Topic 3: Bones, Joints and Muscles of the Shoulder

Question 1

classify glenohumeral joint (shoulder)

Answer 1

synovial, multiaxial, ball and socket joint
articular surfaces: glenoid cavity and head of the humerus

Question 2

scapulothoracic joint

Answer 2

formed by the convex surface of the posterior thoracic cage and the concave surface of the anterior scapula

Question 3

sternoclavicular joint

Answer 3

synovial, plane, multiaxial joint

Question 4

acromioclavicular joint

Answer 4

acromion process and scapula
biaxial, synovial, plane joint

Question 5

pectoralis major

Answer 5

Origin:
- Sternal (sternocostal) head: anterior manubrium and body of sternum
- Clavicular head: medial half of anterior clavicle
Insertion: lateral lip of intertubercular groove/sulcus of humerus
Actions: adduction of the arm at the shoulder joint, medially rotate arm at the shoulder, flex arm at the shoulder join

Question 6

latissimus dorsi

Answer 6

Origin: spinous processes of T6-T12 vertebrae, thoracolumbar fascia, iliac crest and ribs 9-12
Insertion: floor of intertubercular groove/sulcus of humerus
Actions: extension, adduction and medial rotation of shoulder join

Question 7

trapezius

Answer 7

Origin: external occipital protuberance and superior nuchal line of skull, nuchal ligament, spinous process of C7-T12 vertebrae
Insertion: Lateral 1/3 of clavicle, acromion and spine of scapula
Actions:
- Upper part: elevation and rotation of scapula
- Middle part: retraction of scapula
- Lower part: depression and rotation of scapula

Question 8

rhomboid major

Answer 8

Origin: spinous processes of T2-T5 vertebrae
Insertion: medial border of scapula from root of spine to inferior angle
Actions: retraction and rotation of scapula

Question 9

rhomboid minor

Answer 9

Origin: spinous processes of C7 and T1 vertebrae, nuchal ligament
Insertion: medial border of scapula at level root of spine
Actions: retraction and rotation of scapula

Question 10

serratus anterior

Answer 10

Origin: ribs 1-8 (lateral)
Insertion: medial border of scapula
Actions: protraction and rotation of scapula

Question 11

deltoid

Answer 11

Origin: lateral 1/3 of clavicle, acromion and spine of scapula
Insertion: deltoid tuberosity of humerus
Actions:
Anterior part: flexion and medial rotation of shoulder joint
Middle part: abduction of shoulder joint
Posterior part: extension and lateral rotation of shoulder joint

Question 12

coracobrachialis

Answer 12

Origin: coracoid process of scapula
Insertion: middle 1/3 of medial shaft of humerus
Actions: flexion and adduction of shoulder joint

Question 13

teres major

Answer 13

Origin: posterior surface of inferior angle of scapula
Insertion: medial lip of intertubercular groove/sulcus of humerus
Actions: adduction and medial rotation of shoulder joint (can also assist with extension)

Question 14

teres minor

Answer 14

Origin: lateral border of scapula
Insertion: greater tubercle of humerus
Actions: lateral rotation of the shoulder joint

Question 15

subscapularis

Answer 15

Origin: subscapular fossa of scapula
Insertion: lesser tubercle of humerus
Actions: medial rotation of shoulder joint

Question 16

supraspinatus

Answer 16

Insertion: lesser tubercle of humerus
Actions: initiates abduction of shoulder joint

Question 17

infraspinatus

Answer 17

Origin: infraspinous fossa of scapula
Insertion: greater tubercle of humerus
Actions: lateral rotation of the shoulder joint

Question 18

biceps brachii

Answer 18

Origin:
- long head: supraglenoid tubercle of scapula (lateral)
- Short head: coracoid process of scapula (medial)
Insertion: radial tuberosity (and forearm fascia via bicipital aponeurosis)
Actions: flexion of the shoulder joint

Question 19

triceps brachii

Answer 19

Origin: long head: infraglenoid tubercle of scapula
- Lateral head: posterior shaft of humerus (superior to radial groove)
- Medial head: posterior shaft of humerus (inferior to radial groove)
Insertion: olecranon of ulna
Actions: extension of the shoulder joint