Download Wrist and Hand

Wrist and Hand
 Wrist is the most
complex joints of the
body due to the
numerous joints
combined to create
one.
Wrist and Hand
Anatomy
• Carpal bones- Create a
Mnemonic for them. S-L-TP-T-T-C-H
• Two rows of bones
starting on the thumb
side.
• Scaphoid, lunate,
triquetrum, pisiform
Palpate the Scaphoid
• You would palpate the scaphoid in the
anatomical snuff box.
Flexor Retinaculum
• Flexor retinaculum
– Fibrous connective fascia that covers and holds most
of the flexors of the forearm in wrist.
• The flexor retinaculum (transverse carpal ligament, or
anterior annular ligament) is a strong, fibrous band,
which arches over the carpus.
• Converting the deep groove on the front of the carpal
bones into a tunnel, the carpal tunnel
• Flexor tendons of the digits and the median nerve pass.
Extensor Retinaculum
• The extensor retinaculum (dorsal carpal
ligament) is an anatomical term for the fascia
that holds the tendons of the extensor muscles
in place.
• It is located on the back of the forearm, just
proximal to the hand.
Extensor
Retinaculum
Muscles

Thenar /
short thumb
muscles
ABDUCTOR POLLICIS BREVIS
• ORIGIN
Flexor retinaculum, tubercle
of trapezium scaphoid
bones,
• INSERTION
Base of proximal phalanx of
thumb, radial side, and
extensor expansion
• ACTION
Abducts the
carpometacarpal and
metacarpophalangeal joints
of the thumb in a vertical
direction perpendicular to
the place of the palm
FLEXOR POLLICIS BREVIS
• ORIGIN
– Superficial head: flexor
retinaculum and trapezium bone
– Deep head: trapezoid and
capitate bones
• INSERTION
Base of proximal phalanx of
thumb, radial side, and extensor
expansion
• ACTION
Flexes the metacarpophalangeal
and carpometacarpal joints of
the thumb, and assists in
opposition of the thumb toward
the little finger. By virtue of its
attachment into the dorsal
extensor expansion, may extend
the interphalangeal joint
OPPONEN POLLICIS
• ORIGIN
Flexor retinaculum and
tubercle of trapezium bone
• INSERTION
Entire length of first
metacarpal bone, radial side
• ACTION
Opposes (i.e., flexes and
abducts with slight medial
rotation) the
carpometacarpal joint of the
thumb, placing the thumb in
a position so that, by flexion
of the metacarpophalangeal
joint, it can oppose the
fingers.
• ORIGIN
ADDUCTOR POLLICIS
– oblique head: capitate bone,
and bases of second and
third metacarpal bones
– transverse head: palmar
surface of third metacarpal
bone
• INSERTION
Transverse head into ulnar
side of base of proximal
phalanx of thumb, and
oblique head into extensor
expansion
• ACTION
Adducts the
carpometacarpal joint, and
adducts and assists in
flexion of the
metacarpophalangeal joint,
so that the thumb moves
toward the plane of the palm.
Muscles
 Hypothenar / short muscles of little finger
ABDUCTOR DIGITI MINIMI
• ORIGIN
Tendon of flexor carpi ulnaris
and pisiform bone
• INSERTION
By two slips: one into base of
proximal phalanx of little finger,
ulnar side; the second, into the
ulnar border of the extensor
expansion
• ACTION
Abducts, assists in opposition,
and may assist in flexion of the
metacarpophalangeal joint of the
little finger
FLEXOR DIGITI MINIMI BREVIS
• ORIGIN
hook of hamate bone, and
flexor retinaculum
• INSERTION
base of proximal phalanx of
little finger, ulnar side
• ACTION
Flexes the
metacarpophalangeal joint
of the little finger and
assists in opposition of the
little finger toward the
thumb
OPPONEN DIGITI MINIMI HAND
• ORIGIN
hook of hamate bone,
and flexor retinaculum
• INSERTION
entire length of fifth
metacarpal, ulnar side
• ACTION
opposes (i.e., flexes
with slight rotation) the
carpometacarpal joint
of the little finger
Muscles
• Short Hand muscles
• ORIGIN
– #1 and #2: radial surface of
flexor profundus tendons of
index and middle fingers,
respectively.
– #3: adjacent sides of tendon of
flexor digitorum profundus
tendons of middle and ring
fingers
– #4: adjacent sides of tendon of
flexor digitorum profundus of
ring and little fingers
• INSERTION
Into the radial border of the
extensor expansion on the dorsum
of the respective digits
• ACTION
Extend the interphalangeal joints
and simutaneously flex the
metacarpophalangeal joints of the
second through fifth digits.
LUMBRICALS
• ORIGIN
– First: base of first metacarpal bone,
ulnar side
– Second: length of second
metacarpal bone, ulnar side
– Third: length of fourth metacarpal
bone, radial side
– Fourth: length of fifth metacarpal
bone, radial side
• INSERTION
Chiefly, into the extensor expansion
of the respective digit, with possible
attachement to base of proximal
phalanx as follows
–
–
–
–
First: ulnar side of thumb
Second: ulnar side of index finger
Third: radial side of ring finger
Fourth: radial side of little finger
• ACTION
Adduction of thumb, index , ring,
and little finger toward the axial line
through the third digit. Assist in
flexion of metacarpophalangeal
joints,
PALMAR
INTEROSSEI
•
•
•
ORIGIN
– First, lateral head: Proximal one half
of ulnar border of first metacarpal
bone
– First, medial head: radial border of
second metacarpal bone
– second, third, and fourth: adjacent
sides of metacarpal bones in each
interspace
INSERTION
into extensor expansions and to base of
proximal phalanges as follows:
– First: radial side of index finger,
chiefly to base of proxiaml phalanx
– Second: radial side of middle finger
– Third: ulnar side of middle finger,
chiefly into extensor expansion
– Fourth: ulnar side of ring finger
ACTION
Abducts the index, middle, and ring
fingers from the axial line through the third
digit. Assists in flexion of
metacarpophalangeal joints and
extension of interphalangeal joints of the
same fingers.
DORSAL
INTEROSSEI
Fingers
• Also have digital transverse flexion creases proximal, middle, distal (thumb has only 2)
• Fingerprints - improve gripping ability
• Synovial sheaths
– a. radial bursa - encloses tendon of flexor pollicis
longus
– b. ulnar bursa - encloses four tendons each of flexors
digitorum superficialis & profundus
& medially, extends distally to surround the two flexor
tendons to pinkie
– c. Three separate distal sheaths - surround flexor
tendons to index, middle, ring fingers
- from metacarpophalangeal joints to base of distal
phalanx
Fingers
• Fibrous digital sheaths
- dense fibrous
connective tissue
– annular bands surround phalanges
– cruciform bands cross over between
joints
– form osteofibrous
canals - through
which flexor tendons
travel (in their
synovial sheaths)
Flexor Digitorum
Profundus (FDP) &
Superficialis (FDS)
• Flexor digitorum superficialis
(FDS) insert into middle
phalanx.
• Flexor digitorum profundus
(FDP) runs deep to the FDS
until the level of the MP joint
where FDS bifurcates.
• FDP inserts at the base of the
distal phalanx and acts
primarily to flex the DIP joint
as well as all other joints
flexed by FDS.
Blood vessels
• Ulnar artery
– a. deep branch - joins radial to form deep palmar arch
– b. superficial palmar arterial arch, formed by
superficial palmar branch from ulnar artery (more like
the terminal branch of ulnar, which mainly forms the
arch) + superficial palmar branch of radial artery. It
gives off three branches and joint with palmar
metacarpal branches from deep palmar arch to form:
• i) three common palmar digital artery - in the three medial
intermetacarpal spaces; each then divides
• proper palmar digital artery - to medial side of index finger,
radial side of little finger
and both sides of middle & ring fingers
• proper palmar digital artery - little finger, ulnar side, a branch
directly from the superficial palmar arch (or a branch off the
ulnar artery)
Blood vessels
• radial a. - (sits in floor of anatomical snuff
box)
– a. superficial palmar branch - to thenar
muscles, joins superficial palmar arch (ulnar)
– b. princeps pollicis - to thumb, then splits into
two proper digital arteries to both sides of the
thumb
– c. radialis indicis - to lateral index finger
– d. deep palmar arterial arch - formed by Radial
artery (mainly). + deep branch of the ulnar a.
- three palmar metacarpal arteries - between
metacarpals - join common palmar digitals
Deep palmar arterial arch
• three palmar metacarpal arteries
• three perforating arteries to dorsal arch
Dorsal arterial arch
• a. formed by dorsal carpal branch from radial and
ulnar arteries, and terminal branches of the
anterior and posterior interosseus arteries. It is
also joined by the perorating arteries from deep
palmar arch.
• b. Dorsal arch gives off three dorsal metacarpal
arteries, each then splits into dorsal proper digital
arteries
• c. Dorsalis pollicis and dorsalis indicis can be
considered as direct branches from radial dorsal
carpal artery
• d. dorsal proper digital artery - to the medial side
of little finger, direct branch from the dorsal arch
(or branch from the dorsal carpal branch from
ulnar artery).
Nerves
• 1. ulnar nerve - superficial branch of the
ulnar nerve - enters palm on ulnar side of
center; divides:
- three palmar digital branches - to skin of
little finger (both sides), medial side ring
finger
• 2. ulnar nerve - deep branch - to muscles
of fine movements of hand
- hypothenar muscles, interosseous,
medial lumbricals, adductor pollicis
Reading material
• Muscles and Tendons of Hand
• The muscles are arranged in three groups.
• Two are associated with the first and the fifth metacarpals
forming the (1) thenar and (2) hypothenar eminences
respectively . The third group is located deeper in the central
"hollow" of the palm.
• (1) Thenar Muscles - Consist of three intrinsic muscles all
supplied by the recurrent branch of the median nerve.
• Abductor Pollicis Brevis - the most superficial of the thenar
muscles. As its name implies, its abducts the thumb.
• Flexor Pollicis Brevis - located medial to abductor pollicis
brevis. It flexes the proximal phalanx of the thumb.
• Opponens Pollicis - lies deep to abductor pollicis brevis. As its
name implies it produces opposition of the thumb.
• Although NOT part of the thenar muscles, the adductor
pollicis is a fan-shaped muscle located deep to the thenar
muscles. As its name implies, it is involved in adduction of the
thumb. It is supplied by the deep branch of ulnar nerve.
• (2) Hypothenar Muscles - consist of three short
muscles all supplied by the deep branch of the
ulnar nerve.
• Abductor Digiti Minimi - is the most superficial of
the three muscles. It abducts the fifth digit(little
finger) and helps flex its proximal phalanx.
• Flexor Digiti Minimi - lies lateral to the abductor
digiti minimi. It flexes the proximal phalanx of the
fifth digit.
• Opponens Digiti Minimi - lies deep to both the
abductor and flexor digiti minimi. As its name
implies it is involved in opposition of the fifth
digit.
• (3) Centrally located deep muscles - These
consist of the lumbricals and interosseous muscles .
• Lumbricals - These are four slender muscles which
arise from the tendons of flexor digitorum
profundus. Their tendons are inserted into the radial
side of each of the proximal phalanges of the
fingers and into the dorsal extensor
expansion(hood).
• They flex the metacarpophalangeal (MP) joints and
extend the interphalangeal joints.
• Lumbricals 1 and 2 are supplied by the median
nerve while lumbricals 3 and 4 are supplied by the
ulnar nerve.
• Interosseous Muscles - These are divided into
a palmar and dorsal group.
• The three palmar interossei arise from
metacarpals.
• They insert into the proximal phalanx and the
expansion of the extensor digitorum communis.
• Palmar interossei are adductors (PAD). The four
dorsal interossei also arise from metacarpals.
They insert into the proximal phalanges and the
dorsal digital expansion(hood).
• Dorsal interossei are abductors(DAB).
• All of these interossei are supplied by the deep
branch of the ulnar nerve.
• Palmar Fascial Spaces of Hand
• Between the palmar aponeurosis and the interossei are two potential
spaces which are clinicaly important .
• They are located between the flexor tendons and the fascia covering
the interossei.
• The spaces are bounded medially and laterally by septa passing from
the periphery of the palmar aponeurosis posteriorly to the metacarpal
bones.
• A medial septum extends from the medial border of the palmar
aponeurosis to the fifth metacarpal.
• A lateral septum extends from the lateral border of the palmar
aponeurosis to the first metacarpal.
• From the middle of the palmar aponeurosis another septum passes
posteiorly to the third metacarpal. These septa thus create two
midpalmar spaces bounded anteriorly by the flexor tendons and
lumbricals, posteriorly by the interossei, and laterally and medially by
the respective septa.
• Each of the eminences (thenar and hypothenar) as well as the central
palmar area also contain potential spaces which may be the sites of
infection.
• Flexor and Synovial Sheaths
• As the tendons of the long flexor and extensor muscles approach the
hand and eventually terminate on the phalanges two things must
occur.
• First, the flexor tendons must pass deep to the flexor retinaculum
while the extensor tendons must pass under the and extensor
retinaculum. On the palmar side the flexor tendons must then be
anchored to the phalanges in such a way as to prevent "bowstringing".
• This anchoring is performed by fibrous flexor sheaths. Now a
second problem arises however. How do you prevent friction from
occuring at those areas where the tendons come in contact with
sheaths or retinacula? This is accomplished by synovial sheaths.
• On the anterior surface of each digit, from the head of the metacarpal
to the base of the distal phalanx, a strong fibrous flexor sheath is
present. This serves as a tunnel for the flexor tendons of the digits.
• In order to prevent friction from occuring here, synovial sheaths
envelope the tendons. Synovial sheaths are first present at the
retinaculae (flexor and extensor). On the palmar surface, the flexor
pollicis longus tendon enters the osseofibrous tunnel of the thumb and
is inserted into the base of the distal phalanx. On the thumb, the
tendon is completely surrounded by a synovial sheath which extends
into the forearm just proximal to the flexor retinaculum. The eight
tendons of the flexor digitorum superficialis and profundus invaginate a
common synovial sheath. This common sheath also extends into the
forearm to a point just proximal to the flexor retinaculum. In the hand
the sheath continues distally without interruption on the tendons of the
little finger to the distal phalanx. The remainder of this sheath ends in
the mid- palm. The distal ends of the index, middle, and ring fingers
have digital synovial sheaths surrounding each of them. NOTE: In
about 50% of the people the synovial sheath of the flexor pollicis
longus communicates with the common synovial sheath of the
superficialis and profundus tendons.
• On the dorsum of the hand, synovial sheaths are present on each of
the tendons deep to the extensor retinaculum. They extend from a
point just proximal to the retinaculum to a point in the proximal 1/3 of
the dorsum of the hand.
• Nerves of the Hand
• The ulnar, radial, and median nerves supply the hand .
• Ulnar Nerve - It exits the forearm by emerging from the tendon of
flexor carpi ulnaris. It passes onto the flexor retinaculum lateral to the
pisiform bone and medial to the ulnar artery. Both the ulnar nerve and
artery are contained in a canal at this point called Guyon's canal.
Immediately proximal to the wrist the ulnar nerve gives off a branch to
supply skin on the medial side of the palm. It also gives off branches
which supply the skin on the medial half of the dorsum of the hand,
the fifth digit, and medial half of the fourth digit. Motor branches
supply the hypothenar muscles, interossei, and the third and fourth
lumbricals.
• Radial Nerve - The superficial branch of the radial nerve supplies the
skin over the lateral two- thirds of the dorsum of the hand, the dorsum
of the thumb, and proximal parts of the lateral one and one-half digits.
It has no motor branches in the hand.
• Median Nerve - It passes through the carpal tunnel and enters the
hand between the tendons of flexor digitorum superficialis and flexor
carpi radialis. It supplies motor fibers for the thenar muscles and the
first and second lumbricals. It sends sensory fibers to the entire
palmar surface, the sides of the first three digits, the lateral half of the
fourth digit, and dorsum of the distal halves of these digits.
• There are eight small bones of the wrist called carpal bones. They are
arranged in proximal and distal rows. Each contain four bones.
• The proximal row consists of the scaphoid, lunate, triquetrum, and
pisiform.
• The distal row contains the trapezium, trapezoid, capitate, and
hamate.
• All the tendons in the anterior compartment, as well as the main
vessels and nerves funnel down to the region of the wrist, where most,
but not all of them, pass through the neck of a funnel termed the
• carpal tunnel .
• This is a rather narrow passage formed by the carpal bones
posteriorly and the flexor retinaculum anteriorly. The carpal bones are
shaped so as to form a curve and only those bones on the periphery
can be palpated. These are the pisiform and hook of the hamate
medially and the scaphoid and trapezium laterally. It is to these four
bones that the flexor retinaculum attaches thus completing the tunnel.
• NOTE: If you are able to palpate these bones on your own hand you
will notice that they are located in the very proximal part of the palm of
the hand.
• Nine tendons and one nerve pass through the carpal tunnel. These
are the median nerve and the tendons of the flexor pollicis longus,
flexor digitorum superficialis and flexor digitorum profundus.
• The wrist or radiocarpal joint is located between
the distal end of the radius and the carpal bones
.
• The distal end of the radius and the articular
disc of the distal radioulnar joint articulate with
carpal bones in the proximal row namely the
scaphoid, lunate, and triquetrum.
• The lunate and scaphoid contact the radius
directly whereas the articular disc is interposed
between the ulna and the triquetrum.
• A fibrous capsule encloses the joint. Collateral
ligaments also strengthen the joint peripherally.
NOTE: Movements at this joint include:
adduction, abduction, flexion, extension, and
circumduction.