Functional anatomy of the shoulder

Question 1

Bones of the shoulder

Answer 1

Scapula
Humerus
Clavicle

Question 2

What type of bone is the scapula

Answer 2

Irregular

Question 3

Anatomical neck of humerus

Answer 3

Site of attachment of capsule

Site of epiphyseal plate in childhood

Question 4

Surgical neck of humerus

Answer 4

Between the tubercles and the shaft and more frequently fractured then anatomical neck

Question 5

Articulation of shoulder girdle

Answer 5

Sternoclavicular

Acromioclaviculr

Glenohumeral

Scapulothoriacuc

Question 6

What type of joint is the shoulder joint

Answer 6

Ball and socket

Synovial joint

Most mobile

Least stable

Question 7

What deepens the glenoid cavity

Answer 7

Labrum

Question 8

What is responsible for the mobility of the shoulder joint

Answer 8

Shallow glenoid fossa

Disproportion of articular surface

Lax capsule, especially inferiorly

Question 9

What are the static stabilisers of the shoulder joint

Answer 9

Glenoid labrum

Joint capsule

Intracapsular ligaments

Extracapsular ligamements

Question 10

Dynamic stabilisers of shoulder joint

Answer 10

Rotator cuff muscles

Muscles

• deltoid
• coracobrachialis
• long head of biceps
• long head of triceps

Question 11

What are the intracapsular ligaments

Answer 11

3 glenohumeral ligaments

• superior
• middle
• inferior

Question 12

What are the extracapsular ligaments

Answer 12

• coracoacromial ligament
• coracohumeral ligament
• transverse humeral ligament
  
  • holds tendon of long head of biceps in place during shoulder movement

Question 13

What is the coracoacromial arch comprised of

Answer 13

Coracoid process

Coracoacromial ligament

Acromion process

Question 14

What does the coracoacromial arch prevent

Answer 14

Superior dislocation of the humerus

Question 15

What are the muscles of the rotator cuff

SITS

Answer 15

Supraspinatus

Infraspinatus

Teres minor

Subscapular is

Question 16

What muscles of the rotator cuff arise on the dorsal aspect of the scapula

Answer 16

Teres minor

Supraspinatus

Infraspinatus

All insert into greater tubercle of humerus

Question 17

Which muscles arises from the ventral aspect of the scapula

Answer 17

Subscapularis inserts into lesser tubercle of humerus

Question 18

Actions of rotator cuff muscles

Answer 18

Stabilise the shoulder joint, holding the head of the humerus in the glenoid cavity

Question 19

Action of supraspinatus

Answer 19

Initiation and first 15 degrees of abduction

Question 20

What nerve innervates the supraspinatus

Answer 20

Suprascapular nerve - C5,6

Question 21

Action of infraspinatus

Answer 21

Lateral external rotation of arm

Question 22

What nerve innervates the infraspinatus

Answer 22

Suprascapular nerve

C5,6

Question 23

Action of teres minor

Answer 23

Lateral rotation of the arm, weak adductor

Question 24

What nerve innervates the teres minor

Answer 24

Axillary nerve

C5,6

Question 25

Action of subscapularis

Answer 25

Medial and internal rotation of the arm

Question 26

What nerve innervates the subscapularis

Answer 26

Upper and lower subscapular nerves C5,6

Question 27

What other muscles stabilise the joint

Answer 27

Deltoid Coracobrachialis Long head of biceps

Question 28

What is the subacromial space

Answer 28

Space between acromion and head of humerus 1-1.5 cm

Question 29

Blood supply to shoulder joint

Answer 29

Anterior circumflex humeral artery Posterior circumflex humeral artery Suprascapular artery

Question 30

What is responsible for 0-15 degrees of abduction at the glenohumeral joint

Answer 30

Supraspinatus

Question 31

What is responsible for 15-90 degrees of abduction at the glenohumeral joint

Answer 31

Deltoid

Question 32

What is responsible for rotation of scapula at scapulothororacic joint

Answer 32

Trapezium and serrated anterior

Question 33

Nerve supply to deltoid

Answer 33

Axillary nerve

Question 34

What do the anterior fibres of the deltoid do

Answer 34

Flex and internally rotate the arm at the shoulder

Question 35

Central fibres of deltoid

Answer 35

Abduct the arm from 15-90 degrees takes over from supraspinatus

Question 36

Posterior fibres of deltoid

Answer 36

Extend and laterally rotate the arm at the shoulder

Question 37

What do the upper fibres of the trapezius do

Answer 37

Rotate acromion of scapula upwards during abduction of shoulder

Question 38

Lower fibres of trapezius role

Answer 38

Rotate medial spine of scapula downwards

Question 39

Action of serratus anterior

Answer 39

Protraction of scapula Rotation of scapula during abduction of shoulder form 90 - 150 degrees

Question 40

Nerve supply to serratus anterior

Answer 40

Long thoracic nerve C5,6,7

Question 41

What muscles extend the shoulder

Answer 41

Posterior fibres of deltoid- axillary C5,6 Lattisimus dorsi- thoracodorsal nerve C6, 7,8 Teres major - lower subscapular nerve C5, 6

Question 42

What does lasttisimus dorsi do

Answer 42

Extends, adducts and medically rotates te shoulder

Question 43

What does teres major do

Answer 43

Adducts, extends and medially rotates the shoulder

Question 44

What muscles flex the shoulder

Answer 44

Clavicular head of pec major Anterior fibres of deltoid Coracobrachialis Biceps brachii

Question 45

Actions of biceps bracii

Answer 45

Weak contribution to flexion of shoulder Strong supination of foreman Flexor of elbow

Question 46

Adduction of the shoulder

Answer 46

Pec major Lattisimus dorsi Teres major

Question 47

Medial rotation of the shoulder

Answer 47

Sternocostal head of pec major Subscapularis Teres major Lattisimus Doris

Question 48

External rotation of shoulder

Answer 48

Infraspinatus Teres minor