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Saturday, May 03, 2008

Mnemonic for forearm muscles and bone

There are a lot of structures in your upper limb (note that in medical term; arm, forearm and hand means differently from the common usage).

I would like to introduce you on how I remember the names of important muscles and bones in the upper limb. There are various mnemonics created by medical students around the world to master the field of anatomy.

Carpal bones.
I used this mnemonic;

Stop Letting Those People Touch The Cadaver's Hand.

From lateral to medial;
Proximal row - Scaphoid, Lunate, Triquetrum and Pisiform
Distal row - Trapezium, Trapezoid, Capitate and Hamate.

To differentiate trapezium and trapezoid, remember that Trapezium is at Thumb, hence the most lateral bone in distal row of carpal bones.

Extensor muscles of forearm
Rule of 3

3 muscles for wrist extension

  • Extensor carpi radialis brevis
  • Extensor carpi radialis longus
  • Extensor carpi ulnaris

3 muscles for finger extension

  • Extensor digitorum ( for all four fingers)
  • Extensor indicis
  • Extensor digiti minimi

3 muscles for thumb

  • Extensor pollicis longus
  • Extensor policis brevis
  • Abductor pollicis longus

Nerve:
All extensor muscles of forearm are supplied by radial nerve. Injury to radial nerve caused the classical wrist drop due to unopposed flexor muscles :)

Flexor muscles of forearm.
Place your thumb at the palm and put this at your contralateral forearm at your medial epicondyle with your middle finger pointing towards the thumb distally. The forearm must be in supine position.

Your thumb will be below the palm and four fingers will be pointing towards the hand. This represents the layers in flexor muscles in the forearm.

Say PFPF. The first P in your index finger is Pronator Teres. F is for flexor carpi radialis (the middle finger point towards radial bone, hence radialis). The next P is for palmaris longus and F is for flexor carpi ulnaris.

The thumb is for flexor digitorum superficialis.

There are 3 layers in the flexor compartment. The muscles in the deep layer are flexor digitorum profundus (FDP), flexor pollicis longus and pronator quadratus.

Nerve:
All flexor muscles of forearm are supplied by median nerve except one and half. They are flexor carpi ulnaris and half of flexor digitorum profundus.

Muscles of the hand
PAD DAB - palmar hand muscles adduct, dorsal hand muscles abduct

Thenar and hypothenar muscles
All For One And One For All (medial to lateral)

Abductor digiti minimi, Flexor digiti minimi, Opponens digiti minimi, Adductor pollicis, Opponens Pollicis, Flexor Pollicis Brevis, Abductor pollicis brevis

All intrinsic muscles of the hand are innervated by ulnar nerve except these muscles which are innervated by the median nerve

LOAF muscles

Lateral 2 lumbricals, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis

22 comments:

whenimoveon said...

knapakan saya tak berpeluang membaca entry ini kertika saya benar2 memerlukan semua ini 3 hari yang lepas? hhuhuhuhuhuuuuu.........

hafiz238 said...

sorry to hear that. Most of these mnemonics are quite popular and help me to remember the muscles.

chem said...

thanks for these info...interesting

btw, our mnemonic for carpal bones:

She Looks Too Pretty
Try To Catch Her

we've been using this mnemonic since 1st year, and i still remember it, alhamdulillah :)

hafiz238 said...

@ chem, hopefully this post will help someone to know about anatomy.

There are several mnemonics for carpal bone. Some are 18SX and not suitable to be written here. I choose this one since it is easy to remember.

Minci said...

wahhhh.. thank u for imparting this lilpiece of knowledge
:P

Que said...

Hafiz
yg 18sx tu yg Some lovers bla bla tu kan? hiks been using that since first yr coz hillarious

anyway yg LOAF muscle tu is that muscles supplied by median nerve?

Que said...

sudah terang lagi bersuluh, actually tak nampak plak mmg dah tertulis median nerve huhuhu apologies

hafiz238 said...

@minci, you are welcome.

@Que, yup, that is the one :).

LOAF muscles are supplied by median nerve and the rest by ulnar nerve. In late stage of median nerve palsy, you can see thenar wasting.

hahahaha said...

Can you please whisper me on PM what those dirty mneunomics are :D I'm so curious now haha..

Hafiz said...

some things are better left unsaid or in this case, written in this blog ;)

Anonymous said...

it goes something along the lines of 'some lovers try p.......s that they cant handle'! fill in those missing 7 letters as you please!

Anonymous said...

Thanks for sharing the link, but unfortunately it seems to be down... Does anybody have a mirror or another source? Please reply to my post if you do!

I would appreciate if a staff member here at hafiz238.blogspot.com could post it.

Thanks,
Harry

Hafiz said...

to Harry,

I'm not really sure what do you meant by the link is down.

Perhaps you could tell me further.

Anonymous said...

Thanks for sharing this link, but unfortunately it seems to be down... Does anybody have a mirror or another source? Please reply to my message if you do!

I would appreciate if someone here at hafiz238.blogspot.com could repost it.

Thanks,
James

Anonymous said...

For carpal bones..
Some Lovers Try Positions
That They Can't Handle

Anonymous said...

Or... "so long the pinky, here comes the thumb" (you end up at the thumb and go in a circle)

Anonymous said...

Hello there,

This is a inquiry for the webmaster/admin here at hafiz238.blogspot.com.

Can I use some of the information from your blog post above if I give a link back to your website?

Thanks,
Alex

Neda said...

Hey,
just wanted to say thanks, this page has been MAJORLY useful to me! You are a star :)

Anonymous said...

can you please explain the Flexor muscles of forearm section. It seems like it could be really helpful, but I dont understand what your doing here? Thanks a lot....

just starting M1

Anonymous said...

Shy Lovers Try Positions That They Can't Handle

Anonymous said...

thanks a lot for this, it has honestly made it a lot easier to remember everything.

Anonymous said...

Thank you soo much!! This has made memorizing so much easier!