A "typical" long bone, as the name implies, has more length than width.
Label 1: Shaft (Diaphysis).
The long bone has a shaft, with proximal and distal ends. This is called the Diaphysis. The shaft tends to be cylindrical in form.
Label 2: Cortex The shaft has a cortex (outer portion) of dense bony tissue called compact bone
tissue. The cortex is usually thickest at the middle of the shaft.
Label 3: Medullary Cavity
The inside of the shaft is usually hollow, except that it is filled with yellow
marrow in adults and red marrow in small children and infants.
Label 4: Ends (Epiphyses)
At the ends of the long bone, the cortex is much thinner.
Each end is filled with a lattice or sponge-like network of bony tissue, called cancellous
bony tissue. The strands of bone forming this lattice are called trabeculae. The
trabeculae are aligned with the lines of applied forces, particularly tension and
compression. The spaces within the cancellous bony tissue are filled with red marrow.
Label 5: Articular Cartilages
The surface of each end of the bone is covered by an articular cartilage. This cartilage is
located where the bone contacts another bone at a joint. The cartilage is made up of
hyaline-type cartilage tissue. The articular cartilage makes the movement between the
Label 6: The Periosteum
An envelope of FCT called the periosteum surrounds the long bone, except where the
articular cartilages are located.
Some Special Parts. The skeletal muscles pull and create tensions at their
attachments to the bone. These tensions will often cause the bone to react and form
spines, tubercles, ridges, and the like.