Hand Flashcards
What lives in the ulnar notch of the radius to ulnar styloid and separates the ulnar head from carpals while sliding across ulnar head during pronation/supination?
Triangular Fibrocartilage (TFC)
What are the 4 proximal carpals?
Scaphoid, lunate, triquetrum, pisiform
What are the 4 distal carpals?
Trapezium, trapezoid, capitate, hamate
Describe the scaphoid
Largest proximal carpal, most frequently fractured
Describe the lunate
Most common dislocated
Describe the triquetrum
Connects to the triangular fibrocartilage
Describe the pisiform
Embedded in flexor carpi ulnaris tendon
Describe the trapezium
Thumb side
Describe the trapezoid
Connects to second metacarpal
Describe the capitate
Largest of all carpal bones
Describe the hamate
Hook projects anteriorly
Radius + proximal carpals
Radiocarpal joint
Proximal row of carpals+distal row of carpals
Midcarpal joint
Distal carpal + metacarpals
Carpometacarpal (CMC) joints
What is special about the first CMC joint?
It is a saddle joint, allowing the thumb a wide range of movement
Metacarpals + proximal phalanges
Metacarpophalangeal joints
Proximal phalanx + middle phalanx
Proximal Interphalangeal Joints (PIP)
Middle phalanx + distal phalanx
Distal Interphalangeal Joints (DIP)
Does the thumb have PIP or DIP joints?
No, only IP joint
What 4 ligaments surround the wrist?
Palmar radiocarpal, dorsal radiocarpal, ulnar collateral, radial collateral
What is the job for palmar and dorsal radiocarpal?
Keep hand connected to radius (allows hand to rotate with radius when pronating/supinating)
What is the jobs of ulnar and radial collateral?
RC= Strengthen medial parts of joint capsule; UC= Strengthen lateral parts of joint capsule
Where do the palmar and dorsal radiocarpal attach to?
Radius to both rows of carpals
Where does the ulnar collateral attach to?
Ulna to the triquetrum
Where does the radial collateral attach to?
Radius to the scaphoid
Myotome for wrist flexion
C7
Myotome for wrist extension
C6
Myotome for finger abduction/adduction
T1
Myotome for thumb extension
C8
Describe Palmar Ligaments (Plates)
Plates that connect to fan-like portion of collateral ligaments and prevent hyper extension of finger (specifically flexor tendon)
What is palmar aponeurosis?
Fascia that is a continuation of palmaris longus tendon, it connects to flexor retinaculum and is continued by fibrous digital sheaths
What is palmar aponeurosis?
Fascia that is a continuation of palmaris longus tendon, it connects to flexor retinaculum and is continued by fibrous digital sheaths
What is fibrous digital sheaths (pulleys)?
Tubes that enclose synovial sheaths and long fiber flexors within them; they keep tendons from bowstringing away from nones
What is fibrous digital sheaths (pulleys)?
Tubes that enclose synovial sheaths and long fiber flexors within them; they keep tendons from bowstringing away from bones
How many fibrous digital sheaths are there?
5 anular (rounded) and 3 cruciform (cross)
What allows infection to spread from hand to forearm?
The mid palmar space due to being continuous from hand to anterior compartment of forearm through the carpal tunnel
What are the boundaries of the carpal tunnel?
Roof= Flexor retinaculum; walls= scaphoid/trapezoid and pisiform/hook of hamate; floor= carpals between walls and their ligaments
What are the contents of the carpal tunnel?
9 tendons (4 FDS, 4 FDP, 1 FPL) and 1 nerve (median nerve)
Tunnel of guyon vs carpal tunnel
Tunnel of guyon has ulnar nerve pass through while carpal tunnel has median nerve pass through
How many compartments does the extensor retinaculum have?
6
ER Compartment 1 muscles
Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB)
ER Compartment 2 muscles
Extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB)
ER Compartment 3 muscles
Extensor Pollicis longus (EPL)
ER Compartment 4 muscles
Tendon sheath for extensor digitorum (ED) and extensor indicis (EI)
ER Compartment 5 muscles
Extensor digiti minimi (EDM)
ER Compartment 6 muscles
Extensor carpi ulnaris (ECU)
What bones and tendons make up the anatomical snuff box?
Bone= scaphoid; tendons= abductor Pollicis longus, extensor Pollicis brevis, and extensor pollicis longus
What muscles perform thumb flexion?
Flexor Pollicis brevis and flexor Pollicis longus
What muscles perform thumb extension?
Extensor Pollicis longus and extensor Pollicis brevis
What muscles perform thumb abduction?
Abductor Pollicis brevis and abductor Pollicis longus
What muscles perform thumb adduction?
Abductor Pollicis and first dorsal interosseous
What muscles perform thumb opposition?
Opponens Pollicis
What muscles perform finger flexion?
Flexor digitorum superficialis, flexor digitorum profundus, flexor digiti minimi brevis (pinky)
What muscles perform finger extension?
Extensor digitorum, extensor indicis, extensor digiti minimi (pinky)
What muscles perform finger abduction?
Dorsal interossei and abductor digiti minimi (pinky)
What muscles perform finger adduction?
Palmar interossei and adductor pollicis
What do the lumbricals do?
Extend IP’s and flex MCP’s
How do extensor expansions (or hoods) work to extend the fingers?
They hold tendon in finger for expansion
Map the radial artery to the hand
——> superficial branch-> superficial palmar arch
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Radial artery-> dorsal branch -> deep palmar arch
Map the ulnar artery to the hand
—> superficial palmar arch-> common digital arteries-> proper digital | arteries
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Ulnar artery-> deep palmar arch-> palmar metacarpal arteries
Map veins in hand to deep veins of forearm
Superficial venous palmar arch-> deep vein of forearm
Deep venous palmar arch-> deep vein of forearm
Map the veins in hand to superficial veins in arm
Dorsal venous network-> cephalic vein
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——> basilic vein
Dermatome sensory distribution
Single nerve root (c6, c7, c8)
Peripheral sensory distribution
Individual named nerve (superficial branch of radial nerve, ulnar nerve, median nerve)
Myotome definition
Group of muscles inner step by a single spinal nerve
What Myotomes are in the hand and how are they tested?
C8-T1, tested through the interossei
What 2 thenar muscles are not innervated by the median nerve?
Flexor Pollicis brevis and adductor pollicis
Why does a scaphoid fracture have trouble healing, what is the consequence of this?
It receives little blood supply, this can cause avascular necrosis and degenerative joint disease
What is Dupuytren’s Contracture?
Disease affecting palmar fascia and aponeurosis, unknown cause (potentially hereditary) affects men over 50 y/o of N. European descent, occurs in bilateral hands (pulls 4th/5th digits into flexion)
What is tenosynovitis?
Inflammation of synovial sheath of tendon
What causes trigger finger?
Repetitive, forceful use of pulling the finger; fibrous digital sheath becomes thickened and narrow and keeps finger from flexing/extending
What causes De Quervain’s disease?
Sheath around abductor Pollicis longus and extensor Pollicis brevis becomes inflamed; usually repetitive use of gripping activities; sheath= thickened/narrow; pain over snuffbox radiating up lateral forearm, tender to touch
Carpal tunnel syndrome
Median nerve compression caused by decrease tunnel size, enlargement of tunnel contents, fluid retention, infection, or excessive use of finger flexors
Signs and symptoms of carpal tunnel syndrome
Sensation loss, thenar atrophy/wasting, poor coordination/strength of thumb
What is mallet finger
Extensor tendon avulsed from distal phalanx during forced hypertension (cannot extend DIP)
Jersey finger
Distal insertion of FDP avulsed from distal phalanx during loss of forceful grip (cannot flex DIP)
Skier’s thumb
Tear in ulnar collateral ligament of thumb’s MCP capsule from hyoerabduction
What nerve is injured with claw hand?
Ulnar nerve in tunnel of guyon
What are signs of claw hand?
MCP’s are pulled into hypertension by extensor digitorum and medial lumbrical’s cannot overcome the pull due to ulnar nerve injury
What nerve is injured in ape hand syndrome?
Median nerve in wrist/carpal tunnel
Why does ape hand occur?
Thenar muscles affected (cannot abduct thumb from palm, thenar atrophy/wasting) but FPL and 1/2 FPB can flex thumb across palm
What nerve is injured in hand of benediction?
Median nerve in forearm/elbow
Why does hand of benediction occur?
Thenar muscles are affected and cannot abduct thumb, FDS and 1/2 of FDP also affected (cannot flex PIP or DIP of digits 2-3)
What nerve is injured with wrist drop?
Radial nerve could be injured all the way up as far as the radial groove
Why does wrist drop occur?
With radial nerve injured, the wrist extensors cannot extend against gravity
What condition in the hand can occur with a humeral fracture?
Wrist drop, the radial nerve could be injured in the radial groove in the humeral head