Lecture 13: Shoulder Joint

Question 1

What are the two bones involved in the shoulder joint?

Answer 1

Humerus and scapula

Question 2

The scapula’s supraglenoid tubercle attaches what muscle?

Answer 2

long head bicep brachii

Question 3

the scapula’s infraglenoid tubercle attaches what muscle?

Answer 3

long head tricep brachii

Question 4

What is the surgical neck?

Answer 4

the diaphysis of humerus

Question 5

How many greater tubercles are there?

Answer 5

3

Question 6

How many lesser tubercles are there?

Answer 6

1

Question 7

Where does the coracoclavicular ligament insert?

Answer 7

to the coracoid process of the scapula

Question 8

Apart from the scapula, what are the other bones that interact with the head of the humerus?

Answer 8

Acromion and glenoid labrum (ring)

Question 9

Where is the synovial capsule attached to?

Answer 9

around the glenoid labrum

Question 10

What is the extracapsular ligament of the shoulder joint:

Answer 10

coraco-acromial, gaps between the coracoid and acromion

Question 11

What is the intracapsular ligaments of the shoulder joint:

Answer 11

1) Coroco-humeral
2) Tranverse humeral (between greater and lesser tubercles)
3) Glenohumeral

Question 12

What does a bursa do?

Answer 12

Prevents friction between bone and soft tissue and acts as a cushion

Question 13

What are the main tendons involved in the shoulder joint

Answer 13

Subscapularis; supraspinatus; infraspinatus: bicep tendon; subscapularis

Question 14

What does the sacciform synovial membrane do?

Answer 14

allows bicep brachii tendon to move up and down the humerus.

Question 15

Explain what the caracoacromial arch does? (give me 2)

Answer 15

acts as a buffer and prevents superior dislocation

Question 16

What are the rotator cuff muscles? (SIST)

Answer 16

supraspinatus
infraspinatus
subscapularis
teres minor

Question 17

other than the rotator cuff muscles, what are 3 additional muscles that act on the shoulder joint?

Answer 17

Deltoid Major
teres major
coracobrachialis

Question 18

which rotator cuff muscle is only seen on the anterior

Answer 18

Supracapsularis

Question 19

What is the origin and insertion of the supraspinatus?

Answer 19

Origin: supraspinus FOSSA
Insertion: Superior FACET of Greater Tubercle

Question 20

What is the origin and insertion of the infraspinatus?

Answer 20

Origin: Infraspinatus FOSSA
Insertion: Middle FACET of Greater Tubercle

Question 21

What is the origin and insertion of the Teres minor?

Answer 21

Origin: Lateral boarder of the scapula
Insertion: Inferior FACET of Greater Tubercle

Question 22

What is the origin and insertion of the subcapsularis?

Answer 22

Origin: subscapular FOSSA
Insertion: LESSER tubercle

Question 23

What is the origin and insertion of the Deltoid?

Answer 23

Origin: anatomical horseshoe
Insertion: Deltoid tuberosity

Question 24

What is the main function of the subscapularis?

Answer 24

Internally rotates arm

Question 25

What is the main function of the supraspinatus?

Answer 25

Initiates the beginning of ABducts the arm

Question 26

What is the main function of the infraspinatus?

Answer 26

externally rotates arm

Question 27

What is the main function of the teres minor?

Answer 27

externally rotates arm

Question 28

What is the main function of the anterior fibres of the deltoids?

Answer 28

1) flex the shoulder | 2) internally rotate arm

Question 29

What is the main function of the middle fibres (multipennate) of the deltoids? and why?

Answer 29

Adducts the arm. It waits until supraspinatus performs adduction the humerus to 15 degrees from the anatomical position before contracting.

Question 30

What is the main function of the posterior fibres?

Answer 30

1) extend the shoulder | 2) externally rotate arm

Question 31

What is the origin and insertion of the middle fibres of the deltoid?

Answer 31

Origin: acromion Insertion: deltoid tuberosity

Question 32

What two deltoid fibres assist middle fibres with adduction?

Answer 32

anterior and posterior. Its function depends on their spatial orientation of the insertion of the muscle, relative to the axis.

Question 33

What is the origin and insertion of teres MAJOR?

Answer 33

Origin: inferior angle and lateral border of the scapula (posterior side) Insertion: anterior aspect of the humerus

Question 34

What is the main function of teres MAJOR?

Answer 34

1) internally rotates arm | 2) extends shoulder

Question 35

what is the origin and insertion of the coracobrachialis?

Answer 35

Origin: coracoid process (anterior side) Insertion: medial side of humerus

Question 36

What is the main function of coracobrachialis?

Answer 36

1) adduction of shoulder | 2) its a shunt muscle

Question 37

what are the muscles that ABDUCT the arm?

Answer 37

supraspinatus | lateral deltoids

Question 38

What are the muscles that ADDUCT the arm? | 7

Answer 38

``` posterior deltoids anterior deltoids (anterior aspect) pectoralis major (anterior aspect) long head of tricepts coracobrachialis (anterior aspect teres major latissimus dorsi ```

Question 39

What are the arm flexors? (4)

Answer 39

anterior deltoids clavicular head of pectoralis major coracobrachialis bicep brachii

Question 40

What are the arm extensors? (5)

Answer 40

``` posterior deltoids teres major latissimus dorsi long head of triceps sternocostal portion of pectoralis major ```

Question 41

What muscles are responsible for INTERNAL rotation of the ARM?

Answer 41

``` Pectoralis major anterior deltoid subscapularis latissimus dorsi teres MAJOR ```

Question 42

What muscles are responsible for EXTERNAL rotation of the ARM?

Answer 42

posterior deltoids infraspinatus teres MINOR