• Fibro-cartilagenous rim
• Triangular in cross section
• Attach to peripheral margin of glenoid cavity
except above .
• Deepens the glenoid fossa and forms pliable
cushion for ball to roll.
Relations of joint
• Above- Deltoid, supraspinatus, Subacromial
bursa ,and coraco-acromial arch.
• Below-Quadrangular space transmitting axillary
nerve and posterior circumflex humeral
vessels,long head of triceps.
• In front-Subscapularis,coracobrachialis and
short head of biceps .
• Behind-Infraspinatus and teres minor.
• Within capsule-long head of biceps.
• Deltoid muscle covers the joint in front ,behind
and short head of
• Teres minor
1. the long head of
2. the axillary
3. the posterior
Factors maintaining stability
of shoulder joint
• The glenoid labrum deepens the socket.
• Supraspinatus,tension of upper part of the
capsule and coraco-humera ligament prevent
• Tendons of subscapularis, supraspinatus,
infraspinatus and teres minor blend with fibrous
capsule form the musculo-tendinous rotator cuff
act as gardian of the joint.
• The long head of biceps and coracoacromial
arch prevents upward dislocation of the
BURSAE IN RELATION TO
• Communicating-Subscapular bursa
• Noncommunicating –
-subacromial-largest bursa of the body.
-Above acromian process
-Between capsule and coracoid process
-Between teres minor and long head of triceps
-In front and behind the tendon of latissimus
Blood supply and Nerve
• Vascular supply -
Anterior and posterior circumflex humeral,
suprascapular and circumflex scapular vessels.
• Nerve supply-
The capsule is supplied by the suprascapular
nerve (posterior and superior parts), axillary
nerve (anteroinferior) and the lateral pectoral
• Out of total 180 degree elevation, humerus move
120 degree at shoulder joint and the remaining 60
is done by the scapula at the joints of shoulder
• Supraspinatus initiate the abduction upto15 degree
• Further 15 to 90 degree abduction is done by Deltoid
• Infraspinatus and Teres minor rotate the humerus
laterally to overcome the impindgement of greater
tubercle against coraco-acromial arch.
• Contraction of upper and lower fibres of Trepizius and
lower five digitations of Serratus anterior rotate the
scapula and assist the abduction.
• Middle fibres of trepizius stabilize the scapula during
• 55 degrees
• Muscles Involved:
This is a movement in
which the distal end
of the humerus
moves in circular
motion while the
proximal end remains
• It is formed by
DISLOCATIONS OF THE
• The shoulder joint is the
most commonly dislocated
• Sudden violence applied to the
humerus with the joint fully
abducted pushes the humeral
head downward onto the
inferior weak part of the
capsule, which tears, and the
humeral head comes to lie
inferior to the glenoid fossa.
• A subglenoid displacement of
the head of the humerus into
the quadrangular space can
cause damage to the axillary
• This is indicated by paralysis
of the deltoid muscle and
loss of skin sensation over
the lower half of the deltoid.
• Downward displacement of the
humerus can also stretch and
damage the radial nerve.
Rotator cuff tendonitis
• Lesions of the rotator cuff are a
common cause of pain in the
• Excessive overhead activity of
the upper limb may be the cause
of tendinitis, although many cases
• During abduction of the shoulder
joint, the supraspinatus tendon is
exposed to friction against the
• Under normal conditions the
amount of friction is reduced to a
minimum by the large
subacromial bursa, which
extends laterally beneath the
• Degenerative changes in the bursa are followed by
degenerative changes in the underlying supraspinatus
tendon, and these may extend into the other tendons of
the rotator cuff.
• Clinically, the condition is known as subacromial
bursitis, supraspinatus tendinitis, or pericapsulitis.
• It is characterized by the presence of a spasm of pain
in the middle range of abduction when the diseased
area impinges on the acromion.
RUPTURE OF THE SUPRASPINATUS TENDON
In advanced cases of rotator cuff
tendinitis, the necrotic supraspinatus
tendon can become calcified or rupture.
Rupture of the tendon seriously
interferes with the normal abduction
movement of the shoulder joint.
The main function of the supraspinatus
muscle is to hold the head of the
humerus in the glenoid fossa at the
commencement of abduction.
The patient with a ruptured
supraspinatus tendon is unable to
initiate abduction of the arm.
However, if the arm is passively
assisted for the first 15° of abduction,
the deltoid can then take over and
complete the movement to a right
Shoulder joint pain
• The synovial membrane, capsule,
and ligaments of the shoulder joint
are innervated by the axillary
nerve and the suprascapular
• The joint is sensitive to pain,
pressure, excessive traction, and
• The muscles surrounding the joint
undergo reflex spasm in response
to pain originating in the joint,
which in turn serves to immobilize
the joint and thus reduce the pain.
• Injury to the shoulder joint is
followed by pain, limitation of
movement, and muscle atrophy
owing to disuse.