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carpal tunnel syndrome Cheat Sheet (DRAFT) by

I. Definition & Etiology Definition: Entrapment neuropathy of the median nerve as it passes through the carpal tunnel at the wrist. Most common compressive neuropathy. Carpal Tunnel Anatomy: Floor & Sides: Carpal bones (scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate). Roof: Thick, unyielding transverse carpal ligament (flexor retinaculum). Contents: Median nerve and 9 flexor tendons (4 FDS, 4 FDP, 1 FPL).

This is a draft cheat sheet. It is a work in progress and is not finished yet.

What structures form the carpal tunnel?

Floor & Sides:
8 carpal bones (scaphoid, lunate, trique­trum, pisiform, trapezium, trapezoid, capitate, hamate)
Roof:
Transverse carpal ligament (flexor retina­culum)
Contents:
Median nerve + 9 flexor tendons (4 FDS, 4 FDP, 1 FPL)

Pathop­hys­iology of CTS nerve damage progre­ssion?

Early:­Dem­yel­ination due to ischemia
Late:A­xonal degene­ration
End-st­age­:Fi­brosis of Perine­urium /epine­urium
Common cause: Synovial hypert­rophy of flexor tendons

CTS etiology

1. Idiopa­thic: most common - smaller tunnel, familial
2. Mechan­ica­l/O­ccu­pat­ional: repetitive motions, vibrating tools
3. Systemic condit­ions: DM, hypoth­yro­idism, RA
4. Anatomic anomalies: ganglion, persistent median artery
5. Demogr­aphics: women 3x, >40 years, obesity

What is the normal carpal tunnel pressure?

Normal: 2-10 mmHg
Wrist flexion: Increases 8x
Wrist extension: Increases 10x
Pathol­ogical pressure leads to ischemia and nerve damage
 

systemic conditions associated with CTS

Inflam­matory: Rheumatoid Arthritis, Gout
Metabolic: Amyloi­dosis
Hormonal: Pregnancy
Endocrine: Diabetes, Hypoth­yro­idism, Acromegaly
Other: Psoriatic arthritis, mucopo­lys­acc­har­idoses
 

classic triad of CTS symptoms?

1.Pare­sth­esi­as/­Num­bness : median nerve distri­bution (thumb, index, middle, radial half ring finger)
2. Pain: wrist/­hand, radiating to forear­m/elbow
3. Weakne­ss/­Clu­msi­ness: fine motor tasks, dropping objects