Shoulder Muscles Flashcards
Deltoid Origin
Anterior: Lateral 1/3 of anterior clavicle
Middle: Anterior acromion
Posterior: Inferior edge of spine of scapula
Deltoid Insertion
Deltoid tuberosity of humerus
Deltoid Innervation
Axillary Nerve
Deltoid Actions
Anterior: Flexes and medially rotates arm
Middle: Abducts arm beyond initial 15 degrees
Posterior: Extends and lateral rotates arm
Deltoid Blood Supply
Posterior circumflex humeral artery, deltoid branch of thoraco-Acromial artery
Infraspinatus Origin
Infraspinatus fossa of scapula and deep fascia
Infraspinatus Insertion
Middle facet of greater tubercle of humerus
Infraspinatus Innervation
Suprascapular nerve
Infraspinatus Action
Lateral rotation of arm ( with teres minor)
Infraspinatus Blood Supply
Suprascapular artery
Latissimus Dorsi Origin
Spinous processes of T7-L5 vertebrae, thoracolumbar fossa, iliac crest, last 3 ribs
Latissimus Dorsi Insertion
Interubercular sulcus of humerus
Latissimus Dorsi Innervation
Thoracodorsal nerve
Latissimus Dorsi Actions
Extends, adducts, and medially rotates humerus at shoulder
Latissimus Dorsi Blood Supply
Thoracodorsal artery, dorsal perforating branches of 9th, 10th, and 11th posterior intercostal, subcostal and 1st 3 lumbar arteries
Levator Scapulae Origin
Posterior tubercles of transverse processes C1-C4
Levator Scapulae Insertion
Medial border of scapula from superior angle to spine
Levator Scapula Innervation
Ventral Rami of C3-C4 and dorsal scapular nerve
Levator Scapulae Main Action
Elevates scapula medially, inferiorly rotates glenoid cavity
Levator Scapulae Blood Supply
Dorsal Scapular artery, transverse cervical artery, ascending cervical artery
Pectoralis Major Origin
Sternal 1/2 of clavicle, sternum to the 7th rib, cartilages of true ribs, aponeurosis of external oblique muscle
Pectoralis Major Insertion
Lateral lip of intertubercular sulcus of humerus
Pectoralis Major Innervation
Medial and lateral pectoral nerves
Pectoralis Major Main Actions
Flexes and adducts the arm, rotates the arm medially
Pectoralis Major blood supply
Pectoral branch of thoracoacromial artery, perforating branches of internal thoracic artery
Pectoralis Minor Origin
Outer surface of upper margin of ribs 3-5
Pectoralis Minor Insertion
Coracoid process of scapula
Pectoralis Minor Innervation
Medial Pectoral nerve
Pectoralis Minor main actions
Lowers lateral angle of scapula and protracts scapula
Pectoralis Minor Blood Supply
Pectoral branch of thoraco-Acromial and intercostal lateral thoracic artery
Rhomboid Major Origin
Spinous process of T2-T5 vertebrae
Rhomboid Major Insertion
Medial border of scapula below base of spine of scapula
Rhomboid Major Innervation
Dorsal Scapular Nerve
Rhomboid Major Main Actions
Flexes scapula to thoracic wall and retracts and rotates it to depress glenoid cavity
Rhomboid Major Blood Supply
Dorsal scapular OR deep branch of transverse cervical artery, dorsal perforating branches of the upper 5 or 6 posterior intercostal arteries
Rhomboid Minor Origin
Ligamentum nuchae, spines of C7 and T1 vertebrae
Rhomboid Minor
Insertion
Medial border of scapula at spine of scapula
Rhomboid Minor
Innervation
Dorsal Scapular Nerve
Rhomboid Minor
Main Actions
Fixes scapula to thoracic wall and retracts and rotates it to depress glenoid cavity
Rhomboid Minor
Blood Supply
Dorsal Scapular OR deep branch of transverse cervical arter, dorsal perforating branches of the upper 5 or 6 posterior intercostal arteries
Serratus Anterior
Origin
Lateral surfaces of upper 8-9 ribs
Serratus Anterior
Insertion
Costal surface of medial border of scapula
Serratus anterior
Innervation
Long Thoracic Nerve
Serratus Anterior
Main Actions
Protracts and rotates the scapula and holds it against thoracic wall
Serratus Anterior
Blood Supply
Lateral Thoracic Artery
Subclavius
Origin
Upper border of 1st rib and its cartilage
Subclavius
Insertion
Inferior surface of middle third of clavicle
Subclavius
Innervation
Nerve to subclavius
Subclavius
Main Actions
Anchors and depresses clavicle
Subclavius
Blood Supply
Clavicular branch of thoraco-acromial artery
Subscapularis
Origin
Subscapular Fossa
Subscapularis
Insertion
Lesser tubercle of humerus
Subscapularis
Innervation
Upper and lower subscapular nerves
Subscapularis
Main Actions
Medially rotates Arm at Shoulder and Adducts it, helps hold humeral head in glenoid cavity
Subscapularis
Blood Supply
Subscapular Artery, lateral thoracic artery
Supraspinatus
Origin
Supraspinous fossa of scapula and deep fascia
Supraspinatus
Insertion
Superior facet of greater tubercle of humerus
Supraspinatus
Innervation
Suprascapular nerve
Supraspinatus
Main Actions
Initiates arm abduction, acts with rotator cuff muscles
Supraspinatus
Blood Supply
Suprascapular artery
Teres Major
Origin
Posterior surface of inferior angle of scapula
Teres Major
Insertion
Medial lip of intertubercular sulcus of humerus
Teres Major
Innervation
Lower subscapular nerve
Teres Major
Main Actions
Adducts and medially rotates arm
Teres Major
Blood Supply
Circumflex Scapular artery
Teres Minor Origin
Upper 2/3 of posterior surface of lateral border of scapula
Teres Minor Insertion
Inferior facet of greater tubercle of humerus
Teres Minor
Innervation
Axillary Nerve
Teres Minor
Main Actions
Laterally rotates arm
Teres Minor
Blood Supply
Circumflex Scapular Artery