Final answer:
The subcutaneous structure of the forearm from lateral to medial is comprised of the superficial anterior compartment with muscles that bend and tilt the wrist, originating from the medial epicondyle of the humerus, and the superficial posterior compartment with extensor muscles that straighten the wrist, originating from the lateral epicondyle.
Step-by-step explanation:
The subcutaneous contents of the forearm can be understood by examining the muscular compartments and the bones that serve as attachment points for these muscles. From lateral to medial, the forearm's superficial anterior compartment contains muscles that primarily function to bend the wrist toward the body and move the hand to the side away from the body. These muscles include the flexor digitorum superficialis and flexor digitorum profundus, which originate from the medial epicondyle of the humerus.
The medial epicondyle is a prominent bony projection on the medial side of the distal humerus. This is contrasted with the lateral epicondyle of the humerus and the lateral supracondylar ridge, which are smaller and serve as the origin for the posterior forearm muscles, which are typically weaker compared to the anterior forearm muscles.
The superficial posterior compartment of the forearm, which includes muscles such as the extensor radialis longus, extensor carpi radialis brevis, and extensor digitorum, primarily serves to straighten the wrist away from the body and also aids in hand movements to the side away from the body.