Pectoral girdle and shoulder joint Flashcards Preview

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Flashcards in Pectoral girdle and shoulder joint Deck (51)
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1

Extrinsic muscles of the shoulder

Origionate from the torso, and attach to the bones of the shoulder (clavicle, scapula or humerus)

2

Intrinsic muscles of the shoulder

Origionate from the scapula and/or clavicle, and attach to the humerus

3

What are the intrinsic muscles of the shoulder (scapulohumeral group)?

  • deltoid
  • teres major
  • rotator cuff muscles
    • supraspinatus
    • infraspinatus
    • subscapularis
    • teres minor

4

Deltoid attachments

Origionate from the lateral third of the clavicle, the acromion and the spine of the scapula. It attaches to the deltoid tubercle on the lateral aspect of the humerus.

5

Deltoid innervation

Axillary nerve

6

Deltoid actions

  • Anterior fibres - flexion and medial rotation
  • Middle fibres - the major abductor of the arm (takes over from the supraspinatus which abducts the first 15 degrees)
  • Posterior fibres - extension and lateral rotation

7

Teres major attachments

Origionates from the posterior surface of the inferior angle of the scapula. It attaches to the medial lip of the intertubercular groove of the humerus.

8

Teres major innervation

Lower subscapular nerve

9

Teres major actions

Adducts at the shoulder and medially rotates the arm

10

Rotator cuff muscles collective function

Gives the glenohumeral joint additional stability

11

Supraspinatus attachments

Origionates from the supraspinous fossa of the scapula, attaches to the greater tubercle of the humerus.

12

Supraspinatus innervation

Suprascapular nerve

13

Supraspinatus action

Abducts the arm 0-15 degrees, assists deltoid for 15-90 degrees.

14

Infraspinatus attachments

Origionates from the infraspinatus fossa of the scapula, attaches to the greater tubercle of the humerus.

15

Infraspinatus innervation

Suprascapular nerve

16

Infraspinatus actions

Laterally rotates the arm

17

Subscapularis attachments

Origionates from the subscapular fossa, on the costal surface of the scapula. It attaches to the lesser tubercle of the humerus.

18

Subscapularis innervation

Upper and lower subscapular nerves

19

Subscapularis actions

Medially rotates the arm

20

Teres minor attachements

Origionates from the posterior surface of the scapula, adjacent to its lateral border. It attaches to the greater tubercle of the humerus.

21

Teres minor innervation

Axillary nerve

22

Teres minor actions

Laterally rotates arm

23

What are the extrinsic muscles of the shoulder?

  • Superficial
    • trapezius
    • latissumus dorsi
  • Deep
    • levator scapulae
    • rhomboids

24

Trapezius attachments

Origionates from the skull, nuchal ligaments and spinous processes of C7-T12. The fibres attach to the clavicle, acromion and the scapula spine.

25

Trapezius innervation

Motor innervation is from the accessory nerve. It also recieves proprioceptor fibres from C3 and C4 spinal nerves.

26

Trapezius actions

  • Upper fibres - elevates scapula and rotates it during abduction of the arm
  • Middle fibres - retract the scapula
  • Lower fibres - pull the scapula inferiorly

27

Latissimus dorsi attachments

Has a broad origin - arising from the spinous processes of T7-T12, iliac crest, thoracolumber fascia, and the inferior three ribs. The fibres converge into a tendon that attaches to the intertubercular sulcus of the humerus.

28

Latissimus dorsi innervation

Thoracodorsal nerve

29

Latissimus dorsi actions

Extents, adducts and medially rotates the upper limb

30

Levator scapulae attachments

Origionates from the transverse processes of the C1-C4 vertebrae and attaches to the medial border of the scapula.