Abc

2. OBJECTIVES
 Type
 Articular surfaces
 Ligaments
 Relations
 Blood & nerve supply
 Movements
 Scapulo-humeral rhythm
 Applied anatomy

3. : Polyaxial
Ball & Socket type of Synovial joint
Glenoid cavity
Head of
Humerus
Anterior view
Posterior view

4. : Glenoid
fossa of the scapula.
Pyriform in shape
Slight concavity in the
centre.
Lined by hyaline articular
cartilage.
 Socket depth is increased
by glenoidal labrum, a
fibrocartilage lining
the margin.

5. DISTALLY:
 Head of Humerus.
 Hemispherical in shape.
lined by hyaline
articular cartilage.

6.  The head of the
humerus is 3 times
bigger than
the glenoid fossa.
 As a result there is
more mobility at
the cost of
stability.

7.  Stability of a joint is maintained by the
ligaments holding the articulating parts
together.
1. Fibrous capsule
2. Glenohumeral ligaments
3. Transverse humeral ligament
4. Coracohumeral ligament
5. Coracoacromial arch - Secondary socket
(or) ligament

8.  Outer most covering of
the joint.
 Loose all around the joint
to allow free movements.
 PROXIMALLY:
Attached to the margins
of glenoid fossa proximal
to Glenoidal labrum.
Encloses origin of long
head of Biceps.
Capsule

9.  :
Anatomical neck of
humerus, except
inferiorly where the
capsular attachment
extends 1.25cms below
upto the surgical neck.

10.  The synovial membrane lines
the inside of the capsule.
 Reflected from capsule on to
the non articular intracapsular
part of humerus.
Capsule

11.  Forms a tubular
synovial sheath for
the tendon of long
head of biceps.
 The capsule is loose
to allow free
movements.
 The shoulder joint
therefore has more
mobility but at the
cost of stability. Long head of
bisceps

12. 1. Between the tubercles of
humerus – for the tendon of
long head of biceps muscle.
2. On anteromedial side –
communication of the
synovial membrane with the
subscapular bursa.
3. On posterolateral side –
communication of the
synovial membrane with
Infraspinatus bursa.

13.  Anteriorly :
Subscapularis
 Superiorly :
Supraspinatus
 Posteriorly :Infraspinatus
& Teresminor
The laxity & weakness of the capsule is compensated
by tendons of
Subscapularis

14. Most important for stability of the joint.
Tendons blend with the capsule while crossing
it & strengthen it all around except inferiorly.
Weakest part of the capsule is inferior part.
Supraspinatus
Infraspinatus
Teres minor
Axillary
Nerve

15. ATTACHMENTS
 Proximally : Upper end of
anterior border of glenoid
fossa.
 Distally splits into 3 parts
 Superior: Top of lesser
tubercle
 Middle: Lower part of lesser
tubercle
 Inferior: Shaft below lesser
tubercle

16.  Stretches between
the two tubercles.
 Tendon of long head
of biceps passes
deep to it.
 Helps to hold the
tendon in position
during various
movements of the
shoulder.

17.  Lateral margin of
coracoid process
to the anatomical
neck of humerus
between the two
tubercles.
It resists the lateral
rotation & adduction
of humerus.

18.  Coracoid process of
scapula.
 Acromion process of
scapula.
 Coraco acromial
ligament: A triangular
band between tip of the
acromium to lateral
margin of coracoid
process.
Acromion process Coracoid process
Coraco acromial ligament

19. 1.Subscapular bursa
2.Infraspinatus bursa
3.Subcoracoid bursa

20. 4.Subacromial bursa
(Longest bursa in
body)
5.Bursa above
coracoid process
6.Bursa on upper
surface of acromion
process
Sub acromial
bursa

21. Superiorly:
1. Middle fibres of
Deltoid
2. Supraspinatus,
3. Subacromial bursa &
4. Coraco acromial
arch.
1 2
3

22. Inferiorly:
1. Long head of
triceps
2.Axillary nerve
3. Posterior
circumflex
humeral vessels.
Long head of triceps
Axillar nerve &
posterior circumflex
humeral vessels

23.  Anteriorly:
Anterior fibres of
Deltoid,
Subscapularis,
Coracobrachialis &
Short head of
biceps.
 Posteriorly:
Posterior fibres of
Deltoid, Infraspinatus
& Teres minor.

25. Axillary nerve &
Posterior circumflex
humeral vessels winds
round the surgical neck
of humerus in intimate
contact with the inferior
part of the capsule of
the joint.

26.  Arteries
Supra scapular artery.
Anterior & Posterior circumflex humeral
arteries.
Circumflex scapular branch of subscapular
artery.
 Nerves
Lateral pectoral nerve.
Posterior division of Axillary nerve.
Suprascapular nerve.

27. Flexion:
Pectoralis Major, Anterior
fibres of Deltoid,
Coracobrachialis & Biceps
Brachii.
Extension:
Posterior fibres of Deltoid &
Teres major.

28.  Medial rotation:
Anterior fibres of Deltoid,
Pectoralismajor,Teres major,
Latissimusdorsi &
Subscapularis.
 Lateral rotation:
Infraspinatus, Teres Minor &
Posterior fibres of Deltoid.

29.  Adduction:
Deltoid, Pectoralis major
Subscapularis, Teres
major, Coracobrachialis
& Long head of triceps.

30. Abduction is initiated
by Supraspinatus ( S)
muscle.
It abducts the shoulder to
150.

31. Further abduction is
brought by middle fibres
of deltoid ( D).
The supraspinatus
holds the head of
humerus in contact with
glenoid fossa.
Subscapularis, teres
major & infraspinatus
exerts a downward pull.
Balance between
these muscles abducts
the shoulder upto 900.

32. At 900 abduction the
articular surface of
humerus is completely
used.
The humerus is laterally
rotated by teresminor &
infraspinatus muscles.
The articular surface of
humerus faces superiorly &
in now available for further
abduction.

33. The scapula is also
rotated laterally by serratus
anterior ( SA), upper &
middle fibres of trapezius (
T).
This tilts the glenoid
fossa upwards.
Further abduction is now
completed upto 1800.

34.  Upto 900 abduction the movement
involves predominantly shoulder joint.
 900 – 1800 abduction involves both
shoulder joint & scapular rotation.
 For every 20 movement in shoulder joint
there is 10 movement in scapula.
 This is called as scapulo humeral rhythm.

35.  Rotator cuff.
 Supraspinatus tendon, Glenohumeral,
Coracohumeral ligament & Coraco acromial
arch –Supra humeral support.
 Long head of Triceps & Biceps – act like splints
below & above the joint.
 Glenoidal labrum – Deepens the glenoid cavity.

37.  Impingement of
Supraspinatus tendon
on the acromiun
during abduction
leads to tendinitis.
 Diminished vascularity
aggravates.
 Calcium deposition
causes irritation.

38.  Abduction between 600
-
1200
results in severe
pain.
‘PAINFUL ARC
SYNDROME’
 Usually occurs in males
above 50yrs of age, due
to unusual excessive use
of shoulder.
 Could be due to
supraspinatus tendinitis
or subacromial bursitis.

39. Inferior part of the capsule is weak.
Therefore anteroinferior dislocation of shoulder is more
common.
The humeral head slips downwards & forwards &
may press upon the vessels & brachial plexus in
axilla.

40.  Occurs in antero
inferior dislocations.
 Paralysis of Deltoid
& loss of sensation
over skin covering
Deltoid muscle.

41. Throwing baseball or
football forcibly can
cause damage to glenoidal
labrum, capsule & rotator
cuff.
This when not corrected
leads to recurrent
dislocation of shoulder
antero inferiorly.

42.  Caused by adhesive
fibrosis & scarring of
capsule, rotator cuff,
subacromial bursa &
deltoid due to
periarthritis.
 Pain in shoulder, joint
stiffness & restricted
mobility (40 – 60 yrs).
 Disuse atrophy of
surrounding muscles.

44. http://www.youtube.com/watch?v=UVNullyWQv8
http://www.exrx.net/Articulations/Shoulder.html
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