The Wrist and Hand Flashcards
How many carpal bones are there?
8: 4 in proximal row, 4 in distal row.
What carpal bones are in the proximal row?
- pisiform - triquetrum - lunate - scaphoid
What carpal bones are in the distal row?
- hamate - capitate - trapezoid - trapezium
True or false, there is an articular disc between the ulnar and carpals
True
What is the acronym for the carpal bones?
Some - scaphoid Lovers - luate Try - triquetrum Positions - pisiform That - trapezium They - trawpezoid Can’t - capitate Handle - hamate
List the metacarpals from I - V
I - thumb (pollex) II - index finger III - rude finger IV - ring finger V - little finger
What are the three features of each metacarpal bones and phalanges?
head, shaft and base
What do the metacarpals articulate with?
proximal phalanges and distal carpals
What digit has only 2 phalanx?
pollex (thumb) has only distal and proximal phalanx
How many phalanx does digits II - V have?
3 - proximal, middle and distal
Classify the radiocarpal (wrist) joint
synovial, condyloid (ellipsoid) joint
What are the articular surfaces of the radiocarpal joint?
proximal row of carpals (excluding pisiform) and radius and articular discs
What are the two radiocarpal ligaments and what is their purpose?
- palmar and dorsal - ensures the hand follows radius is pronation and supination
What are the two extracapsular ligaments of the radiocarpal joint?
radial collateral and ulnar collateral ligaments
What are the movements at the wrist joint?
- flexion/extension - abduction/adduction (ulnar/radial deviation) - circumduction
What are the wrist flexors?
- flexor carpi radialis - flexor carpi ulnaris - palmaris longus
What are the attachments of the flexor carpi radialis?
medial epicondyle (humerus) to the 2nd and 3rd metacarpals
What is the function of flexor carpi radialis?
helps in abduction (ulnar deviation) and is a flexor
What is flexor carpi radialis’ nerve supply?
median nerve
What are the attachments of flexor carpi unaris?
medial epicondyle (humerus) and ulna to carpals and 5th metacarpals
What are the actions of flexor carpi ulnaris?
helps in adduction (radial deviation) and is a flexor
What is the flexor carpi ulnaris innervated by?
ulnar nerve
What are the attachments of the palmaris longus?
come from medial epicondyle and inserts into connective tissue in middle of palm (palmar aponeurosis)
What flexor is missing in 12% of people?
palmaris longus
What is palmaris longus innervated by?
median nerve
What surface of the wrist do the flexor muscles cross?
anterior
What are the extensors of the wrist?
- extensor carpi radialis longus and brevis - extensor carpi ulnaris
What are the attachments of extensor carpi radialis longus and brevis?
posterior distal humerus and lateral epicondyle to 2nd and 3rd metacarpals
What is the extensor carpi ulnaris longus and brevis innervated by?
radial nerve
What are the attachments of extensor carpi ulnaris?
lateral epicondyle of humerus to carpals and 5th metacarpal
What is extensor carpi ulnaris innervated by?
radial nerve
What muscles cause abduction and adduction of the wrist?
abduction (ulnar deviation) - extensor carpi radialis longus and brevis and flexor carpi radialis adduction (radial deviation)- extensor carpi ulnaris and flexor carpi ulnaris
What muscles does circumduction involve?
all muscles at different times
What are the 3 joints in the hand?
- carpometacarpal - metacarpophalangeal - interphalangeal
What are the movements at the interphalangeal joints?
only flexion and extension
What are the muscles that flex the fingers?
- flexor digitorum superficialis - flexor digitorum profundus
What muscle is deeper, flexor digitorum superficialis or flexor digitorum profundus?
flexor digitorum profundus
What are the attachments of flexor digitorum superficialis?
medial epicondyle of humerus to muddle phalanges (2 -5)
What is the flexor digitorum superficialis innervated by?
median nerve
What are the attachments of flexor digitorum profundus?
originates on ulna and inserts on digits 2 - 5
What is the flexor digitorum profundus innervated by
- median nerve (digits 2 & 3) - ulnar nerve (digits 4 & 5)
What is the muscles that extend the fingers?
extensor digitorum
What are the attachments of extensor digitorum?
lateral epicondyle and inserts on distal phalanges 2 - 5 passing through extensor hoods
What is the extensor digitorum innervated by?
radial nerve
What is the purpose of the extensor hood?
protects tendons
What muscles point the fingers?
Extensor indicis and extensor digiti minimi
What are the attachments of extensor indicis?
distal ulna and interosseous membrane to 2nd metacarpal (under extensor hood)
What is the extensor indicis innervated by?
radial nerve
What are the attachments of extensor digiti minimi?
ulna and interosseous membrane to 5th digit
What is the innervation of extensor digiti minimi?
radial nerve
Describe extensor digiti minimi
small, skinny, deep muscle
What is the extensor retinaculum?
band of tough, fibrous connective tissue on posterior surface of the wrist which stabilizes and contains the actions of tendons of extensor muscles
What are the muscles that move the pollux (thumb)?
flexor pollicis longus, extensor pollicis longus, extensor pollcs brevis, opponens pollics and adductor pollicis longus
What are the attachments of flexor pollcis longus?
radius and interosseous membrane to distal phalanx of pollux
What s the flexor pollics longues nnervated by?
median nerve
What are the attachments of extensor pollics longus and brevis?
extensor surface of radus, ulna and interosseous membrane to distal phalanx of pollux
What is the innervation of extensor pollcs longus and brevis?
radial nerve
Which is shorter, extensor pollicis longus or brevis?
brevis
Which is deep, extensor pollicis longus or brevis?
brevis
What is the attachments of adductor pollics longus?
extensor surface of radius, ulna and interosseous membrane the metacarpal I
What is the adductor pollicis longus innervated by?
radial nerve
What are the attachments of opponens pollicis?
trapezium to metacarpal I
What are the movements allowed by opponens pollicis?
opposition and repostion
What are the intrinsic muscles of the hand?
muscles that move the metacarpals and originate and insert only on these bones
What is the flexor retinaculum?
covers and holds many flexor tendons entering the hand Allows us to grasp and grip objects
What muscles pass in the carpal tunnel?
Within tunnel – flexor digitorum superficialis, flexor digitorum profundus, flexor pollicis longus and median nerve
What is the palmar aponeurosis
Tissue under the skin of the palm that helps form ridges in the palm. Helps increase friction so that we can grasp objects firmly
What forms the carpal tunnel?
The space between the flexor retinaculum and the carpal bones
What tendon inserts into the palmar aponeurosis?
Tendon of palmaris longus inserts into aponeurosis
What is the extensor retinaculum?
a strong fibrous band in the fascia of the distal forearm that attaches to the lateral border of the radius and crosses to attach to 2 carpal bones. Makes a tunnel that transmits tendons beneath it into the wrist
What are the extensor hoods/dorsal digital expansion? What does it allow?
a spreading out of tendons of extensor digitorum as they pass over the back of the metocarpalphalageal joints. Form a hood through intendinous connections from other tendons. Tension on hood leads to extension of the IP joints
What muscles attach to the extensor hoods?
Lumbricals attach to the hood to extend IP joints
What are the three functional regions of the hand?
Thenar region – thumb muscles (4 muscles) Hypothenar regions – 5th digit muscles (3 muscles) Mid-palm region – 3 different muscles
What muscles move the thumb? What movements do they allow?
flexor pollicis brevis - flexion opponens pollicis - opposition adductor brevis - adducton abductor brevis - abduction
What actions can the thumb do?
flexion, extension, adduction, abduction and opposition
What are the muscles of the thumb innervated by?
median nerve except adductor pollicis which is innervated by ulnar nerve
What are the muscles of the hypothenar region? What movements do they produce?
opponens digiti minimi - opposition flexor digiti minimi - flexion abductor digiti minimi - abduction
What are the muscles of the hypothenar region innervated by?
ulnar nerve
Where do adduction and abduction of the finger muscles lie?
laterally
What are some muscles that adduct and abduct the fingers
palmar interrosei - adduction of metacarpophalangeal joints and PAD dorsal interrosei - abduction of MCP joints and DAB
What are the interrosei innervated by?
ulnar nerve
What is the function of the lumbricals?
flex the MCP joints and extend IP joints
What are the lumbricals innervated by?
median and ulnar nerves
What is the position of the hand?
Wrist in slight extension MCP and PIP in some degree of extension, thumb in opposition
What are the function advantages of position of the hand?
Functional advantages – flexors lengthened giving them more torque
What muscles does opening the hand involve?
Opening the hand involves the extrinsic finger extensor and thumb adductors and extensors
What do power grips involve?
Fingers flex around an object from one direction while thumb wraps around in opposite direction. Provides a counterforce to keep the object in contact with the palm and/or fingers
What are the 3 types of power grips?
cylindrical, spherical and hook
What are the joint movements during grips?
- wrist: extended and ulnar deviates. - Fingers: IP joints flexed, MP joints flexed & adducted in spherical grip. - Thumb: mostly adduction, some opposition occurs
When are precision grips used?
Used when manipulating objects with the finger or holding an object between the fingers and thumb – no palm involvement or movement of the proximal joints
What are the types of precision grips?
lateral pinch (key grip), tip to tip (pincer grip), pad to pad (pinch) and lumbricals grip (plate grip)
What muscles are used in precision grips?
The lumbricals and interrosei act on the joints of fingers while the thenar muscles act of the thumb and the pads of the digits are bought into contact
What muscles are used during digital sweep?
Extrinsic muscles involved – extensors (digits) = IP extension Intrinsic muscles involves – lumbricals and interrosei (adducted in sweep, abducted if open hand)
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