The long cylindrical portion of the bone is called:

Appeared in: NVS- 2025

Explanation

The diaphysis is the anatomical term for the elongated shaft of a long bone, which constitutes its main cylindrical part.
It is primarily composed of compact bone that surrounds a central medullary cavity containing bone marrow.
This structure provides the strength and leverage needed for movement and support.
The diaphysis develops from the primary center of ossification.

Option A: The periosteum is a dense fibrous membrane that covers the outer surface of the bone. It is not the cylindrical shaft itself but rather a covering.
Option B: The metaphysis is the narrow portion of a long bone between the epiphysis and the diaphysis. It is the primary site of bone growth in length.
Option C: The epiphysis refers to the expanded ends of a long bone, which articulate with other bones to form joints. It is not the long cylindrical shaft.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of a long bone as background academic context rather than a clinical decision trigger.
Fractures are often classified by their location on the bone. A 'diaphyseal fracture' refers to a break in the shaft of a long bone.
The metaphysis is a common site for osteomyelitis (bone infection) in children because of its rich blood supply and active cell division, making it vulnerable to bacteria.
The periosteum has a rich nerve supply, which is why bone injuries and fractures are typically very painful.

How to Approach the Question

This is a factual recall question testing knowledge of basic anatomy.
Identify the key descriptive phrase in the question: 'long cylindrical portion'.
Mentally visualize a long bone (e.g., the femur in the thigh or the humerus in the arm).
Recall the definitions of the anatomical terms provided in the options.
Match the description 'long cylindrical portion' or 'shaft' to the correct term. The shaft is the diaphysis.
Eliminate the other options by recalling their definitions: epiphysis (ends), metaphysis (growth zone), and periosteum (outer covering).

Concept Tested & Keywords

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E6 Osteology InderbirSingh 5e p. 18-20

Practise the full NVS- 2025

Attempt every question from this paper in a timed mock, then review the full solution for each one.