shoulder anatomy

Question 1

What are the bones of the shoulder girdle?

Answer 1

Scapula, Humerus, Clavicle

Question 2

What joints are part of the shoulder girdle?

Answer 2

Glenohumeral joint, Acromioclavicular joint, Sternoclavicular joint, Scapulothoracic joint

Question 3

What type of joint is the Glenohumeral joint?

Answer 3

Multiaxial synovial ball-and-socket joint

Question 4

What are the articulating surfaces of the Glenohumeral joint?

Answer 4

Humeral head and glenoid fossa of the scapula

Question 5

What structure deepens the glenoid cavity?

Answer 5

Glenoid labrum

Question 6

What is the function of the glenoid labrum?

Answer 6

Deepens the cavity and increases surface area

Question 7

What ligaments are found in the Glenohumeral joint?

Answer 7

• Superior Glenohumeral ligament * Middle Glenohumeral ligament * Inferior Glenohumeral ligament * Coracohumeral ligament * Transverse Humeral ligament

Question 8

What is the role of the coraco-acromial arch?

Answer 8

Prevents superior displacement of the humeral head from the glenoid cavity

Question 9

What is the function of the bursae in the Glenohumeral joint?

Answer 9

Reduce friction between tendons and bones

Question 10

What type of joint is the Acromioclavicular joint?

Answer 10

Plane synovial joint

Question 11

What ligaments stabilize the Acromioclavicular joint?

Answer 11

• Acromioclavicular ligament * Coracoclavicular ligaments (trapezoid and conoid)

Question 12

What is the significance of the Sternoclavicular joint?

Answer 12

Only articulation between the upper limb and the axial skeleton

Question 13

What type of joint is the Sternoclavicular joint?

Answer 13

Synovial, saddle-type joint

Question 14

What are the movements allowed by the Sternoclavicular joint?

Answer 14

• Elevation * Depression * Protraction * Retraction * Rotation

Question 15

What is the scapulothoracic joint?

Answer 15

Not a true anatomical joint formed by the thoracic cage and scapula

Question 16

What are the movements at the shoulder joints?

Answer 16

• Abduction - 180 degrees * Adduction - 45 degrees * Flexion - 180 degrees * Extension - 60 degrees * Lateral Rotation - 90 degrees * Medial Rotation - 70-90 degrees

Question 17

What is the scapulohumeral rhythm?

Answer 17

Ratio of GHJ movement to STJ movement during arm elevation

Question 18

What is the widely accepted ratio of GH elevation to ST upward rotation?

Answer 18

2:1 ratio

Question 19

What muscles are considered primary dynamic stabilizers of the Glenohumeral joint?

Answer 19

Rotator cuff muscles: Supraspinatus, Infraspinatus, Teres Minor

Question 20

What is the primary function of the trapezius muscle?

Answer 20

• Elevates scapula * Depresses scapula * Retracts scapula * Rotates scapula superiorly

Question 21

Fill in the blank: The ________ ligament limits elevation of the pectoral girdle.

Answer 21

Costoclavicular ligament

Question 22

True or False: The scapulothoracic joint allows for a stable base for the Glenohumeral joint.

Answer 22

True

Question 23

What is the significance of the scapula’s position during arm movements?

Answer 23

Orientates the glenoid into an optimal position for GHJ function

Question 24

What is the role of the subscapularis muscle?

Answer 24

Internal rotation of the humerus

Question 25

What is the function of the long head of the biceps brachii?

Answer 25

Flexes elbow and supinates forearm

Question 26

What movements occur at the Scapulothoracic joint?

Answer 26

* Elevation * Depression * Protraction * Retraction * Upward rotation * Downward rotation

Question 27

What stabilizes the Glenohumeral joint?

Answer 27

* Surrounding muscles and tendons * Coraco-acromial arch * Glenoid labrum

Question 28

What is the importance of the fibrocartilage articular disc in the Sternoclavicular joint?

Answer 28

Acts as a shock absorber

Question 29

What is the function of passive stabilisers in the shoulder joint?

Answer 29

Provide some stability ## Footnote Passive stabilisers include structures like the glenoid labrum and ligaments that help stabilize the joint without active muscle contraction.

Question 30

What role does the glenoid labrum play in the shoulder joint?

Answer 30

Deepens socket depth and creates a cavity-compression 'suction' effect ## Footnote The glenoid labrum is a fibrocartilaginous structure that enhances the stability of the shoulder joint.

Question 31

What is the significance of negative intra-articular pressure in the shoulder joint?

Answer 31

Helps in centring the humeral head ## Footnote Negative pressure within the joint contributes to joint stability by keeping the humeral head properly aligned.

Question 32

What are the primary dynamic stabilisers of the glenohumeral joint?

Answer 32

Rotator cuff muscles and long head of biceps ## Footnote The rotator cuff includes the supraspinatus, infraspinatus, teres minor, and subscapularis.

Question 33

Which muscle limits excessive superior translation of the humeral head?

Answer 33

Supraspinatus ## Footnote The supraspinatus is positioned superiorly and plays a critical role in stabilizing the shoulder.

Question 34

What muscles are involved in the upward rotation of the scapula?

Answer 34

Upper traps, lower traps, serratus anterior ## Footnote These muscles work together to facilitate the upward movement of the scapula during arm elevation.

Question 35

Fill in the blank: The _______ lies posterior and limits excessive superior and posterior translation of the humeral head.

Answer 35

Infraspinatus and Teres minor

Question 36

True or False: The deltoid muscle prevents subluxation or dislocation of the humeral head when carrying load.

Answer 36

True ## Footnote The deltoid provides dynamic stabilization, especially during weight-bearing activities.

Question 37

What are the muscles responsible for shoulder flexion?

Answer 37

Pectoralis Major, deltoid (anterior), long and short head of biceps, coracobrachialis ## Footnote These muscles contract to lift the arm forward.

Question 38

What is the role of axio-appendicular muscles in shoulder stability?

Answer 38

Important for optimal scapula positioning during static postures and with movement ## Footnote These muscles connect the axial skeleton to the appendicular skeleton and play a key role in shoulder mechanics.

Question 39

Which muscles are involved in shoulder adduction?

Answer 39

Latissimus Dorsi, Teres Major ## Footnote These muscles pull the arm towards the body, facilitating adduction.

Question 40

List the muscles involved in shoulder extension.

Answer 40

* Latissimus dorsi * Triceps * Teres major ## Footnote These muscles are responsible for moving the arm backward.

Question 41

Fill in the blank: The _______ is a weakened region of the rotator cuff reinforced by the long head of biceps and coracohumeral ligament.

Answer 41

Rotator cuff interval

Question 42

What limits excessive anterior and superior translation of the humeral head?

Answer 42

Subscapularis ## Footnote The subscapularis muscle is located anteriorly and provides stability against forward dislocation.

Question 43

What is the main function of the rotator cuff?

Answer 43

Protects and actively stabilises the GHJ during static and dynamic activities ## Footnote The rotator cuff keeps the humeral head centred in the glenoid fossa.

Question 44

Which muscles are responsible for lateral rotation of the shoulder?

Answer 44

Teres minor, Infraspinatus, Deltoid (posterior) ## Footnote These muscles allow the arm to rotate away from the body.

Question 45

What are the movements associated with the scapulothoracic joint?

Answer 45

* Protraction * Retraction * Depression * Elevation * Downward Rotation * Upward Rotation ## Footnote These movements are essential for shoulder function and range of motion.