Muscles Of The Shoulder And Back (3) Flashcards
0
Q
Which overall group does posterior axio-appendicular muscles belong to?
A
- Intrinsic
1
Q
What are the two different overall types of muscles in the back?
A
- Intrinsic
- Extrinsic
2
Q
What are the three types of posterior axio-appendicular muscles?
A
- Superficial group: Trapezius and latissimus dorsi
- Deep muscles: Levator scapulae and rhomboids
- Scapulo-humeral: deltoid, teres major and 4 rotator cuff muscles
3
Q
Where is the trapezius attached and on which joint does it act?
A
- Direct attachment of pectoral girdle to trunk
- Acts on scapulo-thoracic joint
4
Q
What three parts are there to the trapezius and what body movements do they allow?
A
- Superior: elevates scapula (e.g. Shrugging)
- Middle: retracts scapula (e.g. Squaring of shoulders)
- Inferior: depresses scapula
5
Q
How does the scapula rotate?
A
- Superior and inferior parts of trapezius act together to rotate the scapula upwards and outwards on chest wall (elevating glenoid cavity)
- Serratus anterior muscle also aids upwards rotation of scapula
6
Q
What does scapula rotation allow?
A
- Abduction of arm above horizontal (90 degrees)
7
Q
Describe the latissimus dorsi.
A
- Wide origin
- Narrow insertion
- Large
- Fan shaped
8
Q
What are the attachments for the latissimus dorsi?
A
- Last 6 thoracic vertebrae
- Thoracolumbar fascia
- Iliac crest to floor of intertubercular groove
9
Q
What body movements is the latissimus dorsi responsible for?
A
- Powerful adductor of arm at shoulder joint
- Extends arm at shoulder joint
- Medial rotator
10
Q
What nerve supplies the latissimus dorsi?
A
- Thoraco-dorsal nerve
11
Q
What is the role of rhomboids major and minor?
A
- Retracts scapula
- Rotates scapula depressing glenoid cavity
12
Q
What is the role of levator scapulae muscle?
A
- Elevates scapula
- Rotates scapula depressing glenoid cavity
13
Q
Which nerves supply the levator scapulae muscle?
A
- Dorsal scapula nerve
- Cervical nerve
14
Q
Which are the scapulo humeral muscles?
A
- Deltoid
- Teres major
- Rotator cuff muscles
15
Q
What are the three main fibres of the deltoid muscle and what movement do they allow?
A
- Anterior fibres (clavicular): flexion of arm at SJ
- Middle fibres (acromial): abducts arm from 15-90 degrees
- Posterior fibres (spinal): extends arm at SJ
16
Q
What is the main role of the deltoid?
A
- Powerful abductor of arm at SJ
17
Q
What nerve supplies the deltoid?
A
- Axillary nerve
18
Q
What is the origin and insertion of the deltoid?
A
- Anterior, upper surface of the clavicle
- Acromion
- Spine of scapula
19
Q
What is the origin and insertion of the teres major?
A
- Origin: Inferior angle of scapula
- Insertion: Upper humerus
20
Q
What is the main actions that the teres major plays a role in?
A
- Adducts arm
- Medial rotation
21
Q
Which nerve supplies the teres major?
A
- Lower subscapular nerve
22
Q
Outline the steps to describe a joint.
A
- Articular surfaces
- Capsule
- Ligaments
- Movements
- Blood supply
- Nerve supply
23
Q
What is the shoulder joint also known as?
A
- Gleno-humeral joint.
24
Describe the Gleno-humeral joint.
- Synovial ball and socket joint
- Wide range of movements in multiple planes
- Lined by hyaline cartilage
- Glenoid cavity is deepened by glenoid labrum (ligament)
25
What is a bursae?
- Small sac with synovial fluid to aid movement.
26
Why is the SJ unstable?
- Glenoid cavity is shallow
- Disproportionate articular surfaces for joint
- Loose capsule (lax)
27
What stabilises the SJ?
- Rotator cuff muscles
- Ligaments
- Capsule
28
Why is the SJ so unstable?
- Needs to be able to cover multiplanar movement.
29
Where is the glenoid capsule attached to?
- Glenoid labrum and margins of glenoid cavity of scapula
| - Anatomical neck of humerus
30
What is the 'path' of the capsule?
- Bridges intertubercular groove
| - Dips down medially to surgical neck (to provide laxity for full abduction)
31
Why is there a small opening anteriorly in the glenoid cavity?
- So synovial membrane of SJ can communicate with subscapular bursa
32
Describe the synovial membrane's role in the gleno-humeral joint.
- Synovial membrane lines capsule and bone up to edge of articulating surfaces.
- Tendon of long head of biceps lies within joint cavity
- Tubular sleeve of synovium reflects back around bicep's tendon
- Synovium and joint cavity is continuous with subscapular bursa via gap in capsule.
33
What components is the extra capsular ligament comprised of?
- Coracoacromial ligament (CAL): between acromion and coracoid process
- Coracohumeral ligament (CHL): coracoid process to anterior part of greater tubercle
- Transverse humeral ligament: holds tendon of long head of biceps in place during movement.
34
What is the position and role of the Coracoacromial arch?
- Stong osteoligamentous structure
- Overlies humeral head
- Prevents upper displacement of humerus
35
What are the rotator cuff muscles?
- Collective name for 4 short muscles:
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
36
What are the actions of the individual muscles of the rotator cuff?
- Supraspinatus: initiation and 1st 15 degrees of abduction
- Infraspinatus: Lateral rotation of the arm
- Teres minor: Lateral rotation of arm (weak adductor)
- Subscapularis: medial rotation of arm
37
How do the muscles act as a cuff on the glenoid-humeral joint?
- Tendons blend together to form a cuff
- Tendinous cuff fuses with capsule
- Inserted to greater and lesser tubercles close to articular region
- Tone of the muscles hold them close to the glenoid cavity
- Supraspinatus tendon's separated from CAA by subacromial bursa
38
There's a space between acromion and head of humerus what's in this space and how large is the space?
- ~1-1.5cm
- Subacromial bursa
- Rotator cuff tendons
- Capsule
- Tendon of long head of biceps
39
What are the muscles stabilising SJ?
- Deltoid
| - Long heads of biceps and triceps
40
What is the role of the subscapular bursa?
- Facilitates movement of tendon of Subscapularis muscle of scapula
- Communicates with joint cavity
41
What is the role of the subacromial bursa?
- Facilitates movement of supraspinatus tendon under CAA, deltoid muscle over SJ capsule and greater tubercle of humerus
42
What damage to the subacromial bursa may lead to restriction of movement?
- Inflammation of bursa-subacromial bursitis
| - Pain on abduction of arm from 15-130 degrees
43
What provides overall stability of the SJ?
- Tendons of rotator cuff
- Coracoacromial arch (CAA)
- Gleno-humeral ligaments
- Coracohumeral ligament
- Deepening of GC by glenoid labrum
- Splinting effect of long heads of biceps/triceps
44
Which type of dislocation of the gleno humeral joint is most common and why?
- Anterior
- As humeral head locates anteriorly due to pull of powerful adductors
- Humeral head comes to lie below coracoid process
45
Why may an initial dislocation lead to recurrent dislocation?
- Capsule and rotator cuff may tear
- Poor healing
- Recurrent dislocation.
46
What nerve may be injured during a dislocation of the shoulder?
- Axillary nerve
47
What signs are there of axillary nerve injury?
- Paralysis of deltoid muscle - loss of abduction
| - Loss of sensation in regimental badge area - supplied by lateral cutaneous nerve
48
What problems may tendons of the rotator cuff rubbing under CAA lead to?
- Irritation and inflammation of rotator cuff tendons/SA bursa
- Subacromial bursitis
- Supraspinatus tendinitis
- Rotator cuff injury
- Degeneration and rupture of tendons
49
What are the risk factors associated with rotator cuff injuries?
- Repetitive overuse - e.g. sporting activities/working involving overhead arms (painter)
- Old age - degeneration
- Avascularity of supraspinatus tendon.
