The shoulder joint is formed by the articulation of the humerus with the scapula. It includes the glenohumeral joint as well as the acromioclavicular and sternoclavicular joints. The glenohumeral joint is the most mobile joint in the body and is stabilized by static structures like ligaments and the labrum as well as dynamic structures like the four rotator cuff muscles that surround it.

1. The Shoulder Joint

2. Shoulder Joint
There are a number of articulations in the shoulder
region
The glenohumeral joint is commonly called the
shoulder joint
Other articulations include
• Acromioclavicular joint
• Sternoclavicular joint

3. Shoulder Joint
Sternoclavicular
Joint
Sternoclavicular
Joint

4. Shoulder Joint
Acromioclavicular
Joint
Acromioclavicular
Joint

5. Shoulder Joint
Glenohumeral Joint
Anterior View

6. Shoulder Joint
Glenohumeral Joint
Multiaxial
Synovial
Spheroidal
Anterior View

7. Shoulder Joint
Multiaxial
Synovial
Spheroidal
Posterior View

8. Shoulder Joint
Glenohumeral Joint
Formed by an articulation
between
Scapula
Anterior View

9. Shoulder Joint
Glenohumeral Joint
Formed by an articulation
between
Scapula and Humerus
Anterior View

10. Shoulder Joint
Articulation - Glenoid fossa of Scapula
Anterior View Lateral ViewPosterior View
Right side

11. Shoulder Joint
Articulation – Head of Proximal Humerus
Anterior View Superior ViewPosterior View
Right side

12. Shoulder Joint
The articulating bony
surfaces are not
congruent
The Glenohumeral joint is the most mobile joint in
the body
The glenoid surface is relatively flat
compared to the round head of the
humerus
Right side

13. There are static stabilisers and
dynamic stabilisers
In order to stabilise
the joint and prevent
it from dislocation
there are a number of
soft tissue structures
that interact to
stabilise the joint

14. Static Stabilisers

15. Lateral View
The Glenoid Fossa is flat
and pear-shaped when
viewed from its lateral
aspect

16. Lateral View
It is surrounded by a
fibrocartilaginous rim of tissue,
the Glenoid Labrum,
that deepens the cavity
GlenoidGlenoid GlenoidGlenoid
Labrum
Cross section
through glenoid
Cross section
through glenoid
+ labrum

17. The Glenohumeral
joint is surrounded
by a capsule

18. The Glenohumeral
joint is surrounded
by a capsule

19. There are three
condensations
within the capsule
that form ligaments

20. The
Superior
Glenohumeral
Ligament

21. The
Middle
Glenohumeral
Ligament

22. The
Inferior
Glenohumeral
Ligament

23. In different arm positions different ligaments
tighten to stabilise the joint

24. As the arm is abducted, the inferior
glenohumeral ligament becomes
taut
In different arm positions different ligaments
tighten to stabilise the joint

25. Dynamic Stabilisers
There are four rotator cuff muscles that
surround the shoulder joint
These muscles move the arm, but are also very
important in stabilising the shoulder joint
Subscapularis
Supraspinatus
Infraspinatus
Teres Minor

26. The Subscapularis muscle
attaches to the Lesser
Tuberosity of the Humerus
It arises from the whole of
the ventral surface of the
scapula
It internally rotates the
arm
Subscapularis
The Shoulder

27. It arises from the
Supraspinous Fossa
Suprapinatus attaches to the upper part of the
Greater Tuberosity of the Humerus
It abducts the arm

28. It arises from the
Infraspinous Fossa
It externally rotates
the arm
Infraspinatus attaches to the posterior part of the
Greater Tuberosity of the Humerus
The Shoulder

29. The Humerus
Teres Minor attaches to the postero-inferior part of
the Greater Tuberosity of the Humerus
Posterior View
It arises from the
upper part of lateral
border of the scapula
It also externally
rotates the arm