Upper limb
Tendon sheath of flexor pollicis longus (Radial bursa)
Vagina tendinis musculi flexoris pollicis longi
- Origin
- Begins approximately 2 cm proximal to the wrist crease in the anterior distal forearm
- Insertion
- Traverses the radial aspect of the carpal tunnel and extends continuously to the distal phalanx of the thumb
- Function
- Provides low-friction synovial gliding and nutrition for the flexor pollicis longus tendon
- Innervation
- Sensory branches from the median nerve
- Movement & chain
- Undergoes extensive excursion during thumb interphalangeal flexion and power pinch
- Palpation
- Palpable along the thenar eminence and palmar aspect of the first ray
- Clinical
- Infectious flexor tenosynovitis of the thumb, trigger thumb, and proximal spread into Parona's space
- Segmental innervation
- C7–C8 spinal segments
- In clinical practice
- Evaluation of Kanavel's 4 signs; emergent surgical incision and catheter irrigation to salvage thumb function
- Region in the model
- Upper limb