Blistering of the cornea, accompanied by corneal swelling.  

Band-shaped calcium deposits in the superficial layer of the cornea and Bowman’s membrane. This occurs with chronic intraocular inflammation such as in juvenile rheumatoid arthritis, and with systemic diseases in which there is hypercalcemia.  

Hemorrhage into joint space in hemophiliacs.  

A joint separated into two sections by interarticular cartilage.  

A joint possessing two chief movement axes at right angles to each other.  

A joint in which the round end of one bone fits into the cavity of another bone. A robust and structurally strong type of joint where one bone’s head snugly fits into a deep socket within another bone. The most formidable ball-and-socket joint found in the human body is the hip joint.