Correct Answer: C. Hyaline Cartilage
Hyaline cartilage is the most abundant and widely distributed cartilage type in the human body. Histologically, it is characterised by a homogeneous, glassy (translucent) basophilic matrix with no visible fibres under routine H&E staining — the collagen present (type II) is masked because it has the same refractive index as the surrounding ground substance. Chondrocytes are housed in lacunae, often arranged in isogenous groups (cell nests), surrounded by a deeply staining territorial matrix (capsule) and a lighter interterritorial matrix. The notation "La d" in the image most likely refers to lacunae and the surrounding dense matrix, hallmark features of hyaline cartilage on histological sections.
Hyaline cartilage is found in the articular surfaces of synovial joints, costal cartilages, tracheal rings, bronchi, laryngeal cartilages (thyroid, cricoid), and the nasal septum. It is avascular, aneural, and relies on diffusion for nutrition. Its matrix is rich in type II collagen, aggrecan (a large proteoglycan), and water, giving it compressive strength and a smooth, uniform appearance under the microscope — the defining visual feature that distinguishes it from the other cartilage types.
The image shows a uniform, featureless matrix with chondrocytes in lacunae and no visible fibrous elements — a classic presentation of hyaline cartilage. The absence of dark-staining elastic fibres rules out elastic cartilage, and the absence of coarse collagen bundles rules out fibrocartilage.
Why Other Options Are Wrong
- A. Articular cartilage — Articular cartilage is a form of hyaline cartilage, but it is a subset, not a separate cartilage type in standard histological classification. As a standalone answer, it is too specific and does not represent the general category being tested here. The image depicts generic hyaline cartilage, not a site-specific articular surface.
- B. Elastic cartilage — Elastic cartilage contains abundant elastic fibres (elastin + fibrillin) visible as dark-staining networks on H&E or Verhoeff–Van Gieson staining. The image shows no such fibrous network, ruling out elastic cartilage. Found in the auricle, epiglottis, and Eustachian tube.
- D. Fibrocartilage — Fibrocartilage contains dense bundles of type I collagen arranged in parallel rows, giving it a distinctly fibrous appearance. Chondrocytes are sparse and arranged in rows between collagen bundles. None of these features are present in the image. Found in intervertebral discs, pubic symphysis, and menisci.