Q1

What are the articulating surfaces in the shoulder joint?

  • Ball-and-socket synovial joint
  • Rounded head of humerus
  • Shallow glenoid cavity of scapula, deepened by labrum

Pass criteria

  • Bold to pass

What structures stabilise the shoulder joint?

  • Fibrocartilaginous gelnoid labrum
  • Coraco-acromial arch
  • Anterior glenohumeral ligaments
  • Coracohumeral ligament
  • Transverse humeral ligament
  • Rotator cuff (SITS) muscles:
    • Supraspinatus
    • Infraspinatus
    • Teres minor
    • Subscapularis

Pass criteria

  • Rotator cuff (3/4 muscles), plus 2 others to pass
  • Need to show understanding that there are different elements that contribute to stability.

What muscles are responsible for abduction and adduction of the shoulder joint?

  • Abduction
    • Deltoid (especially acromial part)
    • Supraspinatus (initiates)
    • + upward movement of scapula
  • Adduction
    • Pectoralis major and latissimus dorsi acting in concert
    • Teres major and long head of triceps (synergists)

Pass criteria

  • Abduction: Bold to pass
  • Adduction: 2/4 bold to pass 

Bonus - What muscles are responsible for the other movements of the shoulder?

  • Flexion
    • Pectoralis major (clav head), Deltoid (clav and anterior acromial parts), Coraco-brachialis (synergist)
  • Extension
    • Spinal part of deltoid, Latissimus dorsi, teres major, long head of triceps (synergists)
  • Medial rotation
    • Subscapularis, pectoralis major, latissimus dorsi, teres major, deltoid-clavicular part (synergists)
  • Lateral rotation
    • Infraspinatus, teres minor, deltoid- spinal part (synergists)
  • Circumduction

Bonus - Outline the bursae of the shoulder joint.

  • Subscapular bursa
    • Located between neck of scapula and subscapular tendon
    • Protects tendon
  • Subacromial (subdeltoid) bursa
    • Between acromion, coracoacromial ligament and deltoid superiorly, and supraspinatus tendon and joint capsule inferiorly
    • Facilitates movement of supraspinatus tendon

Q2

Shoulder TextShoulder

Identify the features on this model of a shoulder.

  • Bony
    • Humerus/Humeral head
    • Scapula – coracoid process/acromion/spine/body
    • Clavicle
  • Joints
    • Glenohumeral
    • Acriomioclavicular
  • Ligaments
    • Coracoclavicular – conoid part and trapezoid part – most important for stability AC joint
    • Acromioclavicular – top of clavicle to acromion
    • Glenohumeral ligaments – reinforce anterior part of capsule from glenoid labrum to humerus
  • Tendons
    • Long head of biceps tendon

Pass Criteria:

  • Bold to pass

What anatomical structures (demonstrated on this model) confer stability to the shoulder joint?

  • Joint capsule with fusion of the tendons of scapular muscles
  • Ligamentous: glenohumeral and coracohumeral ligaments
  • Coracoacromial arch superiorly created by coracoacromial ligament
  • Deepening of glenoid cavity by glenoid labrum
  • Tendons of long head of biceps and triceps
  • Note – the major stabilisers are muscles of the rotator cuff but are not demonstrated on the model

Pass Criteria:

  • 3/5 to pass

What structures can be damaged by shoulder dislocation?

PROMPT – for axillary nerve

  • Joint capsule and glenoid labrum damage results in recurrent dislocation
  • Axillary nerve lies below joint capsule – palsy
  • Associated fracture of greater tubercle

Pass Criteria:

  • Bold to pass

Q3

Shoulder Text Shoulder

What muscle are called the 'rotator cuff muscles'?

  • Subscapularis
  • Teres minor
  • Supraspinatus
  • Infraspinatus

Pass Criteria:

  • Must know all 4 to pass

Demonstrate or describe the origins and insertions of the rotator cuff muscles. Note that the model has no rotator cuff muscles.

  • Subscapularis
    • Origin – Medial 2/3 costal surface of scapula
    • Insertion – Fuses with capsule of shoulder joint and into lesser tuberosity of humerus
    • Nerve – Upper and lower subscapular
  • Teres minor
    • Origin – Dorsal surface axillary border of scapula
    • Insertion – Lower facet greater tuberosity humerus
    • Nerve – Posterior branch axillary nerve
  • Supraspinatus
    • Origin – Medial 2/3 supraspinous fossa scapula
    • Insertion – Upper part of greater tuberosity humerus
    • Nerve – Suprascapular nerve C5,6
  • Infraspinatus
    • Origin – Medial 2/3 infraspinous fossa and deep surface infraspinous fascia which covers muscle
    • Insertion – Central facet greater tuberosity humerus
    • Nerve – Suprascapular

Pass Criteria:

  • Must have knowledge about origins, insertions and actions of 2/4

What are the actions of the rotator cuff muscles?

  • Subscapularis
    • Medial rotation of humerus
  • Infraspinatus and Teres minor
    • Lateral rotators of humerus
  • Supraspinatus
    • Initiates abduction and other muscles hold humeral head down
    • Abducts shoulder
  • All muscles stabilise the shoulder joint by bracing humeral head against glenoid (tendons fuse with capsule)

Pass Criteria:


Q4

normal-shoulder-x-rays

Indicate on the X-ray the anatomy of the shoulder joint.

  • Humerus
    • Head – articulates with glenoid
    • Anatomical neck
    • Surgical neck
    • Greater Tubercle
    • Lesser tubercle
  • Scapula
    • Glenoid cavity
    • Neck
    • Acromion process
    • Coracoid process
    • Spine
    • Superior, medial and inferior angle
  • Clavicle
    • Distal portion articulates with acromion

Pass Criteria:

  • Bold to pass

Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID: 7505

Shoulder Anatomy Xray

Image courtesy of wikiradiography

Name the ligaments and describe how they stabilise the shoulder joint.

  1. Glenohumeral ligaments (superior, middle and inferior) consists of three bands, which runs with joint capsule from glenoid fossa to anatomical neck of humerus. They act to stabilise the anterior aspect of the joint.
  2. Coracohumeral ligament – Attaches the base of hte coracoid process to the greater tubercle of the humerus. It supports the superior part of the joint capsule.
  3. Transverse humeral ligament – Spans distance between two tubercles of humerus. Holds the tendon of long head of biceps in the intertubercular groove.
  4. Coracoacromial ligament – Runs between the acromion and coracoid process of the scapula, forming the coraco-acromial arch. This overlies the shoulder joint, preventing superior displacement of the humeral head. 

Pass Criteria:

  • 2/4 to pass

Q5

 Left Humerus - Normal

Identify the features of the humerus on this x-ray.

  • Proximal:
    • Head
    • Anatomical & surgical neck
    • Shaft
    • Greater tuberosity/Lesser tuberosity
  • Distal:
    • Medial & Lateral epicondyles
    • Trochlea
    • Capitulum
    • Lateral & medial supracondylar ridges

Pass Criteria:

  • 6 Bold to pass

Case courtesy of Kellie Grant, Radiopaedia.org, rID: 39526

Humerus with Labels

Image courtesy of wikiradiography

What are the rotator cuff muscles and describe their actions.

  • Subscapularis – medial rotation of humerus
  • Supraspinatus – initiates abduction and abducts shoulder
  • Infraspinatus and teres minor – lateral rotators of humers
  • All 4 muscles stabilise shoulder joint

Pass Criteria:

  • 4 muscles + 1 action to pass

Q6

Media: Photo of brachical plexus (from McMinn’s)

Here is a photo of the right brachial plexus.
Please identify its main features.
Prompt: Please list, and identify where you can, the branches of the cord.

  • Deltoid (4)
  • Biceps (2)
  • Cords
    • Lateral (6)
    • Posterior (20)
    • Medial (12)
  • Musculocutaneous nerve (18)
  • Axillary nerve (1)
  • Radial nerve (21)
  • Median nerve (17)
  • Ulnar nerve (26)

Pass Criteria:

  • Bold to pass

Branches of the cord

  • Lateral cord: Musculocutaneous nerve (18), lateral pectoral nerve, lateral root of the median nerve (8)
  • Posterior cord: Upper (27) and lower (11) subscapular nerves, the thoracodorsal nerve (25), axillary nerve (1), radial nerve (21)
  • Medial cordThe medial root of the median nerve (16), the ulnar nerve (26), the medial cutaneous nerve of the arm (13) and forearm (14), the medial pectoral nerve

Pass Criteria:

  • List at least 2 branches from each cord and identify those in bold

What does the musculocutaneous nerve supply?

  • Motor supply
    • 3 muscles of the anterior compartment of the arm (biceps, brachialis, and coracobrachialis)
  • Sensory supply
    • Skin over the lateral aspect of the forearm (becomes the lateral cutaneous nerve of the forearm after giving off its motor supply)

Pass Criteria:

  • 1 motor and 1 sensory distribution

Elbow & Forearm  Wrist & Hand