Where does the common digital extensor originate?

• A. Lateral epicondyle of humerus
• B. Olecranon tuber
• C. Radial and ulnar tuberosity
• D. Caudal border of the scapula

Answer: (A)

The common digital extensor originates from the lateral epicondyle of the humerus, which is the correct answer. The lateral epicondyle serves as the site of attachment for various extensor muscles of the forelimb, including the common digital extensor. This muscle is significant for extending the digits, and its placement at the lateral epicondyle allows for effective leverage and movement of the forelimb.

The other options refer to anatomical landmarks that are associated with different muscles or regions of the limb. For example, the olecranon tuber is a point of attachment for the triceps brachii muscle, while the radial and ulnar tuberosities are associated with the muscles involved in flexion rather than extension. The caudal border of the scapula is not directly related to the common digital extensor, as it pertains to the shoulder region where other muscles attach. Understanding the origin of muscles like the common digital extensor is crucial for recognizing their function and the mechanics of limb movement.