The Shoulder Joint TEST WEDNESDAY

Anterior Shoulder Muscles

• Coracobrachialis

• Pectoralis Major

• Subscapularis

• Biceps Brachii

Biceps Brachii • Origin• Short head: coracoid

process of scapulaLong head: supraglenoid tubercle of scapula

• Insertion Tuberosity of radius

• Action Flexion of the elbow and shoulder, Supinates forearm

• ***the long head is the “5th rotator cuff”

Coracobrachialis• O: Coracoid process• I: Anteromedial

surface of midshaft of humerus

• Actions: (WEAK!)– Flexion – Adduction of the

shoulder

Pectoralis Major• Origin:

– Medial two-thirds of clavicle– Sternum

• Insertion: intertubercular groove• Actions

– Upper fibers (Clavicular)• Flexion• Horizontal Adduction

– Lower fibers (Sternal)• Internal/medial Rotation• Horizontal adduction

Subscapularis• O: Subscapular fossa• I: Lesser tubercle and

crest of humerus• Actions:

– Internal Rotation• Stabilization • Anterior Rotator Cuff

Muscle.

Superior Shoulder Muscles

• Deltoid

• Supraspinatus

Deltoid• Origin

– Lateral 1/3 of clavicle (Anterior fibers)

– Acromion process (Middle fibers)– Spine of scapula

(Posterior fibers)

• Insertion – deltoid tuberosity

ActionsAnterior –FlexionMiddle – AbductionPosterior –Extension

Supraspinatus• O: Supraspinous

fossa• I: Greater tubercle• Action:

– Abduction• Stabilization• Superior Rotator Cuff

Muscle.• Most injured rotator

cuff muscle

Inferior Shoulder Muscles

• Latissimus Dorsi

• Teres Major

Latissimus Dorsi• O: Spinous process of

lower 6 thorasic and all lumbar and sacral vertebrae; iliac crest

• I: Intertubercular groove

• Actions: – Adduction– Internal Rotation

Teres Major• O: Inferior angle of

scapula• I: Intertubercular

groove• Actions:

– Adduction– Internal rotation

• “Lats little helper”

Posterior Shoulder Muscles

• Infraspinatus

• Teres Minor

• Triceps Brachii

Triceps Brachii • Origin

Long head: infraglenoid tubercle of scapulaLateral head: posterior surface of humerus,

Medial head: posterior surface of humerus,Insertion Olecranon process of ulna

• Action Chief extensor of elbow (long head extends the shoulder)

Infraspinatus• O: Infraspinous fossa• I: Greater tubercle• Actions:

– External rotation

• Stabilization• Posterior Rotator Cuff Muscle• Second most commonly

injured rotator cuff muscle

Teres Minor• O: lateral border of

scapula

• I: Greater tubercle

• Actions: – External rotation

• Stabilization

• Posterior Rotator Cuff Muscle

Muscles of the scapula only

Trapezius• Origin occipital bone,

nuchal ligament, and spinous processes of C7 - T12 vertebrae

• Insertion Lateral third of clavicle, acromion, and spine of scapula

• Action • superior fibers elevate, • middle fibers retract, • inferior fibers depress

scapula;

Levator Scapula

• Origin C1 - C4 vertebrae

• Insertion Superior angle

• Action Elevates scapula

Rhomboid major and minor

Rhomboid major and minor• Origin

Minor: spinous processes of C7 and T1 vertebraeMajor: spinous processes of T2 - T5 vertebrae

• Insertion Medial border of scapula

• Action Retract scapula

Serratus Anterior

• Origin the eight upper frontal ribs

• Insertion lateral border of scapula

• Action protracts scapula

Name the muscle.

Coracobrachialis

Name the action

Flexion and Adduction of the shoulder

Name the muscle.

Pectoralis Major

FunctionHorizontal AdductionInternal roatation

Name the muscle.

Subscapularis

Name the action

Internal rotation of the shoulder

Name the muscle.

Deltoid

Name the action

Abduction of shoulder (middle third)

Flexion (anterior deltoid)

Extension (posterior deltoid)

Name the muscle.

Infraspinatus

Name the action

External rotation

Name the muscle.

Teres Major

Name the action

Adduction of arm

Name the muscle.

Teres Minor

Name the action if the humerus move directly to the posterior

Extension of the shoulder

Name the muscle.

Supraspinatus

Name the action

Abduction of the shoulder

Coracobrachialis Pect. Major

SubscapularisDeltoid

Supraspinatus Teres Major

InfraspinatusTeres Minor