Scapulothoracic Muscles and Arm

Vocabulary terms for muscles of the scapulothoracic region and arm, including origins, insertions, innervations, and actions based on the lecture material.

Trapezius Innervation

Spinal Accessory Nerve ($CN\ XI$)

Trapezius Action (Upper fibers)

Elevate scapula

Trapezius Action

Retraction and upward rotation of the scapula; Lower fibers upwardly rotate and depress scapula

Levator Scapulae Origin

Transverse processes of $C1-4$

Levator Scapulae Action

Elevation and downward rotation of scapula

Levator Scapulae Innervation

Dorsal scapular nerve and cervical nerves ($C3-4$)

Rhomboids (major and minor) Innervation

Dorsal scapular nerve

Rhomboids (major and minor) Action

Elevation, retraction, and downward rotation of scapula

Rhomboid Minor Origin

Spinous processes of $C7-T1$

Rhomboid Minor Insertion

Medial border of the scapula at the level of the spine

Rhomboid Major Origin

Spinous processes of $T2-T5$

Rhomboid Major Insertion

Medial border of the scapula below the spine

Serratus Anterior Origin

Lateral aspect of upper $8$ or $9$ ribs

Serratus Anterior Innervation

Long thoracic nerve

Serratus Anterior Action

Protraction and upward rotation

Pectoralis Minor Insertion

Coracoid process

Pectoralis Minor Action

Depression of scapula

Pectoralis Minor Innervation

Medial pectoral nerve

Pectoralis Major Insertion

Lateral lip of intertubercular groove

Pectoralis Major Action (Clavicular head)

Flexes arm

Pectoralis Major Action (Sternal head)

Extends arm from a flexed position

Pectoralis Major Innervation

Lateral and medial pectoral nerves

Deltoid Innervation

Axillary nerve

Deltoid Action (Anterior fibers)

Flex and internally rotate the arm

Deltoid Action (Posterior fibers)

Extend and externally rotate the arm

Deltoid Origin

Lateral third of the clavicle, acromion, and spine of the scapula

Teres Major Insertion

Medial lip of intertubercular groove

Teres Major Innervation

Lower subscapular nerve

Latissimus Dorsi Insertion

Floor of intertubercular groove

Latissimus Dorsi Innervation

Thoracodorsal nerve

Supraspinatus Insertion

Superior facet of greater tubercle

Supraspinatus Action

Abduction of arm

Supraspinatus Innervation

Suprascapular nerve

Infraspinatus Innervation

Suprascapular nerve

Infraspinatus Action

External rotation of arm

Teres Minor Origin

Upper $2/3$ of axillary border of scapula

Teres Minor Innervation

Axillary nerve

Teres Minor Action

External rotation of the arm

Subscapularis Insertion

Lesser tubercle

Subscapularis Innervation

Upper and lower subscapular nerve

Biceps Brachii Insertion

Radial tuberosity and bicipital aponeurosis

Biceps Brachii Innervation

Musculocutaneous nerve

Biceps Brachii Action (Short head)

Adduction of arm

Biceps Brachii Action (Long head)

Flexes the arm

Brachialis Insertion

Coronoid process and tuberosity of ulna

Brachialis Action

Flexes forearm

Coracobrachialis Origin

Coracoid process

Coracobrachialis Action

Flexes and adducts the arm

Coracobrachialis Innervation

Musculocutaneous nerve

Triceps Brachii Innervation

Radial nerve

Triceps Brachii Insertion

Olecranon process

Triceps Brachii Action

Extends forearm