Question

5 which part of the microscopic bone communicates from outside of bone to the central canal and connects one cent
a canaliculi
b volkmanns canal
c osteon
d lacunae

Explanation:

• Canaliculi: These are small channels that connect lacunae (where osteocytes are located) to each other and to the central canal. Their main function is for nutrient and waste exchange between osteocytes, not for communication from the outside of the bone to the central canal.
• Volkmann's canal: Also known as perforating canals. They run perpendicular to the central (Haversian) canals. They communicate from the outside of the bone (periosteum) to the central canal and also connect one central (Haversian) canal to another, allowing for the passage of blood vessels, nerves etc.
• Osteon: It is the basic structural unit of compact bone. It consists of concentric layers (lamellae) of bone matrix, a central canal (with blood vessels etc.), lacunae, canaliculi etc. It is not a structure that specifically "communicates from outside of bone to the central canal" as its definition is more about being the structural unit.
• Lacunae: These are small cavities in the bone matrix that contain osteocytes. They are connected by canaliculi but do not have the role of communicating from the outside of the bone to the central canal.

Answer:

B. volkmann's canal