1.4.4. Intrinsic Muscles of the Shoulder and Joint Stability / Motility Flashcards

1
Q

What is the downside to the Glenohumeral Joint being the most Mobile in the Body?

A

It is at the Expense of Stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 3 factors which contribute to the Glenohumeral Joints mobility?

A
  1. The Type of Joint
  2. The Bony Surface Ratio
  3. The Laxity of the Joint Capsule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of joint is the Glenohumeral Joint?

A

A Ball and Socket Joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 2 articulating surfaces in the Glenohumeral Joint?

A
  1. Glenoid Cavity

2. Humerus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q
  1. Which if the 2 articulating surfaces of the Glenohumeral Joint is larger?
  2. By how much?
A
  1. The Head of the Humerus

2. By the ratio of 4:1 (Similar to a Gold Ball and a Tee)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the 3 factors which contribute to the Glenohumeral Joints stability?

A
  1. Rotator Cuff Muscles
  2. Glenoid Labrum
  3. Ligaments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do Rotator Cuff Muscles attach to?

A
  1. The Tubercle of the Humerus
  2. The Scapula
  3. Fused with the Joint Capsule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the “Resting Tone” of the Rotator Cuff Muscles?

A

To pull the Head of the Humerus into the Glenoid Cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 4 Rotator Cuff Muscles?

A
  1. Subscapularis
  2. Supraspinatus
  3. Infraspinatus
  4. Teres Minor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What movements, of the Glenohumeral Joint, are generated by Rotator Cuff Muscles?

A
  1. Abduction
  2. Lateral Rotation
  3. Medial Rotation
  4. Adduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where does the Subscapularis attach onto the Scapula?

A

The Subscapular Fossa (on the Costal (anterior) Surface of the Scapula)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where does the Subscapularis attach onto the Humerus?

A

The Lesser Tubercle of the Humerus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the innervation of the Subscapularis?

A

The Upper and Lower Subscapular Nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the function of the Subscapularis?

A

To Medially Rotate the Arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where does the Supraspinatus attach onto the Scapula?

A

The Supraspinous Fossa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where does the Supraspinatus attach onto the Humerus?

A

The Greater Tubercle of the Humerus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the innervation of the Supraspinatus?

A

The Suprascapular Nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the function of the Supraspinatus?

A
  1. Abducts the Arm 0-15 degrees

2. Assists the Deltoid Abduct the arm from 15-90 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where does the Infraspinatus attach onto the Scapula?

A

The Infraspinous Fossa of the Humerus

20
Q

Where does the Infraspinatus attach onto the Humerus?

A

The Greater Tubercle of the Humerus

21
Q

What is the innervation of the Infraspinatus?

A

The Suprascapular Nerve

22
Q

What is the function of the Infraspinatus?

A

To Laterally Rotate the Arm

23
Q

Where does the Teres Minor attach onto the Scapula?

A

The Posterior Surface of the Scapula, adjacent to its Lateral Border

24
Q

Where does the Teres Minor attach onto the Humerus?

A

The Greater Tubercle of the Humerus

25
What is the innervation of the Teres Minor?
The Axillary Nerve
26
What is the function of the Teres Minor?
Laterally Rotates the Arm
27
What is the Glenoid Labrum?
A Fibrocartilaginous Ridge surrounding the Glenoid Cavity
28
What is the function of the Glenoid Labrum?
It Deepens the Glenoid Cavity - reducing the risk of Dislocation
29
What are the functions of the Ligaments in the Glenohumeral Joint?
1. To Reinforce the Joint Capsule | 2. To Create the Coracoacromial Arch
30
What are the 3 Divisions of the Deltoid Muscle?
1. Anterior 2. Middle 3. Posterior
31
Where does the Deltoid attach onto the Main Body?
1. Scapula | 2. Clavicle
32
Where does the Deltoid attach onto the Humerus?
The Deltoid Tuberosity on the Lateral Surface of the Humerus
33
What is the innervation of the Deltoid?
The Axillary Nerve
34
What is the function of the Anterior Fibres of the Deltoid?
Flex the Arm at the Shoulder
35
What is the function of the Posterior Fibres of the Deltoid?
Extend the Arm at the Shoulder
36
What is the function of the Middle Fibres of the Deltoid?
These are the Major Abductors of the Arm
37
What do the Middle Fibres of the Deltoid take over from when Abducting the Arm?
Supraspinatus (after 15 degrees)
38
Where does Teres Major attach onto the Main Body?
The Posterior Surface of the Inferior Angle of the Scapula
39
Where does Teres Major attach onto the Humerus?
The Intertubercular Groove of the humerus
40
What is the innervation of Teres Major?
The Lower Subscapular Nerve
41
What is the function of Teres Major?
1. Adducts the Shoulder | 2. Medially Rotates the Arm
42
1. What does Teres Major form? 2. What passes through this? 3. To reach where?
1. The Inferior Border of the Quadrangular Space 2. Which the Axillary Nerve and Posterior Circumflex Humeral Artery pass through 3. To reach the Posterior Scapular Region
43
What is the Definition of "Intrinsic Muscles of the Shoulder"?
Muscles which Originate from the Scapula and / or the Clavicle, and Attach to the Humerus
44
What are the "Intrinsic Muscles of the Shoulder" also known as?
The Scapulohumeral Group of Muscles
45
What are the 6 Intrinsic Muscles of the Shoulder?
1. Subscapularis (Rotator Cuff Muscle) 2. Supraspinatus (Rotator Cuff Muscle) 3. Infraspinatus (Rotator Cuff Muscle) 4. Teres Minor (Rotator Cuff Muscle) 5. Deltoid 6. Teres Major
46
1. In what Common Injury is the Axillary Nerve (C5/C6) trapped? 2. Where would you test for Loss of Sensation?
1. Surgical Neck of the Humerus Fracture | 2. Skin over the Shoulder (it is a mixed nerve do this will determine if a nerve injury has occurred)