Classification of Bones: Long, Short, Flat, Irregular, and Sesamoid Bones

1. Long Bones

Definition: Long bones are characterized by their greater length than width.

Structure: They consist of a shaft with normally two extremities.

Examples: Humerus, femur, tibia, fibula, ulna, radius, metacarpal, metatarsals, and phalanges.

2. Short Bones

Definition: Short bones are typically as long as they are wide.

Examples: Carpals and tarsals.

3. Flat Bones

Definition: Flat bones are thin and sandwiched between two compact layers.

Function: They provide protection and offer large areas for muscle attachment.

Examples: Scapula, cranial bones, ribs, and the sternum.

4. Irregular Bones

Definition: Irregular bones have complex shapes that don't fit into the previous categories.

Example: Vertebrae.

5. Sesamoid Bones

Definition: Sesamoid bones develop within tendons at sites of high friction or tension.

Function: They improve leverage and protect joints from damage.

Example: Patella (kneecap).