MSK Session 3- Back And Shoulder Muscles, And The Shoulder Joint Flashcards Preview

SOPHIE'S ESA 2 > MSK Session 3- Back And Shoulder Muscles, And The Shoulder Joint > Flashcards

Flashcards in MSK Session 3- Back And Shoulder Muscles, And The Shoulder Joint Deck (36)
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0
Q

What are the three groups of extrinsic back muscles?

A
  • superficial
  • deep
  • scapulo-humeral
1
Q

What are intrinsic back muscles responsible for?

A

Posture

2
Q

What are the two superficial back muscles?

A

Trapezius

Latissimus dorsi

3
Q

What are the 2 deep back muscles?

A

Levator scapulae

Rhomboids

4
Q

What are the 2 scapulo-humeral muscles?

A

Teres major

Deltoid

5
Q

What is the action of each of the parts of the trapezius?

A
  • descending/superior fibres- elevate and rotate the scapula
  • middle fibres- retract the scapula
  • ascending/inferior fibres- depress the scapula
  • abduction past 90 degrees
6
Q

What is the innervation of the trapezius muscle?

A

Spinal accessory nerve

7
Q

What is the action of the latissimus dorsi?

A

Extension, adduction and medial rotation of the upper limb.

8
Q

What is the innervation of the latissimus dorsi?

A

Thoracodosral nerve

9
Q

What is the action of the Levator scapulae muscle?

A

Elevates the scapula

10
Q

What is the innervation to the Levator scapulae?

A

Dorsal scapula nerve

11
Q

What is the action of the rhomboids?

A

Retraction and rotation of the scapula.

12
Q

What is the innervation to the rhomboids?

A

Dorsal scapula nerve

13
Q

Which rhomboid is most superior?

A

Minor

14
Q

What is the action of the the three deltoid segments?

A
  • anterior/clavicular fibres- flexion of the arm
  • middle/acromial fibres - abduction of the arm between 15 and 90 degrees.
  • posterior/spinal fibres - extension of the arm
15
Q

What is the innervation to the deltoid muscle?

A

Axillary nerve

16
Q

What is the action of teres major?

A

Adduction and medial rotation of the arm.

17
Q

What is the innervation to teres major?

A

Lower subscapular nerve

18
Q

What are the four rotator cuff muscles?

A

Supraspinatus
Infraspinatus
Teres minor
Subscapularis

19
Q

What is the general function of the rotator cuff muscles?

A

Support and stabilise the shoulder joint.

20
Q

What is the action and innervation of supraspinatus?

A

Abduction up to 15 degrees

Innervation is the suprascapular nerve

21
Q

What is the action and innervation of infraspinatus?

A

Lateral arm rotation.

Innervation- suprascapular nerve

22
Q

What is the action and innervation of teres minor?

A

Action- lateral rotation and weak adduction

Innervation- axillary nerve

23
Q

What is the action and innervation of subscapularis?

A

Action- medial rotation.

Innervation- upper and lower subscapular nerve

24
Q

What is the articulation of the shoulder joint?

A

The head of the humerus sits in the glenoid cavity, which is deepened by the glenoid labrum.

25
Q

What type of joint is the shoulder joint?

A

A ball and socket synovial joint

26
Q

Why is the shoulder joint unstable and commonly dislocated? (4)

A
  • the glenoid cavity is shallow
  • the movements of the joint are multi planar
  • the capsule is lax
  • the articulating surfaces are disproportionate.
27
Q

How is stability of the shoulder joint achieved? (4)

A
  • rotator cuff muscles
  • other muscles
  • ligaments
  • capsule
28
Q

Which way does the shoulder joint most commonly dislocate and why?

A

Inferiorly and anteriorly.
Because the inferior part of the capsule is the weakest as it is not reinforced by ligaments or the rotator cuff muscles.

29
Q

What is the shoulder joint capsule?

A

A loose, fibrous layer.

30
Q

Why is the capsule lax?

A

To allow full abduction of the arm

31
Q

What are the five ligaments of the shoulder joint?

A
  • glenohumeral- there are three of them (superior, middle and inferior) that move inferolaterally from the glenoid labrum-> humerus.
  • coraco-acromial - between the acromion and coracoid process
  • coraco-humeral - between the coracoid process and the greater tubercle
  • transverse humeral - holds the long head of the biceps tendon in place during movement
  • coraco-acromial arch - prevents upper displacement of the humeral head.
32
Q

How is shoulder dislocation caused? (2)

A
  • by excessive extension and lateral rotation

- trauma to a fully abducted arm

33
Q

Which nerve can be injured during shoulder dislocation? What are the consequences?

A

The axillary nerve

Paralysis of the deltoid muscle and loss of sensation over the regimental patch area.

34
Q

What is painful arc syndrome?

A

It is when the supraspinatous tendon rubs under to the coraco-acromial arch, causing irritation and inflammation of the tendon and subacromial bursa.

35
Q

In painful arc syndrome, when is pain felt worst?

A

During 50-130 degree abduction

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