Arms and Back Muscles

Question 1

Trapezius

Answer 1

Origin: Occipital bone, spinous processes of C7-T12
Insertion: Lateral third of clavicle, acromion process, scapular spine
Action: eleveates/depresses scapula, superior scapula rotation, scapular retration
Innervation: Spinal accessory (XI)

Question 2

Latissimus Dorsi

Answer 2

Origin: Spinous process of T6-T12, iliac crest, thoracolumbar fascia, inferior 3 ribs
Insertion: Intertubercal sulcus of the humerus
Action: Extends, adducts, medially rotates shoulder
Innervation: thoracodorsal

Question 3

Levator Scapulae

Answer 3

Origin: Transverse process of C1-C4
Insertion: Medical boarder of scapula
Action: Elevates scapula
Innervation: Dorsal Scapular

Question 4

Rhomboid major

Answer 4

Origin: Spinous process of T2-T5
Insertion: Medial boarder of the scapula btwn scapular spine and inferior angle
Action: Retraction and downward rotation of scapula
Innervation: Dorsal Scapular

Question 5

Rhomboid Minor

Answer 5

Origin: Spinous Process of C7-T1
Insertion: Medial boarder of scapula at level of scapular spine
Action: retraction and downward rotation of scapula
Innervation: Dorsal scapular

Question 6

Deltoid

Answer 6

Origin: scapula and clavicle
Insertion: lateral surface of humerus (deltoid tuberosity)
Action; Anterior: Flexion, Posterior: extension, Middle: abduction
Innervation: axillary

Question 7

Teres Major

Answer 7

Origin: Posterior surface of inferior angle of scapula
Insertion: Inter-tubercular groove of humerus
Action: Adduction, medial rotation
Innervation: Lower subscapular

Question 8

Supraspinatus:

Answer 8

Origin: Supraspinous Fossa
Insertion: Greater tubercle of humerus
Action: Abduction and assists deltoid
Innervation: Suprascapular

Question 9

Infraspinatus

Answer 9

Origin: infraspinous fossa
Insertion: greater tubercle of humerus
Action: lateral rotation
Innervation: Suprascapular

Question 10

Teres Minor

Answer 10

Origin: Posterior surface of scapula, adjacent to lateral border
Insertion: Greater tubercle of humerus
Action: Lateral rotation, weak adduction
Innervation: axillary

Question 11

Subscapularis

Answer 11

Origin: subscapular fossa
Insertion: lesser tubercle of humerus
Action: medial rotation
Innervation: upper and lower subscapular

Question 12

Subclavius

Answer 12

Origin: Costochondral junction of 1st rib
Insertion: Subclavian groove on inferior surface of middle third of clavicle
Action: Depression of clavicle
Innervation: nerve to subclavius (C5, 6, upper trunk)

Question 13

Pectoralis Major

Answer 13

Origin: Clavicular head: medial half of clavicle; Sternal head: sternum, upper costal cartilage 1-6, aponeurosis of external oblique
Insertion: Lateral lip of intertubercular groove of humerus
Action: Clavicular head: shoulder flexionSternal head: Shoulder extensionBoth: Shoulder adduction and medial rotation
Innervation: Clavicular head: Lateral pectoral nerve; Sternal Head: medial pectoral nerve

Question 14

Pectoralis Minor

Answer 14

Origin: Anterior surface of sternal ends of ribs 3-5
Insertion: Coracoid process of scapula
Action: Scapular protraction and depression
Innervation: Medial pectoral nerve (C8, T1)

Question 15

Coracobrachialis

Answer 15

Origin: Coracoid process
Insertion: Mid-medial surface of humerus
Action: Shoulder flexion and adduction
Innervation: Musculocutaneous (C5, C6, C7)

Question 16

Biceps Brachii

Answer 16

Origin: Long head: supraglenoid tubercle; Short head: coracoid process
Insertion: Radial tuberosity, bicipital aponeurosis of fascia on medial forearm
Innervation: Musculocutaneous (C5, C6, C7)

Question 17

Brachialis

Answer 17

Origin: Anterior, distal half of humerus
Insertion: Coronoid process and tuberosity of ulna
Action: Elbow Flexion
Innervation: Musculocutaneous nerve (C5, C6)

Question 18

Triceps Brachii

Answer 18

Origin: Long head: Infraglenoid tubercle; Lateral head: proximal posterior humerus superior to radial groove; Medial head: inferior 2/3 of posterior humerus
Insertion: All Heads: posterior olecranon process of ulna
Action: Shoulder extension (long head only), elbow extension (all heads)
Innervation: Radial Nerve (C7, C8)

Question 19

Serratus Anterior

Answer 19

Origin: Anterior surface of first 8 or 9 ribs
Insertion: Anterior surface of medial border of scapula
Action: Scapular protraction, upward rotation while shoulder abducts
Innervation: Long thoracic nerve (C5-C7)