Download Functional Anatomy Review of the Shoulder Complex

Functional Anatomy Review of
the Shoulder Complex
.
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
Roof
Floor
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 Muscles
How 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 intraarticular and extraarticular
• Long head depresses
humerus
• Long head tears more
Biceps-Labrum
A-C Joint
Tender A-C joint
Horizontal adduction
painful
Pain and swelling
Degenerates quickly
Cuff 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.
Elevates
IR & ER
Accelerates 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
Dynamic
Stability
Knee
Static
Stability