Shoulder

Question 1

Infraspinatus

Answer 1

Origin: Medial 2/3rds of infraspinous fossa of the scapula

Insertion: Middle facet on posterior surface of the greater tubercle of the humerus

Innervation: C5-C6 Suprascapular nerve

Function: Rotator Cuff muscle: Lateral rotation of the arm at the glenohumeral joint

Question 2

Teres Major

Answer 2

Origin: Elongate oval area on the posterior surface of the inferior angle of the scapula

Insertion: Medial lip of the intertubercular sulcus on the anterior surface of the humerus

Innervation: C5-C6-C7 Inferior subscapular nerve

Function: Medial rotation and ex- tension of the arm at the glenohumeral joint

Question 3

Latissimus Dorsi

Answer 3

Origin: Spinous processes
of lower six thoracic vertebrae and re- lated interspinous ligaments; via the thoracolumbar fascia to the spinous processes of the lumbar vertebrae, related interspinous ligaments, and iliac crest; lower 3-4 ribs

Insertion: Floor of intertubercular sulcus

Innervation: C6 - C7- C8 Thoracodorsal nerve

Function: Adduction, medial rotation, and extension of the arm at the glenohumeral joint

Question 4

Deltoid

Answer 4

Origin: Inferior edge of the crest of the spine of the scapula, lateral margin of the acromion, anterior border of lateral one-third of clavicle

Insertion: Deltoid tuberosity of the humerus

Innervation: C5-C6 Axillary nerve

Function: Major abductor of arm, clavicular fibers assist in flexing the arm; posterior fibers assist in extending the arm

Question 5

Pectoralis Major- Clavicular Head

Answer 5

Origin: Anterior surface of the medial half of the clavicle

Insertion: Lateral lip of intertubercular sulcus of humerus

Innervation: C5 - C6 medial and lateral pectoral nerves

Function: Flexion, adduction and medial rotation of arm at glenohumeral joint.
Clavicular Head: Flexion of the extended arm

Question 6

Pectoralis Major- Sternocostal Head

Answer 6

Origin: Anterior surface of the sternum; first seven costal cartilages; aponeurosis of external oblique

Insertion: Lateral lip of intertubercular sulcus of humerus

Innervation: C6 - C7- C8 - T1

Function: Flexion, adduction and medial rotation of arm at glenohumeral joint.
Sterno-costal head: ex- tension of flexed arm