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Muscle of Shoulder ( Clavicle,

Scapula & Humerus )

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a. Muscles of pectoral girdleb. Muscles associated with scapula c. Muscles of the anterior/posterior compartment of arm

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a. Muscles of pectoral girdle

1.Trapezius 2. Infraspinatus

3. Deltoid 4. Teres Minor5. Latissimus Dorsi 6. Teres Major7. Pectoralis Major 8. Subscapularis9. Supraspinatus 10. Subclavius

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1. TrapeziusOrigin: Upper part: • External occipital proturberance,• Medial third of the superior nuchal line• The ligamentum nuchae,• The spinous process of C7Medial Part: Spinous processes of T1 to T5.Lower Part: Spinous processes of T6 to T12

Insertion:Upper Part: • Lateral third of the clavicle • The medial aspect of the acromion process of the scapulaMiddle Part: • Medial edge of the superior surface of the acromion process of the

scapula • The superior edge of the scapular spineLower Part: Tubercles of the apex of the scapular spine

Action: • Elevation , depression, rotation, adduction of scapula

Innervation: Cranial nerve 11 , Cervical nerve C2-C4

Blood Supply: Branches from the thyrocervical trunk.

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2. DeltoidOrigin: Anterior Part (Clavicular): Anterior border of the lateral third of the clavicleMedial Part (Acromial) : Lateral border of the acromion of the scapulaPosterior Part (Spinal) : Inferior edge of the scapular spine

Insertion: (Clavicular): The deltoid tuberosity on the lateral surface of the proximal humeral shaft(Acromial): The deltoid tuberosity on the lateral surface of the proximal humeral shaft.(Spinal): The deltoid tuberosity on the lateral surface of the proximal humeral shaft.

Action: • (Clavicular) : Anteversion, internal rotation, adduction• (Acromial) : Abduction• (Spinal) : Retroversion, external rotation, adduction

Innervation: Axillary nerve (C5, C6)

Blood Supply: Cephalic vein

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3. Latissimus DorsiOrigin: • Spinous processes of T7-T12• Ribs 9-12• Iliac Crest • Inferior angle of scapula

Insertion: Intertubercular groove of humerus

Action: • Extension arm• Adduction arm• Rotation arm

Innervation: Thoracodorsal nerve (C6 – C8)

Blood Supply: Thoracordosal Artery from the axillary artery

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4. Pectoralis MajorOrigin: • Clavicular part• Sternocostal part• Abdominal part

Insertion: Greater Tubercle

Action: Adduction, Anteversion, Rotation, Retroversion

Innervation: • Medial pectoral nerve (C7, T1) • Lateral pectoral nerve (C5, C6, C7)

Blood Supply: Pectoral branches from the thoraco-acromial artery

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5. SupraspinatusOrigin: Supraspinous fossa of scapula

Insertion: Superior facet of greater tubercle of humerus

Action: • Abduction of arm • Stabilizes humerus

Innervation: Suprascapular nerve (C5,C6)

Blood Supply: • Suprascapular artery from the thyrocervical

trunk • Dorsal scapular artery

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6. InfraspinatusOrigin: Infraspinous fossa of the scapula

Insertion: Middle facet of greater tubercle of the humerus

Action: • Rotation of arm• Stabilizes humerus

Innervation: Suprascapular Nerve (C5, 6)

Blood Supply: • Suprascapular Artery • Circumflex humeral artery from the axillary artery.

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7. Teres MinorOrigin: On the dorsal surface of the middle half of the lateral border of the scapula

Insertion: The lowest of the three facets of the greater tubercle of the humerus

Action: Externally rotates the arm

Innervation: Axillary nerve (C5,6)

Blood Supply: Scapular circumflex artery

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8. Teres MajorOrigin: Posterior aspect of the inferior angle of the scapula

Insertion: Medial lip of the intertubercular sulcus of the humerus

Action: Internal rotation (medial rotation) of the humerus

Innervation: Lower subscapular nerve (C5,6)

Blood Supply: Subscapular and posterior circumflex humeral arteries from the axillary artery

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9. SubscapularisOrigin: Medial two-thirds of volar surface of the scapula

Insertion: Lesser tubercle of humerus

Action: • Internally rotates humerus• Assists with depression of the humeral head

Innervation: Upper and Lower Subscapular Nerve (C5,6)

Blood Supply: Subscapular artery from the axillary artery

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10. SubclaviusOrigin: From the junction of the first rib and its costal cartilage, just anterior to the costoclavicular ligament

Insertion: By muscular fibers to the groove on the inferior surface of the middle of the clavicle

Action: Depression of clavicle

Innervation: Subclavian branch of brachial plexus (C5, C6)

Blood Supply: Clavicular branch from the thoraco-acromial artery and the suprascapular artery

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b. Muscles associated with scapula

1.Levator Scapula

2.Rhomboid Minor

3.Rhomboid Major

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1. Levator ScapulaOrigin: Transverse processes of C1-C4

Insertion: Vertebral border of scapula

Action: • Elevates scapula• Downwardly rotates scapula

Innervation:• Anterior primary rami of (C3 and C4)• Dorsal scapular nerve (C5)

Blood supply: Dorsal Scapular Artery

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2. Rhomboid MinorOrigin: Ligamentum Nuchae and the spinous processes of C7 and T1

Insertion: • Vertebral border of the scapula, • Adjacent to the scapular spine.

Action: • Retraction of the scapula• Downward rotation of the scapula

Innervation: Dorsal scapular nerve C5

Blood Supply: Dorsal scapular artery

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3. Rhomboid MajorOrigin: Spinous processes of T2 – T5

Insertion: • Vertebral border of the scapula• From inferior to the scapular spine

to the inferior angle

Action: • Retraction of the scapula• Downward rotation of the scapula

Innervation: Dorsal scapular nerve C5

Blood Supply: Dorsal scapular artery

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c. Muscles of the anterior/posterior

compartment of arm1.Biceps Brachii2.Brachialis3.Coracobrachialis4.Triceps Brachii

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1. Biceps BrachiiOrigin: • Supraglenoid tubercle of scapula• Coracoid process of scapula

Insertion: Radial tuberosity of radius

Action: • Flexes forearm at elbow• Supinates forearm

Innervation: Musculocutaneous nerve (C5,6)

Blood Supply: Muscular branches of the brachial artery

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2. BrachialisOrigin: Anterior Humerus

Insertion: Coronoid Process of Ulna

Action: Flexes forearm at elbow

Innervation: Musculocutaneous nerve (C5,6)

Blood Supply:• Muscular branches from the brachial

artery • Radial recurrent artery from the radial

artery.

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3. CoracobrachialisOrigin: Coracoid process of scapula

Insertion: Medial humerus

Action: • Flexes arm at shoulder• Adducts arm

Innervation: Musculocutaneous nerve (C5,6,7)

Blood Supply: Muscular branches from the brachial artery

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4. Triceps BrachiiOrigin: • Long head: Infraglenoid tubercle of

scapula• Lateral head: Posterior humerus• Lateral head: Posterior humerus

Insertion: Olecranon process of ulna

Action: Extends forearm at elbow

Innervation: Radial nerve (C6,7)

Blood supply:• Muscular branches• Superior ulnar collateral • Profunda brachii arteries from the

brachial artery.

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