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232 Cards in this Set

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what's the joint that we usually consider to be the "shoulder"?
glenohumeral joint
what kind of joint is the glenohumeral joint?
ball and socket
what makes up the ball and socket of the glenohumeral joint?
ball = head of humerus
socket = glenoid fossa of scapula
what are advantages and disadvantages to the structure of the glenohumeral joint?
the ball is too big for the socket
advantage = great range of motion
disadvantage = easy to dislocate
how is the glenohumeral joint stabilized?
1. acromion process of scapula
2. coracoid process of scapula
3. tendons of rotator cuff muscles
4. tendon of biceps brachii holds humerus in place
what is the weak spot in the glenohumeral joint?
ventral part of joint - is why most dislocations present as inferior from a blow to the abducted arm
how is additional range of motion achieved in the shoulder?
rotation of the scapula
medial rotation = reaching down
lateral rotation = reaching above horizontal plane
point of reference is inferior angle of scapula
what are the motions of the scapula?
lateral rotation, medial rotation, elevation, depression, protraction, retraction
what is retraction of the scapula?
bringing scapula toward midline
what is protraction of the scapula?
pushing scapula away from midline
where are the muscles that move the shoulder?
superficial back, pectoral region, deep within shoulder
what about the trapezius do i need to know to understand shoulder motion?
it holds the upper limbs in place
it's innervated by an accessory nerve, cranial nerve XI
what about the latissimus dorsi do i need to know to understand shoulder motion?
it's an adductor, extensor and medial rotator of shoulder
innervated by the thoracodorsal nerve
what's another, more appropriate name for the pectoral region?
anterior axioappendicular region because the group of muscles here connect the upper limb to the axial skeleton and they can be found anteriorly
what are the three muscles of the anterior axioappendicular region that i need to know?
Pectoralis major and minor, serratus anterior
what's the origin, insertion, innervation and action of the pectoralis major?
origin: medial clavicle, costal cartilage, sternum
insertion: humerus
innervation: lateral and medial pectoral nerves
actions: adductor, medial rotator of humerus
origin, insertion, innervation and actions of pectoralis minor?
origin: ribs 3-5
insertion: coracoid process of scapula
innervation: medial pectoral nerve
actions: stabilizes and medially rotates scapula
origin, insertion, innervation and action of serratus anterior
origin: ribs 1-8
insertion: anterior surface of medial scapular border
innervation: long thoracic nerve
action: stabilizes and laterally rotates scapula, allowing abduction of arm above horizontal plane
why is the long thoracic nerve prone to injury?
not protected by overlying muscle
how is the long thoracic nerve usually damaged?
surgeons accidentally cutting through it, especially while removing lymph nodes for breast cancer patients
stab wounds
blow to shoulder (near where nerve originates from brachial plexus)
what's result of loss of long thoracic nerve?
paralysis of serratus anterior leads to winging of the scapula
what characterizes the muscles of the scapular region?
they originate on the scapula and insert on the humerus
how many muscles do i need to know about in the scapular region?
6
what are the names of the muscles i need to know about in the scapular region?
1. deltoid
2. supraspinatus
3. infraspinatus
4. teres minor
5. teres major
6. subscapularis
origin, insertion, innervation and actions of deltoid muscle
origin: clavicle, acromion, scapular spine
insertion: deltoid tuberosity of humerus
innervation: axillary nerve
actions: jack of all trades
abducts, flexes, extends, medially and laterally rotates - everything BUT adduction OF ARM
origin, insertion, innervation and actions of supraspinatus
origin: supraspinous fossa of scapula
insertion: humerus greater tubercle
innervation: suprascapular nerve
actions: initiates abduction, holds head of humerus in glenoid cavity
origin, insertion, innervation, actions of infraspinatus
origin: infraspinous fossa of scapula
insertion: greater tubercle of humerus
innervation: suprascapular nerve
action: holds head of humerus in glenoid cavity, laterally rotates arm
origin, insertion, innervation, actions of teres minor
origin: lateral border of scapula
insertion: greater tubercle of humerus
innervation: axillary nerve
actions: secures humerus head in glenoid cavity, laterally rotates arm (same as infraspinatus)
origin, insertion, innervation, actions of subscapularis
origin: subscapular fossa
insertion: lesser tubercle of humerus
innervation: upper and lower subscapular nerves
actions: holds humerus head in glenoid cavity, medially rotates humerus
origin, insertion, innervation, actions of teres major
origin: inferior angle of scapula
insertion: humerus shaft
innervation: lower subscapular nerve
actions: adductor and medial rotator of arm
what are the four rotator cuff muscles?
1. supraspinatus
2. infraspinatus
3. teres minor
4. subscapularis
what innervates the rotator cuff muscles?
axillary nerve innervates teres minor, upper and lower subscapular nerves innervates subscapularis and the suprascapular nerve innevates both the supra and infraspinatus
which muscle is most frequently injured when the rotator cuff is torn?
tendon of the supraspinatus tears
what origin and insertions do the rotator cuff muscles have in common?
take origin from scapula, insert onto either greater or lesser tubercle of humerus
what are common actions of rotator cuff muscles?
secure humerus in glenoid fossa, rotate humerus
what is the Triangle of Auscultation? where is it? what is it used for?
Triangle of Auscultation made up by trapzius, teres major and the latissimus dorsi on the bottom
not many deep muscles to it, so can more easily hear respiratory, heart sounds here
where is the triangular space? what comprises it? what's contained in it?
teres minor, teres major, long head of triceps brachii
circumflex scapular artery is contained within here
where is quadrangular space? what's it comprised of? what's contained within the quadrangular space?
teres minor, teres major on bottom, long head of triceps brachii and surgical neck of humerus
in quadrangular space is axillary nerve and the posterior humeral circumflex artery
what are the borders of the subclavian, axillary, brachial arteries?
subclavian artery becomes axillary at lateral border of 1st rib
axillary becomes brachial at the inferior border of teres major
where does the axillary artery become the brachial a.?
at inferior border of teres major
what arteries come off the subclavian artery? what do they supply?
1. thyrocervical trunk - supplies thyroid gland, neck
2. suprascapular a. - supplies supraspinatus and infraspinatus
axillary artery - how many parts? what are they called? how many branches do they have coming off of them? what are their names? how are parts divided?
three parts - 1st part, 2nd part, 3rd part
1st part - one branch, superior thoracic artery
2nd part - two branches; thoracoacromial artery and lateral thoracic a.
3rd part - three branches; subscapular a. and anterior and posterior humeral circumflex arteries
divisions determined by reference to pectoral minor muscle
what does superior thoracic artery look like? what does it supply?
wimpy, and is often missing
supplies 1st and 2nd intercostal spaces
are the AHC and PHC the same size? what are the AHC and PHC?
AHC = anterior humeral circumflex artery
PHC = posterior humeral circumflex artery
PHC is larger
which artery branches off the axillary artery are sometimes missing?
superior thoracic artery,
AHC = anterior humeral circumflex artery
what arteries off the axillary artery have major branches?
thoracoacromial artery - 4 branches
1. acromial branch
2. deltoid branch
3. clavicular branch
4. pectoral branch
subscapular artery
1. thoracodorsal artery (to lats)
2. circumflex scapular artery
3. sometimes lateral thoracic artery branches here instead of off 2nd branch of axillary artery
do arteries have valves?
no, blood can flow any direction depending on pressure
what's collateral circulation?
when part of artery is ligated or occluded, blood can reach its original destination by taking one or more alternative paths
OR
alternative path blood takes to get around major obstruction
where in axillary artery is collateral circulation not possible?
between subscapular artery and origin of profunda brachii (deep brachial artery, distal to axillary)
what does the enlargement of lymph nodes in axilla mean?
infection of upper limb, breast, superior abdomen
how many groups, and what are the names of the different types of axillary nodes?
5 groups
1. apical nodes
2. pectoral nodes
3. subscapular nodes
4. humeral nodes
5. central nodes
where are the APICAL nodes and where does the lymph come from that enters them?
axillary vein near first part of axillary artery
receive lymph from ALL other axillary nodes on way to subclavian lymph trunk
where are PECTORAL nodes?
along vein that accompanies lateral thoracic artery, near pec minor
where are SUBSCAPULAR lymph nodes?
near subscapular vein
where are HUMERAL lymph nodes and where does the lymph come from that passes through them?
along axillary vein near junction of that vein and subscapular vein
almost ALL lymph draining through upper limb goes through humeral nodes
where are CENTRAL lymph nodes?
deep to pec minor near axillary vein by 2nd part of axillary artery
what does plexus mean?
network or braid
where do the rami of the brachial plexus come from?
VENTRAL primary rami of 5th, 6th, 7th, 8th cervical spinal nerves and
1st thoracic spinal nerve
what are the parts of the brachial plexus
5 parts
Rami
Trunks
Division
Cord
Branches
what are the names and structures of trunks of brachial plexus?
3 trunks
upper (superior) - C5 and C6
middle - C7
lower (inferior) - C8, T1
what are the names of the divisions of the brachial plexus
posterior and anterior where upper and middle trunks have anterior divisions facing posteriorly! lower trunk has correct separation
what are the names of the brachial plexus cords?
lateral, posterior, medial (from relationship to axillary artery)
what makes up the posterior cord?
posterior divisions of all trunks
what are the branches of cords and where do they come from?
lateral cord divides into musculocutaneous nerve and part of median nerve
posterior cord divides into axillary and radial nerves
medial cords divide into ulnar and part of median nerve
where does the axillary nerve go and what does it innervate?
through QUADRANGULAR space
innervates deltoid and teres minor
supplies small patch of skin over shoulder with sensation (superior lateral cutaneous nerve of arm)
where is radial nerve and what does it innervate, both muscle and sensation
travels around humerus shaft, on forearm is on radial side
posterior compartments of both arm and forearm
supplies skin over posterior arm, forearm, dorsum of hand
where is musculocutaneous nerve and what does it innervate, provide sensation?
through coracobrachialis muscle
innervates anterior compartment of arm
in forearm, is lateral cutaneous nerve of forearm
where is median nerve and what does it innervate?
becomes principal nerve to anterior compartment of forearm
in hand, is principal nerve of thumb
supplies index and middle fingers with sensation, as well as most of PALM
where is the ulnar nerve and what does it do?
innervates some forearm muscles
primary nerve to small muscles in hand
along ulnar side of forearm
supplies skin on ulnar side of hand, little finger, ULNAR side of ring finger with sensation
how many and what are the names of other nerves that i need to know?
10
1. long thoracic nerve
2. dorsal scapular nerve
3. suprascapular nerve
4 & 5. medial and lateral pectoral nerves
6,7 & 8. upper, middle and lower supscapular nerves
9,10. medial brachial and antebrachial cutaneous nerves
where does the long thoracic nerve come from/made of and what does it innervate?
rami C5, C6, C7 to serratus anterior
where does dorsal scapular nerve come from and what does it do?
from C5 ramus
to rhomboids and levator scapulae
suprascapular nerve - where does it come from, what does it do?
from upper trunk, C5 and C6
to supraspinatus and infraspinatus
where do the lateral and medial pectoral nerves come from and where do they go?
from medial and lateral cords correspondingly
to pectoral muscles, lateral nerve only to pec major
where do upper, middle and lower subscapular nerves come from and what do they do?
all from posterior cord
upper - subscapularis
middle - latissimus dorsi
same as thoracodorsal nerve
lower - subscapularis/teres major
where do the medial brachial and antebrachial cutaneous nerves come from and what do they innervate?
medial cord supplies both nerves
medial brachial cutaneous nerves supply skin on medial side of arm
medial antebrachial cutaneous nerve supplies medial side of forearm
what joints do the muscles of the arm cover?
shoulder, elbow and radioulnar
what actions does the shoulder do?
flexion, extension
adduction, abduction
rotation - medial and lateral
circumduction
what kind of joint is the elbow joint?
hinge joint
what movements do the elbow joint allow?
flexion and extension
what motions take place at radioulnar joint?
supination, pronation
what joints do muscles of the anterior (flexor) compartment of the forearm work on?
elbow, radioulnar, wrist, metacarpophalangeal (MP), interphalangeal (IP) joints
what are the layers of the flexor side of the forearm?
superficial, intermediate and deep
what features of the osteology of the humerus do i need to know?
head,
greater and lesser tubercles
bicipital groove also called intertubercular sulcus
deltoid tuberosity
medial and lateral epicondyles
capitulum
trochlea
coronoid fossa
olecranon fossa
what osteological features of the radius and ulna do i need to know?
olecranon
head of radius
styloid process of radius
radial tuberosity
how many muscles and what are the rules of the anterior compartment of arm
3 muscles
elbow flexors, supinators
innervated by musculocutaneous nerve
what are the muscles of the anterior compartment of the ARM?
1. biceps brachialis
2. coracobrachialis
3. brachialis
origin, insertion, innervation and actions of biceps brachii
origin:
proximal attachment - above glenoid cavity of scapula - long head
coracoid process of scapula - short head
insertion: distal attachment - tuberosity of radius and aponeurosis
innervation: musculocutaneous nerve (esp. C6)
actions: supinates flexed forearm, flexes supinated forearm
origin, insertion, innervation and actions of coracobrachialis
origin: coracoid process of scapula
insertion: shaft of humerus
innervation: musculocutaneous nerve (C6)
actions: adductor, flexor
origin, insertion, innervation and actions of brachialis
origin: humerus shaft
insertion: ULNA
innervation: musculocutaneous nerve
actions: flexes arm
how many muscles and what are the rules of the posterior compartment of the ARM
1 muscle - triceps brachii
is also anconeus, but we don't need to really know
shoulder and elbow extensor
innervated by radial nerve
origin, insertion, innervation and actions of triceps brachii
origin: 3 heads
long head - scapula
medial and lateral heads - shaft of humerus
insertion: olecranon
innervation: radial nerve (esp. C7 and C8)
actions: extensor of forearm
which joints do the biceps brachii cover?
shoulder, elbow, proximal radioulnar
which movements mimic biceps brachii actions?
pretending to turn and pop a cork from wine bottle
what joints do the heads of the triceps brachii cross?
long head - crosses should and elbow joints
lateral and short heads - elbow
besides the musculocutaneous and radial nerves, what other nerves are important to know about in the arm?
intercostobrachial nerve (axilla)
medial brachial cutaneous nerve (superior and medial arm)
what are results of damage to the musculocutaneous nerve (C5, C6)?
weakened supination
weakened forearm flexion
how do you test damage to the musculocutaneous nerve?
muscle strength and biceps tendon reflex (C6)
what is musculocutaneous nerve in the forearm called?
lateral cutaneous nerve of forearm
what does radial nerve do?
sole source of innervation to elbow and wrist extensor
how do you test radial nerve action?
strength of elbow and wrist extension
test cutaneous sensation on dorsum of web of thumb
where does radial nerve travel in ARM and why is this important?
wraps around humerus shaft
important because can be damaged by sharp edges of a broken bone
are there any nerves that pass through the arm without innervating anything in there?
yes, 2
median nerve
ulnar nerve
these are nerves of anterior forearm and hand
what are the rules of the anterior compartment of the forearm
forearm flexors
flex fingers, wrist
pronate forearm
innervated by median nerve
with exceptions
three layers:
superficial, intermediate and deep
what are the layers of the anterior compartment of the forearm?
superficial, intermediate and deep
how many and what are the names of the muscles in the superficial layer of the anterior compartment of the forearm
4
1. flexor carpi radialis
2. palmaris longus
3. flexor carpi ulnaris
4. pronator teres
what's the action and innervation of the flexor carpi radialis?
flexes radial side of wrist
also abductor of wrist
innervated by median nerve
what's action of palmaris longus - where does it insert -why is it clinically important?
weak wrist flexor
inserts onto palm, only one other muscle does this and is the longer of the 2
missing in 14% of population
is superficial and redundant, so tendon is often used as source of tissue for reconstructive surgery
actions, innervation of flexor carpi ulnaris
flexes ulnar side of wrist
adductor of wrist
only forearm muscle COMPLETELY innervated by ulnar nerve
what's the path of the ulnar nerve in the forearm?
posterior to medial epicondyle of humerus (is "funny bone")
reaches hand by running just deep to FCU
what's the action and innervation of the pronator teres? is there anything special that we need to know about it?
pronates, flexes forearm
innervated by median nerve
inserts onto RADIUS, there is no tendon for it at wrist
it doesn't act on hand
all muscles of the SUPERFICIAL layer of the anterior compartment of the forearm take origin from where? why is this clinically relevant?
all superficial anterior compartment forearm muscles originate from medial epicondyle of humerus
this place is called the common flexor origin
is clinically relevant because inflammation causes "Golfer's elbow", is painful repetitive use syndrome
how many muscles are in the intermediate layer of the anterior compartment of the forearm? what are their names?
1 - flexor digitorum superficialis
what does the flexor digitorum superficialis do? what innervates it?
flexes fingers, more superficial of two muscles that do so
innervated by median nerve
how many muscles, and what are their names of the deep layer of the anterior compartment of the forearm?
3
1. flexor digitorum profundis
2. flexor pollicis longus
3. pronator quadratus
function, innervation and location of flexor digitorum profundis
function: finger flexors
tendons going to all four fingers
innervated dually by both median and ulnar
median nerve innervates muscle fibers going to index finger and middle
ulnar nerve innervates muscles going to ring and little fingers
what is the half muscle of the rule that 1 and 1/2 muscles are innervated by the ulnar nerve in the anterior compartment of the forearm?
flexor digitorum profundis
function, innervation of flexor pollicis longus
long flexor of thumb
innervated by branch of median nerve
function, location, innervation of pronator quadratus
function: pronator
location: small deep in forearm near wrist
innervation: median nerve
what are the major nerves of the anterior forearm?
ulnar and median
what is the order of structures in the cubital fossa?
RTBM
LATERAL to medial
radial nerve
Tendon of biceps brachii
Brachial artery
Median nerve
what's the principal nerve of the flexor forearm?
median
where is the median nerve in the forearm, anterior?
flexor side of elbow just lateral to brachial artery
continues tween flexor digitorum superficialis and flexor digitorum profundis
a branch then travels near radius to muscles of deep layer, also supplying wrist
what is pronator syndrome?
when median nerve compressed between two heads of pronator teres
what is the condition caused by the compression of the median nerve between the two heads of the pronator teres
pronator syndrome
what's the significance of the median nerve's location in the cubital fossa?
it can get hit by a needle, causing damage
where does the anterior interosseous nerve come from, where is it and what does it do?
branch of median nerve coming off in middle of anterior forearm
near radius
innervates muscles of deep layer, wrist
what's the path taken by the ulnar nerve in the elbow and forearm?
exception to rule that nerves travel on flexor side of joint
is on extensor side of elbow at medial epicondyle
at forearm, accompanies ulnar artery, just deep to flexor carpi ulnaris
what causes "funny bone"?
compressed ulnar nerve, pushed against medial epicondyle of humerus
where does the brachial artery branch? what are its branches called at that point?
just distal to cubital fossa
radial and ulnar arteries
where is profunda brachii artery and what does it come off of?
branch of brachial artery that follows radial nerve around humerus shaft
where are the radial and ulnar arteries in the forearm?
mid forearm near superficial radial and ulnar nerves
why is it sometimes possible to hit an artery in the cubital fossa?
brachial artery sometimes (3%) branches into radial and ulnar arteries in ARM
ulnar artery will then travel superficially through cubital fossa
name the carpal bones and where they're located
proximal row (radial to ulnar)
scaphoid, lunate, triquetrum (with pisiform)
distal row (radial to ulnar)
trapezium, trapezoid, capitate, hamate with hook
how can i remember where the trapezium vs. trapezoid is?
trapezium rhymes with base of thumb!
one of the carpal bones was once called the navicular - which one and why has it been changed?
the scaphoid was also called navicular
scaphoid and navicular both refer to ship-shapes
there's a navicular in the foot, so to avoid confusion the name was changed
what's another name for the wrist joint?
radiocarpal
what makes up the radioulnar joint?
scaphoid, lunate, triquetrum and distal end of radius
what movements are allowed by the wrist joint?
adduction - ulnar deviation
abduction - radial deviation
flexion, extension
circumduction
what are the joints between the carpals called?
intercarpal joints
where are carpometacarpal joints? which one of these is most important and why
tween carpal bones and metacarpal bones
most important is joint between first metacarpal (thumb) and trapezium
different movements, with different plane of reference because BASE of first metacarpal is saddle-shaped
what movements are possible at thumb? why are these unique
opposition = thumb over palm to touch the tips of the flexed fingers
flexion, extension
abduction, adduction take place at 90 degree angle to plane of abduction adn adduction of fingers
extension refers to movement of the thumb laterally
what is ulnar and radial deviation?
also called adduction and abduction of hand
what does MP stand for? where are they?
metacarpophalangeal joint, knuckles
what movements are possible at MP joints?
flexion, extension
abduction, adduction
circumduction
plane of reference for abduction and adduction is middle finger
what's movement toward and away from middle finger called? what is movement of middle finger called?
abduction is movement of fingers away from middle finger
adduction is the movement of fingers toward the middle finger
middle finger itself can ONLY be ABducted
what does IP stand for? PIP, DIP?
interphalangeal joints
proximal interphalangeal joint
distal interphalangeal joint
from radial to ulnar, what is order of all things going through wrist
1. Radial ARTERY - imp. for pulse
2. TENDON of flexor carpi radialis (FCR)
3. Median NERVE
4. palmaris longus - MUSCLE
5. TENDONS of flexor digitorum superficialis (FDS)
6. Ulnar ARTERY
7. Ulnar NERVE
8. TENDON of flexor carpi ulnaris (FCU)
what is the carpal tunnel? what's in it?
channel formed by carpal bones
covered with sheet of tough connective tissue called flexor retinaculum
9 tendons and nerve passing through
1. four tendons from the flexor digitorum profundus
2. four tendons from the flexor digitorum superficialis
3. FLEXOR POLLICIS LONGUS
median nerve
are there any blood vessels in the carpal tunnel?
no
what is carpal tunnel syndrome?
compression of median nerve from
1. inflammation of synovial sheaths of tendons (from repetitive use of fingers)
2. arthritis
3. anterior dislocation of lunate
how many and what are the compartments of the hand?
3
1. thenar compartment
2. central compartment
3. hypothenar compartment
what are the rules of the compartments of the hand?
Thenar compartment has three muscles acting on thumb, innervated by median nerve
Central compartment muscles act on MP and IP joints, most innervated by deep branch of the ulnar nerve (T1)
hypothenar compartment - muscles act on little finger, innervated by deep branch of ulnar nerve (T1)
how many and what are the muscles of the thenar compartment?
3
1. abductor pollicis brevis
2. flexor pollicis brevis
3. opponens pollicis
position, innervation, action of abductor pollicis brevis
position: anterolateral part of thenar eminence
innervation: RECURRENT branch of median nerve (C8)
action: abduct thumb
position, innervation, actions of flexor pollicis brevis
position: just medial to APB
innervation: RECURRENT branch of median nerve (C8)
action: flexes thumb
position, innervation, action of opponens pollicis
position: deep to APB (ABductor)
innervation: RECURRENT branch of median nerve (C8)
actions: opposes thumb to palm
what are the rules of the hypothenar compartment?
mirror reflection of thenar compartment
3 muscles all innervated by deep branch of ulnar nerve (T1)
base of little finger - hypothenar eminence
how many and what are the names of the muscles of the hypothenar compartment?
3
1. abductor digiti minimi
2. flexor digiti minimi
3. opponens digit minimi
what are actions of muscles of hypothenar compartment?
assume that these are reflected in names
abductor abducts, flexor flexes and opponens opposes
how many muscles are in the central compartment of the hand and what are their names?
3 GROUPS of muscle, 1 muscle
1. lumbricals 1-4
2. palmar interossei 1-3
3. dorsal interossei 1-4
4. adductor pollicis
position, innervation and actions of lumbricals 1-4?
position: from tendons of FDP to extensor expansions of fingers
innervation: median nerve (1,2)
deep branch ulnar nerve (3,4)
actions: flex MPs, extends IPs
"bye bye muscles"
what is the extensor expansion?
these are the tough sheaths around the MPs
position, innervation and actions of palmar interossei 1-3
position: from metacarpals 2,4 and 5 to extensor expansions 2,4 and 5
there isn't one on the middle finger
innervation: deep branch of ulnar nerve (T1)
actions: adduct fingers
assists lumbricals, so are also "bye bye muscles"
position, innervation, actions of dorsal interossei 1-4
position: metacarpals to extensor expansions of digits 2,3 and 4
innervation: deep br. ulnar nerve (T1)
actions: abducts fingers, assists lumbricals
also called bye bye muscles
what does DAB PAD mean?
dorsal interossei abduct and
palmar interossei adduct
how do we test for the integrity of the ulnar nerve, or spinal level T1?
ask patient to adduct the fingers
position, innervation, actions of adductor pollicis
position: from carpal bones and 3rd metacarpal to base of proximal phalanx of thumb
innervation: deep br. ulnar nerve
ONLY thumb muscle innervated by ulnar nerve
actions: adducts thumb
what are the rules of cutaneous innervation in hand?
1. ulnar nerve supplies tip of little finger
2. median nerve supplies tip of index finger
3. SUPERFICIAL branch of radial nerve supplies dorsal webbing of thumb (skin over 1st dorsal interosseous muscle)
define dermatome
pattern of cutaneous innervation supplied from a given spinal level or dorsal root ganglion, vs. a given nerve
why do we need to know dermatomes?
to distinguish between peripheral nerve damage and damage to a sensory ganglion or CNS
what are the rules of dermatomes in the hand?
1. C6- dorsum of thumb
2. C7 - tip of middle finger
3. C8 - tip of the little finger
what causes median nerve injury usually?
trauma to wrist
carpal tunnel compression
compression tween heads of pronator teres - pronator syndrome
what are effects of damage or injury to median nerve?
4 major ones
1. thumb movement limited
2. thenar eminence wastes from atrophy
3. lose cutaneous sensation in hands and fingers - test tip of INDEX finger
4. lose fine motor control of index finger
what causes ulnar nerve injury usually?
don't know, but usually happens at medial epicondyle or in connective tissue tunnel at wrist, of which its the only occupant (canal of guyon)
what are effects of damage or injury to the ulnar nerve?
4 major ones
1. impaired finger abduction and adduction
2. uncoordinated fingers (loss of many intrinsic muscles)
3. "CLAW HAND" from hyperextension of 4th and 5th MPs at rest (loss of interossei and 2 lumbricals)
appears long after injury
4. paresthesia in ulnar palm and little finger- test tip of little finger
what is paresthesia?
abnormal sensation like tingling or prickling feeling
what are the rules of the posterior compartment of the forearm?
11 muscles
2 layers: superficial and deep
actions: extensors, supinators
innervation: branches of radial nerve
how many muscles and what are their names in the superficial layer of the posterior compartment of the forearm?
6
1. brachioradialis
2 and 3. extensor carpi radialis longus
extensor carpi radialis brevis
4. extensor digitorum
5. extensor digiti minimi
6. extensor carpi ulnaris
position, innervation and actions of brachioradialis
position: between arm (brachium and radius)
innervation: primarly by C6 fibers from radial nerve
actions: flexes forearm
position, innervation and actions of extensor carpi radialis longus and brevis
position: radial side of wrist, one longer than other
innervation: longus innervated by C6, C7 fibers in radial nerve
actions: both extend radial side of wrist
how do we test for the integrity of the ulnar nerve, or spinal level T1 specifically?
ask patient to adduct the fingers
position, innervation, actions of adductor pollicis
position: from carpal bones and 3rd metacarpal to base of proximal phalanx of thumb
innervation: deep br. ulnar nerve
ONLY thumb muscle innervated by ulnar nerve
actions: adducts thumb
what are the rules of cutaneous innervation in hand?
1. ulnar nerve supplies tip of little finger
2. median nerve supplies tip of index finger
3. superficial branch of radial nerve supplies dorsal webbing of thumb (skin over 1st dorsal interosseous muscle)
define dermatome
pattern of cutaneous innervation supplied from a given spinal level or dorsal root ganglion, vs. a given nerve
why do we need to know dermatomes?
to distinguish between peripheral nerve damage and damage to a sensory ganglion or CNS
what are the rules of dermatomes in the hand?
1. C6- dorsum of thumb
2. C7 - tip of middle finger
3. C8 - tip of the little finger
what causes median nerve injury usually?
trauma to wrist
carpal tunnel compression
compression tween heads of pronator teres - pronator syndrome
what are effects of damange or injury to median nerve?
4 major ones
1. thumb movement limited
2. thenar eminence wastes from atrophy
3. lose cutaneous sensation in hands and fingers - test tip of little finger
4. lose fine motor control of index finger
what causes ulnar nerve injury usually?
compression usually at medial epicondyle or in connective tissue tunnel at wrist, of which it's the only occupant (canal of guyon)
what are effects of damage or injury to the ulnar nerve?
4 major ones
1. impaired finger abduction and adduction
2. uncoordinated fingers (loss of many intrinsic muscles)
3. "CLAW HAND" from hyperextension of 4th and 5th MPs at rest (loss of interossei and 2 lumbricals)
appears long after injury
4. paresthesia in ulnar palm and littel finger- test tip of little finger
what is paresthesia?
abnormal sensation like tingling or prickling feeling
what are the rules of the posterior compartment of the forearm?
11 muscles
2 layers: superficial and deep
actions: extensors, supinators
innervation: branches of radial nerve
how many muscles and what are their names in the superficial layer of the posterior compartment of the forearm?
6
1. brachioradialis
2 and 3. extensor carpi radialis longus
extensor carpi radialis brevis
4. extensor digitorum
5. extensor digiti minimi
6. extensor carpi ulnaris
position, innervation and actions of brachioradialis
position: between arm (brachium and radius
innervation: primarly by C6 fibers from radial nerve
actions: flexes forearm
position, innervation and actions of extensor carpi radialis longus and brevis
position: radial side of wrist, one longer than other
innervation: longus innervated by C6, C7 fibers in radial nerve
actions: both extend radial side of wrist
position, innervation and actions of extensor digitorum
position: central, not mentioned
innervation: not mentioned some part of radial nerve i assume
actions: extends fingers at MP and weakly at IP, also extends wrist
action of extensor digiti minimi
extends little finger at IP and MP joints
actions of extensor carpi ulnaris
extends and adducts wrist
what is tennis elbow and what's its official name?
tennis elbow is an inflammation of the common extensor tendon, where most of muscles of posterior compartment take origin, on the lateral epicondyle of the humerus
officially referred to as lateral epicondylitis
golfer's elbow officially referred to as medial epicondylitis
what are the names and how many muscles are there in the deep layer of the posterior compartment of the forearm
5 muscles
1. supinator
2. extensor indicis
3,4 extensor pollicis longus and brevis
5. abductor pollicis longus
actions of supinator
supinates forearm with biceps brachii unless arm is extended and then it's the only supinator
actions of extensor indicis
counterpart of extensor digiti minimi
extends index finger (indicis) at MP and IP joints
how many and what are the names of the outcropper muscles? to which compartment do they belong? why are they called outcroppers and what common action do they have?
3 muscles:
1. extensor pollicis longus
2. extensor pollicis brevis
3. abductor pollicis longus
belong to posterior compartment, deep layer of forearm
called outcroppers because they pop out in people with powerful grip
they all act on thumb
where's the anatomical snuffbox? what outlines it? what does tenderness here indicate? what can be felt here?
anatomical snuffbox is on dorsum of thumb
outlined by tendons of extensor pollicis longus and extensor pollicis brevis
tenderness indicates possible scaphoid fracture
radial artery pulse can be felt here
where will radial nerve be tagged on our practical exam?
where it enters forearm on flexor side of elbow, being R in RTBM
between brachialis and brachioradialis
what is radial nerve innervating where it's tagged for our practical exam?
will be innervating brachioradialis and extensor carpi radialis longus
where does radial nerve branch? what are its branches called at that point?
radial nerve branches somewhere near elbow
divides into superficial branch and deep branch of radial nerve
where would i find the superficial branch of the radial nerve and what does it innervate?
starts somewhere near elbow
travels deep to brachioradialis towards wrist
at wrist, supplies skin over radial half of dorsum of hand
where is the deep branch of the radial nerve located and what does it do?
starts somewhere near the elbow
supplies extensor carpi radialis brevis
enters supinator and innervates it
is called something else on other side of supinator
what's nerve coming out of supinator called, where does it come from, and what does it innervate?
called posterior interosseus nerve
comes from deep branch of radial nerve
innervates remaining muscles of posterior compartment of forearm
(aside from supinator, extensor carpi radialis brevis)
how can the radial nerve be injured? what are the combination of effects of radial nerve injury called?
5 causes discussed for radial nerve injury
1. cut by jagged edges of broken humerus
2. cut by deep trauma
3. compressed by improper use of tourniquet
4. compressed from resting arm over back of chair "saturday night palsy"
5. inflammation of supinator (overuse of screwdriver) would compress the deep branch
because it supplies ALL wrist extensors, would only have wrist flexion, resulting in "WRIST DROP"
what are three flexors of the elbow?
1. biceps brachii
2. brachioradialis
3. brachialis
fibers from which rami innervate the part of the radial nerve that goes to the brachioradialis?
C6 fibers - this is important!
which side of the hand contributes most to the power of grip?
ulnar side - apparently this is why we have so many muscles specializing in work of the little finger
what portion of radial nerve innervates the supinator?
C6 fibers
name the two extensors going to the index finger
1. extensor indicis
2. extensor digitorum
the deep palmar arch in part comes from what artery?
radial artery
extensor carpi radialis longus and brevis not only extend the wrist, but also do what?
radially deviate, help with abduction of wrist
where does lunate tend to dislocate?
anteriorly
can someone still extend their IPs after a high radial nerve injury
yes, because of lumbricals and interossei
what would be the effects of an injury to the musculocutaneous nerve? what are some tests to determine if this nerve has been damaged?
effects
1. weak supination - still have supination from supinator
2. when injured at coracobrachialis, would have weaker elbow flexion, but would still be able to do so because of brachioradialis
tests
1. tap on tendon of biceps brachii
2. test for sensation on lateral part of forearm
what would be the result of a high injury to the median nerve?
bishop's hand
can't flex IPs
what are muscles invovled in erb palsy? think in terms of compartments
scapula area - rotator cuff shot
anterior compartment of arm
deltoid gone
radial nerve problems result in:
loss of brachioradialis,
supinator
musculocutaneous nerve damage:
loss of brachialis
biceps brachii
1/2 of extensor carpi radialis longus lost
what are actions lost by erb palsy and why? go through areas again
glenohumeral:
no abduction because rotator cuff shot
no lateral rotation
elbow:
weak flexion because of loss of biceps and brachioradialis, only functioning flexor would be pronator teres
radioulnar joint
no supination
wrist
problems extending wrist
what's the presentation of a patient with erb palsy?
medially rotated, stiff arm (no flexion at elbow), slightly flexed wrist because have problems extending and arm adducted because can't abduct
what nerves are partially lost in erb palsy?
radial, median nerves
what are the only two muscles innervated by fibers from C5 or C6 in the radialis nerve?
brachioradialis and extensor carpi radialis longus
what are the effects of damage to the median nerve from erb palsy?
loss of thumb sensation
completely lost nerves in erb palsy
musculocutaneous, axillary
are any of the pecs affected by erb palsy?
yes actually, the lateral pectoral nerve is mostly made up of C6 fibers
but according to tucker, it's not really affected
is scapula of erb palsy patient winging?
no, serratus anterior is innervated by long thoracic nerve and that doesn't seem to be on my list!