The shoulder joint is a ball and socket joint formed by the humerus, scapula, and clavicle. It has the greatest range of motion of any joint. The glenohumeral joint allows the arm to move in many directions but is less stable due to its shallow socket. A series of muscles including the rotator cuff provide dynamic stability. The shoulder complex also includes the acromioclavicular, sternoclavicular, and scapulothoracic joints. The bones, ligaments, muscles, and nerves of the shoulder are described in detail in the document.

2. INTRODUCTION
Shoulder joint is formed by scapula and clavicle (which is
also called as shoulder girdle)and proximal humerus.
It has the greatest range of motion of any joint in the body.
Due to wide range of movement it is also most unstable
joint compared to other joints of the body.However a series
of complex ligaments and muscle keep it in joint

3. BONES OF SHOULDER JOINT
Articulates at one end with the
sternum (chest bone) and with
the acromion of the scapula at
the other.(Roof of the shoulder)
Forms the front portion of the
shoulder girdle and is palpable
along its entire length with a
gentle S-shaped contour.
Clavicle

4. It is a flat, triangular bone
that lies over the back of the
upper ribs.
It serves as an attachment for
some of the muscles and tendons
of the arm, neck, chest and back
and aids in the movements of the
arm and shoulder.
Anterior View
Posterior View
Scapula

5. The proximal humerus consists of
the head, neck, greater and
lesser tubercles, and the shaft.
The neck lies between the head
and the greater and lesser
tubercles.
The greater and lesser tubercles
are prominent landmarks on
the humerus and serve as
attachment sites for the rotator
cuff muscles.
Proximal Humerus

6. OSSIFICATION CENTRES

7. CLAVICLE
 It’s the 1st bone to ossify .
 It has no medullary cavity.
 It occurs by intramembranous ossification.
 Secondary ossification centres via endochondral.
 Medial epiphysis ossifies at 12-19yrs and fuses at 22 to 25yrs.
 Lateral epiphysis ossifies and fuses at 19yrs.

8. SCAPULA
Body and spine[posterior] ossify at birth
Coracoid process[anterior]-atavastic epiphysis. centre at
1yr,base at 10yrs.
Acromian[lateral projection]-fuses by 22yrs via 2-
5centres form at puberty
 Glenoid-upper 1/4th ossify at 10yrs lower3/4th appear at
puberty ,fuse by 22yrs

10. PROXIMAL HUMERUS
 Humeral head-ossifies at 6mths
 Greater tuberosity-ossifies at 1 to 3yrs
 Lesser tuberosity-ossifies at 4 to 5yrs.
 Physis close at 14-17yrs girls and 16-18yrs boys.

12. Joints of the Shoulder Complex
1. Glenohumeral
2. Acromioclavicular
3. Sternoclavicular
4. Scapulothoracic

13. Glenohumeral
The glenohumeral joint is the most
mobile joint in the body. The ‘socket’
(glenoidfossa) is very shallow, and
doesn’t hold on to the ‘ball’
(humeral head) very well
Joint type: ball and socket synovial
joint
It is therefore up to a group of
muscles (called the Rotator Cuff -
further discussed in the ‘Muscles’
section) to ‘hold the ball in the socket’,
providing stability and some
movement

14. The glenoid labrum also helps
to improve the stability of the
shoulder. The glenoid labrum is
a cartilage ring around the
glenoidfossa. This labrum
makes the ‘socket’ deeper,
giving it a larger and deeper
contact surface to articulate
with the head of the humerus.
The articular capsule is a
fibrous bag of tissue, fused
with local ligaments, which
provides a sealed sac around
the glenohumeral joint.

16. Glenohumeral ligaments
provide anterior stability to the glenohumeral joint
1. Superior (SGHL)
2. Middle (MGHL)
3. Inferior (IGHL)

17. Glenohumeral Joint
Superior GH Ligament
 Resists inferior
translation in rest or
adducted arm
 Well-developed in
50%

18. Glenohumeral Joint
Middle GH Ligament
 Great variability in
proximal attachment &
morphology
 Absent in 30%
 Resists inferior
translation in ABD &
ER
 Restrains anterior
translation (45° ABD)

19. Glenohumeral Joint
Inferior GH Ligament
 3 components (A,P,Ax)
 Resists inferior,
anterior, & posterior
translation

20. CORACOHUMERAL LIGAMENT
 Arises from lateral base of coracoid process and
extends onto both tuberosities.
 It forms roof of bicipital tendon sheath and
strengtens capsule anteriorly.
 Importance-resists inferior and posterior translation.
TRANSVERSE HUMERAL LIGAMENT
 Bridges upper part of bicipital groove through which
long head of biceps passes down.

21. Joint type: plane or sliding synovial joint
Bones involved in the articulation:
Acromion of the Scapula
Distal end of the Clavicle
Movements: only small translations
Anterior/Posterior glide
Superior/Inferior tilt
Rotation
Acromioclavicular Joint

22.  Acromioclavicular ligament – acts to secure the
acromion and clavicle and provides a complete
capsule around the joint.
 Coracoclavicular ligaments – anchor the lateral aspect
of the clavicle to the coracoid process of scapula. It
consists of two small ligaments holding the scapula
laterally, these are:
 Trapeziod - attaches to the trapezoid line on the
inferior surface of the clavicle
 Conoid - attaches to the conoid tubercle of the
clavicle

24. Sternoclavicular Joint

25. Joint type: saddle synovial joint
Sternoclavicular Joint
Bones involved in the articulation:
 Manubrium of the Sternum
 Proximal end of the Clavicle
Movements:
 Anterior/Posterior glide
 Superior/Inferior tilt
 Rotation

26. Take note of the:
 Sternoclavicular ligament
 Costoclavicular and Interclavicular ligaments
Sternoclavicular Joint

27. Scapulothoracic Joint

28. Joint type: not a ‘true’ joint, but known as a ‘pseudo’ joint
Bones involved in the articulation:
 Anterior surface of the Scapula
 Ribcage of the Thorax
Scapulothoracic Joint

29. Movements:
 Protraction and retraction
 Elevation and depression
 Anterior tilt and posterior tilt
 Upward rotation and downward rotation
As there is minimal bony contact, it is up to the muscles
attaching to the scapula and thorax to stabilise and control
movement at this articulation
There is no joint capsule or synovial fluid
Scapulothoracic Joint

33.  The muscles of the shoulder girdle provide vital
stability for the mobile shoulder joint
Muscles of the Shoulder

34. Muscles - Trapezius
Name Origin Insertion Action Innervation
Trapezius (upper,
middle & lower)
External occipital
protuberance,
ligamentumnuch
ae&spinous
processes of C7-
T12
Lateral 1/3of
clavicle,
acromion&
superior edge of
the crest of the
spine of the
scapula
Scapular
stabilisation
Upper – scap
elevation
Middle – scap
retraction
Lower - scap
retraction
Accessory nerv
(XI) C3, 4

35. Muscles - Deltoid
Name Origin Insertion Action Innervation
Deltoid (anterior,
middle &
posterior parts)
Lateral 1/3 of
clavicle, acromion
process + spine of
scapula
Deltoid tuberosity Shoulder
abduction
Axillary nerve

36. Muscles – Levator Scapulae
Levator scapulae Transverse
processes of C1-4
Medial scapula Elevation +
retraction of
scapula
Dorsal scapular
nerve
Name Origin Insertion Action Innervation

37. Muscles – Rhomboid Minor
Rhomboid minor Spinous
processes C7-T1
Medial border of
scapula near
spine of scapula
Scapular
retraction +
medial rotation
Dorsal scapular
nerve
Name Origin Insertion Action Innervation

38. Muscles – Rhomboid Major
Rhomboid major Spinous
processes T2-5
Medial border of
scapula
Scap retraction +
medial rotation
Dorsal scapular
nerve
Name Origin Insertion Action Innervation

39. Muscles - Pectoralis Major
Pectoralis major Sternal +
clavicular
attachments
Intertubercular
groove (lateral lip)
Adduction + IR Medial & lateral
pectoral nerves
Name Origin Insertion Action Innervation

40. Muscles – Pectoralis Minor
Pectoralis minor Outer surfaces
ribs 3, 4 & 5
Coracoid process Medial rotaion
of scapula
Medial pectoral
nerve
Name Origin Insertion Action Innervation

41. Muscles – Teres Major
Name Origin Insertion Action Innervation
Teres major Dorsal scapula
near inferior
angle
Intertubercular
groove
Adduction + IR Lower
subscapular
nerve

42. Muscles - LatissimusDorsi
Latissimusdorsi Thoracolumbar
fascia, T6-S5
spinous processes,
+ iliac crest
Lower 3-4 ribs,
inferior angle of
scapula +
intertubercular
groove
Shoulder E
from flexed
position, sh
adduction + IR
Thoracodorsal
nerve
Name Origin Insertion Action Innervation

43. Muscles – Serratus Anterior
Serratus anterior Upper 8-9 ribs Medial border of
scapula
Scapular
protraction
Long thoracic
nerve
Name Origin Insertion Action Innervation

44. Muscles - Subclavius
Subclavius Subclavian
groove on
clavicle
1st rib Stabilise clavicle Nerve to
subclavius C5,6
Name Origin Insertion Action Innervation

45. Muscles – Biceps Brachii
Biceps brachii –
long head
- short head
Supraglenoid
tubercle of
scapula +
glenoidlabrum
(lh)
Coracoid process
(sh)
Radial tuberosity Shoulder flexion,
elbow flexion &
forearm
supination
Musculocutaneo
us nerve
Name Origin Insertion Action Innervation

46. Muscles – Triceps Brachii
Triceps brachii
-long head
-lateral head
-medial head
Infraglenoid
tubercle (long)
Above spiral
groove (lateral)
Distal to spiral
groove (medial)
Olecranon
process
Long head: sh
adduction
All: elbow E
Radial nerve
Name Origin Insertion Action Innervation

47.  The rotator cuff muscles (supraspinatus, infraspinatus, teres
minor and subscapularis) help to stabilize the humeral head
in the glenoidfossa, plus have roles in shoulder rotation
Rotator Cuff Muscles

48. Muscles - Supraspinatus
Name Origin Insertion Action Innervation
Supraspinatus Medial 2/3
supraspinousfoss
a
Greater
tuberosity
Shabd + dynamic
stability
Suprascapular
nerve

49. Muscles - Infraspinatus
Infraspinatus Medial 2/3
infraspinousfoss
a
Greatertuberosit
y
Sh ER + dynamic
stability
Suprascapular
nerve
Name Origin Insertion Action Innervation

50. Muscles – Teres Minor
Teres minor Upper 2/3 lateral
border of scap
Greater
tuberosity
Sh ER +/-
adduction, +
dynamic stability
Axillary nerve
Name Origin Insertion Action Innervation

51. Muscles - Subscapularis
Subscapularis Medial 2/3
subscapularfossa
Lessertuberosity Sh IR +/-
adduction
Upper & lower
subscapular
nerves
Name Origin Insertion Action Innervation

52. BLOOD SUPPLY

53.  Anterior circumflex
humeral vessels
 Posterior circumflex
humeral vessels
 Suprascapular vessels
 Subscapular vessels

54. NERVE SUPPLY

55.  Axillary nerve
 Suprascapular nerve
 Musculocutaneous nerve

56. Gateways to the Posterior Scapular Region
1. Suprascapular Foramen
2. Quadrangular Space
3. Triangular Space
4. Triangular Interval

57. Gateways to the Posterior Scapular Region
Suprascapular Foramen
It is formed by suprascapular notch of scapula and the
superior transverse scapular ligament,which converts the
notch into a foramen.
The suprascapular nerve passes trough the suorascapular
foramen

60. Gateways to the Posterior Scapular Region
Quadrangular Space
Its boundaries are formed by:
The inferior margin of the teres minor
Surgical neck of humerus
The superior margin of the teres major
Lateral margin of the long head of triceps brachii.
Axillary nerve and posterior circumflex humeral artery
and vein pass trough this space

63. Gateways to the Posterior Scapular Region
Triangular Space
Its boundaries are formed by
The medial margin of the long head of triceps brachii
The superior margin of the teres major
The inferior margins of the teres minor
The circumflex scapular artery and vein pass trough this
space

66. Gateways to the Posterior Scapular Region
Triangular Interval
Boundaries are formed by
The lateral margin of the long head of triceps brachii
The shaft of the humerus
The inferior margin of the teres major
Radial nerve,profunda brachii artery and associated veins
pass trough it

69. Movements

70. The muscles and joints of the shoulder allow it to move
through a remarkable range of motion,
 Arm flexion(0-135*)
 Arm extention(45°-60*)
 Arm abduction (0-180*)
 Arm adduction
 Medial rotation of the arm (90°)
 Lateral rotation of the arm(0-90*)
 circumduction (this is a combination of the above
movement)

71. MOVEMENTS MAIN MUSCLE ACCESSORY MUSCLE
FLEXION
0-135*
PECTORALISMAJOR(clavicular part)
DELTOID ant fibres
Coracobrachialis
Biceps short head
EXTENSION
45-60*
DELTOID post fibres
LATISSMUS DORSI
Teres major
Triceps long head
P major[sternocoastal head]

72. ADDUCTION PECTORALIS MAJOR
LATISSMUS DORSI
BICEPS long head
TRICEPS short head
Teres major
coracobrachialis
ABDUCTION SUPRASPINATUS[0-15*]
DELTOID[15*-90*]
SERRATUS ANTERIOR[90*-180*]
TRAPEZOIDupper,lower fibres[90-
180]
MOVEMENTS MAIN MUSCLE ACCESSORY MUSCLE

73. MEDIAL
ROTATION
[INTERNAL]
90*
PECTORALIS MAJOR
DELTOID ant fibres
LATISSMUS DORSI
TERES MAJOR
subscapularis
LATERAL
ROTATION
[EXTERNAL]
70*-90*
DELTOID posterior fibres
INFRASPINATUS
TERES MINOR
MOVEMENTS MAIN MUSCLE ACCESSORY MUSCLE

74. CIRCUMDUCTION
• Combination
of different
movements,
results in hand
moving along a
circle.