• "...by Magee" (Orthopedic Physical Assessment by Magee?)
• "...by manual therapy"
• "...by MRI"
• "...by markers" (motion analysis/gait markers?)

Figure 8-16: Triceps & Biceps Passive/Active Tension

Figure A - Long Head of Triceps (Passive Tension)

• The long head of triceps crosses both the shoulder and elbow joints
• When the elbow is passively flexed, the triceps is stretched over both joints simultaneously
• This limits elbow flexion range - you can't fully flex the elbow if the shoulder is already extended (the muscle runs out of length)

Figure B - Long Head of Biceps Brachii (Active Tension)

• The biceps also crosses both shoulder and elbow
• When it contracts over both joints, it becomes excessively shortened
• This reduces its active force production during elbow flexion - it's too short to generate full tension efficiently
• This is the concept of active insufficiency (two-joint muscle shortened at both ends)

Text Content: Elbow Stability

At Full Extension:

At 90° Flexion:

• Osseous structures provide the majority of varus stress resistance
• The anterior MCL becomes lax if overstretched → leads to medial instability
• Joint capsule contributes little to distraction resistance at 90°

Close-Packed Position:

• At full extension, the humeroulnar joint is in close-packed position
• Bony contact of olecranon in olecranon fossa = end of extension range

Case 8-4: Swelling (James's Elbow)

• Patient holding elbow in slight flexion due to pain from intra-articular fluid
• ~80° flexion = position of least joint capsule tension = most comfortable position for swelling
• Key teaching point: patients with joint swelling naturally adopt the position of least capsular stretch

Muscle Action Factors (bottom of page):

• Number of joints crossed (one-joint vs two-joint muscles)
• Physiological cross-sectional area (PCSA) - determines force-generating capacity

1. Passive insufficiency = two-joint muscle too tight to allow full ROM (Figure A - triceps limiting flexion)
2. Active insufficiency = two-joint muscle too short to generate force (Figure B - biceps during flexion)
3. Close-packed = full extension for the elbow
4. 80° flexion = resting/comfort position when joint is swollen

What's Inside (8 Sections):