Page 272 - Atlas of Histology with Functional Correlations

This photomicrograph illustrates the transformation of hyaline cartilage into

bone through the process of endochondral ossification. The hyaline cartilage
matrix (6) contains proliferating chondrocytes (7) and hypertrophied
chondrocytes (1) with vacuolated cytoplasm (2). Below these cells are plates
or spicules of calcified cartilage (3) surrounded by osteoblasts (4). As the
cartilage calcifies, a marrow cavity (5) is formed with blood vessels,

hematopoietic tissue (10), osteoprogenitor cells, and osteoblasts (4). The
hyaline cartilage is surrounded by the perichondrium (8). The marrow cavity in
the new bone is surrounded by the periosteum (9).

FIGURE 7.21 ■ Endochondral ossification: zone of ossification. Stain:

hematoxylin and eosin. ×50.

FIGURE 7.22 | Endochondral Ossification:

Formation of Secondary (Epiphyseal) Centers of

Ossification and Epiphyseal Plate in Long Bones

(Longitudinal Section, Decalcified Bone)

The hyaline cartilage in the epiphyseal ends of two developing bones is
illustrated. Both bones exhibit secondary centers of ossification (5, 11).
Although cartilage is nonvascular, numerous blood vessels (1, 6), sectioned in a

different plane, pass through the cartilage matrix to supply the osteoblasts and
osteocytes in the secondary centers of ossification (5, 11). Articular cartilage
(4, 12) covers both articulating ends of the future bone. A synovial or joint
cavity (3) separates the two cartilage models. The inner synovial membrane of
squamous cells lines the synovial cavity (3), except over the articular cartilages

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