Wrist and Hand Anatomy
Moderator: Dr. Asif Sultan
Presented by: Qazi Manaan
• The anatomy of the hand is complex, intricate,
• Absolutely essential for our everyday functional
• Total of 27 bones in hand and wrist.
• These are grouped into carpals, metacarpals,
• The wrist is the most complex joint in the body. It is
formed by 8 carpal bones grouped in 2 rows with very
restricted motion between them.
• All carpal bones participate in wrist function
o except for the pisiform.
• The scaphoid serves as link between each row;
therefore, it is vulnerable to fractures.
• The distal row of carpal bones is strongly attached
to the base of the second and third metacarpals,
forming a fixed unit.
• The hand contains 5 metacarpal bone.
• First Metacarpal articulates proximally with the
• The other 4 metacarpals articulate with the
trapezoid, capitate, and hamate at the base.
• The hand contains 14 phalanges.
• All 4 distal carpal bones articulate with the
metacarpals at the carpometacarpal (CMC) joints.
• At the metacarpophalangeal joints, lateral motion is
limited by the collateral ligaments
• At the CMC joint, the volar plate is part of the joint
capsule that attaches only to the proximal phalanx,
• At the interphalangeal joints:
extension is limited by the volar plate, which attaches
to the phalanges at each side of the joint.
Radial and ulnar motion is restricted by collateral
• The muscles of the hand are divided into:
• All extensors are extrinsic and supplied by radial
• Except for the interosseous-lumbrical complex.
• Group contains:
3 wrist extensors
A larger group of thumb and digit extensors.
• The main extensors at wrist are:
The extensor carpi radialis brevis (ECRB)
extensor carpi radialis longus (ECRL)
extensor carpi ulnaris (ECU)
• At the digits, extension occurs due to:
The extensor digitorum communis,
extensor indicis proprius, and
extensor digiti minimi
• Extension at the thumb is bought about by:
The abductor pollicis longus,
extensor pollicis brevis, and
extensor pollicis longus
• 3 wrist flexors
• A larger group of thumb and digit flexors
• Innervated by the median nerve
• Except for the FCU, and the FDP to the small and ring
finger, which are innervated by the ulnar nerve.
• The main Flexors at the wrist joint are:
The flexor carpi radialis
the flexor carpi ulnaris and
the palmaris longus
• The digital flexors include:
Flexor Digitorum Superficialis
Flexor Digitorum Profundus
Flexor Pollicis Longus
• Situated totally within the hand
• Divided into 4 groups:
• The thenar group
the abductor pollicis
flexor pollicis brevis,
opponens pollicis, and
• The hypothenar group
the palmaris brevis,
abductor digiti minimi,
flexor digiti minimi, and
opponens digiti minimi.
• The lumbrical muscles
the flexion of the MCP
extension of the
• The interossei group
3 palmar and
4 dorsal muscles
• All innervated by the
• Crucial in the gripping mechanism by the thumb.
• It originates from the lateral and medial cords of the brachial
• In the forearm, the motor branches supply the pronator teres,
flexor carpi radialis, palmaris longus, and flexor digitorum
• The anterior interosseus branch innervates the flexor pollicis
longus, flexor digitorum profundus (radial part), and pronator
• Palmar cutaneous branch provides sensation at the
thenar eminence. Also sensory digital branches
provide sensation to the radial three and a half
fingers and corresponding palm area
• As the median nerve passes through the carpal
tunnel, the recurrent motor branch innervates the
• It also innervates the index and middle finger
• Controls fine movement of the fingers
• It originates at the medial cord of the
brachial plexus (C8-T1)
• Sensory to the:
The palmar and dorsal ulnar one and a
• The deep motor branch passes through the Guyon canal in
company with the ulnar artery. It innervates the
the 2 ulnar lumbricals,
the adductor pollicis, and
the deep head of the flexor pollicis brevis
• Innervates the wrist extensors.
• Originates from the posterior cord of the brachial
• At the elbow, motor branches innervate the
brachioradialis and extensor carpi radialis longus
• At the proximal forearm, the radial nerve divides into
the superficial and deep branches.
• The deep posterior interosseous branch innervates all
the muscles in the extensor compartment.
• The superficial branch provides sensation at the radial
aspect of the dorsum of the hand, the dorsum of the
thumb, and the dorsum of the radial three and a half
digits proximal to the distal interphalangeal joints.
• Complex and rich vascular network
• A superficial branch arises at the level of the wrist and
contributes to the superficial palmar arch.
• In the palm it gives off:
Princeps pollicis artery and
Radialis Indicis artery, before terminating in the deep
• It travels into the hand through the Guyon
canal, where it divides into:
• the deep palmar branch and
• the superficial palmar branch.
Superficial Palmar Arch
• Lies directly deep to the palmar fascia.
• It gives rise to the:
volar common digital arteries and
multiple branches to intrinsic muscles and skin.
• Distally,the common digital arteries bifurcate into the
proper digital arteries.
Deep Palmar Arch
• Lies at the base of the metacarpals, deep to
the flexor tendons.
• From its convexity it gives off three
palmar metacarpal arteries.
• Dorsally it gives off three perforating
• Recurrent branches arise from the
concavity to supply the carpal bones
Dorsal Carpal Arch
• Formed by:
the posterior interosseous artery and
a dorsal perforating branch of the anterior interosseous
• Dorsal metacarpal arteries arise from a dorsal carpal
• Veins generally follow
the deep arterial system
as venae comitantes.
• A superficial venous
system also exists at the
dorsum of the hand
and contributes to the
cephalic and basilic
veins in the upper
• The Flexor Retinaculum
• The Palmar Fascia
• Fibrous flexor sheaths in fingers
• The Extensor Retinaculum
• The Palmar fascia consists of resistant fibrous
tissue arranged in longitudinal, transverse,
oblique, and vertical fibers.
• The transverse fibers are concentrated in the
mid palm and web spaces and serve as pulleys
for the flexor tendons proximal to the digital
•The digits contain 2 fascial
bands of clinical importance:
the Grayson ligament and
the Cleland ligament
• The pulley system is critical to flexion of the finger.
• The retinacular system for each of the fingers contains 5
annular pulleys and 3 cruciate pulleys.
• The thumb has 2 annular pulleys and 1
• The system supplies mechanical advantage
by maintaining the flexor tendons close to
the joint's axis of motion. In doing so, the
pulleys prevent bowstringing.
Compartments of the Hand
• 10 separate osteofascial
- dorsal interossei (4
- palmar interossei (3
- adductor pollicis
- thenar and hypothenar
• Typically can be released with
carpal tunnel release and 2
• The skin of the dorsum of the
hand is thin and pliable.
• It is attached to the hand's
skeleton only by loose areolar
tissue, where lymphatics and
• explains why edema of the
hand is manifested
predominantly at the dorsum.
• The skin of the palmar surface of the hand is
• This enhances skin stability for proper grasping
• The skin is most firmly anchored to the deep
structures at the palmar creases.
• Blood supply is through numerous small, vertical
branches from the common digital vessels.
• High concentration of sensory nerve organs
essential to the hand's normal function.