Functional Anatomy Review of the Shoulder Complex

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Objectives

• Review specific functional anatomy of the shoulder complex.

• Understand the biomechanics of the shoulder complex.

• Identify sources of pain• Not all anatomical illustrations are

completely accurate

General Principles of the Shoulder

• Shoulder is complex• Cuff insertion is anterior• Cuff is always activated• Tendon of cuff is less

vascular• Small muscle for long

lever arm = mechanical disadvantage

• Many other structures can affect the shoulder (ie neck and scapula)

Roof and Floor

RoofFloor

Functional Anatomy of the Shoulder Complex

• 25%-30% of the humerus contacts the glenoid.

• Glenoid is shallow • Why is there an

unstable bony configuration?

• Muscular activity is very important

Superficial MusclesHow often do you see a tear of

these?

Bony Shoulder Anatomy

Bony Posterior Shoulder Anatomy

Anterior Orientation

Muscles - Dynamic Stabilizers

Capsular Tissue

Cuff/Capsule

Capsule

Capsule

Biceps Tendon

• Can be both intra-articular and extra-articular

• Long head depresses humerus

• Long head tears more

Biceps-Labrum

A-C Joint

Tender A-C jointHorizontal adduction painfulPain and swellingDegenerates quicklyCuff path. vs. A-C jt. degen.Spurs can sever the cuff.

A-C Joint

Spur

Vascularity

Angle of Inclination

Rotator Cuff Position

Posterior Capsule

• Thin• Close assoc. with cuff.• Contract cuff=

tightening of capsule• Tight posterior cuff

can cause impingement at the subacromial space

• Demo.

Coracohumeral Ligament

Suspends humerus.Little function.Thoracic kyphosis increase laxity = cuff works harder

R-C Function (cont.)

Compresses the G-H joint.ElevatesIR & ERAccelerates and decelerates the arm

Hammock Effect

Inverted Hammock

Humeral Head Depression

Massive Rotator Cuff Tear

Neuromuscular Inhibition

Pain Swelling

Instability

Functional Stability of the Shoulder

Shoulder Knee

Dynamic Stability Static

Stability

omuscular Component