biomechanics of the shoulder joint and is mainly focused on the acromioclavicular joint. the shoulder is one of the largest and most complex joints in the body. the shoulder joint is formed where the humerus (upper arm bone) fits into the scapula (shoulder blade), like a ball and socket joint. the acromion is a bony projection off the scapula. the clavicle (collarbone) meets the acromion in the acromioclavicular joint.

1. SHOULDER COMPLEX
DR.NEHAPT
LECTURER
SB COLLEGE OF PHYSIOTHERAPY
MPT NEUROLOGY

2. AC Joint
1. Introduction (Definition)
2. Bones
3. Muscles
4. Action/Movement
5. Nerve Supply
6. Ligaments/Tendons
7. Problems associated with the AC Joint
8. Treatment

3. Acromioclavicular Joint
• The Acromioclavicular joint , or AC Joint , is one
of four joints that comprise the Shoulder
complex.
• The AC joint is not as mobile as the large main
shoulder joint.
• This joint has meniscus, which allows the joint
to move.

4. Bones
• It is formed by articulation of small facets
present :
i. At the Lateral end of the clavicle .
ii. Acromion process of the scapula.
• The bones are held together by a fibrous
capsule ( Hyaline cartilage) and by the articular
disc .

5. Fig. Articulating surfaces of the AC Joint

6. Muscles
•The muscles which attached are:-
•Pectoralis Major
•Sternocleidomastoid
•Deltoid
•Trapezius

8. Action/movement
• The action/movements which occurs at AC joint are:-
1. Elevation
2. Depression
3. Protaction
4. Retraction
5. Circumduction

9. Fig. Action/movements

10. Nerve Supply
Lateral supraclavicular nerves
(C4) from the cervical plexus

11. Ligaments
• These are acromioclavicular and coracoclavicular
ligaments.
• Acromioclavicular ligament
• Coracoclavicular ligament :- It comprises of two parts:
(a) conoid
(b) trapezoid

13. Problems Associated with AC Joint
1. Dislocation of the acromioclavicular joint:
It may take place following a severe blow on
the superolateral part of the shoulder.
Consequently the shoulder separates from the
clavicle amd falls due to the weight of the limb

14. Fig. Shoulder Separation

15. •

16. 2. Osteoarthritis and distal clavicular
Osteolysis
• Osteoarthritis of the AC joint may occur after injury,
repetitive overuse or, more rarely, as a primary
phenomenon. It commonly occurs in middle age, due to
degeneration of the fibrocartilaginous disc.
• Distal clavicular osteolysis may occur:
• Spontaneously in rheumatoid arthritis,
hyperparathyroidism, gout, multiple myeloma, systemic
sclerosis and massive essential osteolysis (Gorham's
disease).
• Due to infection.
• Particularly in upper limb weight training and also in
those who are involved in throwing sports.

17. Fig. Osteoarthritis ( osteophtes bone spurs)

18. Fig . Osteolysis

19. Treatment
Immediate first aid for any AC joint injury is to apply the PRICE principles of REST, ICE,
COMPRESSION and ELEVATION.
1. Protection
2. Apply Ice or Cold therapy and compression wrap as soon as possible to reduce pain
and swelling.
3. Wear a sling to immoblize the shoulder and ease pain by taking the weight of the arm.
4. Anti-inflammatory such as ibuprofen medication to reduce pain inflammation as well
as diagnose the injury and assess how bad it is . If a bad AC joint injury is not properly
treated it can lead to long term deformity in the form of a lump on top of the shoulder
5. Ultrasound for minor injuries, IFT (Interferential Therapy) for particular areas or TENS
for radiating pain relief can be used in more severe cases.
6. AC Joint Taping:- An AC joint taping should be applied which fixes and supports the
joint into the correct position to assist with healing. The joint may need taping for 2-3
weeks

20. Fig. Treatment

21. Taping