Innervation Of The Muscles Of The Shoulder Girdle

Explanation
The m. deltoideus is innervated by the axillary nerve. The axillary nerve arises from the posterior cord of the brachial plexus and supplies motor innervation to the deltoid muscle. This nerve also provides sensory innervation to the skin over the deltoid muscle. The other nerves listed (suprascapular nerve, radial nerve, and dorsal scapular nerve) do not directly innervate the deltoid muscle.

Explanation
The supraspinatus muscle is innervated by the suprascapular nerve. The suprascapular nerve arises from the upper trunk of the brachial plexus and passes through the suprascapular notch to reach the supraspinatus muscle. It provides motor innervation to the supraspinatus, allowing it to initiate abduction of the shoulder joint. The other nerves listed (radial nerve, axillary nerve, and dorsal scapular nerve) innervate different muscles and do not directly innervate the supraspinatus.

Explanation
The correct answer is suprascapular nerve. The suprascapular nerve is responsible for innervating the m. infraspinatus. It originates from the upper trunk of the brachial plexus and passes through the suprascapular notch to reach the infraspinatus muscle. The radial nerve primarily innervates the muscles of the posterior compartment of the arm and forearm, while the medial pectoral nerve innervates the pectoralis major and minor muscles. The axillary nerve innervates the deltoid and teres minor muscles. Therefore, the suprascapular nerve is the correct choice for innervation of the infraspinatus muscle.

Explanation
The axillary nerve is responsible for innervating the m. teres minor. This nerve originates from the posterior cord of the brachial plexus and passes through the quadrangular space along with the posterior circumflex humeral artery. It provides motor innervation to the teres minor muscle, which is located in the rotator cuff of the shoulder joint. The axillary nerve also provides sensory innervation to the skin over the deltoid muscle.

Explanation
The subscapular nerve innervates the m. teres major. This nerve arises from the posterior cord of the brachial plexus and is responsible for providing motor innervation to the subscapularis muscle as well as the teres major muscle. The teres major muscle is located on the posterior aspect of the upper arm and is involved in movements such as adduction and medial rotation of the arm. Therefore, the subscapular nerve is responsible for providing the necessary innervation for the proper functioning of the m. teres major.

Explanation
The correct answer is subscapular nerve. The subscapularis muscle is innervated by the subscapular nerve, which is a branch of the posterior cord of the brachial plexus. The subscapular nerve arises from the posterior cord, travels through the axilla, and innervates the subscapularis muscle, which is located on the anterior surface of the scapula. The other nerves listed (radial nerve, suprascapular nerve, and axillary nerve) do not innervate the subscapularis muscle.