Important Muscles Flashcards
Sternocleidomastoid: O and I
O: Mastoid process and lateral third of superior Nuchal line
I: Manubrium of sternum and medial third of clavicle
Sternocleidomastoid: Inn and action
Inn: Spinal part of CN XI (motor) and ventral rami C2,3 (proprioception)
Action: Tilts head towards same shoulder. Rotates head to opposite side.
Trapezius: O and I
O: Medial third of superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of C7 and all thoracic vertebrae
Insertion: Lateral third of clavicle, acromion and spine of scapula
Trapezius: Inn and action
Innervation: Spinal part of CN XI [motor] and branches of C3 and C4 [proprioception]
Action: Shrugs the shoulder, retracts and rotates the scapula
Latissimus Dorsi: O and I
Origin: Thoracolumbar fascia, spinous processes of the lower thoracic and lumbar vertebrae
Insertion: Floor of the bicipital groove
Lat Dorsi: Inn and Action
Innervation: Thoracodorsal nerve [C6, 7, 8]
Action: Adducts, extends and medially rotates the arm
Levator Scapulae: O and I
Origin: Transverse processes of C1 and C2 Posterior tubercles of the transverse processes of C3 and C4 Insertion: From the superior angle to the root of the spine of the scapula
Levator Scapulae: Inn and action
Innervation: Dorsal scapular nerve [C5]
Action: Elevates the scapula
Scalenus anterior: O and I
Origin: Anterior tubercles of the transverse processes of C3, 4, 5 and 6
Insertion: Scalene tubercle on the upper inner aspect of the first rib
Scalenus Anterior: Inn and action
Innervation: Anterior rami of C4, 5 and 6
Action: Ipsilateral lateral flexion of the neck
Scalenus medius: O and I
Origin: Posterior tubercles of the transverse processes of C2 to C6
Insertion: Upper aspect of the 1st rib between groove for the subclavian artery and the tubercle
Scalenus Medius: Inn and action
Innervation: Anterior rami of C3 to C7
Action: Ipsilateral lateral flexion of the neck
Serratus anterior: O and I
Origin: Lateral aspects of the upper 8 ribs
Insertion: Along the medial aspect of the inferior surface of the scapula
Serratus Anterior: Inn and action
Innervation: Long Thoracic Nerve [C5, 6 and 7]
Action: Draws the scapula forwards and rotates the scapula
Deltoid: O and I
Origin: Lateral third of clavicle, acromion and spine of the scapula
Insertion: Deltoid tubercle of the humerus
Deltoid: Inn and Action
Innervation: Axillary nerve [C5 and C6]
Action: Abducts the arm [15o to 90o]. Anterior fibers flex and medially rotates the arm. Posterior fibers extend and laterally rotate arm
Pectoralis Major: O and I
Origin: Sternum, upper 6 costal cartilages and medial half of clavicle
Insertion: Lateral lip of the bicipital groove
Pec Major: Inn and action
Innervation: Medial and lateral pectoral nerves [C5, 6, 7 and C8, T1]
Action: Adducts, flex and medially rotates the arm; it also extends the flexed arm
Supraspinatous: O and I
Origin: Supraspinous fossa of the scapula
Insertion: Superior facet of the greater tuberosity of the humerus
Supraspinatous: Inn and action
Innervation: Suprascapular nerve [C5 and C6]
Action: Initiates abduction [0-15o] of the arm
Infraspinatous: O and I
Origin: Infraspinous fossa of the scapula
Insertion: Middle facet of greater tuberosity of the humerus [just below supraspinatus insertion]
Infraspinatous: Inn and action
Innervation: Suprascapular nerve [C5 and C6]
Action: Externally rotates the humerus
Teres Major: O and I
Origin: Oval depression on the lateral aspect of the dorsum of the scapula above the inferior angle Insertion: Medial lip of the bicipital groove
Teres Major: Inn and act
Innervation: Lower subscapular nerve [C5 and 6]
Action: Extends, adducts and medially rotates the arm
