Shoulder Joint

Question 0

What reduces the disproportion between the head of humerus and the glenoid fossa?

Answer 0

Fossa is deepened by a fibrocartilage rim - the glenoid labrum

Question 1

What is the glenohumeral joint formed by?

Answer 1

Head of humerus with glenoid cavity of scapula

Question 2

What is a bursa?

Answer 2

A fluid filled sac which acts as a cushion between tendons and other joint structures

Question 3

Name two clinically important bursa in the joint and where they are located

Answer 3

Subacromial - inferior to deltoid and acromion, superior to supraspinatus tendon and joint capsule.

Subscapular - between subscapularis tendon and the scapula.

Question 4

Name three ligaments of the joint and the aspect that they stabilise

Answer 4

Glenohumeral - anterior
Coracohumeral - supports the superior part
Transverse humeral - holds the tendon of the long head of the biceps in the intertubercular groove

Question 5

What forms the coraco-acromion arch? What is its function?

Answer 5

Coracoacromion ligament

Prevents superior displacement of the humeral head

Question 6

Which arteries supply the glenohumeral joint?

Answer 6

The posterior and anterior circumflex humeral arteries

Question 7

Which nerves supply the joint?

Answer 7

Axillary, suprascapular and lateral pectoral nerves

Question 8

What are all the movements of the glenohumeral joint?

Answer 8

Extension and flexion
Abduction and adduction
Medial and lateral rotation

Question 9

What muscles extend the shoulder?

Answer 9

Posterior deltoid
Latissiumus dorsi
Teres major

Question 10

Which muscles perform flexion?

Answer 10

Biceps brachii
Pec major
Anterior deltoid
Coracobrachialis

Question 11

Abduction?

Answer 11

0-15: supraspinatus
15-90: middle deltoid
90*+: trapezius and serratus anterior

Question 12

What muscles do adduction?

Answer 12

Pec major, latissiumus dorsi and teres major

Question 13

Muscles for medial rotation?

Answer 13

Subscapularis, pec major, latissimus dorsi, teres major

Question 14

Lateral rotation

Answer 14

Infraspinatus, teres minor

Question 15

Name the rotator cuff muscles

Answer 15

Supraspinatus
Infraspinatus
Teres minor
Subscapularis

Question 16

What factors contribute to the stability of the joint?

Answer 16

Rotator cuff muscles
Glenoid labrum
Ligaments

Question 17

Attachments of the supraspinatus?

Answer 17

Supraspinatus fossa on posterior surface of scapula

Greater tuberosity of humerus

Question 18

Innervation of supraspinatus?

Answer 18

Suprascapular nerve

Question 19

Actions of the supraspinatus?

Answer 19

First 15* of abduction

Question 20

Attachments of infraspinatus?

Answer 20

Infraspinous fossa

Greater tubercle of humerus

Question 21

Innervation of infraspinatus?

Answer 21

Suprascapular nerve

Question 22

Actions of the infraspinatus?

Answer 22

Lateral rotation of the arm

Question 23

Attachments of the subscapularis?

Answer 23

Subscapular fossa on costal surface of scapula

Lesser tubercle of humerus

Question 24

Innervation of the subscapularis?

Answer 24

Upper and lower subscapular nerves

Question 25

Action of the subscapularis?

Answer 25

Medially rotates the arm

Question 26

Innervation of the teres minor?

Answer 26

Axillary nerve

Question 27

Action of the teres minor?

Answer 27

Lateral rotation of the arm

Question 28

What causes pain in rotator cuff tendonitis?

Answer 28

When the arm is abducted, the tendon of the supraspinatus muscle rubs against the coracoacromial arch.
Degenerative changes in the subacromial bursa and tendon cause friction.

Question 29

What is the characteristic sign of rotator cuff tendonitis?

Answer 29

Painful arc - pain during middle of abduction

Question 30

Which muscles carry out protraction and retraction of the scapula?

Answer 30

Protraction - serratus anterior

Retraction - (middle fibres of) trapezius and rhomboids

Question 31

Which muscles carry out depression and elevation of scapula?

Answer 31

Elevation - trapezius, levator scapulae

Depression - relaxation of these muscles

Question 32

Which muscles carry out lateral/upward rotation of scapula?

Answer 32

Lateral - Upper and lower fibres of trapezius

Medial (tilt glenoid cavity inferiorly) - latissimus dorsi, levator scapulae, rhomboids

Question 33

What are the clinical effects of a torn supraspinatus tendon?

Answer 33

Failure of initiation of adduction in first 15 degrees

During adduction, limb will suddenly drop after 90 degrees