MSK Shoulder Module 2

Scapation

Arms rotated naturally 30-40 degrees anterior of the frontal plane

Scapulothoracic joint

Not a true joint

• Elevates/depress, ABD/ADD, upward/downward

Sternoclavicular joint

• saddle or ball and socket, triaxial

• elevation, depression, protraction, retraction, posterior rotation, anterior rotation

• only direct bony attachment of the shoulder complex to the axial skeleton

Acromioclavicular joint

Gliding joint, biaxial

• anterior/posterior and superior/inferior gliding

GHJ

• ball and socket, triaxial

• Flex/extend, ABD/ADD, internal and external rotation

adhesive capsulitis

frozen shoulder, thickening and tightening of GHJ capsule that limits mobility

Closed pack of scapula

ABD and external rotation (like washing hair)

open pack of scapula

horizontal ADD (like putting on a seatbelt)

scapular dyskinesis

weakness of muscles that can result in altered resting or active position of the scapula (since the scapula is connected to ribcage via soft tissue)

scapular winging

weak serratus anterior (long thoracic nerve), medial border of the scapula tilts posteriorly away from the rib cage due to the unrestrained dorsal pull of the trapezius

Hemiparesis and how it can impact body

weakness of one side of the body, can strain the joint capsule as the weight of gravity pulls downward without muscle opposition

• Eventually, this pulling elongates ligamentous fibers of the capsule and causes partial dislocation (glenohumeral subluxation)

bicipital tendinitis

• With rotator cuff weakness, the long head of the biceps may become inflamed as it supplies compensatory force for shoulder elevation

Thoracic outlet syndrome

• poor posture and repetive motions

• compression of structures between space between the clavicle and the first ribs

• pain, numbness, and tingling in fingers

Saturday night palsy/crutch palsy

• Loss of triceps and forearm extensors and supinators

• Cannot lift the wrist or fingers

• Radial nerve impairment and compression in the axilla area

When can axillary nerve be impaired

surgical procedures, GH dislocation, fracture of the humeral

Erbs palsy

• injury to the brachial plexus C5-C6 typically occurs during childbirth

• Arm hangs limp, wrist bent, difficulty moving it away from the body

Klumpke’s Palsy

• also during childbirth but lower brachial plexus injury (C8-T1)

• claw hand

Force coupling

Frequent in the shoulder, 2 or more muscles on opposing sides of a joint work together to provide stability and create movement

• Ie. e., the deltoid pulls upward and outward, while the rotator cuff muscles teres minor and infraspinatus pull down

Obligatory external rotation

NEED this for shoulder elevation, at about 90 degrees of elevation, the humerus needs to clear the greater tubercle from hitting the acromion

• prevents subacromial impingement

Open pack of GHJ capsure

• 55 degrees ABD, 30 degrees horrizontal ADD, slight ER

• Less resistance from stabilizing ligaments to enhance mobility

• Would not want to test muscle strength because it is most at risk for dislocation