Upper Extremity Muscles Flashcards
Supraspinatus
O: supraspinous fossa of the scapula
I: greater tubercle of the humerus
A: assistance in arm abduction, stabilization of the humerus
N: suprascapular nerve
Infraspinatus
O: infraspinous fossa of the scapula
I: greater tubercle of the humerus
A: ER of the arm, stabilization of the humerus
N: suprascapular nerve
Teres minor
O: lateral border of the scapula
I: greater tubercle of the humerus (inferior facet)
A: ER of the arm, stabilization of the humerus
N: axillary nerve
Subscapularis
O: subscapular fossa
I: lesser tubercle of the humerus
A: IR of the arm, stabilization of the humerus
N: upper and lower subscapular nerves
Teres major
O: inferior angle and lower part of the lateral border of the scapula
I: intertubercular sulcus (medial lip) of the humberus
A: adduction and medial rotation of the humerus
N: lower subscapular nerve
Serratus anterior
O: lateral parts of the 1st to 8th ribs
I: medial border of the scapula
A: protraction and rotation of the scapula
N: long thoracic nerve
Levator scapulae
O: transverse process of the atlas and axis, posterior tubercles C3 and C4
I: posterior surface of the medial scapular border (from the superior angle to the root of the spine of the scapula)
A: elevation of the scapula
N: anterior rami of the nerves C3 and C4, dorsal scapular nerve (branch of the C5)
Rhomboid major
O: spinous processes of the T2-5 vertebrae
I: inserts onto the medial border of the scapula
A: retracts scapula, stabilizes scapula against thoracic wall
N: dorsal scapular nerve
Trapezius
O: superior nuchal line, external occipital protruberance, nuchal ligament, spinous processes of C7-T12 vertebrae
I: lateral third of the clavicle, acromion and spine of the scapula
A: elevation, depression, and retraction of the scapula
N: spinal accessory nerve, C3 and C4 spinal nerves
4 rotator cuff muscles
supraspinatus
infraspinatus
teres minor
subscapularis
Pectoralis major
O: medial half of the clavicle (clavicular head), anterior surface of the sternum, 1st to 6th costal cartilages, aponeurosis of external oblique muscle (sternocosotal head)
I: crest of greater tubercle of humerus
A: adduction and IR of humerus
N: lateral nad medial pectoral nerves
Pectoralis minor
O: anterior surface of the 3rd, 4th, and 5th ribs and the fascia overlying the intercostal spaces
I: medial border and superior surface of the coracoid process of the scapula
A: protraction of the scapula, pulls the coracoid process anteriorly and inferiorly, accessory muscle in respiratory
N: medial pectoral nerve
Deltoid
O: lateral third of the clavicle, acromion, and spine of scapula
I: deltoid tuberosity of the humerus
A: abduction and stabilization of the shoulder joint
N: axillary nerve
Latissimus dorsi
O: spinous processes of T5-L5 and sacrum, iliac crest, X-XII ribs
I: intertubercular groove of the humerus
A: contracting insertion > origin = adduction, extension, IR of arm.
Contracting origin > insertion = rotation of the trunk
N: thoracodorsal nerve (C6-C8)
Brachialis
O: distal half of the anterior side of the humerus and intermuscular septa
I: coronoid process and ulnar tuberosity
A: elbow flex
N: musculocutaneous and radial nerves
Biceps brachii
O: long head - supraglenoid tubercle of the scapula.
Short head - apex of the coracoid process of the scapula
I: radial tuberosity of the radius
A: elbow flex, supinate, accessory shoulder flex at GH jt
N: musculocutaneous nerve
coracobrachialis
O: coracoid process of the scapula
I: anteromedial surface of the humerus
A: adduction and flexion of the arm
N: musculocutaneous nerve
Triceps brachii
O: long head - infragenoid tubercle of the scapula
Medial head - posterior surface of the humerus
Lateral head - posterior surface of the humerus
I: olecranon
A: elbow ext
N: radial nerve