GENERAL HISTOLOGY

Detailed explanation-1: -The brachial plexus provides somatic motor and sensory innervation to the upper extremity, including the scapular region. As the brachial plexus travels through the posterior triangle of the neck into the axilla, arm, forearm, and hand, it contains various named regions based on how the plexus is formed.

Detailed explanation-2: -Finally, the brachial plexus gives rise to five main terminal branches that are responsible for the most of motor and sensory innervation of the upper limb, and they include the musculocutaneous, axillary, radial, median and ulnar nerves.

Detailed explanation-3: -The musculocutaneous nerve is responsible for innervating the flexors of the arm, including the biceps brachii, coracobrachialis, and the medial aspect of the brachialis. The radial nerve innervates the triceps brachii, lateral aspect of the brachialis, anconeus, brachioradialis, and extensor carpi radialis longus.