Exam 1 Muscles Flashcards
Descending Trapezius
Origin: spinous processes C1-C7, occipital bone
Insertion: clavicle (lateral 1/3)
Innervation: Spinal Accessory Nerve (CN11)
Action: draws scap upward, rotates glenoid cavity superiorly, tilts the head to the same side, rotates the head to the opposite side
Transverse Trapezius
origin: aponeurosis @ T1-T4 spinous processes
insertion: acromion
innervation: spinal accessory nerve (CN11)
action: draws scap medially
ascending trapezius
origin: spinous processes T5-T12
insertion: scapular spine
innervation: spinal accessory nerve (CN11)
action: draws scap medially downward
latissimus dorsi
origin: vertebral part –> spinous processes T5-T12, scapular part–> inferior angle of the scap, costal part –> ribs 9-12, iliac part –> iliac crest (posterior 1/3)
insertion: floor of the bicipital groove of the humerus
innervation: thoracodorsal nerve (C6-C8)
action: IR, Ext, ADD, respiration (cough muscle)
levator scapulae
origin: transverse processes of C1-C4
insertion: superior angle of the scapula on the medial border (b/w the superior angle and the superior portion of the spine)
innervation: dorsal scapular nerve (C4-C5)
action: draws scap medially upward while moving the inferior angle medially, inclines the neck to the same side
rhomboid major
origin: spinous processes T1-T4
insertion: medial border of scapula below the spine
innervation: dorsal scapular nerve (C4-C5)
action: steadies scap, draws scap medially upwards, retracts scap and tilts glenoid cavity inferiorly
rhomboid minor
origin: spinous processes of C6 and C7
insertion: posterior medial border of scapula @ the level of the spine
innervation: dorsal scapular nerve (C4-C5)
action: steadies scapula, draw scapula medially upwards, retracts the scapula and tilts the glenoid cavity inferiorly
deltoid
origin: clavicular part –> lateral 1/3 of clavicle, acromial part –> acromion, spinal part –> spine of the scapula
insertion: deltoid tuberosity of humerus
innervation: axillary nerve (C5,C6)
action: clavicular part –> flexion, IR, ADD, acromial part –> ABD, spinal part –> Ext, ER, ADD
supraspinatus
origin: supraspinous fossa of the scapula
insertion: greater tuberosity of humerus
innervation: suprascapular nerve (C4-C6)
action: ABD
infraspinatus
origin: infraspinous fossa of the scapula
insertion: greater tuberosity of the humerus
innervation: suprascapular nerve (C4-C6)
action: ER
teres minor
origin: lateral border of the scapula
insertion: greater tuberosity of the humerus
innervation: axillary nerve (C5-C6)
action: ER, weak ADD
subscapularis
origin: subscapular fossa
insertion: lesser tuberosity of humerus
innervation: upper and lower subscapular nerves (C5,C6)
action: IR
teres major
origin: inferior angle of the scapula
insertion: medial lip of the intertubercular sulcus of the humerus
innervation: lower subscapular nerve (C5-C7)
action: IR, ADD, EXT
pectoralis major (clavicular part)
origin: clavicle (medial half)
insertion: lateral border of the crest of the bicipital groove of the humerus
innervation: medial and lateral pectoral nerves (C5-T1)
action: shoulder ADD, IR, flexion, assist in respiration when the shoulder is fixed
pectoralis major (sternocostal part)
origin: sternum and costal cartilage of ribs 1-6
insertion: lateral border of the crest of the bicipital groove of the humerus
innervation: medial and lateral pectoral nerves (C5-T1)
action: shoulder ADD, IR, flexion, assist in respiration when the shoulder is fixed
pectoralis major (abdominal part)
origin: rectus sheath (anterior layer)
insertion: lateral border of the crest of the bicipital groove of the humerus
innervation: medial and lateral pectoral nerves (C5-T1)
action: shoulder ADD and IR
pectoralis minor
origin: ribs 3-5 near their costal cartilage
insertion: coracoid process of the scapula
innervation: medial pectoral nerve (C6-T1)
action: draws scapula downward –> inferior angle to move posteromedially , rotate glenoid cavity inferiorly, assist with respiration
subclavius
origin: first rib
insertion: inferior surface of clavicle
innervation: nerve to subclavius (C5,C6)
action: steadies the clavicle w/in the SC joint
serratus anterior
origin: first to ninth ribs
insertion: costal aspect of the medial border of the scapula
innervation: long thoracic nerve (C5-C7)
action: superior part –> lowers a raised arm
entire muscle –> protraction, elevates the ribs when the shoulder is fixed
inferior part –> rotates the scapula laterally
biceps brachii
origin: long head –> supraglenoid tubercle, short head: coracoid process
insertion: radial tuberosity and bicipital aponeurosis
innervation: musculocutaneous nerve (C5,C6)
action: elbow flexion and supination
shoulder flexion
humeral head –> stabilization during deltoid contraction, ABD and IR
brachialis
origin: humerus (distal half of anterior surface)
insertion: ulnar tuberosity
innervation: musculocutaneous nerve (C5,C6) and radial nerve (C7, minor)
action: elbow flexion