Shoulder joint vs shoulder girdle- Muscles of upper limb

Question 1

What is the difference between the shoulder girdle and shoulder joint?

Answer 1

Shoulder girdle is a complex of 3 joints:
- Acromioclavicular joint
- Sternoclavicular joint
- Glenohumeral joint

It is made up if the scapulae & the clavicles.

Shoulder joint is just the Glenohumeral joint.
- ball of the humerus fits into socket made in the scapula called the Glenoid fossa.

Question 2

Osteology of scapula i.e. anatomy- bony landmarks

Answer 2

NOTE: anatomy- learn!

Question 3

Osteology of the humerus?

Answer 3

NOTE: anatomy- learn

Question 4

What is the function of shoulder girdle muscles?

Answer 4

• To move the scapula.
• Have a wide range of movement at the expense of stability.

Question 5

Name the muscles of the shoulder girdle and their action?

Answer 5

TRPLS

Trapezius- Laterally rotate scapula during abduction of arm. Upper fibres elevate, middle fibres retract scapula, lower fibres pull scapula inferiorly.
- Innervated by Spinal assessory nerve

Rhomboids (major & minor)- Scapula retraction & medial rotation.

Pectoralis minor- Anchors scapula by pulling it against chest wall. Protractor of scapula (minor role in this)

Levator scapulae- scapula elevation

Serratus anterior- Scapula protraction & lateral rotation. Prevents winging of the scapula.

Question 6

Name the movements of the scapulae. Which muscles perform each movement?

Answer 6

1. Retraction:
   - middle trapezius
   - rhomboid major
   - rhomboid minor
2. Protraction (hunching your back)
   - serrates anterior
   - pectoralis minor
3. Elevation
   - Upper trapezius
   - levator scapulae
4. Depression:
   - Lower trapezius
   - pectoralis minor
5. Lateral rotation of scapula
   - trapezius
   - serrates anterior
6. Medial rotation (elevation & retraction together) of scapula
   - Rhomboid major
   - rhomboid minor
   - pectorals minor
   - levator scapulae

NOTE: view notes to understand movements- v important?

Question 7

Name the movements of the scapulae. Which muscles perform each movement?

Answer 7

1. Retraction:
   - middle trapezius
   - rhomboid major
   - rhomboid minor
2. Protraction (hunching your back)
   - serrates anterior
   - pectoralis minor
3. Elevation
   - Upper trapezius
   - levator scapulae
4. Depression:
   - Lower trapezius
   - pectoralis minor
5. Lateral rotation of scapula
   - trapezius
   - serrates anterior
6. Medial rotation (elevation & retraction together) of scapula
   - Rhomboid major
   - rhomboid minor
   - pectorals minor
   - levator scapulae

NOTE: view notes to understand movements- v important!

Question 8

What is the function of the shoulder joint muscles?

Answer 8

• Act on the gleno-humeral joint to move the shoulder.
• So they must attach to the humerus!!

Question 9

Name the muscles of the shoulder joint and their actions?

Answer 9

1. Deltoid:
   - Shoulder abuduction of anterior fibres
   - flexion of shoulder
   - flexion of posterior fibres of shoulder
2. Pectoralis Major
   - Shoulder flexion
   - medial rotation
   - adduction when working with extensors
   - pectoralis major- sternal head: flexion of shoulder from anatomical position
   - pectorals major- clavicular head: extend shoulder from flexed position
3. Latissimus dorsi
   - shoulder extension
   - medial rotation
   - adduction when working w/ flexors
4. teres major
   - Shoulder extension
   - medial rotation
   - adduction when working w/ flexors
5. Coraco-brachialis
   - weak shoulder flexor

Rotator cuff:

6. . Supraspinatus
   - Initiates shoulder abduction
7. Infraspinatus
   - lateral rotation of shoulder
8. Teres minor
   - lateral rotation of shoulder
9. Subscapularis
   - medially rotation of shoulder

Question 10

Location of shoulder girdle muscles?

Answer 10

NOTE: anatomy- learn important!

Question 11

Location of joint muscles?

Answer 11

NOTE: anatomy- learn important!

Question 12

Name the muscles that perform: extension, flexion, adduction, abduction, internal rotation, external rotation & circumduction

Answer 12

Extension:
- Posterior deltoid
- latissiumus dorsi
- teres major

Flexion:
- Pectoralis major
- anterior deltoid
- coracobrachialis
- Biceps brachii weakly assists.

Abduction:
- supraspinatus- 0-15
- Deltoid- 15-90
- Trapezius & serratus anterior (the scapula needs to be rotated to achieve abduction past 90°)- past 90

Adduction:
- Pectoralis major
- latissimus dorsi
- teres major.

Internal rotation:
- Subscapularis
- pectoralis major
- latissimus dorsi
- teres major
- anterior deltoid

External rotation:
- Infraspinatus
- teres minor.

NOTE: learn the location of these muscles- v important!