Shoulder Flashcards
Rhomboid Major
Action: Adduct, elevate and downwardly rotate scapula (S/T joint).
Origin: Spinous processes of T2 - T5.
Insertion: Medial border of the scapula between the spine of the scapula and inferior angle.
Nerve: Dorsal scapular C4, 5.
Rhomboid Minor
Action:** **Adduct, elevate and downwardly rotate scapula.
Origin: Spinous Process of C7 & T1.
Insertion: Upper portion of medial border of the scapula, across from spine of the scapula.
Nerve: Dorsal Scapular C4, 5.
Levator Scapula
Action: Unilaterally: Elevate and downwardly rotate scapula. Laterally flex head and neck. Rotate head and neck to same side. Bilaterally: Extend head and neck.
Origin: Transverse process of C1-C4.
Insertion: Medial border of scapula, between superior angle and superior portion of spine of scapula.
Nerve: Cervical 3, 4 and dorsal scapular C4, 5.
Serratus Anterior
Action:** **With origin fixed: Abduct, upwardly rotate and depress the scapula. Hold the medial border of the scapula against the rib cage.
With the scapula fixed: May act to elevate the thorax during forced inhalation.
Origin: External surfaces of upper 8-9 ribs.
Insertion:** **Anterior surface of medial border of the scapula.
Nerve:** **Long thoracic C5, 6, 7, 8.
Deltoid
*note differences between anterior and posterior fibers*
Function: All fibers: Abduct the shoulder (G/H joint).
- Anterior fibers-* Flex, medially rotate and horizontally adduct the shoulder (G/H joint).
- Posterior fibers-* Extend, laterally rotate and horizontally abduct the shoulder (G/H joint).
Origin: Lateral one-third of clavicle, acromion and spine of scapula.
- *Insertion:** Deltoid tuberosity.
- *Nerve:** Axillary C5, 6
Pectoralis Major
*note the differences between the fibers*
Action: All fibers- Adduct and medially rotate shoulder G/H joint. Assist to elevate the thorax during forced inhalation (with arms fixed).
- Upper fibers- *Flex and horizontally adduct the shoulder.
- Low fibers*- Extend shoulder at G/H joint.
Origin: Medial half of clavicle, sternum and cartilage of ribs 1-6.
Insertion: Crest of greater tubercle of humerous.
Nerve: Upper fibers- Lateral pectoral C5, 6, 7.
Low fibers- Lateral and medial pectoral C6, 7, 8, T1.
Pectoralis Minor
Action: Depress, abduct and downwardly rotate the scapula (S/T joint). With the scapula fixed: assist to elevate the thorax during forced inhalation.
Origin: Ribs 3, 4, 5.
Insertion: Medial surface of coracoid process of the scapula.
Nerve: Medial pectoral, with fibers from a communicating branch of the lateral pectoral C(6), 7, 8, T1.
Subclavius
Action: Depress the clavicle and draw it anteriorly. Elevate the first rib to assist during inhalation. Stabilize the sternocalvicular joint.
Origin: First rib and cartilage.
Insertion: Inferior surface of middle one-third of clavicle.
Nerve: Subclavian C5, 6.
Biceps Brachii
*note difference between short and long heads*
Action: Flex elbow (humeroulnar joint). Supinate forearm (radioulnar joint). Flex the shoulder (G/H joint).
Origin: Short head-Coracoid process of scapula.
Long head-Supraglenoid tubercle of scapula.
Insertion: Tuberosity of the radius and aponeurosis of the biceps brachii.
Nerve: Musculotaneous C5, 6.
Triceps Brachii
*note differences between the muscle heads*
Action: All heads- Extend the elbow (humeroulnar joint).
Long head- Extend and adduct the shoulder (G/H joint).
Origin: *Long head- *Infraglenoid tubercle of scapula.
- Lateral Head*- Posterior surface proximal half of the humerous.
- Medial Head*- Posterior surface of distal half of humerous.
Insertion: Olecranon process of the ulna.
Nerve: Radial C6, 7, 8, T1.
Coracobrachialis
Action: Flex and adduct the shoulder (G/H joint).
Origin: Coracoid process of the scapula.
Insertion: Medial surface of the mid-humeral shaft.
Nerve: Musculocutaneous C6, 7.
Trapezius
*note the differences between upper, middle and lower fibers*
Action: *Upper fibers: *Bilaterally- Extend the head and neck. Unilaterally- Elevate and upwardly rotate the scapula (S/T joint). Laterally flex the head and neck to the same side. Rotate the head and neck to the opposite side.
- Middle Fibers*- Adduct and stabilize the scapula (S/T joint).
- Lower Fibers*- Depress and upwardly rotate the scapula (S/T joint).
Origin: External occipital protuberance, medial portion of superior nuchal line of the occiput, ligamentum nuchae and spinous process of C7-T12.
Insertion: Lateral one-third of clavicle, acromion and spine of scapula.
Nerve: Spinal portion of cranial nerve XI (accessory) and ventral ramus C2, 3, 4.
Latissimus Dorsi
Action: Extend, adduct and medially rotate the shoulder (G/H joint).
Origin: Inferior angle of scapula, spinous process of T7-T12, last three or four ribs, thoracolumbar aponeurosis and posterior iliac crest.
Insertion: Intertubercular groove of the humerus.
Nerve: Thoracodorsal C6, 7, 8.
Teres Major
Action: Extend, adduct and medially rotate the shoulder (G/H joint).
Origin: Inferior angle and lower one-third of lateral border of the scapula.
Insertion: Crest of the lesser tubercle of the humerus.
Nerve: Lower subscapular C5, 6, 7.
Which muscles are known as the Rotator Cuff Muscles?
- Supraspinatus
- Infraspinatus
- Teres Minor
- Subscapularis
Acronym: SITS
