THENAR SPACE OF HAND:
The arrangement of fascia and fascial septa in hands is such that many spaces are formed
like thenar space of hand
FEATURES:
SHAPE – Triangular
SITUATION – under the outer half of the hollow palm
EXTENT:
a. PROXIMAL – Distal margin of flexor retinaculum
b. DISTAL - Proximal transverse palmar crease
COMMUNICATIONS:
a. PROXIMAL – Forearm space of Parona.
b. DISTAL - Fascial sheath of first lumbrical
BOUNDARIES:
ANTERIOR:
➢ Short muscles of thumb
➢ Flexor tendons of the index finger
➢ First lumbrical
➢ Palmar aponeurosis
POSTERIOR: Transverse head of adductor pollicis
LATERAL: Tendon of flexor pollicis longus and lateral palmar septum
MEDIAL: Intermediate palmar septum
CONTENTS:
• Short muscles of thumb
• Palmar aponeurosis
• Flexor tendons of index finger with first lumbricals
• Transverse head of adductor policis
• Flexor pollicis longus tendon
APPLIED ANATOMY:
• This space is of surgical importance as they may become infected and distended with
pus.
• Incision to drain the pus: Incise in the first web posteriorly
THENAR MUSCLES:
ABDUCTOR POLLICIS BREVIS:
ORIGIN – Tubercle of scaphoid and Crest of trapezium and Flexor retinaculum
INSERTION - Base of proximal phalanx of thumb in its lateral side
NERVE SUPPLY- Median nerve
ACTION – Abduction of thumb
FLEXOR POLLICIS BREVIS: Arises by two heads.
ORIGIN -Superficial head: Flexor retinaculum & Crest of trapezium
DEEP: Capitate and trapezoid bone
INSERTION-base of proximal phalanx of thumb on its lateral side
NERVE SUPPLY- Median nerve
ACTION- Flexes metacarpal joint of thumb.
OPPONENS POLLICIS:
ORIGIN- Flexor retinaculum and Crest of trapezium
INSERTION-Base of proximal phalanx of thumb on its medial aspect
NERVE SUPPLY- Median nerve
ACTION – Pulls thumb medically and forward across palm, that is opposing thumb
towards the finger
APPLIED ANATOMY:
• Damage to median nerve impairs the action of thenar muscles as thenar muscles are
solely supplied by median nerve
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