Back ( Shoulder Girdle ) and Shoulder Muscles

Question 1

Deltoid Muscle

Answer 1

ORIGIN: Lateral 1/3 Clavicle, Acromion, Spine of the Scapula
INSERTION: Deltoid Tuberosity

                            ACTION: Abduction of the Shoulder

Anterior Fibers:
Flex,Medially Rotate, Horizontally ADDUCT the shoulder ( G/H Joint )

Posterior Fibers:
Extend, Laterally Rotate, Horizontally ABDUCT the shoulder ( G/H Joint )

Question 2

Trapezius Muscle’s

Answer 2

ORIGIN:
Pas descendens: linea Nuchae superior, Ligament Nuchae, Protuberantia Occipitalis Externa

Pars Transversa: Processus Spinosis C7-Th12

Pars Ascendens: Processus Spinos C7-Th12

INSERTION:
Lateral 1/3 of Clavicle, Acromion & Spine of the Scapula

ACTION:

Pars Descendens:
Bilateral - Extend the head & neck
Unilateral - Laterally flex the head & neck to the same side
- Rotate the head & neck to the same side
- Rotate the head & neck to the opposite side
- Elevate the Scapula
- Upwardly rotate the Scapula
Pars Transversa: Adduct & Stabilize scapula
Pars Ascendens: Depress & Upwardly rotate Scapula

Question 3

Latissimus Dorsi Muscle

Answer 3

ORIGIN: Inferior angle of Scapula, Spinous Processes of T7-L5 , Thoracolumnar Aponerousis, Posterior Iliac Crest

INSERTION: Intertubercular Gorve of the Humerus

ACTION:
Extension, Adduction, Medial Rotation of the shoulder

Question 4

Teres Major Muscle

Answer 4

ORIGIN: Inferior angle & lower 1/3 of the lateral border of the Scapula

INSERTION: Crest of the Lesser Tubercle of the Humerus

ACTION:
Extension, Adduction, Medial rotation of the shoulder

Question 5

Rotator Cuff Muscle’s

Answer 5

Musculo-tendinous Cuff
Ensures active Stability

M.Teres Minor T
M.Infraspinatus I
M.Supraspinatus S
M.Subscapularis S

Question 6

Supraspinatus Muscle

Answer 6

ORIGIN: Supraspinous Fossa of the Scapula

INSERTION: Greater Tubercle of the Humerus

ACTION:
Abduction of the Shoulder
Stabilizes the head of the Humerus in the GLENOID ACTIVITY

Question 7

Infraspinatus Mucsle

Answer 7

ORIGIN: Infraspinatus Fossa of the Scapula

INSERTION: Greater Tubercle of the Humerus

ACTION:
Lateral Rotator, Adductor of the Shoulder
Stabilize the head of the Humerus in the GLENOID ACTIVITY

Question 8

Teres Minor Muscel

Answer 8

ORIGIN: Upper 2/3 of the Lateral border of the Scapula

INSERITION: Greater Tubercle of the Humerus

ACTION:
Lateral Rotator, Adductor of the shoulder
Stabilize the head of the Humerus in the GLENOID ACTIVITY

Question 9

Subscapularis Muscel

Answer 9

ORIGIN: Subscapularis Fossa of the Scapula

INSERTION: Lesser Tubercle of the Humerus

ACTION:
Medial Rotator of the Shoulder
Stabilizes the head of the Humerus in the GLENOID CAVITY

Question 10

Rhomboid Muscles

Answer 10

ORIGIN:
Major - Spinous processes of T2 to T5
Minor - Spinous processes C7 and T1

INSERTION:
Major - Medial border of the scapula between the spine and inferior angle
Minor - Medial upper portion of the scapula, across from spine of the scapula

ACTION: Scapular Adduction ( ST Joint ), Elevevation ( ST Joint ), Downward Rotation ( ST Joint )

Question 11

Levator Scapula Muscle

Answer 11

ORIGIN: Transverse process of C1 - C4

INSERTION: Medial border of scapula, between superior angle and superior portion of spine of scapula

ACTION:
Scapular Elevation ( ST Joint ), Downward rotation ( ST Joint )
Lateral flexion of the head and neck, Rotation of the head and neck

Question 12

Serratus Anterior Muscle

Answer 12

ORIGIN: External surfaces of upper 1-9th ribs

INSERTION: Anterior surface of medial border of the scapula

ACTION: Scapular Abduction (ST Joint), Upward rotation, Depression

Question 13

Pectoralis Major Muslce

Answer 13

ORIGIN: Medial half of the clavicle + Sterum + Cartilage of 1 - 6th rib

INSERTION: Crest of greater tubercle ( Humerus )

ACTION: Adduction, Medial Rotation of the shoulder + Thoracic Elevation during forced inhalation ( With arm fixed )

Upper Fibers: Flexion and Horizontal Adduction of the shoulder ( GH Joint )

Lower Fibers: Extension of the shoulder ( GH Joint )

Question 14

Pectoralis Minor Muscle

Answer 14

ORIGIN: 3-5th rib

INSERTION: Medial surface of the Coracoid Process of the Scapula

ACTION: Depression, Abduction, Downward Rotation of the Shouler ( ST Joint )

With Scapula Fixed: Elevation during forced Inhalation

Question 15

Subclavius Muscle

Answer 15

ORIGIN: 1. Rib and Cartilage

INSERTION: Inferior surface of the 1/3 Scapula

ACTION: Depression of the Clavicle, Elevation of the 1. Rib, Stabilizing the Ster.Clav. Joint

Question 16

Biceps Brachii Muscle

Answer 16

ORIGIN:

Long head - Supraglenoid Tubercle of Scapula

Short Head - Coracoid process of Scapula

INSERTION: Tuberosity of Radius, Aponeurosis of Biceps Brachii

ACTION: Flexion of the elbow, Supination of forearm, Flexion of the Shoulder

Question 17

Triceps Brachii Muscle

Answer 17

ORIGIN:

Long head - Infraglenoid Tubercle

Lateral head - Posterior surface of proximal half of Humerus

Medial head - Posterior surface of distal half of Humerus

INSERTION: Olecranon process of the Ulna

ACTION:
All: Extension of the Elbow
Long head: Extension of the Shoulder, Adduction of Shoulder

Question 18

Coracobrachialis Muscle

Answer 18

ORIGIN: Coracoid Process
INSERTION: Medial surface of mid-numeral shaft

ACTION: Flexion and Adduction of the shoulder (GH Joint)