Structure of Long Bone

Question 1

What are the two main structures of long bone?

Answer 1

Diaphysis (shaft)

& Epiphysis (ends)

Question 2

What are the 3 characteristics of Diaphysis?

Answer 2

• Shaft of long bones
• Composed of compact bone that surrounds the medullary cavity
• Yellow bone marrow (fatty) is contained 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 cartilage
• 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 cartilage

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)

Question 6

What are the 2 kinds of bone membranes?

Answer 6

Periosteum

&

Endosteum

Question 7

What are the characteristics of Periosteum?

Answer 7

Outer fibrous layer of bone; composed of dense irregular connective tissue

-

Question 8

What are the characteristics of Endosteum?

Answer 8

Delicate membrane covering internal medullary surfaces of bone

Question 9

Where is Red Marrow found?

Answer 9

• In infants: found in the medullary cavity and all areas of spongy bone for every bone
• In adults: found in the spongy bone of flat bones, and the epiphysis of some long bones

Question 10

What is osteogenesis imperfecta?

Answer 10

Bone matrix contains inadequate collagen (low tensile strength) and bones fracture easily.
Genetic and often present at birth, resulting in multiple (often fatal) fractures as infant descends the birth canal