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Transcript of Hand anatomy new
Wrist and Hand Anatomy
Moderator: Dr. Asif Sultan
Presented by: Qazi Manaan
Overview
• The anatomy of the hand is complex, intricate, and fascinating.
• Absolutely essential for our everyday functional living.
Bone Anatomy
• Total of 27 bones in hand and wrist.
• These are grouped into carpals, metacarpals, and phalanges.
• 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 trapezium.
• The other 4 metacarpals articulate with the trapezoid, capitate, and hamate at the base.
• The hand contains 14 phalanges.
JOINTS
• 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, allowing hyperextension.
• 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 ligaments.
Muscles and Tendons
• The muscles of the hand are divided into:
Intrinsic and
Extrinsic group.
Extrinsic extensors
• All extensors are extrinsic and supplied by radial nerve.
• 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
Extrinsic Flexors
• 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
Intrinsics
• Situated totally within the hand• Divided into 4 groups: the thenar, hypothenar, lumbrical, and interossei muscles.
• The thenar group consists of:
the abductor pollicis brevis,
flexor pollicis brevis,
opponens pollicis, and
adductor pollicis muscles.
• The hypothenar group consists of:
the palmaris brevis,
abductor digiti minimi,
flexor digiti minimi, and
opponens digiti minimi.
• The lumbrical muscles contribute to
the flexion of the MCP joints and
extension of the interphalangeal joints.
• The interossei group consists of:
3 palmar and 4 dorsal muscles • All innervated by
the ulnar nerve.
Zones of the Hand
Flexor Zones
Extensor Zones
NERVES
• 3 nerves:
Median
Ulnar
Radial
Median nerve• Crucial in the gripping mechanism by the thumb.• It originates from the lateral and medial cords of
the brachial plexus (C5-T1).• In the forearm, the motor branches supply the
pronator teres, flexor carpi radialis, palmaris longus, and flexor digitorum superficialis muscles.
• The anterior interosseus branch innervates the flexor pollicis longus, flexor digitorum profundus (radial part), and pronator quadratus muscles.
• 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 thenar muscles
• It also innervates the index and middle finger lumbrical muscles
Signs of a Lesion:
• Benediction Sign :
• Ape Thumb Deformity:
• Median Claw Hand:
Pen Test
Ulnar nerve• Controls fine movement of the
fingers• It originates at the medial cord
of the brachial plexus (C8-T1)• Sensory to the: hypothenar eminenceThe palmar and dorsal ulnar
one and a half fingers
• The deep motor branch passes through the Guyon canal in company with the ulnar artery. It innervates the
hypothenar muscles all interossei, the 2 ulnar lumbricals, the adductor pollicis, and the deep head of the flexor pollicis brevis
Signs of a lesion:
• Ulnar Claw Hand:
Froment’s Sign
Egawas’ Test
Card Test
Radial nerve
• Innervates the wrist extensors.• Originates from the posterior cord of the
brachial plexus (C6-8).• At the elbow, motor branches innervate
the brachioradialis and extensor carpi radialis longus muscles.
• 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.
Signs of a lesion
• Wrist Drop
• Loss of Supination:
Blood Supply
• Complex and rich vascular network
Radial Artery
• Course
• 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 palmar arch.
Ulnar Artery
• 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 arteries.
• 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 artery. • Dorsal metacarpal arteries arise from a
dorsal carpal arch
MODIFIED ALLEN TEST
Veins
• 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 extremity.
Deep Fascia
• The Flexor Retinaculum• The Palmar Fascia• Fibrous flexor sheaths in fingers • The Extensor Retinaculum
• FLEXOR 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 pulleys.
•The digits contain 2 fascial bands of clinical importance:
the Grayson ligament and
the Cleland ligament
Pulley
• 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 oblique pulley.
• 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.
.
Extensor Retinaculum and the 6 compartments
Compartments of the Hand
• 10 separate osteofascial compartments: - dorsal interossei (4 compartments) - palmar interossei (3 compartments) - adductor pollicis - thenar and hypothenar
• Typically can be released with carpal tunnel release and 2 dorsal incisions
SKIN
• 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 veins course.
• explains why edema of the hand is manifested predominantly at the dorsum.
• The skin of the palmar surface of the hand is unique
ThickGlabrousLess Pliable• This enhances skin stability for
proper grasping function.
• 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.
Thank You