Lecture 4.2: The Shoulder Joint Flashcards

1
Q

Shoulder Joint: Glenohumeral Joint

A
  • Head of humerus fits into Glenoid Cavity of the Scapula
  • Lined by hyaline cartilage
  • Glenoid Cavity deepened by Glenoid Labrum (fibrocartilage)
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2
Q

Is the Shoulder Joint stable? Why?

A
  • Inherently unstable!
  • Glenoid cavity shallow
  • Disproportion of articular surfaces
  • Multiplanar movements
  • Lax capsule
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3
Q

How is the stability of the Shoulder Joint increased? (4)

A

1) Capsule
2) Ligaments (Extracapsular and Intracapsular)
3) Muscles of the rotator cuff (4) –> these are very important!
4) Other muscles

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4
Q

What is the Shoulder Capsule attached to?

A

• Glenoid Labrum & margins of Glenoid Cavity
• Anatomical neck of humerus
• Bridges intertubercular groove & dips down medially to surgical neck
(provides laxity for full abduction)

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5
Q

Why does the Shoulder Capsule have a small anterior opening?

A

• Communication between synovial shoulder joint and subscapular bursa

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6
Q

Shoulder Joint: Synovial Membrane

A

Lines capsule & Lines bone within capsule up to edge of articulating surfaces

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7
Q

Where is the tendon of the long head of biceps located?

A
  • Tendon of long head of biceps lies within joint cavity
  • Tendon acquires a tubular sleeve of synovium as it enters joint
  • This synovium surrounds the tendon up to its insertion on scapula
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8
Q

Extracapsular Ligaments: Coracoacromial Ligament

A
  • MOST important

* Between acromion and coracoid process

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9
Q

Extracapsular Ligaments: Coracohumeral Ligament

A

• From base of coracoid process to anterior part of greater tubercle

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10
Q

Extracapsular Ligaments: Coracoclavicular Ligament

A

• Can be torn from AC joint dislocation

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11
Q

Extracapsular Ligaments: Transverse Humeral Ligament

A

• Holds tendon of long head of biceps in place during movement

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12
Q

Intracapsular Ligaments

A
  • 3 Glenohumeral Ligaments (Superior, Middle, Inferior)
  • Fibrous bands extending between Glenoid Labrum and Humerus
  • Part of Fibrous Capsule and reinforces capsule anteriorly
  • Can only be seen from inside the capsule
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13
Q

Coracoacromial Arch (CAA)

A
  • Formed by: Coracoacromial Ligament + Acromion + Coracoid Process
  • Strong bony and ligamentous structure
  • Overlies humeral head
  • Prevents upper displacement
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14
Q

Rotator Cuff Muscles: SITS

A

S: upraspinatus
I: nfraspinatus
T: eres Minor
S: ubscapularis

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15
Q

Importance of Rotator Cuff Muscles

A

They are the most important structures that give stability to the shoulder joint

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16
Q

What do Tendons of Rotator Cuff Muscles do?

A
  • Tendons BLEND to form a cuff
  • Cuff fuses with fibrous capsule (of joint) and strengthens it
  • Tone in muscles holds humeral head close to Glenoid Cavity
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17
Q

What separates the Supraspinatus Tendon from the Coracoacromial Arch?

A

The Subacromial Bursa

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18
Q

Actions of the Rotator Cuff and Nerve: Supraspinatus

A
  • Initiation and first 15 degrees of abduction

* Suprascapular Nerve (C5,6)

19
Q

Actions of the Rotator Cuff and Nerve: Infraspinatus

A
  • Lateral rotation of arm

* Suprascapular Nerve (C5,6)

20
Q

Actions of the Rotator Cuff and Nerve: Teres Minor

A
  • Lateral rotation of arm/weak adductor

* Axillary nerve (C5,6)

21
Q

Actions of the Rotator Cuff and Nerve: Subscapularis

A
  • Medial rotation of arm

* Upper and Lower Subscapular Nerve

22
Q

Other Muscles that help stabilise the Shoulder Joint (3)

A
  1. Deltoid
  2. Long Head of Biceps
  3. Long head of Triceps
23
Q

Where does the Long Head of Biceps attach on the Shoulder Joint?

A

• Attaches to Supraglenoid Tubercle

24
Q

Where does the Long Head of Triceps attach on the Shoulder Joint?

A

• Attaches to Infraglenoid Tubercle

25
Q

Where does the Deltoid attach on the Shoulder Joint?

A

Attaches to lateral clavicle, acromion, scapula spine and humerus

26
Q

Importance of Subacromial Bursa in Movement?

A

Facilitates movement of:
• Supraspinatus tendon under CAA
• Deltoid muscle over the shoulder joint capsule & greater tubercle of humerus

27
Q

What happens if the Subacromial Bursa becomes Inflammed?

A
  • Subacromial Bursitis
  • Causes pain on abduction of arm between 50-130 degrees
  • ‘Painful arc’ Syndrome
28
Q

Importance of Subscapular Bursa in Movement?

A

• Facilitates movement of subscapularis tendon over scapula

[• Communicates with joint cavity]

29
Q

What is the most common dislocation of the Glenohumeral Joint? What usually causes it?

A
  • Anterior Dislocation
  • Humeral head comes to lie below coracoid process
  • Usually caused by trauma on a fully abducted arm
30
Q

What does an Anterior Dislocation look like externally?

A

Loss of round contour of shoulder —> appears square

31
Q

When is Axillary Nerve Damage caused?

A
  • Injured in dislocation

* Injured during fracture of surgical neck of humerus

32
Q

What area experiences a loss of sensation during Axillary Nerve Damage?

A

• Loss of sensation in “Regimental Badge Area
• Area over central part of Deltoid
[• Supplied by Axillary Nerve (C5,6)]

33
Q

What is a more extreme effect of Axillary Nerve Damage?

A
  • Motor function loss

* Loss of Deltoid muscle (no abduction of arm)

34
Q

What is ‘Painful Arc’ Syndrome?

A

It is when the Supraspinatus Tendon rubs under CAA (Coracoacromial Arch)

35
Q

What can ‘Painful Arc’ Syndrome lead to? (3)

A
  • Subacromial Bursitis (+/- calcification)
  • Supraspinatus Tendonitis (+/- calcification)
  • Degeneration and rupture of tendons
36
Q

Risk Factors for ‘Painful Arc’ Syndrome (4)

A
  • Repetitive overuse (sports, work involving overhead use of arms)
  • Ageing (degeneration of tendons)
  • Avascularity of supraspinatus tendon
  • Slight differences in anatomy = may increase chances of impingement
37
Q

Symptoms of ‘Painful Arc’ Syndrome (2)

A
  • Irritation and inflammation of the supraspinatus tendon/subacromial bursa
  • Pain during 60-120 degrees of abduction arc
38
Q

What is the first spinal ligament you encounter in deep skin and subcutaneous tissue during a Lumbar puncture?

A

Supraspinous Ligament

39
Q

What is the role of the Ligamentum Nuchae?

A

It maintains the secondary structure of neck and supports the head

40
Q

What is Lordosis?

A

Lordosis refers to the normal inward curvatures of the spine at the cervical and lumbar regions

41
Q

What is Kyphosis?

A

Kyphosis refers to the normal outward curvature of the spine specifically at the thoracic region

42
Q

What is Carpal Tunnel Syndrome?

A
  • Pressure on a nerve in your wrist

* It causes tingling, numbness and pain in your hand and fingers

43
Q

Cutaneous Nerve Area vs Dermatome

A

Cutaneous innervation refers to the area of the skin which is supplied by a specific cutaneous nerve

Dermatomes are similar; however, a dermatome only specifies the area served by a spinal nerve