Muscle Actions, Attachments, and Nerve Supply

Flashcards covering muscle actions, origins, insertions, and nerve supply for various muscles.

What is the primary action of the Serratus anterior?

Scapular abduction and scapular lateral rotation.

What is the origin of the Serratus anterior?

Outer surfaces and superior borders of the upper 8, 9, or 10 ribs; fascia covering corresponding intercostal muscles.

What is the insertion of the Serratus anterior?

Costal surface of the medial border of the scapula including the superior angle and the inferior angle.

What nerve supplies the Serratus anterior?

Long thoracic nerve (C5-7).

What is the primary action of the Levator scapulae?

Scapular elevation and scapular medial rotation.

What is the origin of the Levator scapulae?

Transverse processes of the upper 4 cervical vertebrae.

What is the insertion of the Levator scapulae?

Medial border of the scapula between the superior angle and the root of the spine.

What nerve supplies the Levator scapulae?

Third and fourth cervical nerves; dorsal scapular nerve (C3-5).

What is the primary action of the Trapezius (upper fibers)?

Scapular elevation.

What is the origin of the Trapezius (upper fibers)?

Medial one-third of the superior nuchal line of the occipital bone; external occipital protuberance; ligamentum nuchae.

What is the insertion of the Trapezius (upper fibers)?

Posterior border of the lateral one-third of the clavicle.

What nerve supplies the Trapezius (upper fibers)?

Spinal accessory nerve (C3-4).

What is the primary action of the Trapezius (middle fibers)?

Scapular adduction.

What is the origin of the Trapezius (middle fibers)?

Spinous processes of T1 to T5 and the corresponding supraspinous ligament.

What is the insertion of the Trapezius (middle fibers)?

Medial border of the acromion process and the superior border of the rest of the spine of the scapula.

What nerve supplies the Trapezius (middle fibers)?

Spinal accessory nerve (C3-4).

What is the primary action of the Trapezius (lower fibers)?

Scapular depression and scapular adduction.

What is the origin of the Trapezius (lower fibers)?

Spinous processes of T6 to T12 and the corresponding supraspinous ligament.

What is the insertion of the Trapezius (lower fibers)?

Tubercle at the apex of the triangular surface at the medial end of the spine of the scapula.

What nerve supplies the Trapezius (lower fibers)?

Spinal accessory nerve (C3-4).

What is the primary action of the Rhomboid minor?

Scapular adduction and scapular medial rotation.

What is the origin of the Rhomboid minor?

Inferior portion of the ligamentum nuchae; spinous processes of C7 and T1 and the corresponding supraspinous ligament.

What is the insertion of the Rhomboid minor?

Base of the smooth triangular region at the root of the spine of the scapula.

What nerve supplies the Rhomboid minor?

Dorsal scapular nerve (C4-5).

What is the primary action of the Rhomboid major?

Scapular adduction and scapular medial rotation.

What is the origin of the Rhomboid major?

Spinous processes of T2 to T5 and the corresponding supraspinous ligament.

What is the insertion of the Rhomboid major?

Medial border of the scapula between the root of the spine and inferior angle.

What nerve supplies the Rhomboid major?

Dorsal scapular nerve (C4-5).

What is the primary action of the Deltoid (anterior fibers)?

Shoulder flexion and shoulder internal rotation.

What is the origin of the Deltoid (anterior fibers)?

Anterior border of the lateral one-third of the clavicle.

What is the insertion of the Deltoid (anterior fibers)?

Deltoid tuberosity on the lateral aspect of the humeral shaft.

What nerve supplies the Deltoid (anterior fibers)?

Axillary nerve (C5-6).

What is the primary action of the Deltoid (middle fibers)?

Shoulder abduction.

What is the origin of the Deltoid (middle fibers)?

Lateral border and superior surface of the acromion process.

What is the insertion of the Deltoid (middle fibers)?

Deltoid tuberosity on the lateral aspect of the humeral shaft.

What nerve supplies the Deltoid (middle fibers)?

Axillary nerve (C5-6).

What is the primary action of the Deltoid (posterior fibers)?

Shoulder extension and shoulder external rotation.

What is the origin of the Deltoid (posterior fibers)?

Inferior lip of the crest of the spine of the scapula.

What is the insertion of the Deltoid (posterior fibers)?

Deltoid tuberosity on the lateral aspect of the humeral shaft.

What nerve supplies the Deltoid (posterior fibers)?

Axillary nerve (C5-6).

What is the primary action of the Supraspinatus?

Shoulder abduction.

What is the origin of the Supraspinatus?

Medial two-thirds of the supraspinous fossa.

What is the insertion of the Supraspinatus?

Superior facet of the greater tuberosity of the humerus.

What nerve supplies the Supraspinatus?

Suprascapular nerve (C5-6).

What is the primary action of the Coracobrachialis?

Shoulder flexion and adduction.

What is the origin of the Coracobrachialis?

Tip of the coracoid process.

What is the insertion of the Coracobrachialis?

Middle of the medial aspect of the shaft of the humerus.

What nerve supplies the Coracobrachialis?

Musculocutaneous nerve (C5-7).

What is the primary action of the Pectoralis major?

Shoulder horizontal adduction and shoulder internal rotation.

What is the origin of the Pectoralis major?

Clavicular head: anterior border of the medial third of the clavicle. Sternal head: medial half of the anterior surface of the sternum; cartilage of the first 6 or 7 ribs; aponeurosis of the external abdominal oblique.

What is the insertion of the Pectoralis major?

Lateral lip of the intertubercular groove of the humerus.

What nerve supplies the Pectoralis major?

Medial and lateral pectoral nerves (C5-6, C6-8, T1).

What is the primary action of the Pectoralis minor?

Scapular protraction and scapular medial rotation.

What is the origin of the Pectoralis minor?

Outer surfaces of ribs 2-4 or 3-5 near the costal cartilages; fascia over corresponding external intercostals.

What is the insertion of the Pectoralis minor?

Medial border and upper surface of the coracoid process of the scapula.

What nerve supplies the Pectoralis minor?

Medial and lateral pectoral nerves (C5-8, T1).

What is the primary action of the Subscapularis?

Shoulder internal rotation.

What is the origin of the Subscapularis?

Medial two-thirds of the subscapular fossa of the scapula.

What is the insertion of the Subscapularis?

Lesser tuberosity of the humerus; anterior aspect shoulder joint capsule.

What nerve supplies the Subscapularis?

Upper and lower subscapular nerves (C5-6).

What is the primary action of the Infraspinatus?

Shoulder external rotation.

What is the origin of the Infraspinatus?

Medial two-thirds of the infraspinous fossa.

What is the insertion of the Infraspinatus?

Middle facet of the greater tuberosity of the humerus.

What nerve supplies the Infraspinatus?

Suprascapular nerve (C5-6).

What is the primary action of the Teres minor?

Shoulder external rotation.

What is the origin of the Teres minor?

Upper two-thirds of the lateral aspect of the dorsal surface of the scapula, adjacent to the lateral border of the scapula.

What is the insertion of the Teres minor?

Inferior facet of the greater tuberosity of the humerus.

What nerve supplies the Teres minor?

Axillary nerve (C5-6).

What is the primary action of the Teres major?

Shoulder extension and shoulder internal rotation.

What is the origin of the Teres major?

Posterior surface of the inferior angle of the scapula.

What is the insertion of the Teres major?

Medial lip of the intertubercular groove of the humerus.

What nerve supplies the Teres major?

Lower subscapular nerve (C5-7).

What is the primary action of the Latissimus dorsi?

Shoulder extension, shoulder adduction, and shoulder internal rotation.

What is the origin of the Latissimus dorsi?

Posterior layer of the thoracolumbar fascia that takes attachment from the lumbar and sacral spinous processes, the corresponding supraspinous ligament, and the posterior aspect of the crest of the ilium; spines of the lower 6 thoracic vertebrae anterior to the attachment of trapezius; lower 3 or 4 ribs; inferior angle of the scapula.

What is the insertion of the Latissimus dorsi?

Floor of the intertubercular groove of the humerus.

What nerve supplies the Latissimus dorsi?

Thoracodorsal nerve (C6-8).