Unit 2 Flashcards
Trapezius origin
Medial third of superior nuchal line; external occipital protuberance; nuchal ligament; spinous processes of C7-T12 vertebrae
trapezius insertion
Lateral third of clavicle; acromion and spine of scapula
trapezius innervation
Spinal accessory nerve (CN XI) (motor fibers) and C3, C4 spinal nerves (pain and proprioceptive fibers
trapezius actions
Descending: elevates
Ascending: depresses
Middle/all parts together: retracts scapula
Descending and ascending: rotate glenoid cavity superiorly
rhomboid major origin
Spinous processes of T2-T5 vertebrae
rhomboid major insertion
Medial border of scapula from level of spine to inferior angle
rhomboid major innervation
Dorsal scapular nerve (C4, C5)
rhomboid major action
Retract scapula and rotate glenoid cavity inferiorly; fix scapula to thoracic wall
rhomboid minor origin
Nuchal ligament; spinous processes of C7 and T1 vertebrae
rhomboid minor insertion
Smooth triangular area at medial end of scapular spine
rhomboid minor innervation
dorsal scapular nerve C4 C5
rhomboid minor action
Retract scapula and rotate glenoid cavity inferiorly; fix scapula to thoracic wall
levator scapula origin
Posterior tubercles of transverse processes of C1-C4 vertebrae
levator scapulae insertion
Medial border of scapula superior to root of scapular spine
levator scapulae innervation
Dorsal scapular nerve (C4, C5) and cervical (C3, C4) nerves
levator scapulae action
Elevates scapula and rotates its glenoid cavity inferiorly by rotating scapula
supraspinatus origin
supraspinous fossa of scapula
supraspinatus insertion
superior facet of greater tubercle of humerus
supraspinatus innervation
suprascapular nerve C4, C5, C6
supraspinatus action
initiates and assists deltoid in abduction of arm; acts with rotator cuff muscles
infraspinatus origin
infraspinous fossa of scapula
infraspinatus insertion
middle facet of greater tubercle of humerus
infraspinatus innervation
Suprascapular nerve C5 C6
infraspinatus action
laterally rotates arm; acts with rotator cuff muscles
teres minor origin
middle part of lateral border of scapula
teres minor insertion
inferior facet of greater tubercle of humerus
teres minor innervation
axillary nerve C5 C6
teres minor action
laterally rotates arm; acts with rotator cuff muscles
teres major origin
posterior surface of inferior angle of scapula
teres major insertion
medial lip of intertubercular sulcus of humerus
teres major innervation
lower subscapular nerve C5 C6
teres major action
adducts and medially rotates arm
pectoralis major origin
Clavicular head: anterior surface of medial half of clavicle Sternocostal head: anterior surface of sternum, superior 6 costal cartilages, aponeurosis of external oblique muscle
pectoralis major insertion
lateral lip of intertubercular sulcus
pectoralis major innervation
lateral and medial pectoral nerves; clavicular head C5 C6, sternocostal head (C7, C8, T1)
pectoralis major action
adducts and medially rotates humerus; draws scapula anteriorly and inferiorly. Acting alone, clavicular head flexes humerus and sternocostal head extends it from flexed position
pectoralis minor origin
3rd to 5th ribs near their costal cartilages
pectoralis minor insertion
medial border and superior surface of coracoid process
pectoralis minor innervation
medial pectoral nerve C8 T1
pectoralis minor action
stabilizes scapula by drawing it inferiorly and anteriorly against the thoracic wall
serratus anterior origin
external surfaces of lateral parts of 1st through 8th ribs
serratus anterior insertion
anterior surface of medial border of scapula
serratus anterior innervation
long thoracic nerve C5 C6 C7
serratus anterior action
protracts scapula and holds it against thoracic wall, rotates scapula
deltoid origin
anterior lateral third of clavicle, middle: acromion, posterior: spine of scapula
deltoid insertion
deltoid tuberosity of humerus
deltoid innervation
axillary nerve C5 C6
deltoid action
Clavicular (anterior): flexes and medially rotates arm acromial (middle): abducts arm
spinal (posterior): extends and laterally rotates arm
subscapularis origin
subscapular fossa (most of anterior scapula)
subscapularis insertion
lesser tubercle of humerus
subscapularis innervation
upper and lower subscapularis nerves C5 C6 C7
subscapularis actions
medially rotates arm; as part of rotator cuff, helps hold head of humerus in glenoid cavity
subclavius origin
junction of first rib and costal cartilage
subclavius insertion
inferior surface of middle third of clavicle
subclavius innervation
nerve to subclavius C5 C6
subclavius action
anchors and depresses clavicle
coracobrachialis origin
tip of coracoid process of scapula
coracobrachialis insertion
middle third of medial surface of humerus
coracobrachialis innervation
musculotaneous nerve C5 C6 C7
coracobrachialis action
helps flex and adduct arm; resists dislocation of the shoulder
biceps brachii origin
short head: tip of coracoid process of scapula
long head: supraglenoid tubercle of scapula
biceps brachii insertion
tuberosity of radius and fascia of forearm via bicipital aponeurosis
biceps brachii innervation
musculotaneous nerve C5 C6 C7
biceps brachii action
supinates forearm and when supine flexes forearm; short head resists dislocation of the shoulder
brachialis origin
distal half of anterior surface of humerus
brachialis insertion
coronoid process and tuberosity of the ulna