Clavicle – Anatomy Notes
1. Clavicle
- It is a long bone.
- Supports the shoulder so that the arm can swing.
- It has one shaft and two ends.
2. Side Determination & Anatomical Position
- Hold clavicle horizontally:
1) Lateral end is flat, medial end is large and quadrilateral.
2) Shaft: convex forward in medial 2/3rd, concave forward in lateral 1/3rd.
3) Inferior surface grooved in middle 1/3rd.
3. Peculiarities of the Clavicle
1) Only long bone that lies horizontally.
2) Entirely subcutaneous.
3) First bone to ossify.
4) Only bone that ossifies in membrane.
5) Has two primary ossification centers.
6) Medullary cavity in medial 2/3rd.
7) Occasionally pierced by middle supraclavicular nerve.
4. Features of the Shaft
Divided into:
- Lateral 1/3rd:
- Flattened vertically.
- Borders: Anterior (concave), Posterior (convex).
- Surfaces: Superior (subcutaneous), Inferior (conoid tubercle, trapezoid ridge).
- Medial 2/3rd:
- Rounded.
- Surfaces:
- Anterior: convex.
- Posterior: smooth.
- Superior: rough (medial part).
1. Clavicle
- It is a long bone.
- Supports the shoulder so that the arm can swing.
- It has one shaft and two ends.
2. Side Determination & Anatomical Position
- Hold clavicle horizontally:
1) Lateral end is flat, medial end is large and quadrilateral.
2) Shaft: convex forward in medial 2/3rd, concave forward in lateral 1/3rd.
3) Inferior surface grooved in middle 1/3rd.
3. Peculiarities of the Clavicle
1) Only long bone that lies horizontally.
2) Entirely subcutaneous.
3) First bone to ossify.
4) Only bone that ossifies in membrane.
5) Has two primary ossification centers.
6) Medullary cavity in medial 2/3rd.
7) Occasionally pierced by middle supraclavicular nerve.
4. Features of the Shaft
Divided into:
- Lateral 1/3rd:
- Flattened vertically.
- Borders: Anterior (concave), Posterior (convex).
- Surfaces: Superior (subcutaneous), Inferior (conoid tubercle, trapezoid ridge).
- Medial 2/3rd:
- Rounded.
- Surfaces:
- Anterior: convex.
- Posterior: smooth.
- Superior: rough (medial part).
