Sievert: Anterior Hand, Joints of the upper limb and nerve lesions Flashcards
Are there intrinsic hand muscles in the dorsum of the hand?
No
The anterior hand can be divided into what two compartment muscles? What are the two muscles of the metacarpals and tendons of the hands?
thenar and hypothenar compartment muscles;
lumbricals and interossei
2 compartments beneath the palmar aponeurosis. Which goes to the thumb? Which goes to little finger?
thenar compartment (lateral to aponeurosis)** thumb hypothenar compartment (medial to aponeurosis) ** little finger
What are the three thenar muscles? What are the three hypothenar muscles?
Opponens pollicis Abductor pollicis brevis Flexor pollicis brevis; Opponens digiti minimi Abductor digiti minimi Flexor digiti minimi brevis;
A disease of the palmar fascia resulting in thickening and shortening of fibrous bands on the palmar surface of the hand and fingers
Dupuytren’s contracture
What nerve innervates the three thenar compartment muscles?
median nerve
Is the ADductor pollicis innervated by the median nerve?
No, it’s not a thenar compartment muscle
What nerve innervates the three hypothenar muscles?
ulnar nerve
What passes through the carpal tunnel?
9 tendons (4 tendons of the flexor digitorum profundus, 4 tendons of the flexor digitorum superficialis, flexor pollicis longus) and the medial nerve
Do the ulnar artery and nerve pass through the carpal tunnel?
No
Which two tendons of the flexor digitorum superficialis are most anterior??
tendons to digits 3&4
Which thenar muscle is most lateral? Which attaches to the base of the metacarpal?
abductor pollicis brevis; opponens pollicis
A strong flexor retinaculum that encompasses 9 tendons and the median nerve. Ulnar artery and nerve do not pass through it.
carpal tunnel
When there is compression of the carpal tunnel, what nerve are you worried about? What are the main side effects?
Median nerve; will cause weakness in the thumb (3 thenar muscles) and numbness in 3.5 digits!
(blank) are muscles in between the metacarpals. (blank) are muscles in between the long tendons.
interossei; lumbricals
The synovial tendon sheaths of digits 3, 4, and 5 can become infected and rupture. Where will the contents be released? What can this cause?
into the midpalmar space; rupture will cause adhesions of all of the tendons in that space, which causes everything to start binding up
If the synovial tendon sheath of digit 2 ruptures, where will the contents be released?
into the thenar space
The thumb is considered the first digit. The little finger is the fifth digit.
Ok.
Which 2 digits have synovial sheaths that tend not to rupture into the midpalmar or thenar spaces. Why? Where do they rupture instead? Is this more or less serious than a midpalmar/thenar rupture?
Tendon sheaths of 1 and 5 can become infected and rupture into the forearm, because their sheaths extend up into the forearm. A rupture here is not as serious!!
T/F: Tendon sheaths of 2,3+4 can become infected and rupture into the thenar (2) or midpalmar (3+4) space.
True
What holds the long flexor tendons tightly against the metacarpals and the phalanges? What band is on the proximal phalanx? What band is on the middle phalanx? What band is near the MP? The PIP? The DIP?
The fibrous digital sheaths; A2; A4; A1; A3; A5
odd ones are nearer the joints
As tendons pass through to attach to phalanges, they must be held down by dense CT bands. This protects from bowstringing. There are 5 (blank) bands that go over the top (A1-A5). There are also (blank) portions, which are much weaker. A2 and A4 are in the middle of the proximal and middle phalanx. 1, 3, and 5 are nearer the joints.
There is a synovial tendon sheath that covers the tendon.
Tendons don’t have a good blood supply, but get some supply from the inferior aspect via an extension of the synovial tendon sheath.
annular; cruciform
Where do lumbricals originate from? Where do they insert? What are they innervated by? Which side of the bone are they located on?
from the flexor digitorum profundus tendons; insert into the extensor hoods; innervated by median (2 on radial side) and ulnar nerves (2 on ulnar side); always on the RADIAL side
What is the action of the lumbricals?
flex MP joint; extend PIP and DIP (salute)
So, collectively what does the ulnar nerve supply?
Ulnar nerve supplies all intrinsic muscles of the hand EXCEPT for the thenar compartment muscles and the 2 lumbricals on the radial side
Interosseous muscles are dorsal and palmar muscles. How many on the palmar side? How many on the dorsal side? Where do they originate? Where do they insert?
3 palmar; 4 dorsal; they originate from the metacarpals; insert on the extensor hoods
What do the interosseous muscles do? What are they innervated by?
DAB the PAD. Dorsal interossei ABduct. Palmar interossei ADduct. They are all innervated by the ulnar nerve.
The interossei pass (blank) to the MP axis, so they help flex at the MP joint. They extend at PIP and DIP because they pull on the (blank)
anterior; extensor hood
Interossei and lumbricals pass (blank) to the MP axis, so any pull at this joint causes flexion. As you pull on the extensor hood, this causes extension at the PIP and the DIP, because lateral and central bands pass (blank) to transverse axis.
anterior; dorsal (posterior
What would happen if you pull away the central band of the extensor tendon?
The lateral band will change position and move anterior to the axis. This will cause extension at the DIP or flexion at the PIP
(blank) come off of deep tendons, while the (blank) are closer to the bones.
lumbricals; interossei
This artery courses dorsally through the snuffbox and gives off branches that communicate with ulnar artery through the deep arch of the palm
radial artery
Which arch supplies the most significant flow to the anterior hand?
the superficial arch
T/F: Collateral flow to the hand is NOT the same in everyone. Use Allen test to check for dominant supply.
True
Lumbrical and interosseous muscles insert into the (blank)
extensor hood
What muscle flexes the DIP?
flexor digitorum profundus
What muscle flexes the PIP?
flexor digitorum superficialis
What is the most common wrist fracture in children? What portion of this bone undergoes necrosis when there is non-union due to poor blood supply?
fracture of scaphoid; proximal portion can undergo necrosis
What is the lateral antebrachial cutaneous a branch of? What nerve roots contribute to it?
musculocutaneous nerve; c5, c6, c7
Is the posterior forearm innervated by the superficial branch of the radial nerve?
no; this only supplies cutaneous innervation to the hand.
What is the anterior arm innervated by? What muscles does this nerve specifically supply?
musculocutaneous; biceps brachii, brachialis, coricobrachialis
What innervates the anterior forearm?
the median nerve goes to everything except the flexor carpi ulnaris and 2 digits of the flexor digitorum profundus (ulnar)
What innervates the anterior hand??
all ulnar nerve, except for thenar compartment muscles and 2 lumbricals on functional midline on the radial side (median)
What innervates the shoulder?
axillary nerve (to deltoid and teres minor)
What innervates the posterior arm and forearm?
radial nerve
All the intrinsic muscles of the hand are
innervated by the ulnar nerve except which two? What are these exceptions innervated by?
the thenar compartment muscles (three) and the lumbricals to the functional midline on the radial side (median)
How does damage to the brachial plexus generally present?
as muscle atrophy
What is Erb-Duchenne paralysis? What is most affected?
damage to the upper trunk of the brachial plexus; shoulder movements affected most dramatically
In Erb’s palsy what will happen to the elbow? The wrist? The grasp?
Lose C5/C6, so lose musculocutaneous (anterior compartment muscles), so this will cause extension of elbow to be predominant. The wrist may be flexed. Grasp will be ok.
How can Erb’s palsy present in adults?
a bit of internal rotation of the shoulder (gesture: gimme your money!!!)
What nerves are affected most by Erb’s palsy?
musculocutaneous
axillary
suprascapular
What can cause Erb’s palsy?
a bad fall on the shoulder
but most likely from a difficult birth, like pulling on an infant’s head while the shoulder is passing through the birth canal
What is Klumpke’s paralysis? What movements are affected most dramatically?
damage of lower trunk of brachial plexus (C8/T1); hand movements most affected
What can cause Klumpke’s paralyis?
hanging off a cliff
pulling a baby out of the birth canal by their arm…
In Klumpke’s palsy, which muscles are chiefly affected? What happens to the grasp? What syndrome may be present? Why?
muscles of forearm and hand are chiefly affected; grasp is weak and the affected limb is small; Horner’s syndrome is present, due to interruption of fibers to the cervical sympathetic trunk (sympathetics to the head are supplied by T1) (this will cause constricted pupils)
Where is the axillary nerve most likely to be damaged? What will damage to the axillary nerve cause?
at the surgical neck of the humerus; weakened abduction because you lose the deltoid (supraspinotis can assist in abduction!!); weakened lateral rotation because you lose the teres minor and posterior deltoid (can still get lateral rotation from infraspinotis)
What will damage to the musculocutaneous nerve cause?
weakened arm flexion; almost cannot flex forearm
Why do you get SOME forearm flexion if you damage the musculocutaneous nerve?
SOME flexion provided by the brachioradialis (posterior compartment muscle with anterior compartment function)
What will damage to the radial nerve cause? What most often causes damage to this nerve?
no forearm extension (loss of triceps)
(if the fracture is below the triceps, you can get SOME extension)
arm may be slightly flexed (loss of long head of the triceps which extends)
loss of grip strength (loss of extendors to the hand);
most often the result of a mid-humeral shaft fracture
Does the superficial radial nerve act on the forearm?
NO, just a sensory nerve that ends in the hand as cutaneous branches to the fingers
Innervates posterior arm muscles
Posterior cutaneous nerve of forearm
Radial nerve
Damage to the radial nerve will result in varying effects depending on the location. Damage high in the arm will cause (blank), weak or absent wrist and digit (blank) and no (blank) at the elbow. This will also have an effect on grip strength. Why? Damage in the forearm will have an effect primarily on the wrist and digit (blank)
wrist drop; extension; extension; no grip strength because you lose extensors to the hand; extensors
Gives off motor branches to anterior arm muscles. Gives off cutaneous branch (lateral antebrachial cutaneous) to lateral forearm
musculocutaneous
In the forearm, what does the median nerve innervate?
all anterior compartment muscles, except the flexor carpi ulnaris and two digits of the flexor digitorum profundus
What does the median nerve innervate in the hand?
2 lumbricals (to the 2nd and 3rd digits)
thenar compartment muscles
3.5 digits
Where is a common place where damage occurs to the median nerve? What does this cause?
at the elbow; lose all flexion in PIP and DIP of 2&3, but not complete for 4&5. Derotated thumb. (papal blessing)
Where else can damage the median nerve occur? What muscles will be involved?
at the wrist (in the carpal tunnel); this will effect the first 2 lumbricals (minimal effect) and the thenar compartment muscles (wasting, derotated thumb)
What will damage to the ulnar nerve cause in the forearm?
loss of flexor carpi ulnaris and 1.5 digits provided by flexor digitorum profundus
What will damage to the ulnar nerve cause in the hand?
loss of all muscles except the thenar compartment and 2 lumbricals
loss of 1.5 digits
What can cause trauma to the ulnar nerve?
fracture of the medial epicondyle
Describe ulnar nerve palsy (it’s complicated)
CLAW HAND: lose all interossei and lose two lumbricals. Will have hyperextension at MP joints. The hyperextension causes flexion of the fingers because of the overriding pull of the flexor tendons (FDS and FDP). The pull isn’t as severe in digits 2 and 3 because the lumbricals are still working.
Ulnar nerve palsy: Most significant feature is the loss of innervation to the interossei muscles resulting in (blank) at the MP joints. This hyperextension cause a concomitant (blank) of the fingers due to the tethering pull of the FDS and FDP. This pull isn’t as severe in digits 2 and 3. Why?
hyperextension; flexion; those 2 lumbricals are still working
Ulnar nerve palsy (claw hand) Hyperextension at what digits? Less hyperextension at what digits? Why? Causes flexion at what digits? Why? Interossei have a major function of flexing MP joint. So what will loss of interossei (innervated by ulnar nerve) cause?
4&5;
2&3 ** they still have lumbricals
4&5;
overriding pull of extensor tendons
If you take out lumbricals 4&5, what will happen at the MP joint? What will happen at the PIP and DIP?
hyperextension at the MP joint; flexion at PIP and DIP
What 3 things can cause the hand to take on distinctive positions following tendon and ligaments injuries?
loss of movement unopposed pulls (papal blessing: taking away certain muscles can allow counteracting muscles to take over) shifted axes (when you tear lateral bands off of extensor hood, its possible for the axis at the PIP AND DIP to shift from extension to flexion)
What’s a jersey finger caused by?
tear of the FDP off of the distal phalanx?
How do you distinguish between a FDP vs FDS injury?
To test for FDP injury, try to flex at DIP of potentially injured finger. If you can flex, not injured.
To test for FDS injury, pull back all unaffected fingers and try to flex “affected” finger.
What causes a mallet finger?
injury to the joint extensor tendon at the DIP (damage to the lateral bands of the central tendon as they insert on the dorsum of the distal phalanx)
What causes a boutonniere deformity of the fingers?
tear of the central extensor tendon (will cause migration of the lateral bands, such that the PIP is now anterior to the axis and will cause flexion at the PIP, with extension at the DIP)
Where are metacarpal ligaments typically torn? What aids in their repair?
at the 4th and 5th metacarpal; transverse metacarpal ligaments help hold the metacarpal in place during repair and help stabilize the hand to prevent “shortening” of the metacarpal
What are the axes of rotation at the glenohumeral joint?
vertical: lateral and medial rotation
AP: ab and adduction
transverse: flexion and extension
What are the axes of rotation at the humeroulnar joint?
transverse: flexion and extension
What are the axes of rotation at the humeroradial joint?
vertical: rotation (pronation and supination)
transverse: flexion and extension
What are the axes of rotation at the radioulnar joint?
vertical: rotation (pronation and supination)
What are the axes of rotation at the radiocarpal joint?
transverse axis: flex and extend
AP axis: ad and abduction
Which carpometacarpal joints allow for much movement? Why is this important? Which joint is multiaxial and allows for ad-ab, flexion/extension, and rotation?
1st and 5th, important for grasping; 1st
Which metacarpal-phalangeal joints are biaxial and allow for ab/ad and flexion/extension? Which are uniaxial
2-5 are biaxial; 1 is uniaxial (no ab/ad)
What is the axis of rotation at the IP joints?
transverse: flexion and extension
What’s the difference between synovial and nonsynovial joints?
synovial: skeletal elements are separated by a joint cavity or space with synovial fluid. They are “freely moveable.”
nonsynovial: skeletal elements are directly connected or continuous. They are “non-movable.”
Give a few examples of non-synovial FIBROUS joints.
sutures in skull (joined by dense CT)
tooth socket
interosseous membrane (between radius and ulna)
Typically, nonsynovial fibrous joints do not allow for much movement. What are some exceptions?
interosseous membrane
Nonsynovial cartilaginous joints are joints in which the skeletal elements are connected by cartilage. This allows for slight movement. What are some examples?
pubic symphysis
intervertebral discs
Most upper limb joints are … what kind?
synovial
What kind of joint is this:
cavity separates the skeletal components and contains synovial fluid
articulating surfaces covered by hyaline/articular cartilage
freely moveable
synovial joints
Components of synovial joint?
skeletal elements articular cartilage joints capsule synovial fluid synovial membrane ligaments
Ligaments of joints can be extracapsular, capsular, or intracapsular. Which is essentially just a thickening of the synovial cavity? Which involves a ligament within the capsule (ex: cruciate ligament)?
capsular ligament; intracapsular
Why does the clavicle break where it does?
coracoclavicular ligaments
What would happen without the AC and CC ligaments?
AC separations would be more common
What ligament is essentially a roof of the glenohumeral joint and helps stabilize the head of the humerus?
Coracoacromial ligament
What increases the depth of the glenoid fossa? What can happen to thist structure?
the glenoid labrum: a continuous ring of cartilage. This helps to deepen the socket. The glenoid labrum is easy to rip off from its attachment to the bone, because the long head of the biceps is attached to it.
What strengthens the GH capsule posteriorly and superiorly?
What strengthens the GH capsule anteriorly?
What about inferiorly?!
supraspinotis infraspinotis teres minor; subscapularis and the superior, middle, and inferior glenohumeral ligaments; no tendons inferiorly **
What way will the GH joint most commonly dislocate? Why?!
anterior-inferior, because there are no tendons to support the capsule
T/F: There is a little “bursa” that surrounds the tendon of the bicipital long head as it
emerges from the glenohumeral joint capsule between the lesser and greater tubercle
of the humerus.
this is a common site of “bursitis a.k.a. bicipital tenosynovitis.
Ok, it’s true
What provides the greatest stability for the GH joint?
the rotator cuff muscles (SITS)
During what motions are rotator cuff tears most common?
abdcution
extension
What muscle attaches to the glenoid labrum?
long head of the biceps
What’s more common: shoulder separation or tear of the coracoclavicular ligament?
shoulder separation; a blow to the clavicle is more likely to cause the clavicle to break than to tear the ligament…
What are the three articulations of the elbow joint?
humeroulnar **elbow joint
humeroradial
proximal radioulnar
Why is the capsule of the elbow baggy on the anterior and posterior aspects?!
to facilitate flexion and extension
What does the radial collateral ligament do?
prevents adduction of the forearm
What does the ulnar collateral ligament do?
prevents abduction of the forearm
The radial collateral ligament attaches to the annular ligament. What does the annular ligament do? What can happen to the annular ligament in children?
holds the head of the radius against the capitulum; this annular ligament can be torn in children, because the head of the radius is not fully developed
What does the annular ligament surround?
the radial head
What are the three joints between the radius and ulna? Which of these joints has a disc? What are these joints involved in?
proximal radioulnar (annular ligament) middle radioulnar (interosseous membran) distal radioulnar** has a disc; the joints are involved in pronation and supination
The transverse carpal ligament, or the flexor digitorum, attaches to what 4 bones? 2 laterally? 2 medially?
scaphoid and trapezium; pisiform and hamate
What do transverse metacarpal ligaments do?
stabilize the hand in single metacarpal fractures
This ligament of the elbow is made up of three bands and is frequently damaged during pitching
ulnar collateral ligament
List the wrist bones!
Scaphoid Lunate Triquetrum Pisiform Trapezium Trapezoid Capitate Hamate
