Questions and Answers
What is the primary origin of the trapezius muscle?
Which action is performed by the upper fibers of the trapezius?
What is the insertion point for the latissimus dorsi muscle?
What is the primary action of the pectoralis major muscle?
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Which nerves are responsible for the motor supply of the trapezius muscle?
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Which of the following muscles originates from the spines of the lower six thoracic vertebrae?
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Which nerve supplies the pectoralis minor muscle?
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What action do the middle fibers of the trapezius perform?
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What is the origin of the subclavius muscle?
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How does the serratus anterior assist in scapula movement?
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Where does the latissimus dorsi muscle insert?
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Which of the following is NOT an origin point for the trapezius muscle?
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What happens if the scapula is fixed during contraction of the pectoralis minor?
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Which muscle is responsible for stabilizing the clavicle during shoulder movements?
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What is the insertion point of the serratus anterior muscle?
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Which of the following actions does the clavicular fibers of the pectoralis major assist with?
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What is the primary action of the thoracodorsal nerve?
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Which nerve innervates the levator scapulae?
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Which muscle is responsible for raising the medial border of the scapula upward and medially?
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Which of the following muscles attaches to the medial border of the scapula?
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What is the origin of the rhomboid major muscle?
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Which muscle is located at the upper part of the medial border of the scapula and is involved in its elevation?
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Which nerve innervates both the rhomboid minor and rhomboid major muscles?
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What is the primary action of the levator scapulae muscle?
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Which muscle is responsible for laterally rotating the arm and stabilizing the shoulder joint?
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What is the primary action of the Subscapularis muscle?
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Which nerve innervates the Teres major muscle?
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Where does the Teres minor muscle originate?
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What action does the Teres major muscle perform?
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What is the primary action of the deltoid muscle?
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Which nerve supplies the deltoid muscle?
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Where does the supraspinatus muscle originate?
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What is the insertion point of the infraspinatus muscle?
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What action is performed by the supraspinatus muscle?
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Which muscle is responsible for the lateral rotation of the arm?
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Which of the following muscles is NOT responsible for abducting the arm?
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What is the nerve supply for the supraspinatus muscle?
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Study Notes
Muscles Connecting the Upper Limb to the Thoracic Wall
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Pectoralis Major: Originate from clavicle, sternum, and upper six costal cartilages; insert on the lateral lip of the bicipital groove of the humerus. Innervated by medial and lateral pectoral nerves. Key actions include adduction and medial rotation of the arm, with clavicular fibers assisting in arm flexion.
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Pectoralis Minor: Originates from the third to fifth ribs and inserts on the coracoid process of the scapula. Supplied by the medial pectoral nerve. Functions to depress the shoulder point and, if the scapula is fixed, elevates the originating ribs.
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Subclavius: Begins at the first costal cartilage and attaches to the clavicle. The nerve to subclavius supplies this muscle. It depresses and steadies the clavicle during shoulder movements.
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Serratus Anterior: Arises from the upper eight ribs, attaching to the medial border and inferior angle of the scapula. Innervated by the long thoracic nerve. Responsible for drawing the scapula forward around the thoracic wall while assisting in scapular rotation.
Muscles Connecting the Upper Limb to the Vertebral Column
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Trapezius: Originates from the occipital bone, ligamentum nuchae, and spines of cervical and thoracic vertebrae. Insertions include the lateral third of the clavicle and the acromion and spine of the scapula. Innervated by the spinal accessory nerve and C3, C4. Functions include elevating, retracting, and rotating the scapula.
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Latissimus Dorsi: Originates from the iliac crest, lumbar fascia, lower six thoracic vertebrae, and lower ribs, inserting at the floor of the bicipital groove of the humerus. Supplied by the thoracodorsal nerve. It extends, adducts, and medially rotates the arm.
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Levator Scapulae: Starts from the transverse processes of the first four cervical vertebrae and inserts on the medial border of the scapula. Innervated by C3, C4, and the dorsal scapular nerve. Primarily raises the medial border of the scapula.
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Rhomboid Minor and Major: Minor originates from the ligamentum nuchae and spines of cervical and first thoracic vertebrae; Major originates from the second to fifth thoracic spines. Both insert at the medial border of the scapula and are supplied by the dorsal scapular nerve. Their main actions involve raising the medial border of the scapula upward and medially.
Muscles Connecting the Scapula to the Humerus
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Deltoid: Composed of anterior, middle, and posterior fibers; originates from the lateral third of the clavicle, acromion, and spine of the scapula, inserting at the mid-lateral shaft of the humerus. Innervated by the axillary nerve. Abducts the arm; anterior fibers flex and medially rotate, while posterior fibers extend and laterally rotate.
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Supraspinatus: Originates from the supraspinous fossa of the scapula, inserting at the greater tuberosity of the humerus. Innervated by the suprascapular nerve. Key action is abduction and stabilization of the shoulder joint.
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Infraspinatus: Originates from the infraspinous fossa of the scapula, inserting at the greater tuberosity of the humerus. Also supplied by the suprascapular nerve. Responsible for laterally rotating and stabilizing the shoulder joint.
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Teres Major: Begins at the lower third of the lateral border of the scapula and inserts at the medial lip of the bicipital groove of the humerus. Innervated by the lower subscapular nerve. It medially rotates and adducts the arm, assisting in shoulder stabilization.
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Teres Minor: Originates from the upper two-thirds of the lateral border of the scapula and inserts at the greater tuberosity of the humerus. Innervated by the axillary nerve. Functions similarly to infraspinatus, providing lateral rotation and stability to the shoulder joint.
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Subscapularis: Originates from the subscapular fossa, inserting at the lesser tuberosity of the humerus. Supplied by upper and lower subscapular nerves. Key role in medial rotation and stabilization of the shoulder joint.
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Description
Test your knowledge on the muscles that connect the upper limb to the thoracic wall. This quiz covers origins, insertions, nerve supply, and actions of these crucial muscles. Perfect for anatomy students and professionals looking to refresh their understanding.
