1. FUNCTIONAL ANATOMY OF THE SHOULDER AND UPPER ARM
UNIT 2: PSE4U
FUNCTIONAL ANATOMY OF THE SHOULDER AND UPPER ARM

2. OBJECTIVES
Identify and discuss the role of each of the following components of the shoulder
Bony anatomy
Joint articulations
Static stabilizers
Dynamic stabilizers
Identify and discuss common acute and chronic injuries associated with the shoulder

3. Bony Anatomy

4. Joint Articulations Glenohumeral joint Acromioclavicular joint
Sternoclavicular joint
Scapulothoracic joint (not shown)

5. Important Bony Landmarks

6. Acromioclavicular Joint (AC joint)
a gliding joint within the shoulder. This joint is specific to primates and humans, allowing for the ability to raise the arm above the head. This joint functions as a pivot point, acting like a strut to help with movement of the scapula resulting in a greater degree of arm rotation. Also, the AV joint allows for the transmission of force from the upper arm to the rest of the skeleton

7. Sternoclavicular Joint
The only true joint attaching the upper extremity to the axial skeleton
Clavicle
1st Rib
Sternum
Sternoclavicular Ligament
Costoclavicular Ligament

8. The Shoulder = glenohumeral jt
The glenohumeral joint is a ball-and-socket joint that allows for the arm to move in a circular rotation as well as movement of the arm towards and away from the body. The motion that the glenohumeral joint provides is flexion, extension, abduction and adduction.

9. Static Stabilizers (ligaments)
Coracoclavicular. l
Acromioclavicular. l
Coraco-acromial Lig.
Superior, Middle and Inferior Glenohumeral Ligament
Glenohumeral joint capsule
Acromioclavicular
Coracoclavicular
Coracoacromial

10. Dynamic Stabilizers: Muscles of the Rotator Cuff
Remember:
S (subscapularis)
I (infraspinatus)
T (teres minor)
S (supraspinatus)

11. Supporting Muscles of the GHJ
Pectoralis Major
Deltoid
Long Head of Biceps

12. Role of the Rotator Cuff
Hold the head of the humerus in the small and shallow glenoid fossa of the scapula. During elevation of the arm, the rotator cuff compresses the glenohumeral joint in order to allow the large deltoid muscle to further elevate the arm. In other words, without the rotator cuff, the humeral head would ride up partially out of the glenoid fossa and the efficiency of the deltoid muscle would be much less.

13. Movements of the Pectoral Girdle
Elevation
Depression
Abduction
Adduction
Upward
Rotation
Downward

14. Innervation
Shoulder girdle muscles primarily innervated by cervical & brachial plexus
From Seeley RR, Stephens TD, Tate P: Anatomy and physiology, ed 6, Dubuque, IA, 2003, McGraw-Hill

15. Injuries to the Rotator Cuff
Acute
Tear (fall)
Chronic
Tendonitis (overuse)
Impingement
To pinch –
supraspinatus gets pinched between the humerus and the acromion and/or the coracoacromial ligament.

16. Shoulder Dislocation
Dislocation occurs when a bone is displaced from its original location
Usually involves damage to the joint capsule and the ligaments that hold the joint together
Signs and symptoms include:
Joint looks awkward or deformed
Joint is painful
Joint is not useable

17. Healthy Shoulder
Dislocated Shoulder

18. TYPES OF DISLOCATIONS Anterior (85%) Inferior (5%)
Posterior (10%)
Subcoracoid Dislocation

19. ANTERIOR DISLOCATION
Arm in abduction and external rotation. Force is taken on the hand or arm which increases the external rotation of the arm causing the head of the humerus to dislocate.

20. INFERIOR DISLOCATION
Arm is in excessive abduction and a force is taken on the hand pushing the head of the humerus inferiorly out of the glenoid.

21. Subcoracoid Dislocation

22. Subcoracoid Dislocation

23. Anterior Dislocation

24. POSTERIOR DISLOCATION
The arm is in flexion and adduction. Force is taken on the hand, causing the head of the humerus to be push out the glenoid posteriorly.

25. POSTERIOR DISLOCATION
The coracoid process may be prominent. The elbow will be at the side and the hand on the stomach. Attempting to turn the arm out causes shoulder pain.

26. For any dislocated shoulder, do not try to reduce the joint
For any dislocated shoulder, do not try to reduce the joint. Do not pull on the arm.
Try to immobilize as best you can (difficult).
Medical referral!

27. Shoulder Separation
Separation: occurs when bones held together by fibrous ligaments tear and separate from each other.
There are several grades of separation depending on the severity of the torn ligaments

28. Grades of Shoulder Separation

29. Healthy Shoulder
Separated Shoulder

30. YIKES!!