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Shoulder Joint & Its Applied Anatomy

By

Dr.P.Sasikala



Introduction



Articulation

• Between rounded headof humerus and shallow,pear-shaped glenoidcavity of scapula.

• Articular surface coveredby hyaline articularcartilage.

• Glenoid cavity isdeepened by glenoidlabrum (fibrocartilaginousrim).



Type

• Synovial ball-and-socket joint.

Capsule

• Surrounds joint and attached :

- Medially to the scapula beyond the supraglenoid

tubercle and the margins of the labrum.

- Laterally to the anatomical neck of humerus.

• Thin and lax, allow wide range of movement.

• Strengthened by slips of tendons of subscapularis m.,supraspinatus m., infraspinatus m. & teres minor(rotator cuff muscles).







Ligaments

• Glenohumeral Ligament

- 3 weak bands (superior, middle & inferior) of fibrous tissue thatstrengthen the anterior (front) of capsule.

• Transverse humeral Ligament

- Bridge the upper part of bicipital grooves of humerus (between

greater and lesser tubercles).- Tendon of long head biceps brachii passes deep to it.

• Coracohumeral Ligament

- Stretches from root of the coracoid process of scapula to greatertuberosity of humerus.

- Strength the capsule above.• Coracoacromial Ligament

- Accessory ligament.

- Extends between coracoid process of scapula and acromion.

- Protects the superior aspect of joint.







Bursae Related To The Joint

• Subacromial (Subdeltoid)

bursa• Subscapularis bursa

• Infraspinatus bursa





Synovial Membrane

• Lines capsule and is

attached to the margins of the cartilage covering thearticular surface.

•Extends through theanterior wall of the capsuleto form the subscapularisbursa beneath thesubscapularis muscle.

• Forms tubular sheatharound the tendon of thelong head biceps brachii.





Blood Supply

• Anterior circumflex

humeral vessels

• Posterior circumflex

humeral vessels

•Suprascapular vessels

• Subscapular vessels



-Blood Supply



Nerve Supply

• Axillary nerve

• Suprascapular

nerve

• Musculocutaneous

nerve



Relations • Superiorly

Supraspinatus m.

Subacromialbursa

Coracoacromialligament

Deltoid m.

• Inferiorly

Long head tricepsbrachii m.

Axillary nerve

Post. circumflexhumeral vessels



Relations

Anteriorly

Subscapularis

m.

Coracobrachialis

Short head of

biceps brachii

Deltoid



Relations

PosteriorlyInfraspinatus

Teres minor

Deltoid

Within the jointTendons of long

head biceps

brachii



Movements



• Flexion – Arm moves

forwards &

medially.

• Extension – Arm

moves backwards &laterally.

Flexion & Extension

MAIN ACCESSORYMOVEMENT



• Abduction – Arm

moves away from

trunk.

• Adduction – Arm

moves towards thetrunk.

Abduction & Adduction

MAIN

ACCESSORY

MOVEMENT



• Medial rotation –

Hand moves

medially.

• Lateral rotation –

Hand moveslaterally.

Medial & Lateral Rotation

MAIN ACCESSORYMOVEMENT



• Combination of

dif. movements,

results in hand

moving along acircle.

Circumduction



Applied AnatomyDislocation

is an injury to your joint in which the ends of your bones areforced from their normal positions.

This injury temporarily deforms and immobilizes your joint and

may result in sudden and severe pain.

The shoulder is more prone to dislocate than any other joint.

This due to :• laxity of the capsule

• Disproportionate area of articular surfaces

Occurs when the arm is abducted

3 types of shoulder joints:

• Glenohumeral joint

• Acromioclavicular joint

• Sternoclavicular joint



Applied Anatomy Dislocation of glenohumeral joint

Glenohumeral joint Extremely mobile

Providing wide movement at the

expense of stability

Relatively small bony glenoid cavity

Supplemented by :• Robust fibrocartilagious glenoid labrum

• Ligamentous support

Make it susceptible to dislocation

Divided into :

Anterior dislocation

Posterior dislocation

A li d A t



Applied Anatomy Anterior dislocation

Occurs most frequently.

Usually associated with an isolated traumatic incident.

Clinically, all anterior dislocation are anteroinferior.

Once joint capsule and cartilage disrupted

Joint is susceptible to further (recurrent) dislocation

When dislocation occurs,

During abduction, the head of humerus presses against the lower unsupported partof capsular ligament

Thus, almost always the dislocations primarily subglenoid, later it may becomesubcoracoid, subclavicular or subspinous.

Dislocations ends with :

a) Axillary nerve injured (by direct compression of humeral head on the nerveinferiorly as it passes through quadrangular space)

b) Lengthening effect of humerus may stretch the radial nerve which cause radialnerve paralysis



Applied Anatomy

Occasionally, anteroinferior dislocation associated with

fracture and require surgical reduction.

Posterior dislocation

Rare

Most common cause :

• Extremely vigorous muscle contraction

associated with

An epileptic seizure

caused by

electrocution











Applied Anatomy Fractures of the clavicle and dislocations of the acromioclavicular

and sternoclavicular joints

Its relative size and the potential forces that it trasmits from the upper limb to the trunk, it is not surprising that it is often fractured.

The typical site of fracture is the middle third.

The medial and lateral thirds are rarely fractured.

The acromial end of the clavicle tends to dislocate at the

acromioclavicular joints with trauma

The outer third of the clavicle is joined to the scapula by the conoid

and trapezoid ligaments of the coracoclavicular ligament.

Minor injury,

tends to

Tear the fibrous joint capsule and ligaments of the acromioclavicular

joint

resulting

Acromioclavicular separation on a plain radiograph







Applied Anatomy More severe trauma

disrupt the conoid and trapezoid ligaments of coracoclavicular

ligament

results in elevation and upward subluxation of the clavicle

The typical injury at the medial end of the clavicle is an anterior or posterior dislocation of the sternoclavicular joint.

Importantly, a posterior dislocation of the clavicle may impinge on

the great vessels of the superior mediastinum and compress or

disrupt them.













SHOULDER TIP PAIN

Irritation of the diaphragm from any surrounding pathology

causes referred pain in the shoulder

This is so because the phrenic nerve and supraclavicular

nerves both arise from spinal segment C3,C4

FROZEN SHOULDER / ADHESIVE CAPSULITIS Is a disorder in which capsule and CT surrounding the

glenohumeral joint becomes inflamed and stiff, and grows

together with abnormal bands of tissue, called adhesions,

greatly restricting motion and causing chronic pain

The patient may recover spontaneously in about 2 years





INFLAMMATION OF THE SUBACROMIAL

(SUBDELTOID) BURSA

Subacromial Bursa between supraspinatus and deltoid

muscles laterally and acromion medially

Supraspinatus tendinopathy

-this bursa may become inflamed, making movements of the

glenohumeral joint painful

Treated by injection of corticosteroid





CLINICAL CASE

A 35-year-old baseball pitcher came to the clinic with a historyof a recurrent dislocation of the shoulder. An MRI scan wasperformed to assess the shoulder joint prior to any treatment.

The MRI demonstrates the anatomical structures in multiple planes,

allowing the physician to obtain an overview of the shoulder and toassess any structures that may have been damaged and requiresurgical repair

The MRI findings are typical for an anterior inferior dislocation

These injuries include the abutment of the posterior superior aspectof the humeral head on the anterior inferior aspect of the glenoidcavity



Continued…

• This type of injury (when recurrent) may avulse a small

fragment of the glenoid labrum and some cases this may attach

to a small fragment of bone (the Bankart lesion).

• When the shoulder is relocated, the intergrity of the capsular

atttachment antero-inferiorly has been disrupted and make it

more prone to dislocate

• An arthroscopic repair was performed

(is surgery that uses a tiny camera called an arthroscope to examine or

repair the tissues inside or around shoulder joint. The arthroscope is

inserted through a small incision (cut) in your skin)





Thank You!

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