The Shoulder Flashcards
What are the six intrinsic muscles of the shoulder?
Deltoid Teres Major Supraspinatus Infraspinatus Teres Minor Subscapularis
Deltoid
Origin:
Anterior: lateral 1/3 of the clavicle
Middle: acromion of the scapula
Posterior: spine of the scapula
Insertion: deltoid tuberosity on the humerus
Actions: All parts together: abducts Anterior: flexes/medial rotate arm Middle: abducts the arm Posterior:extend/lateral rotate arm
Innervation: axillary nerve
Teres Major
Origin: inferior angle and lower part of lateral border of the scapula
Insertion: medial lip of the intertubercular sulcus (humerus)
Action: extends, adducts, and medially rotates the arm
Innervation: lower subscapular nerve
Supraspinatus
Origin: supraspinous fossa
Insertion: greater tubercle (superior facet)
Action: abducts the arm
Innervation: suprascapular nerve
Infraspinatus
Origin: infraspinous fossa
Insertion: greater tubercle (middle facet)
Action: laterally rotates the arm
Innervation: suprascapular nerve
Teres Minor
Origin: lateral border of the scapula
(above the origin of teres major)
Insertion: greater tubercle (inferior facet)
Action: laterally rotates the arm
Innervation: axillary nerve
Subscapularis
Origin: subscapular fossa
Insertion: lesser tubercle (humerus)
Action: medially rotates the arm
Innervation: upper and lower subscapular nerves
What 4 muscles are part of the rotator cuff?
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
Subscapular artery
Branch of thryrocervical trunk
Branch of the subclavian
Supplies: supraspinatus and infraspinatus
Posterior circumflex humoral artery
Arises from the axillary artery
Supplies: teres minor
Circumflex scapular artery
Branch of the subscapular artery
Contributes to scapular anastomosis
Supplies: teres major and teres minor
Pectoralis Major
Origin: medial half of the clavicular head, sternum, costal cartilages 1-6, and aponeurosis of external oblique muscle
Insertion: lateral lip of intertubercular sulcus
Action:
Both heads: adducts, medially rotates the arm, depresses, protracts scapula
Clavicular head: flexes the arm
Sternocostal head: extends arm from flexed position
Innervation: lateral and medial pectoral nerves
Pectoralis Minor
Origin: Ribs 3-5 (near the costal cartilages
Insertion: coracoid process
Action: depresses and protracts the scapula
Innervation: medial pectoral nerve
Subclavius
Origin: Junction of rib 1 and its costal cartilage
Insertion: subclavian groove on the inferior surface
Action: protracts and rotates the scapula
Innervation: nerve to the subclavius
Serratus Anterior
Origin: Ribs 1-9
Insertion: medial border of the scapula
Action: protracts and superiorly rotates the scapula
Innervation: long thoracic nerve
Thoracoarcomial trunk
Clavicular branch: supplies the subclavius
Acromial: supplies part of the deltoid
Deltoid: supplies part of the deltoid
Pectoral: supplies the pectoralis minor and part of the pectoralis major
Lateral Thoracic Artery
Supplies the lateral structures of the thorax and breast
Supplies the serratus anterior and part of the pectoralis major
What are the 3 joints that make up the shoulder complex?
Glenohumeral Joint
Acromioclavicular Joint
Sternoclavicular joint
What are the 4 muscles of the pectoral region?
Pectoralis Major
Pectoralis Minor
Subclavius
Serratus anterior
What are some important things about the glenohumeral joint?
The head of the humerus articulates with the glenoid fossa
Ball and socket joint (synovial)
The glenoid fossa is shallow: permits movements over stability
It is the most mobile joint in the human body
