Module 3: Posterior Forearm, Hand, and Wrist Flashcards
What are the attachments of the brachioradialis?
origin: lateral supracondylar ridge of humerus
insert: distal radius, lateral to styloid process
What nerve innervates brachioradialis?
radial c5-6
What is the action of brachioradialis?
flex elbow
What are the attachments of extensor carpi radialis longus?
origin: lateral supracondylar ridge of humerus
insert: base of 2nd metacarpal
What nerve innervates extensor carpi radialis longus?
radial c6-8
What is the action of extensor carpi radialis longus?
extend wrist, radial deviation, flex elbow
What are the attachments of extensor carpi radialis brevis?
origin: lateral epicondyle of humerus
insert: base of 3rd metacarpal
What nerve innervates extensor carpi radialis brevis?
radial c6-8
What are the actions of extensor carpi radialis brevis?
extend wrist and radial deviation
What are the attachments of extensor digitorum?
origin: lateral epicondyle
insert: extensor expansion of digits 2-5
What nerve innervates extensor digitorum?
radial c6-8
What are the actions of extensor digitorum?
extend phalanges and wrist
What are the attachments of extensor digiti minimi?
origin: lateral epicondyle
insert: digital expansion of 5th digit
What nerve innervates extensor digiti minimi?
radial c7-8
What are the actions of extensor digiti minimi?
extend 5th digit
What are the attachments of extensor carpi ulnaris?
origin: lateral epicondyle
insert: base of 5th metacarpal
What nerve innervates extensor carpi ulnaris?
radial c6-8
What are the actions of extensor carpi ulnaris?
extend wrist and ulnar deviation
What are the superficial posterior forearm muscles?
- brachioradialis
- extensor carpi radialis longus
- extensor carpi radialis brevis
- extensor digitorum
- extensor digiti minimi
- extensor carpi ulnaris
What are the attachments of supinator?
origin: lateral epicondyle, radial collateral ligament, supinator crest of ulna
insert: lateral surface of proximal radius
What nerve innervates the supinator?
radial nerve c5-6
What is the action of the supinator?
supinates forearm
What are the attachments of extensor indicis?
origin: posterior surface of ulna + interosseous membrane
insert: digital expansion of 2nd digit
What nerve innervates extensor indicis?
radial c7-8
What is the action of extensor indicis?
extend 2nd digit
What are the 2 deep posterior forearm muscles?
- supinator
- extensor indicis
What are the attachments of abductor pollicis longus?
origin: proximal posterior radius, ulna, interosseous membrane
insert: base of 1st metacarpal + trapezium
What nerve innervates abductor pollicis longus?
radial c6-8
What are the actions of abductor pollicis longus?
abducts + extend thumb of carpometacarpal joint + radial deviation
What are the attachments of extensor pollicis longus?
Origin: middle 1/3 of posterior surface of ulna + interosseous membrane
insert: base of 1st distal phalanx
What nerve innervates extensor pollicis longus?
radial c6-8
What are the actions of extensor pollicis longus?
extend thumb
What are the attachments of extensor pollicis brevis?
origin: posterior radial surface + interosseous membrane
insert: base of 1st proximal phalanx
What nerve innervates extensor pollicis brevis?
radial c6-8
What are the actions of extensor pollicis brevis?
extend thumb + extend and abduct CMC joint
What are the outcropping muscles of the forearm?
-abductor pollicis longus
- extensor pollicis brevis
- abductor pollicis brevis
What happens to the radial nerve when it bifurcates?
- superficial branch becomes the cutaneous nerve
- deep radial nerve passes through the supinator and becomes the posterior interosseous nerve
What is the extensor retinaculum and its role?
- thickening of ante brachial fascia
- directs tendons in precise way for precise movement of the digits and prevents bowstringing
What are the general actions of the posterior compartment of the forearm?
extension and supination of wrist/forearm
What is the neurovasculature of the posterior forearm?
- posterior interosseous nerve and artery
- recurrent interosseous artery
What are the thenar muscles?
- abductor pollicis brevis
- flexor pollicis brevis
- opponens pollicis
What are the attachments abductor pollicis brevis?
Origin: the transverse carpal lig.
Insert: to the radial side of the base of the proximal
phalanx of the thumb and tubercle of trapezium
What are the actions of abductor pollicis brevis?
abduct thumb
What nerve innervates abductor pollicis brevis?
recurrent branch of median c6-t1
What are the attachments of flexor pollicis brevis?
Origin: the transverse carpal lig. & trapezium
Insert: to the radial side of the base of
the proximal phalanx of the thumb; deep head blends with opponens pollicis
What nerve innervates flexor pollicis brevis?
recurrent branch of median nerve (superficial head) c6-t1
deep branch of ulnar nerve (deep head) c8-t1
What are the actions of abductor pollicis brevis?
abduct thumb
What are the actions of flexor pollicis brevis?
flex MCP thumb
What are the attachment opponens pollicis?
Origin: the transverse carpal lig. & trapezium
Insert: to the palmar surface of the 1st
metacarpal
What nerve innervates opponens pollicis?
recurrent br of median n c6-t1
What Is the action of opponens pollicis?
thumb opposition
What are the 3 hypothenar muscles?
- opponens digiti minimi
- flexor digiti minimi brevis
- abductor digiti minimi
What are the attachments of opponens digiti minimi?
from the hook of the hamate to the ulnar margin of the shaft of the 5th
metacarpal
What nerve innervates opponens digiti minimi?
deep br of ulnar nerve c8-t1
What is the action of opponens digiti minimi?
opposition of pinky
What are the attachments of flexor digiti minimi brevis?
from the hamate to the ulnar side of the base of the proximal phalanx of
the 5th digit
What nerve innervates flexor digiti minimi brevis?
deep br of ulnar c8-t1
What is the action of flexor digiti minimi brevis?
flex MCP of pinky
What are the attachments of abductor digiti minimi?
from the pisiform to the ulnar side of the base of the proximal phalanx of
the 5th digit
What nerve innervates abductor digiti minimi?
deep br of ulnar n c8-t1
What is the action of abductor digiti minimi?
abduct pinky
What are the attachments of adductor pollicis?
from the capitate & 2nd & 3rd metacarpals (oblique head) & the palmar
aspect of the 3rd metacarpal (transverse head) to the base of the proximal phalanx of
the thumb
What nerve innervates adductor pollicis?
deep br of ulnar n c8-t1
What is the action of adductor pollicis?
adduct thumb
What is the significance of the transverse and oblique head of adductor pollicis?
deep br of ulnar n and deep palmar of radial nerve run through heads
What are the attachments of the lumbricals?
tendons of Flexor digitorum profundus to radial aspect of dorsal expansion 2-5 digits
What nerve innervates the lumbricals?
deep br ulnar 3rd and 4th (c8-t1)
median n 1st and 2nd (c7-c8-t1)
What is the action of the lumbricals?
flexes MCP and extend IP joints of digits 2-5
What are the attachment of palmar interossei?
from the palmar aspects of metacarpals 2, 4 & 5 to the dorsal digital
expansions of digits 2, 4, 5
What nerve innervates the palmar interossei?
deep br of ulnar n c8-t1
What are the actions of palmar interossei?
adduct MCP, flex MCP, extend IP 2, 4 and 5 digits
What are the attachments of the dorsal interossei?
from the adjacent sides of the metacarpals to the proximal phalangeal
bases & dorsal digital expansions of digits 2-4
What nerve innervates the dorsal interossei?
deep br ulnar c8-t1
What are the actions of the dorsal interossei?
abducts MCP, flex MCP, extend IP digits 2-4
What are the joints of the wrist and hand?
distal radioulnar = pivot
radiocarpal = ellipsoidal or condyloid
carpometacarpal
1. thumb = saddle
2. 2nd-5th = plane/ gliding
metacarpophalangeal = ellipsoidal
interphalangeal = hinge
mid carpal and inter carpal
What are the attachments and actions of the transverse carpal ligament?
attach: scaphoid and trapezium to pisiform and hamate
function:
- maintain carpal arch
- prevents bowstringing of flexor tendons
- protects median n
houses: FDP, FDS, FPL, median n.
What is the significance of the transverse carpal ligament with carpal tunnel syndrome?
sheaths in ligament prone to swelling causing compression of the median n.
What are the 8 carpal bones?
distal: trapezium, trapezoid, capitate, hamate
proximal: pisiform, triquestrum, lunate, scaphoid
What are the bones of the digits?
phalanges 2-5 (P, M, D)
1st digit (P, D)
What are the attachments of the collateral ligaments of the MCP joints?
dorsal of proximal phalanx to palmar distal phalanx
What is the function of the collateral ligaments of MCP joints?
stabilize MCP joints
How does the extensor hood work?
- on the back of digits
- allows long digital flexors (FDS, FDP) and short muscles of hand (lumbricals , interossei) to act on MCP, PIP, and DIP joints
- pull on hood flex MCP joint, extend IP joints
What are the boundaries and contents of the anatomical snuff box?
- extensor pollicis longus tendon
- extensor pollicis brevis tendon
- extensor retinaculum
scaphoid bone and radial artery
How many intrinsic hand muscles are there?
18
What are the compartments of the extensor retinaculum?
- APL, EPB
- ECR (L+B)
- EPL
- ED, EI
- EDM
- ECU
What is the function of a volar plate?
limits hyperextension of phalanges
What is the function of the triangular fibrocartilage complex?
connect ulnar side to wrist joint
What are the actions involved in opposition?
- abduction + medial rotation of 1st metacarpal
- flexion of 1st metacarpal at MCP joint
- reinforcement via adductor pollicis + FPL
What are the actions of the fingers?
- add/abduction
- flex + ext MP
- flex + ext IP
What are the actions of the thumb?
- add/abduction
- extension
- opposition
What is the cutaneous innervation of the dorsal hand?
- median = tips of 2, 3, 4 digits
- radial = dorsum of hand and 2, 3, 4 digits
- ulnar = dorm of hand and half of 4 and 5 digits
What is the cutaneous innervation of the palmar aspect of the hand?
- median = palm, thumb, 2 to half of 4
- radial = medial thumb
- ulnar palmar of 5 and half of 4
