Hand Flashcards
What are the functions of the hand?
-Tactile/ sensory
-Communication
-Manipulation
-Grip/ hold
=Power
=Precision
=Opposition/ defensive
What are the bones of the hand?
27 bones (+ sesamoids)- protuberances on palm side for ligament and muscle attachment
-Carpals (x8)
=2 rows: 4 proximal (curved surfaces, articulation in ellipsoid joint), 4 distal (flatter, articulation with metacarpals)
-Metacarpals (x5) (longer than phalanges, flat proximal end, rounded distal)
-Proximal phalanges (x5)
-Middle phalanges (x4)
-Distal phalanges (x5)
=Phalanges have concave base and convex surface distally
What is the pneumonic to remember the carpals?
Some= scaphoid (lateral, wrist articulation)
Lovers= Lunate (medial, wrist articulation)
Try= Triquetral (medial to lunate, 3 sided triangular bone)
Positions= Pisiform (sesamoid, anteriorly on top of triquetral)
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That= Trapezium (most lateral, elongated, saddle shape articular surface for metacarpal 1, thumb has more movement)
They= Trapezoid (medial, wedged in, does not lie under the thumb, bigger posteriorly, narrow triangular)
Cant= Capitate (largest carpal, central axis of movement)
Handle= Hamate (articulates with two metacarpals, elongated distal end, protrusion into palm= hook/ hanalus)
What are the joints of the hand?
- Radiocarpal (wrist)
- Intercarpal= planar, limited movement (sliding)
- 1st Carpo-metacarpal= saddle
- Carpo-metacarpal (x4)= plane
- Metacarpophalangeal (x5)= ellipsoid, increased mobility
- Interphalangeal (x9)= proximal/distal, hinge joint, flexion/extension only
What are the movements of the wrist, fingers and thumb?
- W: flexion/extension, abduction/adduction, circumduction (no rotation)
- F: flexion/extension (MCP, DIP, PIP), abduction/ adduction (MCP only relative to 3rd digit), circumduction (MCP only)
- T: flexion/extension (CMC, MCP, IP), abduction/adduction (CMC, MCP), Circumduction/ Opposition (CMC, MCP)- movements take place at 90 degrees to finger movements
What are the extrinsic muscles?
Forearm muscles= move hand from afar for power
-Anterior (flexor)
-Posterior (extensor)
Complex movements= interaction between groups
What are the intrinsic muscles?
Within hand, smaller muscles moving few digits for precision, fine digital control
=Flexion and extension of digits
=Abduction and adduction of digits
=Specific movements of the thumb and little finger
=Intrinsic structures do not affect the wrist joint
=Majority of motor innervation comes from the ulnar nerve
-Thenar eminence
-Hypothenar eminence
-Deep muscles
What are the extrinsic wrist/ hand flexors?
Anterior forearm, median nerve
-Flexor retinaculum
-Palmar aponeurosis
-Flexor digitorium profundus (FDP)= flexes to distal interphalangeal joint
-Flexor digitorium superficialis (FDS)= flexes to proximal
=Flexor tendons of wrist, wrist and digits, thumb
=FDS tendon (split)
=FDP tendon (emerging)
What are the features of the carpal tunnel?
Gateway to hand, extrinsic flexor tendons, median nerve
- Flexor pollicis longus tendon
- Flexor retinaculum/ transverse carpal ligament
- Ulnar NVB
- Median nerve
- FDS, FDP tendons
What are the extrinsic extenders?
All radial nerve innervated Only 1 extensor digitrum in forearm but designated long extensor for index and little finger -Extensors of : =the wrist =wrist and digits =retinaculum =digits 2 and 3 =thumb muscles
Describe the hand
- Highly complex
- 19 muscles within hand
- 2 major named nerves and branch of third
- 2 arteries forming 2 arches
- 2 veins forming 2 plexi
What are the parts of the Thenar Eminence?
Muscles associated with the thumb
Moves thumb (digit 1 ), median nerve, all insert on base of proximal phalanx
-Abductor pollicis brevis (most superficial)
-Opponens pollicis (deepest)
-Flexor pollicis brevis (deep to abductor p.b. and medial)
(All For One)
=All muscles median nerve innervated
What are the parts of the Hypothenar Eminence?
Muscles associated with little finger
Moves little finger (digit 1), ulnar nerve, all insert on base of proximal phalanx
-Abductor digiti minimi (most superficial and medial)
-Flexor digit minimi brevis (deep and lateral) no longus
-Opponens digiti minimi (deepest and most lateral)
(All For One and One For All)
=All muscles ulnar nerve innervated
What are the deep hand muscles?
Additional control over digits/ thumb, mainly ulnar nerve, mixed functions
- Lumbricals
- Adductor pollicis (oblique)
- Palmar interossei (x3)
- Adductor pollicis (transverse)
- Dorsal interossei (x4)
What are the nerves of the hand?
-Median
-Ulnar
-Radial
=Includes motor and sensory information, intrinsic and extrinsic supply
Describe the anatomy of the hand
27 named bones (+ sesamoids) 6 joint levels 24 tendons from extrinsic muscles 19 intrinsic muscles 3 major nerves 2 major arteries
What are the connective tissues of the hand?
-Palmar aponeurosis
=Thick layer of deep fascia
=Protective, covers palm
=Anchored to skin and subcutaneous tissue minimises loose tissue
-Transverse Carpal Ligament / Flexor Retinaculum
=Thick ligamentous band
=Connects medial and lateral side of carpal arch
=Forms carpal tunnel
-Digital sheaths:
=Lie on the anterior surface
=Begin at metacarpophalangeal joints
=Prevent tendon ‘bowstringing’
-Extensor hood
=Posterior continuation of sheaths
=Expands around metacarpophalangeal joints
=Anchors extensor tendons; provides insertion point
Describe wrist movements
-Major wrist movements controlled by 5 muscles:
=3 extensors (posteriorly)= extensor carpiulnaris (medial), extensor carpiradialis longus (lateral), brevis underneath
=2 flexors (anteriorly)= flexor carpiradialis muscle (lateral), flexor carpiulnaris (medial, bigger belly)
-‘Carpi’ muscles: insert into carpals
=Sit at the four ‘corners’ of the wrist
-Same compartment: flexion / extension
-Opposing compartments: abduction / adduction
What are the digit (2-5) movements and extrinsic muscles?
-Forearm provides gross movements of the four fingers:
=Flexion / extension only
=Abduction / adduction = intrinsic muscles
-Primary muscles (tendons to phalanges:
=Flexor digitorum superficialis / profundus (deep)- anterior compartment
=Extensor digitorum- posterior
-Secondary muscles to specific fingers:
=Extensor indices
=Extensor digiti minimi
What are the movements and extrinsic muscles of digit 1?
-The thumb received dedicated extrinsic muscles:
=All contain ‘pollicis’ – ‘strong’ digit
-Four extrinsic muscles:
=Flexor pollicis longus (large, anterior)
=Extensor pollicis longus + brevis
=Abductor pollicis longus (oblique arrangement)
What is the Anatomical Snuffbox?
-Triangular depression at the base of the thumb posteriorly
-Most obvious with thumb extended
-Borders formed from tendons passing to thumb:
=Medially: extensor pollicis longus
=Lateral: abductor pollicis longus, extensor pollicis brevis
-Clinical landmark:
=Radial artery passes through – pulse
=Scaphoid can be palpated
What makes up the carpal tunnel?
-Route for extrinsic flexor tendons to reach palmar surface of hand
=Floor and walls: carpal bones
=Roof: Flexor retinaculum
-9 tendons pass through
=FDS, FDP, FPL
-Accompanied by median nerve (superficial to tendons)
What is carpal tunnel syndrome?
-Carpal tunnel is a restrictive space
-Any swelling, inflammation or irritation can cause compression
-Nerve compression impinges on nerve function
-Carpal Tunnel Syndrome
=Loss of motor function
=Loss of sensation
Describe the structures of the Palm
Additional centrally-positioned structures control hand movements
=Long flexor tendons from forearm
=Adductor pollicis (2 heads= proximal oblique and distal transverse)
=Branching vasculature
-Three ‘sets’ of muscles also reside here:
=Lumbricals + Interossei (x2)
-Muscles located deep to palmar aponeurosis
What are the Lumbricals?
-A group of 4 thin muscles
=Lumbricus – worm-like
-Unusual course:
=Originate from the tendons of FDP
=Insert into the extensor hoods of fingers
-Flex metacarpophalangeal joints (cross anteriorly)
-Extend interphalangeal joints (insert posteriorly)
What are the Interossei?
-Deepest’ muscles located in the hand
=Inter - between ; Ossei – bones
-Originate from shafts of each metacarpal
-Insert into the base of the proximal phalanges
-Two sets:
=Dorsal x4: abduction (Digits II – IV only) (deepest layer)
=Palmar x3/4: adduction (Digits II, IV and V (not III; sometimes I)
PAD and DAB
Describe the arterial blood supply to the hand
- Brachial artery located in arm divides into radial and ulnar arteries distal to elbow joint
- Ulnar artery merges medially and superficial to carpal tunnel, radial artery passes lateral to carpal tunnel
- Deep palmar: ulnar
- Superficial palmar: radial
Describe the Superficial Palmar Arch
-Arterial arch formed from =Ulnar artery (dominant) =Superficial palmar artery (radial) -Located deep to palmar aponeurosis =Superficial to long tendons in palm -Branches supply medial have of digit 2, all of digits 3-5
Describe the Deep Palmar Arch
-Arterial arch formed from: =Radial artery (dominant) =Deep palmar artery (ulnar) -Located deep to long flexor tendons =Pass between adductor pollicis heads -Supplies: =Thumb (princeps pollicis), lateral ½ digit II -Radial artery also supplies dorsal hand: =Dorsal carpal arch
Describe the venous return of the hand
-Mimics pattern of arterial supply
-Deep veins follow arterial supply
=Return to ulnar + radial venae comitantes
-Superficial veins drain to dorsal venous network
=Medially: basilic vein
=Laterally: Cephalic vein
-Highly variable!
Describe the extrinsic motor innervation of the hand
-Follow rules of compartmentalisation
-Anterior forearm:
=Majority = median nerve
=Ulnar innervates ½ FDP, Flexor carpi ulnaris
-Posterior forearm:
=Entirely innervated by radial nerve
Describe the intrinsic motor innervation of the hand
Two motor nerves in hand: -Ulnar: =Hypothenar eminence =Majority of deep palmar muscles -Median =Thenar eminence =Lateral 2 lumbricals -No radial nerve motor supply
Describe cutaneous innervation of the hand
All three nerves provide cutaneous / sensory innervation:
-Ulnar nerve:
=Medial aspect of hand: ½ digit IV, full V
-Median nerve:
=Palmar surface; ½ digit IV, full I – III, dorsal fingertips
-Radial nerve:
=Dorsal surface; thumb, ½ digit IV, full II + III (minus fingertips)
