ORGANIZE! Posterior Forearm Muscle Innervation

The video tutorial explains the innervation of the extensor muscles in the posterior compartment of the forearm, focusing on the radial nerve and its branches. It introduces the rule of 222, which helps in understanding the innervation pattern of muscles before and after the elbow joint. The radial nerve bifurcates into a superficial sensory branch and a deep motor branch, which further becomes the posterior interosseous nerve. The tutorial details the muscles innervated by each branch, emphasizing the importance of understanding the radial nerve's pathway.

Which nerve innervates all muscles in the posterior compartment of the forearm?

• Radial nerve

• Median nerve

• Musculocutaneous nerve

• Ulnar nerve

What is the primary function of the superficial radial nerve?

• Motor innervation to forearm muscles

• Sensory innervation to the hand

• Motor innervation to hand muscles

• Sensory innervation to the forearm

What is the 'rule of 222' in the context of forearm muscle innervation?

• Two muscles innervated by the deep radial nerve, two by the posterior interosseous nerve, and two by the superficial radial nerve

• Two muscles innervated by the musculocutaneous nerve, two by the ulnar nerve, and two by the median nerve

• Two muscles innervated by the radial nerve before the elbow, two after the elbow, and two by the deep radial nerve

• Two muscles innervated by the ulnar nerve, two by the median nerve, and two by the radial nerve

Which two muscles are innervated by the radial nerve before it crosses the elbow joint?

• Supinator and extensor carpi radialis brevis

• Triceps brachii and anconeus

• Extensor digitorum and extensor digiti minimi

• Brachioradialis and extensor carpi radialis longus

Which muscle is innervated by the deep radial nerve before it enters the Supinator Tunnel?

• Extensor carpi radialis brevis

• Extensor digitorum

• Anconeus

• Brachioradialis

What happens to the deep radial nerve after it exits the Supinator Tunnel?

• It becomes the superficial radial nerve

• It becomes the posterior interosseous nerve

• It innervates the triceps brachii

• It provides sensory innervation to the hand

Which nerve innervates all other extensor muscles in the posterior forearm not covered by the rule of 222?

• Posterior interosseous nerve

• Deep radial nerve

• Median nerve

• Superficial radial nerve