This presentation provides a concise histological analysis of the classical intervertebral disc, located between two vertebral bodies. The disc is primarily composed of fibrocartilage, which is histologically defined by the appearance of dense collagenous fibers interspersed with occasional, tiny chondrocytes residing within lacunae. Structurally, the disc is differentiated into two regions optimized for cushioning: the softer, gelatinous, water-rich inner area known as the nucleus pulposus, and the denser, fibrous outer ring called the annulus fibrosis. Both regions are forms of fibrocartilage.
Analyzing the Intervertebral Disc: Histology and Structure
0:07 Location and Composition: The slide shows a classical intervertebral disc situated between two vertebral bodies (made of membranous bone). The connecting tissue is cartilage.
0:0:29 Definition of Fibrocartilage: Fibrocartilage is typically found where bone touches bone, including intervertebral discs, the pubic symphysis, and the menisci of the TMJ and knees.
1:04 Key Identification Algorithm: Fibrocartilage is differentiated from fibrous connective tissue by the presence of a few small chondrocytes living inside lacunae, which is the key diagnostic feature.
1:39 Functional Structure: The intervertebral disc is designed as a cushion, meaning it is softer and more gelatinous on the inside and denser towards the periphery.
1:57 Nucleus Pulposus: The looser, inner region of the disc, which contains considerably more water, is called the nucleus pulposus (named because it is pulpy).
2:08 Annulus Fibrosis: The outer, peripheral fibrocartilage is more fibrous, dense, and ring-like, and is therefore called the annulus fibrosis.
2:21 Key Takeaway: Both the nucleus pulposus and the annulus fibrosis are composed of fibrocartilage and together constitute the intervertebral disc.