Anterior Hand-Sievert Flashcards
How is the anterior hand divided?
thenar & hypothenar compartments
*this applies to muscles, lumbricals, interossei
T/F There are intrinsic hand muscles in the dorsum of the hand.
False. There are not.
Where do you flex your hand?
at the creases of your thumb & fingers
What is the palmar aponeurosis?
this is a tendinous thing that covers the intrinsic muscles of your palm
**it makes it more difficult to peel the skin away from the palm of the hand
What are the sections of your palms that aren’t covered by the palmar aponeurosis called? Where are they located?
Thenar compartment: thumb area
Hypothenar compartment: pinky area
**these are areas on either side of the palmar aponeurosis.
How many muscles are found in the thenar & hypothenar compartments? What names do they share? Are these compartments covered by the palmar aponeuroses?
3 muscles are in each compartment
OAF: opponens; abductor, flexor
**NOT covered by the aponeurosis
What is something bad that can happen to your palmar aponeurosis ?
it can undergo contractures–>Dupuytren’s Contracture
**disease of the palmar fascia, thickening & shortening of fibrous bands on the palmar surface of the hand & fingers
What connects to the palmar aponeurosis?
the palmaris longus tendon
What are the thenar muscles exactly? What innervates them?
O: opponens pollicis
A: abductor pollicis brevis
F: flexor pollicis brevis
Nerve: median nerve
What are the hypothenar compartment muscles exactly? What innervates them?
O: opponens digiti minimi
A: abductor digiti minimi
F: flexor digiti minimi (brevis)
Nerve: ulnar nerve
What’s the deal w/ the adductor pollicis?
this is not a thenar compartment muscle
therefore, it isn’t innervated by the median nerve
**considered an adductor of the thumb, innervated by the ulnar nerve.
Which of the OAF muscles is most lateral in the thenar compartment?
abductor pollicis brevis
Where does the flexor pollicis brevis go?
to the metacarpal pharyngeal joint
Where does the opponens pollicis attach?
to a metacarpal
What does the median nerve travel thru? What does the ulnar nerve travel thru?
Median Nerve–>carpal tunnel
Ulnar Nerve–>Guyon’s canal (gets compressed w/ cyclists resting their wrist on the handlebar)
What happens when the median nerve is damaged?
then the thenar carpal muscles are useless
can’t grasp if you don’t have thumb movements
can be damaged w/ carpal tunnel syndrome
What passes thru the carpal tunnel?
Median Nerve
9 tendons w/ an associated bursa
**this includes flexor digitorum superficial is, flexor digitorum profundus, flexor pollicis longus
As far as which fingers are supplied…describe the orientation w/i the carpal tunnel.
The middle 2 fingers’ supply is located right above the lateral 2 fingers’ supply.
Which ligament makes up the carpal tunnel, that is on the superior surface?
flexor retinaculum
What is the first thing that you will probably recognize if you have carpal tunnel?
numbness, tingling in your thumb, index finger, middle finger, half of your ring finger–that is the structures which are supplied by the median nerve.
What is the name of the muscles that connect the metacarpals?
interossei
What is the name of the muscle type that is associated w/ the tendons?
lumbricals
What can cause an infection in the midpalmar space?
rupture of the synovial tendon sheath of digits 3, 4, or (theoretically) 5.
- *this is dangerous b/c it can cause adhesions to tendons as they pass thru the midpalmar space.
- *middle finger is infected…you could lose your whole hand.
- *have to inject an antibiotic
What can cause an infection of the thenar space?
rupture of the synovial tendon sheath of digit 2 & (theoretically 1).
Which fingers usu create infections in the midpalmar or thenar space & which ones don’t? Why?
Digits 2, 3, 4 create infections.
3 & 4 in midpalmar space
2 in thenar space
**digits 1 & 5 usu don’t because their sheaths extend into the forearm. If they ruptured, they would likely rupture in the forearm.
What are the bursa associated w/ the thumb & pinky finger?
Thumb: radial bursa
Pinky Finger: ulnar bursa–>passes thru the carpal tunnel
What are fibrous tendinous sheaths? What is their function? What are the 2 types?
they are osseofibrous bands on the fingers
they hold the long flexor tendons tightly against the metacarpals & phalanges
Anular & Cruciate
Describe the anular & cruciate bands.
Cruciate: cross over the finger in a cross formation. Less important.
Anular: bands that go across (A1-A5) More important
Where are the following anular bands located? A1, A2, A3, A4, 5?
A1: MP joint A2: middle of the proximal phalanx A3: PIP joint A4: middle of the middle phalanx A5: DIP joint
T/F There is a synovial tendon sheath associated w/ the finger.
True. There is a tendon sheath that is located beneath the anular & cruciate bands & above the finger tendon.
It slides back & forth b/w movement of the finger.
Tendons don’t really have a blood supply. Explain the blood supply that the tendons of the finger sorta have.
They do have some blood supply that comes in from the inferior aspect via an extension of the synovial tendon sheath.
Where do the lumbrical muscles originate from? Where do they go to?
Origin: off the deep tendons that come from the flexor digitorum profundus tendon.
Go to: phalanges, to the extensor hood.
Lumbricals are always on which side of the finger?
radial side
What is the action of the lumbricals?
Flex @ the MP joint b/c they pass anterior to it
Extend @ the PIP & DIP b/c they pull on the extensor hood
What is the innervation of the lumbricals?
radial half innervated by the median nerve (first 2 lumbricals)
ulnar half innervated by the ulnar nerve (second 2 lumbricals)
When we are talking generally about the hand what does the ulnar nerve innervate?
everything except for the thenar compartment muscles (there are 3) & the radial half of the lumbricals (there are 2)
When we are talking about the forearm what does the median nerve innervate?
everything except the ulnar half of the flexor digitorum profundus & the flexor carpi ulnaris
Where do interosseus muscles start & end? Where are they located?
Start: @ the metacarpals
End: @ the extensor hoods
**they are located in b/w fingers on the anterior & posterior sides of the hand BUT they are considered anterior compartment muscles
Why are all the interosseus muscles considered anterior compartment muscles even tho some of them are located on the dorsum of the hand?
this is b/c of their innervation. They are all innervated by the ulnar nerve.
How many interosseus muscles are found on the palmar surface of the hand? What is their action?
3 palmar interosseus muscles (mostly unipenate)
These adduct.
PAD
How many interosseus muscles are found on the dorsal surface of the hand? What is their action?
4 dorsal interosseus muscles (mostly bipenate)
These abduct.
DAB
The abductor digiti minimi is on the dorsal surface of the hand, to the medial side of the pinky finger. It abducts the finger. Why in the world isn’t it considered an interosseus muscle?
b/c it is considered to be a part of the hypothenar compartment
When the interosseus muscles pass the MP joint are they anterior or posterior?
they are anterior to the joint
similar in this way to the lumbricals
What is the significance of both lumbricals & interosseus muscles inserting in the extensor hood?
significance is that they will both cause flexion @ the MP joint (b/c they pass anterior) & extension @ the PIP & the DIP (b/c they pull on the extensor hood & pass dorsal to the finger)
T/F there are bands of the lumbricals & interosseus muscles that appear to pass dorsal to the phalanx.
TRUE This is a part of the explanation of their action, like the extension of the PIP & DIP or something.
Describe the basic structure of the tendons near the end of the finger, including the extensor hood.
palmar side of the finger:
FDS splitting @ PIP & FDP going underneath until it reaches the DIP.
dorsal side of the finger:
long extensor tendon becoming central band which ends @ the PIP. interosseus muscles seem to give good contribution to this.
lateral band on either side of the central band which ends @ the DIP. lumbrical muscles seem to give a good contribution to this.
What could happen to your finger if you suddenly lost your central band?
your lateral band could slip off to the side & you would get extension @ the DIP but flexion @ the PIP
What could happen to your finger if you suddenly lost your lateral band?
you wouldn’t be able to extend @ DIP, your distal phalanx.
You would get mallet finger.
Which muscle is located closer to the bone–interosseus or lumbricals?
interosseus muscles
What are the actions of the FDP & FDS on the finger?
FDP flexes DIP
FDS flexes PIP
If you are using your FDP & FDS & flexing your fingers…what else is needed to make a tight fist?
extensor tendons @ your wrist
Describe the collateral flow in the hand.
Radial artery forms the deep palmar arch. This anastomoses w/ the ulnar artery’s deep palmar branch. It gives off 3 palmar metacarpal arteries that join the common palmar digital arteries from the superficial arch. Ulnar artery forms the superficial palmar arch. This anastomoses w/ the superficial palmar branch of the radial artery. It gives off common palmar digital arteries (which joint palmar metacarpal arteries) & split into proper palmar digital arteries.
What is the Allen test used for? How does this relate to the collateral flow of the hand?
used to determine the source of dominant blood supply in the hand.
sometimes people want to use the radial artery for bypass. Need to first make sure it isn’t dominant.
Everybody’s collateral flow is different!
What is the most common wrist fracture in children?
fracture of the scaphoid
Describe a scaphoid fracture.
radial artery gives off the palmar carpal branch. this supplies the scaphoid. When you have a fracture of the scaphoid it compromises your blood supply & becomes difficult to heal. Non-union can become a problem. the proximal portion of the scaphoid can even start to undergo necrosis.
Okay, so we are talking cutaneous nerve innervation patterns. What branch of the radial nerve takes care of the back of the hand? Which branch takes care of the back of the arm & forearm?
Arm & Forearm: posterior cutaneous of the radial nerve
Back of the Hand: superficial radial nerve
Which cutaneous nerve takes care of the radial side of the forearm? What is this a branch off of? Which cranial nerves can it be traced back to?
lateral antebrachial cutaneous nerve
branch of the musculocutaneous nerve
this comes from the brachial plexus & is a C5, C6, C7 deal.
Anterior compartment of the arm is innervated by?
musculocutaneous nerve
Anterior compartment of the forearm is innervated by?
All median nerve
Except: ulnar half of the flexor digitorum profundus & the flexor carpi ulnaris (ulnar nerve)
Anterior hand is innervated by?
all ulnar nerve except thenar compartment muscles & radial half of the lumbricals
**median nerve innervates these exceptions
The posterior compartment of the shoulder is innervated by?
axillary nerve–>goes to the deltoid & teres minor
The posterior arm & forearm is innervated by what?
radial nerve