True/False On The Shoulder Girdle P.1

Explanation
The m. deltoideus is a muscle that is innervated by the axillary nerve. It also originates along a continuous U-shaped line of attachment to the clavicle and the scapula. This means that the muscle starts at one end of the U-shape on the clavicle, extends across the top of the shoulder, and ends at the other end of the U-shape on the scapula. Therefore, the statement is true.

Explanation
The statement "m. deltoideus is the shortest muscle in the shoulder girdle" is false. The m. deltoideus, also known as the deltoid muscle, is actually one of the largest muscles in the shoulder girdle. It is a triangular-shaped muscle that covers the shoulder joint and is responsible for various movements of the arm, such as abduction, flexion, and extension. Therefore, it cannot be considered the shortest muscle in the shoulder girdle.

Explanation
The m. deltoideus, also known as the deltoid muscle, is indeed triangular in shape. It is a large muscle located in the shoulder and is responsible for the movement and stability of the shoulder joint. The triangular shape of the deltoid muscle allows it to cover and protect the shoulder joint from various angles, providing strength and support to the upper arm.

Explanation
The statement is false because the m. deltoideus, also known as the deltoid muscle, is indeed attached to the clavicle. The deltoid muscle is a large, triangular muscle that covers the shoulder joint and is responsible for various movements of the arm. It originates from the clavicle, acromion process of the scapula, and the spine of the scapula, and inserts into the deltoid tuberosity of the humerus. Therefore, it is incorrect to say that the m. deltoideus is not attached to the clavicle.

Explanation
The statement is true because the m. deltoideus, also known as the deltoid muscle, is responsible for arm abduction. This muscle is located in the shoulder and is responsible for lifting the arm away from the body, allowing for movement in multiple directions. It is a powerful muscle that plays a crucial role in various arm movements, including abduction.

Explanation
The statement is false because the m. supraspinatus is not located on top of the m. deltoideus. Instead, the m. supraspinatus is located below the m. deltoideus.

Explanation
Both the m. teres minor and m. deltoideus muscles are innervated by the axillary nerve. This means that the axillary nerve supplies the necessary motor signals for these muscles to contract and perform their respective functions. Therefore, the statement is true.

Explanation
The acromion is actually considered a site of origin of the m. deltoideus. The m. deltoideus is a muscle that covers the shoulder joint and is responsible for various movements of the arm. It has three parts, one of which originates from the acromion, along with other origins such as the clavicle and scapula. Therefore, the statement that the acromion is not considered a site of origin of the m. deltoideus is false.

Explanation
The statement is false because the correct order of the muscles mentioned is m. supraspinatus, m. infraspinatus, and then m. teres major. Therefore, m. teres major is not located between m. supraspinatus and m. infraspinatus.

Explanation
The statement is true because the site of origin of the m. supraspinatus, which is a muscle in the human body, is indeed the fossa supraspinata. The fossa supraspinata is a shallow depression located on the posterior aspect of the scapula (shoulder blade), specifically above the spine of the scapula. This is where the muscle originates from before it inserts onto the greater tubercle of the humerus bone.

Explanation
The statement is false because the supraspinatus muscle actually originates from a fossa located on the posterior side of the scapula, not the anterior side.

Explanation
The statement "m. supraspinatus inserts on the lesser tubercle" is false. The supraspinatus muscle actually inserts on the greater tubercle of the humerus bone. The greater tubercle is located on the lateral side of the humerus, while the lesser tubercle is on the anterior side. Therefore, the correct answer is false.

Explanation
The statement is true because the supraspinatus muscle does indeed insert on the greater tubercle. The greater tubercle is a bony prominence located on the humerus bone of the upper arm. The supraspinatus muscle is one of the four muscles that make up the rotator cuff in the shoulder joint. It originates from the supraspinous fossa of the scapula and attaches to the greater tubercle of the humerus. This insertion allows the supraspinatus muscle to play a crucial role in shoulder abduction and stabilization.

Explanation
The correct answer is False. The supraspinatus muscle is actually innervated by the suprascapular nerve, not the axillary nerve. The suprascapular nerve arises from the upper trunk of the brachial plexus and provides motor innervation to the supraspinatus muscle, which is responsible for initiating abduction of the shoulder joint. The axillary nerve, on the other hand, innervates the deltoid muscle and the teres minor muscle.

Explanation
The supraspinatus muscle is indeed innervated by the suprascapular nerve. This nerve originates from the upper trunk of the brachial plexus and passes through the suprascapular notch to reach the supraspinatus muscle. Once it reaches the muscle, it provides motor innervation, allowing for contraction and movement of the supraspinatus. Therefore, the statement is true.

Explanation
The m. supraspinatus does not rotate the arm medially. It is actually responsible for initiating the abduction of the arm at the shoulder joint. Medial rotation of the arm is primarily performed by the subscapularis muscle. Therefore, the statement is false.

Explanation
The m. supraspinatus is indeed responsible for initiating the abduction of the arm. This muscle is located in the supraspinous fossa of the scapula and is part of the rotator cuff. When it contracts, it helps to lift the arm away from the body in the initial phase of abduction. Therefore, the statement is true.

Explanation
The correct answer is False. The m. supraspinatus is not located inferiorly to the m. teres minor. In fact, it is located superiorly to the m. teres minor.

Explanation
The statement is false because the muscles m. subscapularis and m. infraspinatus are actually found behind the scapula, not in front of it. These muscles are part of the rotator cuff group and are responsible for various movements of the shoulder joint.

Explanation
The suprascapular and circumflex scapular arteries are indeed responsible for the blood supply of the supraspinatus muscle. These arteries provide the necessary oxygen and nutrients to the muscle, allowing it to function properly. Without a sufficient blood supply, the supraspinatus muscle would not be able to perform its role in shoulder movement and stability. Therefore, the statement is true.