Download Anatomy of wrist and Hand

Anatomy of
wrist and Hand 1
Assistant professor
Dr. Alaa A. Alharba
Orthopedic &Hand Surgeon
The Hand as a Functional Unit
• At the distal end of the upper limb is the important
prehensile organ __ the Hand.
• The hand is the primary means through which human
beings physically interact with the environment
around them.
• Much of the importance of the hand depends on the
pincer action of the thumb, which enables us to grasp
objects between the thumb and index finger. The
extreme mobility of the first metacarpal bone makes
the thumb functionally as important as all the
remaining four fingers combined.
• The hand serves three
basic functions:
 Sensory perception:
in the form of pain, light
touch, vibration,
temperature
recognition, and
proprioception
 Pincer function:
(precise function).
 Power grip: (making a
fist). Fist is made by
flexing the MCP joints
and IP joints with
extension of the wrist.
Making a ‘strong fist’
with the wrist flexed is
very difficult.
The hand has two basic
positions:
• (a)
Position
of
rest
(relaxation):
wrist
and
fingers are in flexion
position.
• (b) Position of function:
the wrist extended, fingers
in flexion, and the thumb in
opposition. This slight wrist
flexion make the long flexor
and extensor tendons of the
fingers are working to their
best mechanical advantage.
• Bones:
• There are 8 CARPAL
BONES made up of
two rows of four:
• Proximal( lat. to
med.):
scaphoid,
lunate,
triquetral,
and pisiform.
• Distal:
trapezium,
trapezoid, capitate,
and hamate.
• Bones:
• Metacarpals:
• There are five metacarpal
bones each of which has a
base, shaft, and head. The
first metacarpal of the thumb is
the shortest and most mobile,
it does not lie in the same
plane as the others but
occupies a more anterior
position.
• The bases of metacarpal
bones articulate with the
distal row of the carpal
bones, while the heads
articulate with the proximal
phalanges
Bones:
• Phalanges:
• There
are
three
phalanges for each
finger, but only two
for the thumb.
Joints of the Hand and Fingers
Intercarpal Joints:
•
Articulation between the
individual bones of the
proximal carpal row ; between
the individual bones of the
distal carpal row; and finally,
the midcarpal joint: between
the proximal and distal carpal
rows.
• Ligaments: the carpal bones
are united by strong anterior,
posterior, and interosseous
ligaments.
Intercarpal Joints:
• Capsule: it surrounds each
joint.
• Synovial membrane: it lines
the capsule and attached to
the margins of the articular
surfaces. The joint cavity of
midcarpal joint extends
between the two rows and
between the individual
bones forming the proximal
ad distal rows.
• They are plane synovial
joints allow a small gliding
movement.
Carpometacarpal joint of the Thumb
• It is an articulation
between the base of
the first metacarpal and
the trapezium.
• It is synovial saddle
joint.
• It
allows
flexion,
extension,
adduction,
abduction, and rotation
(opposition).
• Other carpometacarpal
joints are plane joints.
Metacarpophalangeal (MCP)Joints:
• It is an articulation
between the head of
metacarpal bone and the
base of the proximal
phalanx.
They
are
synovial
condyloid
joints
allow
flexion,
extension, abduction and
adduction ( except in the
thumb the adduction and
abduction are in the
carpometacarpal joint).
Metacarpophalangeal Joints:
• Ligaments:
• The collateral ligaments: are
cord-like bands present on each
side of the MCP joints. These
ligaments are lax in extension
allow abduction and adduction of
fingers, and become taut in
flexion making abduction and
adduction more difficult.
• Capsule: surronds the joint.
• Synovial membrane: lines the
capsule and is attached to the
margins of the articular surfaces.
Interphalangeal Joints
They are synovial hinge joints that have structure similar
to that of the metacarpophalangeal joints. There are
proximal (PIP) and distal (DIP) joints.
The Palm of the Hand
Skin of the palm
• It is thick and hairless.
It is bound down to the
underlying deep fascia
by numerous fibrous
bands. The skin show
many flexure creases at
the sites of skin
movement, which are
not necessarily placed
at the site of joints.
Sweet glands are
present in large
numbers.
Hand Skin Creases:
1. Proximal and Distal flexion
creases of fingers: mark the
approximate locations of PIP
& DIP joints respectively.
2. Web flexion creases: at the
level of midpoint of the
proximal phalanges.
3. Proximal & Distal transverse
palmar flexion creases: cross
the palm transversely mark
the level of MCP joints.
4. Longitudinal
interthenar
crease.
5. Proximal & distal wrist
creases
DIP
PIP
Web
crease
3
4
5
The Palm of the Hand:
Skin:
• Nerve Supply: the sensory
supply of palm skin are:
 Palmar cutaneous branch of
the median nerve: supplies the
lateral aspect of the palm.
 palmar cutaneous branch of
the ulnar nerve: supplies the
medial aspect of the palm.
Deep Fascia:
• Is thickened to form the flexor
retinaculum and palmar
aponeurosis