Upper Extremity Week 1 Structure Information: Muscles Flashcards
Latissimus dorsi
(C6-8)
attachments- from lower thoracic spinous processes, thoracolumbar fascia & iliac crest to the floor of the intertubercular sulcus of the humerus
actions- adduction, extension & medial rotation of humerus
innervation- THORACODORSAL NERVE
Levator scapulae
(C4-5)
attachments- from transverse processes of C1-C4 to the superior angle & superomedial border of the scapula
actions- elevation & downward rotation of the scapula
innervation- DORSAL SCAPULAR NERVE (sensory: direct branches of C3-4)
Pectoralis major
(clavicular head C5-7; sternocostal head C8-T1)
attachments- from clavicle, costal cartilages, sternum & aponeurosis of the external oblique to the lateral lip of the intertubercular sulcus of the humerus
actions- humeral adduction, flexion & medial rotation (sternocostal portion assists with extension of the flexed arm)
innervation- MEDIAL AND LATERAL PECTORAL NERVES
Pectoralis minor
(C5-T1)
attachments- from outer surfaces of ribs 3-5 to the coracoid process
actions- anterior tilt of scapula; assists with depression of the shoulder & forced inspiration
innervation- MEDIAL AND LATERAL PECTORAL NERVES
Rhomboids
(C4-5)
attachments- major: from spinous processes T2-5; minor: from ligamentum nuchae & spinous processes C7-T1 to the medial border of the scapula
actions- scapular retraction, elevation (upper) & downward rotation
innervation- DORSAL SCAPULAR NERVE (sensory: direct branches of C3-4)
Serratus anterior
(C5-7)
attachments- from the outer surfaces & superior borders of upper eight-ten ribs to the costal surface of the medial border of the scapula
actions- scapular protraction & upward rotation
innervation- LONG THORACIC NERVE
Subclavius
(C5-6)
attachments- from 1st rib & cartilage to the undersurface of the clavicle
actions- depresses & stabilizes the clavicle
innervation- subclavian nerve
Trapezius
(Accessory n. [CN XI] motor; C3-4 sensory)
attachments- from the superior nuchal line, external occipital protuberance, ligamentum nuchae, & cervical & thoracic spinous processes to the clavicle, acromion & scapular spine
actions- scapular elevation (upper), depression (lower), retraction (middle) & upward rotation (upper & lower)
innervation- ACCESSORY NERVE (CN XI; motor) & C3-4 (sensory)
Deltoid
(C5-6; anterior, middle, & posterior portions)
attachments- from the clavicle, acromion & spine of the scapula to the deltoid tuberosity of the humerus
actions- flexion & medial rotation (anterior), abduction (primarily middle), extension & lateral rotation, horizontal extension (posterior) of humerus
innervation- AXILLARY NERVE
Supraspinatus
(C4-6)
attachments- from the medial 2/3 of the supraspinous fossa to the superior facet of the greater tubercle of the humerus & to shoulder joint capsule
actions- initiates humeral abduction & laterally rotates humerus; stabilizes glenohumeral joint (reinforces superior aspect of joint capsule)
innervation- SUPRASCAPULAR NERVE
Infraspinatus
(C5-6)
attachments- from the medial 2/3 of the infraspinous fossa to the middle facet of the greater tubercle of the humerus & to shoulder joint capsule
actions- lateral rotation of humerus; stabilizes glenohumeral joint
innervation- SUPRASCAPULAR NERVE
Teres minor
(C5-6)
attachments- from the upper 2/3 of the dorsal surface of the lateral border of the scapula to the inferior facet of the greater tubercle of the humerus & to shoulder joint capsule
actions- lateral rotation of humerus; stabilizes glenohumeral joint
innervation- AXILLARY NERVE
Subscapularis
(C5-6)
attachments- from the subscapular fossa to the lesser tubercle of the humerus
actions- medial rotation of humerus; stabilizes glenohumeral joint
innervation- UPPER AND LOWER SUBSCAPULAR NERVES
Teres major
(C5-6)
attachments- from the dorsal surface of the inferior angle scapula & lower 1/3 of the lateral border of the scapula to the medial lip of the intertubercular sulcus of the humerus
actions- humeral adduction, medial rotation, & extension
innervation- LOWER SUBSCAPULAR NERVE
