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The Shoulder Complex

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Complicated Region of the Body.

Bones: Clavicle: “S” shaped

Vulnerable to injury Scapula:

flat and triangular Humerus:

spherical

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Scapula and the HumerusScapula and the Humerus

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Articulations: Sternoclavicular Joint Acromoclavicular Joint Glenohumeral Joint Scapulothoracic Joint

Ligaments Sternoclavicular Acromioclavicular

Anterior, posterior, superior, inferior portions Coracoclavicular ligament which is divided into two other

ligaments. Glenohumeral

Surrounded by a capsule Reinforced by the superior, middle, and inferior GH

ligament and a tough coracohumeral ligament

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MUSCULATURE

Two Groups in GH Joint Produce dynamic motion and establish stability to

compensate for arrangement of bone and ligaments for a great deal of mobility

• Originate on the axial skeleton – attach to humerus Latissiumus dorsi & pectoralis major

• Originate on the scapula – attach to humerus Deltoid, teres major, coracobrachialis

• Other Muscles: Subscapularis, Infraspinatus, Teres Minor, Supraspinatus Short rotator muscles Triceps and Biceps

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Rotator Cuff Muscles

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SCAPULAR MUSCLES

Third group of muscles Attaches axial skeleton to scapula

Levator scapula Trapezius Rhomboids Serratus anterior and posterior

Provide dynamic stability to shoulder complex

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Scapular Muscles

levator scapulaedeltoid

infraspinatusteres minorteres major

levator scapulaeinfraspinatusteres major

supraspinatusteres minor

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Bursae Subacromial Bursa

Most important Easily subjected to trauma when the humerus is in the

overhead position• compresses

Nerve Supply Cervical Vertebrae (C5 – C6, & T1)

Blood Supply Subclavian artery Becomes the Brachial artery just after the 1st rib

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Bursae, and Nerve Supply

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BLOOD SUPPLY

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FUNCTIONAL ANATOMY

Movement of the shoulder is critical to maintain the positioning of the humeral head relative to the glenoid.

Helps control humeral head movement Rotator Cuff contraction, they dynamically

tighten the capsule Helps center the humeral head relative to the glenoid.

Crucial with ANY over head activity Scapulohumeral Rhythm

As humerus elevates to 30’ no movement 30-90’ scapula abducts & upwardly rotates 180’ humeral abduction & sternoclavicular jt. moves

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RECOGNITION OF SPECIFIC INJURIES Fractures:

Acromioclavicular (common) Caused by outstretched arm, fall on the tip of shoulder, direct impact Athletes usually supports the fx’d. side, tilts head and chin to opposite

side Deformity, pain, swelling

Scapular (infrequent) Direct impact, or when force is transmitted through humerus to

scapula Pain with movement

Humeral Shaft- (occasionally)

• Direct blow, fall on the arm• Comminuted or transverse with deformity due to muscular pull

Proximal – dangerous to nerves and blood supply• Direct blow, dislocation, impact received by falling on an outstretched arm

Head of humerus (Epiphyseal fx)• Occur in ages 10 or younger• Direct blow or indirect blow• Difficult to recognize

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Fracture of ClavicleFracture of Clavicle

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Humeral shaft, Proximal & Epiphyseal

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Injuries ContinuedInjuries Continued

Sprains Sternoclavicular (uncommon)

Initiated by a direct force transmitted through the humerus

Acromioclavicular Extremely vulnerable especially in collision sports Direct impact to the TIP of the shoulder that forces

the acromion process downward, backward, and inward

• The clavicle is pushed down against the rib cage

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Rockwood’s Classification of AC SprainsRockwood’s Classification of AC Sprains

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Sternoclavicular & Acromioclavicular Sternoclavicular & Acromioclavicular SprainsSprains

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DISLOCATIONSDISLOCATIONS

Account for 50% of all dislocations Two Types

Anterior• Most common• Direct impact to the posterior aspect of shoulder

Forced abduction, external rotation, and extension that forces the humeral head out (arm tackle)

• Bankart’s Lesion (Labrum tear)• Hill Sachs Lesion (creates a divot in humeral head)• Slap Lesion (injury to labrum and long head of biceps)

Posterior• Account for 1 – 4.3%• Extremely Rare• Forced Adduction and Internal rotation of shoulder or fall on an

extended internally rotated arm

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DislocationsDislocations

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Impingements Involves mechanical compression of

Supraspinatus tendon, subacromial bursa, and long head of biceps tendon

Related to shoulder instability and overhead activities Failure of RC muscles to maintain position

Bursitis Overuse Chronic Inflammation

Biceps Brachii Ruptures Caused by powerful concentric & eccentric contraction

Occurs near the origin of muscle Athlete will hear a “SNAP”, then feels sudden intense pain

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Biceps Tendon RuptureBiceps Tendon Rupture

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Throwing MechanicsThrowing Mechanics

Consists of 5 Phases

Windup or Preparation 1st movement until ball leaves glove Lead leg strides forward Both shoulders abduct, externally rotate and horizontally rotate

Cocking Begins when hands separate Ends when Maximum external rotation of humerus has ocurred Lead foot touches ground

Acceleration Lasts from Maximum external rotation until ball release Humerus abducts, horizontally abducts, and internally rotates Scapula elevates, abducts, and rotates upward

Deceleration From ball release until Maximum shoulder internal rotation External rotators of the RC muscles contract eccentrically (lengthening) to decelerate

the humerus Rhomboids contract eccentrically to decelerate the scapula

Follow-through From Maximum shoulder internal rotation until the end of motion When athlete is in balanced position

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Phases of ThrowingPhases of Throwing

www.chrisoleary.com/projects/Baseball/Pitchin...

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Nolan Ryan & Jake PeavyNolan Ryan & Jake Peavy

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Randy JohnsonRandy Johnson