Trail Guide Muscles, Shoulder

Front 1

Subclavius

Back 1

O: 1st Rib/Cartiledge
I: Lateral, Inferior Clavicle
A: Depress Clavicle Inferiorly & Anteriorly; Elevate 1st Rib (to assist w/breathing), Stabilize sc jt
N: Subclavian

Front 2

Pectoralis Minor

Back 2

O: 3rd, 4th, 5th Ribs
I: Coracoid Process
A: Depress the scapula (st jt); Abduct the scapula (st jt); Tilt the scapula anteriorly (st jt)
If scapula is fixed: may assist with forced inhalation
N: Medial pectoral

Front 3

Serratus Anterior

Back 3

O: Surfaces of upper 8-9 ribs
I: Anterior, medial surface of scapula
A: Abducts the scapula (st jt); Depress the scapula (st jt); Holds the medial scapula border to the rib cage
If scapula is fixed, may assist w/forced inhalation
N: Long thoraic

Front 4

Levator Scapula

Back 4

O: Transverse processes of 1-4 cervical vertebrae
I: Superior, medial scapula
A: Elevate scapula; Downward rotation of the scapula (st jt); Laterally flex the head & neck; rotate head & neck (same side)
Bilaterally: Elevates the head & neck
N: Dorsal scapular and cervical nerves

Front 5

Supraspinatus

Back 5

O: Supraspinatus fossa of the scapula
I: Greater Tubercle of the Humerus
Abduct the shoulder
Stabalize head of the humerus in the glenoid cavity
N: Suprascapular

Front 6

Infraspinatus

Back 6

O: Infraspinatus fossa of the scapula
I: Greater tubercle of the Humerus
Adduct the shoulder (gh jt)
Extend the shoulder (gh jt)
Horizontally abduct the shoulder (gh jt)
Stabilize the head of the humerus in the glenoid fossa
N: Suprascapular

Front 7

Teres Minor

Back 7

O: Superior half of the lateral scapular border
I: G. tubercle of the humerus
Adduct the shoulder (gh jt); Extend the shoulder (gh jt); Horizontally abduct shoulder (gh jt); Stabilize the head of the humerus in the glenoid fossa
N: Axillary

Front 8

Subscapularis

Back 8

O: Subscapular fossa of the anterior scapula
I: Lesser tubercle of humerus
Medially rotate the shoulder (gh jt); stabilize the head of the humerus in the glenoid cavity
N: Upper & Lower subscapular

Front 9

Latissimus Dorsi

Back 9

O: T6 to sacrum including posterior iliac crest
I: L tubercle of the humerus
Extend the shoulder (gh jt); Adduct the shoulder (gh jt); Medially rotate the shoulder (gh jt)
N: Thoracodorsal

Front 10

Teres Major

Back 10

O: Lateral inferior border of the Scapula
I: L Tubercle
Extend shoulder (gh jt); Adduct shoulder (gh jt); Medially rotate shoulder (gh jt)
N: Lower Subscapular

Front 11

Trapezius

Back 11

O: Occipital proturbance, C7-T12
I: Lateral 1/3 Clavicle, Acromion, 1/3 Scapular Spine
Bilaterally: Extend Neck & Head
Unilaterally: Flex Neck & Head (same side); turn neck & head (opp side); Elevate scapula (st jt); Upward rotation of scapula (st jt)
Middle Fibers: Adduct scapula & stabilize (st jt)
Lower fibers: Depress scapula & Upwardly rotate scapula
N: Spinal accessory & cervical plexus

Front 12

Deltoid

Back 12

O: 1/3 Clavicle, acromion, 1/3 scapula
I: Deltoid Tuberocity
All fibers: Abduct shoulder
Anterior fibers: flex shoulder; medially rotate shoulder; Horizontally adduct shldr (gh jt)
Posterior Fibers: Extend shldr; laterally rotate shldr; horizontally abduct
N: Axillary from brachial plexus

Front 13

Rhomboid Major & Minor

Back 13

O Major: Spinous processes T2-5 O Minor: Spinous processes c7-t1
I Major: Medial border of scapula between spine of scapula & inferior angle I Minor: Upper portion of the medial border of the scapula, across from the spine of the scapula
Adduct scapula (st jt); elevate scapula (st jt); downwardly rotate scapula (st jt)
N: Dorsal scapular from brachial plexus

Front 14

Pectoralis Major

Back 14

O: Medial 1/2 of clavicle, sternum & cartledge of 1-6 ribs
I: G Tubercle of Humerus
All Fibers: Adduct shoulder (gh jt); Medially rotate shldr; Assist in elevating thorax during forced inhalation (fixed arm)
Upper fibers: Flex shoulder (gh jt), horizontally adduct shldr
Lower fibers: Extend shoulder
N: Medial & lateral pectoral