Functional and Clinical Anatomy of Shoulder

Question 1

What are the joints present in the shoulder?

Answer 1

Glenohumeral joint
Sternoclavicular joint
Acroclavicular joint
Scapulothoracic joint

Question 2

What connects the shoulder to the axial skeleton?

Answer 2

Acroclavicular joint and sternoclavicular joint.

Question 3

What type of joint is the glenohumeral?

Answer 3

Ball and socket joint. This is enclosed by a fibrous sheath called the joined capsule from the humerus and border of the glenoid fossa. Inner surface contains synovial membrane to produce synovial fluid for lubrication.

Question 4

What type of joint is the sternoclavicular joint?

Answer 4

Saddle-shaped synovial joint which connects shoulder to axial skeleton. It avoids damage by transferring force using the costaclavicular ligament away from clavicle to the sternum.

Question 5

What is an important feature of the shoulder joint?

Answer 5

Glenoid cavity where the large humerus articulates is shallow, so it is very mobile but the joint requires stabilisation.

Question 6

What is the glenoid labrum?

Answer 6

Rim surrounding the glenoid cavity which deepens the fossa to further stabilise the glenohumeral joint for shock absorption.

Question 7

What structures are responsible for stabilising the glenohumeral joint?

Answer 7

Joint capsule- fluid filled sac enclosing the joint

And the glenohumeral ligament, coracohumeral ligament and coracoacromial ligament.

Question 8

What are the glenohumeral ligaments?

Answer 8

Superior, middle and inferior glenohumeral ligaments.
They stabilise the anterior aspect of the shoulder joint, especially in abduction.

Question 9

What is the most important structure for the stability of the shoulder joint?

Answer 9

Inferior glenohumeral ligament

Question 10

What are the coracoclavicular ligaments?

Answer 10

Trapezoid ligament and Conoid ligament which connects coracoid process of scapula to clavicle. When a fall to the shoulder occurs, these ligaments experience strain because the corocoid process of the scapula transmits force to all the ligaments attached.

Question 11

How does the shoulder and clavicle move?

Answer 11

Glenoid process moves anteriorly when vertical (upward/downwards) movement occurs. Glenoid process moves superolaterally when horizontal movement (side to side) occurs.

Question 12

What is a FOOSH?

Answer 12

Fall on out stretched hand causes strain on the coracoclavicular ligaments which transfers force to clavicle. The glenoid process moves medially.

Question 13

What happens in shoulder dislocation?

Answer 13

Humerus moves out of glenoid fossa, causing the rotator cuff muscles to spasm and pull humeral head either
Anteriorly (more common)
Posteriorly

Question 14

What is the role of the rotator cuff muscles?

Answer 14

4 muscles which stabilise the joint capsule via concavity compression of the humerus:
Supraspinatous which attaches superiorly to humerus
Infraspinatous
Teres minor
Subcapsularis muscle (anteriorly)

Question 15

What is concavity compression?

Answer 15

Compressing humerus head into the glenoid fossa for stabilising in movement.

Question 16

What is the innervation of the supraspinatous?

Answer 16

Supracapsular nerve along with the infraspinatous muscle. It is responsible for shoulder ABDUCTION.

Question 17

What is the innervation of the infraspinatous?

Answer 17

Supracapsular nerve along with supraspinatous muscle. It is responsible for EXTERNAL ROTATION.

Question 18

What is the innervation of the teres minor?

Answer 18

Axillary nerve. It is responsible for EXTERNAL ROTATION.

Question 19

What is the innervation of the subcapsularis muscle?

Answer 19

Upper and lower subcapsular nerve from the brachial plexus. It is responsible for INTERNAL ROTATION.

Question 20

Where does the subscapularis attach?

Answer 20

Lesser tubercle of humerus

Question 21

Where does the rotator cuff muscle dislocate?

Answer 21

Inferiorly because there are few muscles

Question 22

Which muscle group in the back is important for shoulder movement?

Answer 22

Extrinsic muscles of the back:
Lattisiumus dorsi which inserts into the intertubercular groove of humerus
Rhomboid minor, major and Levator scapulae which have insertions of scapulae spine

Question 23

What is the blood supply to the deltoid muscle?

Answer 23

Posterior circumflex artery

Question 24

What is the consequence of a fracture to the surgical neck of humerus?

Answer 24

Damages axillary nerve and posterior circumflex artery.
-> This results in paralysis of deltoid and teres minor muscle and loss of sensation to region.

Question 25

What are the shoulder movements?

Answer 25

Flexion/extension
Abduction/Adduction
Internal/External rotation

Question 26

What is the bursa of the shoulder?

Answer 26

Multiple fluid filled sacs in the glenohumeral joint
which reduces friction. It lies between the acromion process of scapula and the supraspinatous attachment to humerus.

Question 27

What happens in shoulder abduction?

Answer 27

External rotation of the humerus at 120 degrees with scapula rotation at 60 degrees

Question 28

Why is there a painful arc in abduction?

Answer 28

Issue with the glenohumerus where:
Subacromial bursa becomes swollen
Inflammation of the supraspinatous tendon

Acromicroclavicular issue

This can occur due to repetitive use in overhead sports.

Question 29

Why does supraspinatous tendonitis occur?

Answer 29

Impingement (pinching) of the tendon on the acromion process as it passess from the humerus.

Question 30

What is rotator cuff syndrome?

Answer 30

Strain of muscles in the rotator cuff due to repetitive overhead movement, causing degeneration of the muscle. Commonly, tears occur in the supraspinatous muscle because the elevation of the muscle during abduction is limited by the acromion.

Question 31

What is frozen shoulder?

Answer 31

Inflammation of the shoulder capsule which prevents movement, most common in middle aged women. Greater risk with diabetics.

Question 32

Which rotator cuff muscle causes abduction of shoulder?

Answer 32

Supraspinatous

Question 33

Which rotator cuff muscle causes internal rotation?

Answer 33

Subcapsularis

Question 34

Which rotator cuf muscle causes external rotation?

Answer 34

Teres minor and infraspinatous

Question 35

Which rotator cuff muscles attach onto the greater tubercle of humerus?

Answer 35

Supraspinatous
Infraspinatous
Teres minor

Question 36

Which rotator cuff muscles do not attach onto the greater tubercle of humerus?

Answer 36

Subcapsularis which attaches to the lesser tubercle of humerus.

Question 37

Where does teres major insert?

Answer 37

Intertubercular groove, along with pectoralis major. This is also where the biceps long head travels through.