Ms 5: The Shoulder Joint And Associated Muscles

Front 1

Describe the glenohumeral joint
1. Type
2. Articular surfaces
3. Capsule
4. Ligaments
5. Special features
6. Movements

Back 1

1. Type: synovial ball and socket joint
2. Articular surfaces:
- Head of humerus
- Glenoid fossa of scapula
- Articular surfaces are not a good fit = allows extensive movement
- Shallow glenoid fossa is deepened by fibrocartilagenous (not hyaline) rim = glenoid labrum
3. Capsule:
- Thin and loose = allows movement
- Apertures for bursa which act as cushions from friction points
• Subacromial bursa = separate to joint cavity under the coracoacromial arch and continuous with subdeltoid bursa
• Subscapular bursa = continuous with cavity beneath the tendon of subscapularis (which can lead to squashing and inflammation)
4. Ligaments
- Glenohumeral = 3 parts (superior, middle and inferior)
- Transverse humeral
- Coracohumeral
- Coracoacromial (forming the coracoacromial arch)
5. Also aperture in the capsule for the tendon of biceps brachii, which is attached within the joint capsule
6. 360 degree movement = flexion, extension, adbduction, adduction, external and internal rotaion, circumduction

Front 2

What are the 8 muscles associated with the shoulder joint?

Back 2

1. Pectoralis major
2. Deltoid
3. Latissimus dorsi
4. Teres major
5. Subscapularis
6. Supraspinatus
7. Infraspinatus
8. Teres minor

Front 3

Describe the features of pectoralis major:
1. Origin
2. Insertion
3. Nerve supply
4. Movement

Back 3

1. Origin:
- 2 heads = clavicular and sternocostal
- Medial third clavicle
- Sternum
- Upper six costal cartilages
2. Insertion: Lateral border intertubercular groove
3. Nerve Supply: Medial & lateral pectoral nerves C7,8, T1
4. Action: Adduction, flexion, medial rotation of shoulder, accessory muscle for respiration

Front 4

Describe the features of deltoid:
1. Origin
2. Insertion
3. Nerve supply
4. Movement

Back 4

1. Origin = 3 parts (anterior, middle and posterior):
- Lateral third clavicle
- Acromion process
- Spine of scapula
2. Insertion: Deltoid tuberosity on lateral aspect of humerus
3. Nerve Supply: Axillary circumflex C5,6
4. Action: Abduction (middle), flexion (anterior), extension of shoulder (posterior)

Front 5

Describe the features of latissimus dorsi:
1. Origin
2. Insertion
3. Nerve supply
4. Movement

Back 5

1. Origin:
- Spines of vertebrae T6 – L5
- Sacrum
- Posterior iliac crest
2. Insertion:
- Floor of intertubercular groove
3. Nerve Supply: Thoraco-dorsal nerve C6,7,8
4. Action: Adduction, extension, medial rotation of shoulder

Front 6

Describe the features of teres major:
1. Origin
2. Insertion
3. Nerve supply
4. Movement

Back 6

1. Origin: Posterior surface inferior angle of scapula
2. Insertion: Medial lip of intertubercular groove
3. Nerve Supply: Lower subscapular nerve C6,7
4. Action: Adduction, extension, medial rotation of shoulder (same as Latissimus Dorsi )

Front 7

Describe the features of coracobrachialis:
1. Origin
2. Insertion
3. Nerve supply
4. Movement

Back 7

1. Origin: coracoid process of the scapula with biceps brachii
2. Insertion:
iddle third of med border of humerus
3. Innervation: Musculocutaneous N (C5,6,7) which runs through muscle
4. Action: Flexes and weakly adducts arm

Front 8

What are the rotator cuff muscles?

Back 8

1. Supraspinatus
2. Infraspinatus
3. Teres minor
4. Subscapularis

Front 9

Describe the features of supraspinatus:
1. Origin
2. Insertion
3. Nerve supply
4. Movement

Back 9

1. Origin: Supraspinous fossa
2. Insertion: Greater tuberosity of humerus
3. Nerve Supply: Suprascapular nerve C4, 5,6
4. Action: Abduction of arm = initiation before deltoid takes over, stability of the shoulder joint
Note: Subacromial bursa lies above the tendon and below the coracoacromial arch

Front 10

Describe the features of infraspinatus:
1. Origin
2. Insertion
3. Nerve supply
4. Movement

Back 10

1. Origin: Infraspinous fossa
2. Insertion: Middle facet greater tuberosity
3. Nerve Supply: Suprascapular nerve C5,6,
4. Action: Lateral rotation

Front 11

Describe the features of teres minor:
1. Origin
2. Insertion
3. Nerve supply
4. Movement

Back 11

1. Origin: Lateral border dorsal surface scapula
2. Insertion: Inferior facet greater tuberosity below infraspinatus
3. Nerve Supply: Axillary nerve C5,6,
4. Action: Lateral rotation and adduction of arm

Front 12

Describe the features of subscapularis:
1. Origin
2. Insertion
3. Nerve supply
4. Movement

Back 12

1. Origin: Subscapular fossa scapula
2. Insertion: Lesser tuberosity of humerus
3. Nerve Supply: Upper & lower subscapular nerves C5,6,7
4. Action: Medial rotation