Costochondritis
Description
- Inflammation of costochondral or costosternal junctions.
Epidemiology
- More common in younger female patients.
Presentation
- Sharp, positional chest pain that may worsen with deep inspiration.
- Focal tenderness to chest palpation (characteristic sign of costochondritis 🆚 differential diagnosis).
Differential Diagnosis
- Myocardial infarction
- Pulmonary embolism

De Quervain Tenosynovitis
Description
- Noninflammatory thickening of the abductor pollicis longus and extensor pollicis brevis tendons.
Presentation
- Pain or tenderness at the radial styloid.
- Positive Finkelstein test→ pain at radial styloid with active or passive stretch of thumb tendons.
Risk Factors
- New mothers (lifting baby)
- Golfers
- Racquet sport players
- “Thumb” texters.

De Quervian tendonopathy.mp4
Dupuytren Contracture
Description
- Fibroblastic proliferation and thickening of the superficial palmar fascia.
Common Location
- Typically involves nodules at fascia of the base of the ring and little fingers that may evolve into fibrotic chords.
Etiology
- Unknown.
- Thought to be due to overstimulation of WNT signaling pathway.
Epidemiology
- Most frequently seen in males > 50 years old of Northern European descent.


Flexion contracture of the small fingers
Ganglion Cyst
Description
- Fluid-filled swelling overlying joint or tendon sheath.
Common Location
Pathophysiology
- Mucoid degeneration of periarticular tissue
- Mucinous fluid collects via a 1-way valve mechanism due to repetitive movement
Presentation
- Usually painless but can cause mild aching or compressive symptoms
- Smooth, rubbery, round structure that overlies a joint or tendon & Transilluminates (🆚tumors, lipoma; lack Transillumination)
Prognosis
- Usually resolves spontaneously.

Lipoma
Definition
- Very common, benign tumors that arise from the subcutaneous fat.
Presentation
- Single or multiple round, soft, rubbery mobile, discrete nodules or masses
- Typically on the trunk, neck, and/or extremities
- Slow-growing
- Typically nontender and asymptomatic
Histopathology
- Normal mature adipocytes of mesenchymal origin
- Fibrous capsule


Iliotibial Band Syndrome
Description
- Overuse injury of the lateral knee.
Epidemiology
- Common in runners (repetitive flexion and extension of the knee )
Cause
- Pain in the lateral knee occurs due to friction of iliotibial band against the lateral femoral epicondyle.

Limb Compartment Syndrome
Pathophysiology
- Increased pressure within the fascial compartment of a limb→ Venous outflow obstruction and arteriolar collapse→ anoxia, necrosis, rhabdomyolysis→ acute tubular necrosis.
Causes
- Significant long bone fractures (e.g., tibia)
- Reperfusion injury
- Animal venoms.
Diagnosis
- Lab values
- ↑ serum creatine kinase
- Presentation
- Severe pain and tense, swollen compartments
- Passive stretch of muscles in the affected compartment.
- Motor deficits→ late signs of irreversible muscle and nerve damage.
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5 P’s of acute limb ischemia: Pain, pallor, paresthesia, pulselessness, paralysis.
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Management
- surgical decompression (fasciotomy)

**Compartment syndrome of the lower leg**

Important to memorize components of each compartment
Medial Tibial Stress Syndrome (Shin splints)
Definition
- Exercise-induced pain along the posteromedial border of the tibia
Epidemiology
- Common in runners and military recruits.
Pathophysiology