Structures of the Hand Flashcards
What is the palmar aponeurosis
Palmar fascia made of fibrous connective tissue that thickens in the centre of the hand
What is the palmar aponeurosis continuous with
Palmaris longus tendon
Flexor retinaculum
What does the palmar aponeurosis do
Protects underlying muscle compartments
What are the fibrous digital sheaths
Extensions of the palmar aponeurosis
Cover the synovial sheaths in the digits and keep them in place
What do the synovial sheaths of the fingers contain
Flexor tendons
What is the extensor retinaculum
Thickening of fascia on dorsum of hand
Keeps extensor tendons in position and prevents bowstringing
What are palmar plates
Present on palmar side of each MCP and IP joint
Limit hyperextension of digit
Enhances stability
Where are the collateral ligaments of the fingers
Medial and lateral sides of each MCP and IP joint
What do collateral ligaments of the fingers do
Taut when fingers flexed, limiting abduction
Lax when fingers extended, allowing abduction
Which tendons allow flexion of the fingers
Flexor digitorum profundus
Flexor digitorum superficialis
Where do the flexor tendons pass (FDP & FDS)
Through carpal tunnel
Enter hand where they are protected by common flexor sheath
Enter fingers in digital synovial sheaths
What is the course of FDS in the finger
FDS tendon splits near base of proximal phalanx
Inserts into intermediate phalanx
What is the course of FDP in the finger
Passes through split in FDS and inserts onto distal phalanx
What happens to extensor tendons of fingers as they reach the metacarpals
Flatten and become extensor expansions
Where do the extensor expansions go
Fan out and warp around metacarpal and proximal phalanx, joining onto palmar plate
Spreads out further distally into a median band and two lateral bands
