Download Flexor retinaculum

Anatomy of
wrist and Hand 2
Assistant professor
Dr. Alaa A. Alharba
Orthopedic &Hand Surgeon
Deep Fascia : of the palm
Is thickened to form the flexor retinaculum and palmar aponeurosis
• Retinaculum:
• It is a specialized thick bands of deep
fascia that hold the long flexor and
extensor tendons in position at the
wrist.
 Flexor retinaculum
 Extensor retinaculum
•
Flexor retinaculum:
It stretches across the
front of the wrist and
convert
the
concave
anterior surface of the
carpal bones into an
osteofascial
tunnel
(
Carpal tunnel), for the
passage of the median
nerve and the flexor
tendons of the thumb and
fingers.
Flexor retinaculum:
• It is attached medially to
the pisiform bone and
hook of the hamate and
laterally to the tubercle of
the scaphoid and
trapezium bone. The
attachment to the
trapezium consists of
superficial and deep parts
and forms a synoviallined tunnel for passage
of the tendon of the flexor
carpi radialis.
• The upper border of the
retinaculum
corresponds to the
distal transverse skin
crease in front of the
wrist and is continuous
with the deep fascia of
the forearm. The lower
border is attached to
the palmar aponeurosis
Carpal Tunnel:
• The bones of the hand
and flexor retinaculum
form the carpal tunnel .
The median nerve lies
in a restricted space
between the tendons
of the flexor digitorum
superficialis and the
flexor carpi radialis
muscles.
Palmar aponeurosis :
• is a triangular and occupies
the central area of the palm.
It’s apex is attached to the
distal border of the flexor
retinaculum and receives
the insertion of Palmaris
longus tendon. The base
divides at the base of
fingers into four slips. Each
slip divides into two bands,
one pass superficially to the
skin and other passing
deeply to the root of fingers
to fuse finally with the
fibrous flexor sheath and
the deep transverse
ligament
Palmar aponeurosis :
• The medial and lateral
borders
of
the
aponeurosis
are
continuous with the
thinner deep fascia
covering the thenar and
hypothenar
muscle
groups.
• Functions: to improve
hand grip by providing
firm attachment to the
overlying skin and to
protect the underlying
tendons
The Dorsum of the Hand
The Dorsum of the Hand
• Skin:
It is thin, hairy, and freely mobile on the
underlying tendons and bones.
• Sensory nerve supply:
 Superficial branch of radial nerve:
it supplies the lateral two thirds of the
dorsum of the hand. It divides into
several dorsal digital nerves that
supply the thumb, index, and middle
fingers, and the lateral sides of the
ring finger.
• Posterior cutaneous branch of
ulnar nerve: it supplies the
medial third of the dorsum of the
hand. It divides into several dorsal
digital branches that supply the
medial side of the ring and the
sides of the little finger.
Extensor retinaculum
• The retinaculum is
attached medially to the
pisiform and hook of
the hamate and
laterally to the distal
end of the radius. The
upper and lower
borders of the
retinaculum are
continuous with the
deep fascia of the
forearm and hand
respectively.
• The
extensor
retinaculum
send
fibrous septa pass to
the underlying radius
and ulna and form six
compartments
that
contain the tendons of
the extensor muscles.
Each compartment is
provided with a synovial
sheath , which extends
above and below the
retinaculum.
These compartments from radial to ulnar side
1.
2.
3.
4.
1st :contains the tendons of
Abductor pollicis longus(AbPL)
and extensor pollicis
brevis(EPB) have a separate
synovial sheaths but share a
common compartment.
2nd:contains the tendons of
Extensor carpi radialis longus(ECRL)
and brevis(ECRB) tendons share a
common synovial sheath and are
situated on the lateral part of the
posterior surface of the radius.
3rd:contains the tendons of Extensor
pollicis longus tendon(EPL) winds
around the medial side of the dorsal
tubercle of the radius.
4th:contains the tendons of Extensor
digitorum(ED) and extensor indicis(EI)
tendons share a common synovial
sheath and are situated on the lateral
part of the posterior surface of the
radius.
5.5th: contains the
tendons of Extensor digiti
minimi(EDM) tendon is
situated posterior to the
distal radioulnar joint.
6.6th contains the
tendons of Extensor carpi
ulnaris(ECU) which grooves
the posterior aspect of the
head of the ulna.