The Shoulder and Scapula

Shoulder Joint

glenohumeral joint; very mobile

Sternum

sterno-clavicular joint (only bony attachment of girdle to torso)

Scapula

-spine of scapula

-acromium process (most lateral)

-coracoid process (anterior)

-glenoid fossa (shoulder socket), almost flat; has glenoid labrum that will deform with stress; good for mobility but can tear

-does not attach to ribs or back; floating on the ribcage; supported by muscles

Humerus

head of the humerus- small; does not fit tight within the glenoid fossa

Bones of the Shoulder Girdle

sternum, clavicle, scapula, humerus

Possible Actions of the Scapula

-elevation

-depression

-abduction (protraction)

-adduction (retraction)

-upward rotation

-downward rotation

-forward tilt

-return from forward tilt

Possible Actions of the Shoulder

-Sagittal Plane: flexion (180 degrees to your ear), extension (to 0 degrees), hyperextension (about 45 degrees)

-Frontal Plane: abduction (180 degrees but must outwardly rotate humerus to not hit acromion), adduction (movement of arm to your side)

-Transverse Plane: inward (internal) rotation (60-80 degrees), outward (external) rotation (80-90 degrees)

-Combination: horizontal flexion (flexion + aDDuction), horizontal extension (extension + aBDuction)

Scapulohumeral Rhythm

-shoulder and scapular movement are “integrally tied” to each other; one affects the other

-to obtain full range in shoulder movement the scapulae also most move

Rules of Association

-when the humerus is more than 2-3 degrees away from a position of extension, the scapula is upwardly rotated, except then the shoulder joint is hyperextended and adducted, the scapula is downwardly rotated

-when the humerus is anterior to the frontal plane bisecting the shoulder joint, the scapula is abducted

-when the humerus is posterior to the frontal plane bisecting the shoulder joint, the scapula is adducted

-when the shoulder is hyperextended, with inward rotation, the scapula is forward tilted

-ALWAYS ANALYZE THE SHOULDER ACTIONS FIRST TO APPLY THE RULES OF ASSOCIATION!

Muscles of the Scapula

-rhomboids: major/minor

-levator scapulae

-pectoralis minor

-serratus anterior

-subclavius

-trapezius

Rhomboids

adduction, elevation, downward rotation

Levator Scapulae

elevation, assists in adduction and downward rotation

Pectoralis Minor

forward tilt, assists in depression and abduction

Serratus Anterior

abduction, lower fibers upwardly rotate

Subclavius

depression, may assist with forward tilt and abduction (slightly)

Trapezius

adduction and upward rotation

-upper: elevate, upward rotate, adduct

-middle: adduct

-lower: adduct, upward rotation, depression

Upper Back Tension

shoulder down dilemma: co-contraction of the elevators (upper trapezius and depressors (low traps, pectoralis minor, subclavius)- this does not allow scapulae to upwardly rotate when arms go up in frontal or sagittal plane and creates tension

Pectoralis Minor Syndrome

can be caused by the “shoulders down dilemma”; referred pain in rhomboids and neck, possible numbness in fingers due to tightness of pectoralis minor

Muscles that Move the Shoulder

-pectoralis major

-latissimus dorsi

-teres major and minor

-infraspinatus & supraspinatus

-deltoids: anterior/middle/posterior

-subscapularis

-coracobrachialis

-biceps brachii

-triceps brachii (longhead)

Pectoralis Major

-upper: flexion, adduction, inward rotation

-middle: adduction, inward rotation, horizontal flexion

-lower: extension, adduction, inward rotation

-all: horizontal flexion, inward rotation

Latissimus Dorsi

extension, adduction, inward rotation, horizontal extension only with inward rotation

Teres Major

extension, adduction, inward rotation, assist with horizontal extension only with inward rotation

Teres Minor

extension, adduction, outward rotation, horizontal extension when the shoulder is outwardly rotated

Infraspinatus

extension, adduction, outward rotation, horizontal extension when the shoulder is outwardly rotated

Deltoids

-anterior: flexion, adduction, inward rotation, horizontal flexion

-middle: abduction

-posterior: extension, outward rotation, adduction, horizontal extension

-all: abduction

Supraspinatus

abduction (synergistic with middle deltoid)

Subscapularis

inward rotation, assists with horizontal flexion and adduction

Coracobrachialis

flexion, adduction, horizontal flexion

Biceps Brachii

-long head: flexion, assists in abduction; originates above glenoid cavity

-short head: flexion, assists in adduction, and horizontal flexion; originates at coracoid process

Triceps Brachii-Long Head:

extension, adduction; originates below glenoid fossa

Rotator Cuff Muscles

-teres minor, infraspinatus, supraspinatus, subscapularis

-muscles responsible for stabilizing the very shallow glenohumeral joint

-need to be balanced in strength and flexibility

Shoulder Problems

dislocations common at the front high diagonal (3/4 flexed), requires strong latissimus dorsi and teres major

Conditioning

necessary for lifting, partnering, and inversions

“Itis”

bicipital tendonitis (inflammation of long head of biceps at bicipital groove), bursitis of the anterior deltoid bursa

Principles of Lifting

1) start with and maintain good alignment

2) lower your own center of gravity before lifting

3) apply as much force as possible with your legs

4) apply the force at the lifted dancer’s center of gravity

5) apply force in a vertical direction

6) keep the lifted dancer’s center of gravity over your own base of support

Why do injuries occur?

-technique adaptations: poor posture, poor muscle control, decreased flexibility, compensation (learned behaviors)

-nutrition: calcium/vitamin D (bone health), fad diets (can lack essential nutrients), good carbs (need whole grains and fiber), good proteins (leaner white meat, turkey, chicken), good fat (unsaturated, nuts, fish, olive oil), supplements (not regulated so use with caution, vitamins not needed with healthy diet (vitamin D important in colder climates), hydration (water is usually sufficient for rehydration, your body is 70% water, can’t lose much without an effect

-strength/flexibility imbalances

-smoking

-sleep: > 7 hours/night ideal, naps < 60 minutes, sleep debt = intoxication

Concussions

-mild traumatic brain injury: blunt or shear trauma to brain

-symptoms: headache, blurred vision, personality change, nausea, vomiting, amnesia, LOC

-diagnosis: testing by doctor and possible CT scan to check for bleeding

-cervical spine injury: no neck pain is good after trauma

-do not give medication right away, can mask symptoms

-return to activity is individualized based on resolution of symptoms and cognitive recovery

Acute Injuries

-concussions, fracture, dislocation, subluxation, sprains and strains

-pops, snaps, crackles, zings, burning, tingling, numbness

-pain, loss of function, obvious deformity, bleeding, constitutional symptoms (fever nausea, etc)

Chronic Injuries

uncontrolled pain, loss of function, unresolving, new or worsening symptoms

PRICE

P- protection

I- ice

C- compression

E- elevation

R- rest

RICE Research

old research- use ice in first 24-72 hours 20 minutes at a time no more than once per hour to reduce swelling and inflammation

new research- ice can slow metabolic processes and nerve conduction velocity impeding inflammatory process

PRICE Protection/Prevention

-protection: taping, wrapping, bracing, walking boot, crutches, wheelchair, etc

-prevention: balanced strength/flexibility, cross-train, efficient alignment