Structure of Long Bone

Question 1

What are the two main structures of long bone?

Answer 1

Diaphysis

& Epiphyses (epiphysis = singular)

Question 2

What are the 3 characteristics of Diaphysis?

Answer 2

• Tubular shaft that forms the axis of long bones
• Composed of compact bone (aka cortical bone) that surrounds the medullary cavity
• Yellow bone marrow (fatty) is containted in the medullary cavity

Question 3

What are the characteristics of Epiphysis?

Answer 3

• Expanded ends of long bones
• Exterior is compact bone, and the interior is spongy bone
• Joint surfaces are covered with articular (hyaline) cartilage & periochondrium
• Epiphyseal plate (cartilage) separates diaphysis from epiphyses until the end of puberty
• Epiphyseal line (detected on x-ray) separates the diaphysis from the epiphyses after growth in length stops (epiphyseal plate ossifies [fused])

Question 4

What covers the joint surfaces of long bones?

Answer 4

articular (hyaline) cartilage & periochondrium

Question 5

What separates diaphysis from epiphyses after growth in length stops (puberty)?

Answer 5

Epiphyseal plate (cartilage)

or

Epiphyseal line (detectable on x-ray)