Kinesiology 2222A/B Lecture Notes - Lecture 21: Extensor Carpi Ulnaris Muscle, Extensor Pollicis Longus Muscle, Flexor Digitorum Profundus Muscle
16 Dec 2016
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Anatomy Lecture November 22nd 2016
• Flexor digitorum profundus innervated by the ulnar nerve. Tendon of the the digit on 5,
and half of digit 4
• The supinator and extensor carpir radial londus are on the back of the hand
• Posterior forearm
o Really want to understand the function
o Named according to action. E.g. extensor digitorum
o Common origin is the lateral epicondyle
o Extensor digitoum
▪ Posterior forearm
▪ There is only one extensor digitorum
▪ On the anterior side there is 2 extenders.
▪ Extends the digits. Goes to the distal phalynx of digits 2-5
o Extensor carpi radialis longus and brevis
▪ He groups them together
▪ 2 attachments distally, metacarpal # 2 and # 3
▪ longus attaches to 2, brevis is 3
• he doest are aout this a futio
▪ this extends the wrist, the carpal region, does not extend the digits
▪ on the radial side, therefore extensor Capri radialis
o Extensor Digiti Minimi
▪ Extends digit #5, the small finger
▪ Extends just this finger
▪ Goes to the distal phalynx of digit 5
o Extensor Carpi Ulnaris
▪ Distally entends the carpals
▪ Wont get to the digits
▪ Must cross the ulnar side, the 5th metacarpal
▪ Runs down the ulnar side.
o Flexor carpi ulnaris
▪ Causes adduction of the wrist, or ulnar deviation
o Opposite for the capir radialis
o The same movements occur with the extensor muscles
▪ E.g. extensor carpi ulnaris causes adduction of the wrist, or ulnar
radiation, in addition to extension of the wrist.
• Depper region
o Mostly moves the thumb
o One moves the index finger
o Extensor indicis
▪ Extends the index finger
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▪ Inserts distally on the phalynx of digit #2
o Proximal attachments are in the forearm
o Common origin for these muscles are the radius and ulna
• Extensor policis longus and brevis
o Two muscles called the extensors
o Polic is known as the thumb
o One goes to the distal phalynx and one goes to the proximal phalynx
o Doest are if e differetiate etee the logus ad reis
o These do the same thing
• Abductor policis longus
o This abducts the thumb
o Belives it attaches to the proximal phalynx
• Supinator
o Posterior forearm muscle
o Attaches from the lateral epicondyle
o Attaches to the radius, hence it is responsible for us supinating
• All are innervated by the radial nerve
o Extensor region in the arm, or triceps, posterior comparments, extensors are all
innervated by the radial nerve.
• Extensor pollicis longus
o If you extend your thumb, and create a pocket. The snuff box
• Extensor polilicis brevis contracts too
• All extensors contract (including the abductor pollicis???)
• In the hand
• Same innvervation as forearm
o Anterior
o Mendial and ulnar nerve
o He will being in radial nerve where necessary
• Intrinsic muscles of the hand
o Thenar group
▪ Muscles the move the thumb
▪ All muscles are innervated by the median nerve (
o Hypothenar group
▪ Muscles that move the pinky
▪ Muscles that flex the digiti minimi
▪ Abductors
▪ Muslces involved in opposition
▪ All muscles here are known as the hypothenar group
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▪ Innervation is the ulnar nerve
• Media ere traels ithi the arpel tuel reated the aprel oes ad…
• Carpal tunnel also contains a bunch of the flexors and the median nerve
• If these flexor muscles are constatnyl being used to flex the digits
• This could arise friction, and could cause inflammation. This is touch for enclosed
muscles, they have no-where to go
• Carpal tunnel syndrome, the inflammation of these muscles cause pressure on this
nerve.
• All of these muscles are innervated by the median nerve. Typing a lot requires use of the
flexor muscles
• This ulnar nerve will not be a part of carpal tunnel, is on the outside of capral tunnel.
• Why would you have short and long muscles in this area?
o Long muscles are stronger (opening up jars for example)
o Finer movements (associated with thenar and hypothenar group
Lumbrincals and Interossei
• Lumbricals (wont talk about) – cause flexion of the digits
o Just tendon attachments, not to bone.
• Dorsal and palmer interossi
o PADs and DABS
▪ The ones you can see from the palm are the PADS, called the palmer
interossi
▪ Adduct the digits
o DABS
▪ Can only see from the dorsal of the hand
▪ Calls them the DABS
▪ Abduct the digits
• Muscles in hand vs forearm
o Comes down to strength
The Brachial Plexus
• Entanglement of nerves
• Affords some redundancy in the innervation of muscles
• Multiple ways a muscle can be innervated
• E.g. brown colored branch
o Multiple ways nerves can get here.
o Why this is important. Say you damage your spinal cord
▪ The nerves still have innervation and can get innervation to the muscle
because it is linked to so many spine
o E.g. diaprhgm. Innervated by C3, C4, C5 keep the diragram ALIVE
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find more resources at oneclass.com
Document Summary
Anatomy lecture november 22nd 2016: flexor digitorum profundus innervated by the ulnar nerve. Tendon of the the digit on 5, and half of digit 4: the supinator and extensor carpir radial londus are on the back of the hand, posterior forearm, really want to understand the function, named according to action. E. g. extensor digitorum: common origin is the lateral epicondyle, extensor digitoum, posterior forearm, there is only one extensor digitorum, on the anterior side there is 2 extenders, extends the digits. If you extend your thumb, and create a pocket. The snuff box: extensor polilicis brevis contracts too, all extensors contract (including the abductor pollicis???) In the hand: same innvervation as forearm, anterior, mendial and ulnar nerve, he will being in radial nerve where necessary. The brachial plexus: entanglement of nerves, affords some redundancy in the innervation of muscles, multiple ways a muscle can be innervated, e. g. brown colored branch, multiple ways nerves can get here, why this is important.
