Download MBBS Anatomy PPT 103 Shoulder Joint Notes

Learning objectives

?Anatomy of shoulder joint

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?Formation , type & components

?Rotator cuff

?Relations /nerve & blood supply

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?Movements & muscles producing them

?Dislocations /nerve injuries

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Articulation - Rounded head of humerus &

Shallow , glenoid cavity of scapula.

Glenoid

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cavity


? Articular surfaces are covered by articular - hyaline cartilage.
? Glenoid cavity is deepened by fibro cartilaginous rim called glenoid labrum.

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Synovial membrane

?lines fibrous capsule & attached to

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margins of the cartilage covering the
articular surfaces.

?forms a tubular sheath around the

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tendon of the long head of biceps brachii.

?It extends through anterior wall of

capsule to form subscapularis bursa

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beneath subscapularis muscle.


Synovial membrane

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Musculotendinious/Rotator cuff

?Supraspinatus ? superiorly

?Infraspinatus & Teres minor- posteriorly

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?Subscapularis ? anteriorly
?Long head of triceps ? inferiorly ( axillary n &

post circumflex humeral artery ? lax and least
supported) ?

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?most common dislocations ? Inferiorly axillary n

palsy ?loss of abduction

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NERVE SUPPLY of Shoulder joint

NERVE SUPPLY of Shoulder joint

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1. axillary n 2. suprascapular n &
3. lateral pectoral nerve.


Shoulder joint - spaces

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Quadrangular space

Triangular space

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?Sup - teres minor

?Sup ? teres major

?Inf - teres major

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?Medially- long head

?Medially - long head of of triceps

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triceps

?Laterally ?

?Laterally ? lateral head triceps(humerus)

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of triceps (humerus)

?

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?Contents ? in spiral

Contents ? axillary

groove Radial nerve

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nerve & posterior
circumflex humeral

& profunda brachii

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artery

artery

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Shoulder Joint -

Upper Limb

Dr Brijendra Singh

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Prof & Head

Department of Anatomy

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AIIMS Rishikesh


Shoulder joint -movements:

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? Flexion

?

Abduction

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?

Lateral

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? Extension

?

Circumduction

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rotation

?

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Medial
rotation


Flexion - 90?

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1. Deltoid - ant
2. Pectoralis major
3. Biceps brachii
4. Coracobrachialis

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Extension is - 45?
?Deltoid post

?Latissimus dorsi

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?Teres major


Abduction:

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?Initiated - supraspinatus 0 to 18

?19 120 - middle fibers of deltoid.

?Subscapularis

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?Infraspinatus

?Teres minor

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?Above 90 by rotation of scapula

?Trapezius & Serratus Anterior

?Supraspinatus: initiates abduction(0 to 15) and

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holds the head of the humerus against glenoid
fossa of scapula;

?Latter function of supraspinatus allows deltoid

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muscle to contract and abduct humerus at
shoulder joint.

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Adduction:
Normally upper limb
can be swung 45?
across front of chest.

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?pectoralis major

?latissimus dorsi

?teres major

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?teres minor

Lateral rotation
Is about 40 - 45?.

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POST -

?infraspinatus

?teres minor

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?posterior fibers of

the deltoid muscle

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19


Medial rotation:
?Normal medial rotation is

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about 55?.

?performed by : muscles

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attached at BG - ANT


?pectoralis major

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?Subscapularis

?latissimus dorsi

?teres major

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?anterior fibers of deltoid.

Circumduction:

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This is a movement

in which distal end

of humerus moves

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in circular motion

while proximal end

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remains stable.

?It is -
1.Flexion,
2.Abduction,

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3.Extension &
4.Adduction

Successively

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2.

the axillary
nerve

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3.

the posterior
circumflex humeral

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vessels

Inferiorly:

1.

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the long head of
the triceps muscle

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Stability of the shoulder joint
?This joint is unstable because of :

? shallowness of glenoid fossa

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? weak ligaments

?Its strength almost entirely depends on tone of

rotator cuff muscles.

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?Tendons of these muscles are fused to

underlying capsule of shoulder joint.

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?Least supported part of joint lies in inferior

location, where it is unprotected by muscles.

Wrist drop

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? A subglenoid displacement of the head of the humerus into the quadrangular

space can cause damage to the axillary nerve.

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? 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

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radial nerve.


?A subglenoid displacement of head of

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humerus into quadrangular space can
cause damage to axillary nerve.

?This is indicated by paralysis of the

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deltoid muscle and loss of skin
sensation over lower half of the deltoid.

?Downward displacement of humerus

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can also stretch and damage radial
nerve.

Shoulder pain

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27


Branches from 1st part of subclavian artery

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? suprascapular artery,

(branch from 1st part of
subclavian artery)

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distributed to supraspinous
and infraspinous fossae of
scapula.

? superficial cervical artery,

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which gives off a deep
branch that runs down
medial border of scapula.

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Branches from 3rd part of axillary artery

? subscapular artery and its

circumflex scapular branch

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supply subscapular and
infraspinous fossae of scapula.

? anterior & posterior circumflex

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humeral artery.

? Both circumflex arteries form

an anastomosing circle around

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surgical neck of the humerus.