gross- forearm & wrist (osce II)

Question 1

what bones does the radius attach to at the proximal & distal end? (name the specific parts of those bones)

Answer 1

proximal end (closer to shoulder): attaches to capitulum of humerus & radial notch of ulna

distal end: makes the wrist joint w/ the scaphoid & lunate bones

Question 2

how do you determine side of the radius?

Answer 2

the radius is the lateral bone of the forearm

• head is small and circular and is at the top (attaches humerus)
• radial tuberosity is that circular crater on the side → faces anteromedially (kinda forward but also a bit towards the right)
• and the styloid process (outward bony projection at the bottom) projects laterally at the distal end

Question 3

what is the annular ligament and what is its purpose?

Answer 3

strong, fibrous band of tissue that forms a ring around the head of the radius bone within the elbow joint

stabilizes the proximal (at the top) radioulnar joint and allows for rotatory movement of forearm (supination/protonation)

Question 4

whats the difference b/w radial notch and radial tuberosity?

Answer 4

not the same!!

radial notch: ON THE ULNA, depression that articulates with head of radius (forms proximal/superior radioulnar joint)

radial tuberosity: ON THE RADIUS, bony projection on radius where the biceps brachii muscle attaches

Question 5

ulnar collateral ligament & radial collateral ligament + purpose?

Answer 5

radial collateral ligament: connects humerus to the radius, kinda like a vertical piece of tape
- stabilizes outer (lateral) side of the elbow joint

ulnar collateral ligament: strong, triangular ligament that connects ulna to medial epicondyle of humerus
- stabilizes inner side of elbow joint

Question 6

what is the neck of the radius?

Answer 6

narrow section just below the head and above the radial tuberosity

I dont like this card that much

Question 7

what are the 3 borders on the shaft of the radius and how do you find them?

what is the anterior & posterior oblique line?

Answer 7

1. medial/interosseous border → sharpest of the 3 borders, attaches to interosseous membrane (why called interosseous border too)
   - easiest to find, just faces the ulna and is sharp
2. anterior border → trace down in front from the radial tuberosity (is oblique- slanted at the top then towards bottom is straight vertical) down towards styloid process
   - anterior oblique line: oblique (top slanted) part of the anterior border
3. posterior border → mirror image of the anterior border just on the backside
   - posterior oblique line: upper oblique part of the border

Question 8

what are the 3 surfaces on the shaft of the radius?

Answer 8

1. anterior surface: space b/w the medial & anterior border, on the front/facing ulna side
2. lateral surface: space b/w the posterior & anterior border, on the lateral side
3. posterior surface: b/w the posterior & medial border, on the backside (obv)

Question 9

what are the 5 surfaces at the distal end (bottom) of the radius?

Answer 9

1. anterior surface → front side, has a thick prominent ridge
2. posterior surface → back side, has 4 grooves, one of them is called dorsal tubercle of lister (middle most prominent line)
3. medial surface → has the ulnar notch (like a cutie patootie lil dip all the way at the bottom), faces towards ulna too obv
4. lateral surface → has the styloid process
5. inferior surface → the bottom part of the bone, has a triangular area (thats more lateral- towards the styloid process) that attaches to the scaphoid bone and a quandragular area (thats more medial- towards the ulna) that attaches to the lunate bone

Question 10

proximal & distal radioulnar joints

Answer 10

both are pivot joints

proximal radioulnar joint: near the elbow
- formed by head of radius & radial notch of ulna
- main supporting structure is the annular ligament

distal radioulnar joint: near the wrist
- formed by ulnar notch of radius & head of ulna
- main supporting structure is the articular disc

both joints help in protonation/supination

Question 11

what are the 4 types of forearm fractures?

Answer 11

1. Colles’ Fracture (most common- dinner fork deformity)
2. Smith’s Fracture (reverse of the colles’)
3. Monteggia’s Fracture (Ulna fracture + dislocated radius)
4. Galeazzi’s Fracture (radius fracture + dislocated ulna)

MUGR mnemonic → monteggia ulnar, galeazzi radius

Question 12

colles’ fracture vs. smith’s fracture

Answer 12

colles’ fracture: aka dinner fork deformity
- fall on outstretched hand → radius moves posteriorly (down)
- styloid process breaks off too (right above it is where the fraction is)
- wrist joint also goes up
= hand looks like upside down fork

smith’s fracture: reverse of a colles’ fracture
- caused by falling on flexed wrist (hand bent inward)
- radius moves anteriorly (forward)
- hand tilts upwards

Question 13

monteggia & galeazzi’s fractures

Answer 13

Monteggia’s Fracture: ulnar fracture + dislocation of proximal radioulnar joint (at elbow)
- ulna breaks & radius pushed out of its normal elbow joint position

Galeazzi’s Fracture: radial fracture + dislocation of distal radioulnar joint (at wrist)
- radius breaks & ulna moves out of its position at the wrist joint

Question 14

whats different about the wrist attachment of ulna from radius?

Answer 14

the ulna does not articulate with the carpal bones in the wrist!!

Question 15

how do you determine side of the ulna?

Answer 15

• upper end is hook like with the concavity facing anteriorly
• the lateral border is sharp
• the styloid process (bony projection) faces the posterior medial side at the lower end

Question 16

the 4 bony landmarks of the proximal end of the ulna

Answer 16

1. olecranon process: large curved bony part at the top, fits into the olecranon fossa of the humerus
2. trochlear notch: the inside, actual C-shaped depression at the top of the humerus
   - forms hinge joint of the elbow
   - trochlea of humerus articulates here
3. coronoid process: like the line in front of the trochlear notch, fits into coronoid fossa of humerus (above the trochlea)
4. radial notch: a small groove on the lateral side of the ulna, forms the proximal radioulnar joint w/ head of radius

2 processes, 2 notches

Question 17

how many surfaces are there of the olecranon process & coronoid process? (ulna)

Answer 17

olecranon process: 5 surfaces
- superior
- anterior
- posterior
- medial
- lateral

coronoid process: 4 surfaces
- superior
- anterior
- medial
- lateral

of the processes, not the whole head!

Question 18

what is the ulnar tuberosity?

Answer 18

right below the coronoid process of ulna, small rough bump on the anterior side

attachment site for the brachialis muscle’s tendon

Question 19

what are the 3 borders of the shaft of the ulna?

Answer 19

1. lateral/interosseous border: sharp in the middle 2/3rd, on the side of the radius, start from supinator crest and trace down
2. anterior border: thick & rounded, down from the ulnar tuberosity to styloid process on the front side
3. posterior border: subcutaneous (right at the skin, can feel it through skin), on the backside

doesnt have medial - radius had medial

Question 20

what is the supinator crest? (ulna)

Answer 20

the little groove at the top of the lateral border (right below the radial notch)

attaches the supinator muscle

Question 21

what are the 3 surfaces of the shaft of the ulna?

Answer 21

1. anterior surface: frontside of the ulna (I cant tell specifics)
2. medial surface: faces towards the body when ulna is placed anatomically
3. posterior surface: all throughout the backside of the ulna

Question 22

what is olecranon fracture?

Answer 22

break in the olecranon caused by direct trauma (fall into the elbow)

• affects ability to straighten arm

was just mentioned on the slides by name & cause

Question 22

whats different about the head of the ulna?

Answer 22

its on the bottom (facing the wrist)- contains the styloid process

whereas in the other bones we did so far, the head was at the top

Question 23

what are the layers of the muscles of the anterior comp. of forearm, how many are in each, and what are their names?

Answer 23

total 8 muscles

1. superficial layer: 4 muscles
   - pronator teres
   - flexor carpi radialis
   - palmar longus
   - flexor carpi ulnaris
2. intermediate: 1 muscle
   - flexor digitorum superficialis
3. deep group: 3 muscles (3 P’s)
   - flexor digitorum Profundus
   - flexor Pollicis longus
   - Pronator quadratus

Question 24

what **nerve** supplies most of the anterior compartment of the forearm? what is the exception?

Answer 24

**median nerve** → all muscles except the 1.5 supplied by the ulnar nerve **ulnar nerve** → flexor carpi ulnaris (*helps in wrist flexion*) & medial half of flexor digitorum profundus (*flexes the ring & little finger*)

Question 25

what arteries supply blood to the **anterior comp. of forearm**?

Answer 25

radial & ulnar artery

Question 26

why do some muscles have multiple origins? (*for own understanding*)

Answer 26

Origin → The fixed or less movable attachment point Insertion → The attachment that moves during contraction can have more origins if the muscle *spans 2 bones, has 2 or more heads that fuse, or needs more stability & force production*

Question 27

usually, what do lateral (radial) side & medial side muscles do?

Answer 27

lateral side: **abduction** medial side: **adduction** - like how flexor carpi radialis does abduction & flexor carpi ulnaris adducts!!

Question 28

what are the origins & insertions of the 4 muscles of the **superficial group** of the **anterior comp. of forearm**?

Answer 28

**pronator teres**: medial epicondyle (humeral head) & coronoid process of ulna (ulnar head) → lateral surface of radius **flexor carpi radialis**: medial epicondyle → base of 2nd & 3rd metacarpals **palmaris longus**: medial epicondyle → palmar aponeurosis **flexor carpi ulnaris**: medial epicondyle (humeral head) & olecranon (ulnar head) → pisiform, hamate, base of 5th metacarpal

Question 29

what are the actions of the 4 muscles of the **superficial group** of the **anterior comp. of forearm**?

Answer 29

**pronator teres**: pronates forearm, flexion of forearm (weaker) **flexor carpi radialis**: flexes & ABducts wrist (*cause on the lateral side*) **palmaris longus**: wrist (hand) flexion (but chaptgpt says weak) **flexor carpi ulnaris**: flexes & ADDucts wrist (*cause on the medial side*)

Question 30

what are the origins, insertions, & action of the **flexor digitorum superficialis** (intermediate group of ant. comp. of forearm)?

Answer 30

has 3 origin points- humeroulnar head, radial head **origins**: medial epicondyle (humerus), medial border of coronoid process (ulna), anterior oblique line (radius) **insertion**: middle phalanx of medial 4 fingers (*middle tasbeeh region*) - splits into 4 tendons before the fingers & then splits into further **2 in the fingers** (THE FLEXOR DIGITORUM PROFUNDUS PASSES THROUGH THE GAP!!!) **action**: flexes middle phalanx of fingers (*cause think thats where its inserting*) and assists in flexing proximal phalanx & hand

Question 31

what are the origins & insertions of the 3 muscles of the **deep group** of the **anterior** comp. of **forearm**?

Answer 31

**flexor digitorum profundus**: anteromedial surface of shaft of ulna → distal phalanges of middle 4 fingers **flexor policus longus**: anterior surface of shaft of radius & interosseous membrane → distal phalanx of thumb **pronator quadratus**: distal ulna → distal radius

Question 32

what are the actions of the 3 deep muscles of the ant. comp. of forearm?

Answer 32

**flexor digitorum profundus**: flexes distal phalanx of fingers, assists in flexion of middle & proximal phalanges (*plural for phalanx*) and wrist **flexor pollicis longus**: flexes distal phalanx of thumb **pronator quadratus**: pronates forearm

Question 33

entire course of the **median nerve** from brachial plexus to tip of finger

Answer 33

**C5-T1** spinal nerves → **lateral & medial cords** → forms near axilla and runs down arm next to brachial artery (**no branches/purpose in the arm, just runs**) → passes through the *cubital fossa* b/w 2 heads of pronator teres → in the beginning third of anterior forearm gives rise to other branches & **anterior interosseous branch** → then goes into distal forearm to give rise to **palmar cutaneous branch** → enters hand by passing through **carpal tunnel**, palmar cutaneous branch passes above (superficial) to the **flexor retinaculum** → in hand divides into **recurrent branch** (supplies thenar muscles - thumb) & **median + lateral portion** → lateral portion gives rise to **3 proper palmar digital nerves** (supply thumb & radial side of index finger) → medial portion divides into **2 common palmar digital branches** (further split into proper digital nerves for sides of index, middle, and ring finger)

Question 34

anterior interosseous nerve (muscular + articular branches)

Answer 34

"deep motor branch" branch of the **median nerve** that runs b/w the radius & ulna- has **only motor** function innervates **3 muscles**: - flexor digitorum profundus (lateral half) - flexor pollicis longus - pronator quadratus *deep group muscles* **articular branches** (joint branches): - wrist - distal radioulnar joint - joints of hand

Question 35

palmar cutaneous branch of median nerve

Answer 35

"sensory branch that escapes the tunnel" - branch of the **median nerve** that passes ABOVE the flexor retinaculum (escapes the carpal tunnel) is **sensory only** - provides feeling to skin over thumb & base of thumb/palm ish area (called **thenar eminence** carpal tunnel syndrome **does not affect this nerve** b/c it doesn't go through tunnel → palm sensation remains intact over thenar eminence even if median nerve is compressed in the carpal tunnel!

Question 36

what does "articular branches" mean? (*for own knowledge*)

Answer 36

small nerve branches that **go to joints** comes from "articulation" which means a **joint where two bones meet** these branches help provide sensation or contribute to joint function

Question 37

what are lumbricals? + what is their function

Answer 37

**4** small, worm-like muscles in the hand, located deep to the palmar fascia, **b/w the metacarpal bones** **function**: flex metacarpophalangeal (MCP) joints and extend interphalangeal (IP) joints (*MCP = the knuckles, IP = b/w the phalanges like the places where the fingers bend*) - classic example is *holding a pea in ur fingers* -thats what they do - originate from the tendons of the **flexor digitorum profundus (FDP)** - numbered 1 to 4 starting from side of the thumb and going to pinky - each finger is attached to **2 lumbricals** except thumb which is only associated with the **1st lumbrical**

Question 38

innervation of the lumbricals

Answer 38

lateral 2 lumbricals (of index & middle fingers) = innervated by **median nerve** medial 2 lumbricals (of little & ring fingers) = innervated by **ulnar nerve**

Question 39

entire course of the **ulnar nerve** from the brachial plexus to the tip of the finger

Answer 39

**C8 & T1** → **medial cord** of brachial plexus → no branches in upper arm except **articular branch to elbow joint** → runs down **medial** side of brachial artery→ middle of arm, pierces **medial intermuscular septum** to go into the back (posterior) of arm → runs behind **medial epicondyle** of humerus (*can be palpitated here- funny bone sensation is bc of this being hit*) → enters medial side of **ant. comp. of forearm** passing **b/w 2 heads of flexor carpi ulnaris** → runs behind **flexor carpi ulnaris** & in front of **flexor digitorum profundus** (*supplies both but only medial half of profundus*) → before reaching wrist, gives off 2 branches- **palmar cutaneous branch** & **dorsal cutaneous branch** → at wrist, enters **guyon's canal** → goes into hand to divide into **superficial branch (sensory) & deep branch motor)** → sensory branches extend all the way to the tups of the little and half of ring finger providing sensation

Question 40

what are the **palmar & dorsal (posterior) cutaneous branches** of the **ulnar nerve** and what do they provide sensation to?

Answer 40

*ulnar nerve gives these branches right before reaching the wrist* **palmar cutaneous branch** → passes over the flexor retinaculum (not through the carpal tunnel) - provides sensation to the **medial part of the palm** **dorsal (posterior) cutaneous branch** → goes around the ulna to the back of the hand where it crosses ABOVE the extensor retinaculum - divides into several **dorsal digital nerves** that supply **skin** of **medial side of the ring finger & sides of the ring finger** (*quite literally 1 and 1/2 cause only does half of the ring finger*) *both are cutaneous so only do sensory innervation not motor innervation* THESE SUPPLY FRONT OF PALM AND BACK OF FINGERS - DIFF FROM THE SUPERFICIAL BRANCH THAT SUPPLIES FRONT OF FINGERS

Question 41

what is **guyon's canal**?

Answer 41

also called **ulnar tunnel** fibro-osseous tunnel on the medial side of the hand next to the carpal tunnel where the **ulnar nerve & ulnar artery** pass through

Question 42

what are the **superficial and deep branches** of the ulnar nerve & what do they supply?

Answer 42

*ulnar nerve splits into these 2 branches after passing the guyon's tunnel into the hand* **superficial branch (sensory)** → palmar cutaneous branches (**common palmar digital & proper palmar digital**) supplies skin of the medial 1.5 fingers (half of ring, full pinky) fingers on the palmar side - also has a muscular branch that supplies **palmaris brevis muscle** **deep branch (motor)** → supplies most of the intrinsic muscles of hand including: - **hypothenar muscles** (control little finger- abductor digiti minimi, flexor digiti minimi, opponens digiti minimi) - **medial 2 lumbricals (3 & 4)** (for ring & lil finger) - **all interossei muscles (palmar & dorsal)** (finger movement) - **adductor pollicis (both head)** (thumb adduction)

Question 43

complete course of the **ulnar artery**

Answer 43

brachial artery splits at the **cubital fossa**, ulnar artery is the larger of the 2 terminal branches → branches into the **anterior & posterior ulnar recurrent arteries** that **anastomose** around elbow joint → travels medially, behind (deep to) **pronator teres muscle** → in the top of the forearm, branch into **common interosseous artery** that splits into the → **anterior & posterior interosseous artery**→ passes behind **flexor digitorum superficialis** & in front of **flexor digitorum profundus** (between them) → at wrist, gives off **dorsal & palmar carpal branches** (*that contribute to the dorsal & palmar carpal arches*) → passes above the **flexor retinaculum** (not thru the carpal tunnel) → enters **guyon's tunnel** → immediately divides into **superficial** (*main contributor to superficial palmar arch) & **deep branch** (*joins deep palmar arch of radial artery*) → ends by forming **superficial palmar arch** → which gives rise to **3 common palmar digital arteries** → each further divides into **2 proper palmar digital arteries** to supply the fingers → **anastomoses** w/ superficial palmar branch of radial artery

Question 44

what is the ulnar pulse?

Answer 44

palpable beating of the **ulnar artery** which is found on the medial side of the anterior wrist - less prominent than the radial pulse, but can be felt with proper positioning

Question 45

what are the **anterior and posterior interosseous arteries** and what do they do?

Answer 45

- branch off from the **common interosseous artery** that branches from the **ulnar artery** anterior → runs w/ anterior interosseous NERVE posterior → supplies the extensor muscles **function**: - provide nutrient arteries to the radius & ulna - supply adjacent muscles in the anterior & posterior compartments - end by taking **anastomosis around wrist joint**

Question 46

difference b/w dorsal carpal arch, dorsal arch, and superficial palmar arch? (*for own knowledge*)

Answer 46

**dorsal carpal arch**: arterial network on back of WRIST (supplies wrist & dorsum of hand) **dorsal arch (dorsal venous arch)**: vein network on the back of the hand (drains blood into larger veins) **superficial palmar arch**: arterial network in the PALM (supplies palm & fingers) dorsal carpal arch & superficial palmar arch form anastomoses, dorsal venous arch does not (its veins- they drain, not supply)

Question 47

anastomoses around the wrist joint **imp**

Answer 47

done by the **dorsal & palmar carpal arches** **dorsal carpal arch**→ on the back of wrist, formed by contributions from: - **radial artery** (dorsal carpal branch) - **ulnar artery** (dorsal carpal branch) - **posterior interosseous artery** - **anterior interosseous artery** (small contribution) **palmar carpal arch**→ on the front of wrist, connects w/ arteries of **deep palmar arch** (supply deep structures of hand), formed by: - **radial artery** (palmar carpal branch) - **ulnar artery** (palmar carpal branch) - **anterior interosseous artery**

Question 48

entire course of the **radial artery**

Answer 48

arises from brachial artery in the **cubital fossa** at the **neck of the radius** (is *smaller* of the 2 branches)→ travels **laterally** along forearm, behind (deep) the **brachioradialis muscle**→ in middle of forearm, becomes more **superficial** running b/w **brachioradialis & flexor carpi radialis**→ gives off 2 branches- **radial recurrent artery** (*takes place in anastomosis around elbow joint*) & **palmar carpal branch** (*arises just before wrist, forms part of superficial palmar carpal arch*) → superficial in wrist and can be palpated at **radial pulse**→ gives off **superficial palmar branch** (*joins superficial palmar arch from ulnar artery*) & **dorsal carpal branch** (contributes to dorsal carpal arch*) → curves around lateral side of wrist, passes through **anatomical snuffbox**→ passes **1st dorsal interosseous & adductor pollicis muscles** to form the **deep palmar arch** → which gives off **princeps pollicis artery** (supplies thumb), **radialis indices artery** (supplies lateral index finger), **palmar metacarpal arteries** (supply deep hand structures) → **ends by anastomosing w/ deep branch of ulnar artery** to form the **deep palmar arch** (supplies deep hand muscles)

Question 49

Palmar interossei muscles

Answer 49

Total 3: **2nd, 4th, & 5th fingers** Insert into extensor hood and base of proximal phalanges **function**: adduct fingers towards middle finger at the metacarpophalangeal joints

Question 50

how are the boundaries of the **cubital fossa** defined/what muscles hit the boundaries?

Answer 50

has a superior, medial, & lateral border (makes a triangle) also has floor & roof (inside of the actual triangle itself) **superior border** (also called the base): imaginary line b/w the 3 epicondyles of the humerus **lateral border**: brachioradialis muscle **medial border**: pronator teres muscle **floor**: *the muscular layer*, has the supinator muscle laterally and brachialis muscle medially **roof**: skin & fascia, reinforced by the bicipital aponeurosis

Question 51

where are the brachialis, brachioradialis, & coracobrachialis muscles located? (*for own knowledge*)

Answer 51

**brachialis** muscle is behind the biceps **brachioradialis** is on the lateral side coming out from the bottom of biceps hitting the middle of the radius **coracobrachialis** is medial to the biceps, and only goes down to about half the length of the humerus

Question 52

what are the **contents** of the cubital fossa? what is the mnemonic to remember them?

Answer 52

*MBBR* M → **median cubital nerve** (imp. bc this is where *most of blood is taken* from for blood tests) B → **brachial artery** (where *blood pressure is taken from*- imp) B → **biceps muscle** (tendon) R → **radial nerve** (and its deep branch)

Question 53

how can you spot the palmaris longus muscle on a cadaver?

Answer 53

has a short belly, long tendon

Question 54

posterior/lateral compartment of the forearm- how are these muscles divided into layers?

Answer 54

**12 muscles total** **superficial layer**- has 7 of them -*all originate from the humerus and run distally down the forearm* **mnemonic**: Beer Lifting, Break Dancing Muscles, Unless Atrophied - but first 2 are actually from the **lateral compartment** **deep layer**- has 5 of them - 1 muscle for index finger, 3 for the thumb, and 1 to supinate the forearm

Question 55

what are the 2 muscles of the **lateral** layer of the **post. comp. of forearm**? what is the mnemonic to remember them? give their origin/insertion/actions.

Answer 55

*Beer Lifting Muscles* - both originate from lateral **supracondylar ridge** of humerus B → **brachioradialis** - **insertion**: radial styloid process - **action**: elbow flexion (*need to drink some beer*), rotates arm to mid prone position (*need to pick up beer glass*) L → **extensor carpi radialis Longus** - **insertion**: base of 2nd metacarpal on the back of hand- like *back part of hand before index finger region* - **action**: abducts hand (*what you need to take a sip*) and extends hand (*kinda helps you grab the beer*)

Question 56

which nerve supplies the 2 muscles of the **lateral compartment** of forearm?

Answer 56

radial nerve

Question 57

what are the 5 muscles in the **superficial layer** of the **post. comp. of forearm**? what is the mnemonic to remember them? list their actions too.

Answer 57

*Break Dancing Muscles Unless Atrophied* B → **extensor carpi radialis Brevis** - **action**: does the same as its bhai extensor capri radialis longus only just originates from lateral epicondyle instead (extends & abducts hand at wrist joint) D → **extensor Digitorum** - **action**: extends the fingers (not thumb) & the wrist (*what you need if u wanna do break dancing moves*) M → **extensor digiti Minimi** - **action**: extends the pinky finger U → **extensor carpi ulnaris** - **action**: extends & ADDUCTS hand at wrist joint A → **anconeus**, smallest muscle in superficial layer, just a triangle, originates from back of lateral epicondyle and connects to ulna - **action**: extends elbow joint

Question 58

what are the origins/insertions of the 5 muscles in the **superficial layer** of the **post. comp. of forearm**?

Answer 58

all originate from the **lateral epicondyle of humerus** B → **extensor carpi radialis Brevis** - **insertion**: base of 3rd metacarpal D → **extensor Digitorum** - **insertion**: middle & distal phalanges of medial 4 fingers M → **extensor digiti Minimi* - **insertion**: extensor hood of the little finger U → **extensor carpi ulnaris** - insertion: base of 5th metacarpal A → **anconeus** - insertion: olecranon process of ulna

Question 59

which nerve supplies all of the muscles of the posterior compartment of the forearm?

Answer 59

**deep branch of radial nerve** - except the anconeous which is just radial nerve, not the deep branch

Question 60

what are the muscles of the **deep layer** of the **post. comp. of forearm**?

Answer 60

*1 for index finger, 3 for thumb, 1 for supination* - supinator - extensor indicis - abductor pollicis longus - extensor pollicis brevis - extensor pollicis longus

Question 61

what are the origins/insertions/actions of the 5 muscles of the deep layer of the **post. comp. of forearm**?

Answer 61

**supinator** - lateral epicondyle of humerus, annular ligament of radioulnar joint, ulna → neck & shaft of radius - **supinates** **extensor indicis** - posterior surface of shaft of ulna (*back of ulna basically*) → extensor hood of index finger - **extends index finger** **abductor pollicis longus** - posterior surface of radius & ulna → base of first metacarpal bone (thumb) - **abducts & extends** the thumb **extensor pollicis brevis** - posterior surface of radius → base of proximal phalanx of thumb - **extends the part it inserts into** **extensor pollicis longus** - posterior surface of ulna → base of distal phalanx of thumb - **extends the part it inserts into** *the 3 thumb muscles insert into the thumb from bottom to top of thumb in alphabetical order- remember their insertions this way*

Question 62

what is forearm compartment syndrome? what are the symptoms & the treatments?

Answer 62

any edema in forearm (fluid buildup) can cause **compression of blood vessels** that affects vein & then arteries - serious and needs to be treated right away otherwise can have **irreversible damage to muscles** - b/c its so tightly packed in there that there's barely any extra room **symptoms**: altered skin sensation, pain disproportionate to injury (caused by pressure on nerves), pain on passive stretching of muscles, tenderness of skin, absence of capillary refill in nail beds **treatment**: incision across deep fascia to decompress the area

Question 63

what is tennis elbow?

Answer 63

partial tearing/degeneration of the **common extensor's tendon** at the **lateral epicondyle** of humerus → causes edema from the friction **symptoms**: pain & tenderness over the lateral epicondyle with pain radiating down the lateral side of forearm

Question 64

what is volkmann's ischemic contracture? causes and symptoms?

Answer 64

permanent deformity of hand & wrist due to ischemic necrosis of forearm muscles (*lack of oxygen/blood supply for too long = muscles died*) "**claw like deformity**" brachial artery went into spasm → reduced arterial flow → ischemic necrosis → muscle fibers replaced w/ fibrous tissue **causes**: fractures to supracondyle, untreated forearm compartment syndrome, tight casts

Question 65

what is stenosing synovitis of abductor pollicis longus/extensor pollicis brevis?

Answer 65

**cause**: repeated friction b/w tendons of these muscles & the styloid process of radius → edema & swelling leads to inflammation & thickening of these muscles → **movement of tendons becomes restricted** - severe cases require surgical incisions

Question 66

course of the entire **radial nerve** from brachial plexus to top of the fingers including the pathways of the deep & superficial branches

Answer 66

**C5-T1** → **posterior cord** of brachial plexus → comes out of axilla & immediately enters **posterior comp. of arm**→ winds around back of arm in **radial groove** of humerus w/ bestie **profunda brachii vessels** → pierces **lateral intermuscular septum** above the **lateral epicondyle** to enter the **anterior comp. of arm** b/w brachialis & brachioradialis → goes into **cubital fossa**→ divides into **superficial & deep branches** at the lateral epicondyle

Question 67

what is the pathway/supply of the superficial branch of the radial nerve?

Answer 67

- is direct continuation of the radial nerve runs down brachioradialis muscle on the **lateral side of brachial artery**→ separates from artery at distal part of forearm→ goes above **extensor retinaculum** and divides into several **dorsal digital nerves**→ supplies **sensory** innervation to **dorsal lateral hand** (skin over lateral 3 1/2 fingers except tips)

Question 68

pathway/supply of the deep branch of the radial nerve?

Answer 68

splits from radial nerve in front of **lateral epicondyle** of humerus in cubital fossa→ pierces **supinator muscle** (in posterior compartment) to become **posterior interosseous nerve**→ eventually reaches posterior forearm, supplying **all extensor muscles** & articular branches to wrist and carpal joints

Question 69

name the carpal bones of the hand and the mnemonic to remember them

Answer 69

*She Looks Too Pretty, Try To Catch Her* from thumb to pinky near the wrist → she look too pretty then from thumb to pinky again at top → try to catch her S → **Scaphoid** L → **Lunate** T → **Trapezium** P → **Pisiform** T → **Trapezium** T → **Trapezoid** C → **Capitate** H → **Hamate**

Question 70

which structures pass **above (superficial)** the flexor retinaculum?

Answer 70

- palmar cutaneous branch of median nerve - tendon of palmaris longus - palmar cutaneous branch of ulnar nerve - ulnar artery - ulnar nerve - flexor carpi ulnaris tendon *think ulnar's pura khaandan*

Question 71

which structures pass **below (deep)** the flexor retinaculum? (carpal tunnel)

Answer 71

**basically the carpal tunnel** - median nerve - 4 tendons of flexor digitorum superficialis - 4 tendons of flexor digitorum profundus - tendon of flexor pollicis longus - tendon of flexor carpi radialis *SPPLCR - May you Show Patty Patterns Lovely Cars w/ Radios?*

Question 72

what is the purpose of the superficial fascia of the palm?

Answer 72

it divides the sub-cutaneous fat into small tight compartments *just on that 1 random slide*

Question 73

what are 3 structures that the deep fascia of of the palm is specialized to form?

Answer 73

- flexor/extensor retinaculum at the wrist - palmar aponeurosis - **fibrous flexor sheaths** in the fingers: wrap around the finger tendons and have synovial sheath inside

Question 74

what is the purpose of the palmar aponeurosis?

Answer 74

triangular thickening of deep fascia in the central area of the palm - base is at the fingers and apex is towards the flexor retinaculum **function**: - gives firm attachment to overlying skin - improves grip - protects underlying tendons

Question 75

attachments of the **flexor retinaculum**

Answer 75

**medially**: pisiform bone & hook of hamate **laterally**: tubercle of scaphoid & crest of trapezium **on each side**: gives slips of attachment **proximally**: blends w/ fascia of forearm **distally**: continuous w/ palmar aponeurosis & palmar fascia

Question 76

muscles of the thenar & hypothenar eminence and how to remember them

Answer 76

*One For All (thenar) & All For One (hypothenar)* One → Opponens Pollicis For → Flexor Pollicis Brevis All → Abductor Pollicis Brevis All → Abductor Digiti Minimi For → Flexor Digiti Minimi Brevis One → Opponens Digiti MInimi

Question 77

thenar and hypothenar muscles are innervated by which nerve?

Answer 77

thenar → **median nerve** (recurrent branch) hypothenar → **ulnar nerve** (deep branch) *for ex. patient can't abduct thumb, know median nerve is damaged*

Question 78

what is carpal tunnel syndrome ?

Answer 78

same as forearm compartment syndrome except in the carpal tunnel fluid build up → no drainage → median nerve compressed → hand muscles paralyzed if untreated for too long

Question 79

movements of palmar and dorsal interossei

Answer 79

*PAD & DAB* palmar → adduct fingers dorsal → abduct fingers

Question 80

what is handlebar neuropathy?

Answer 80

people who ride long distances on bicycles with their **hands in extended position** = hand grips put **pressure on hooks of hamates** = **compresses ulnar nerve** results in **sensory loss on medial side of hand** & **weakness** of the intrinsic hand muscles

Question 81

pointing index finger/hand of Benedict is a sign of what nerve's damage?

Answer 81

median nerve

Question 82

what are the superficial and deep palmar arches formed by? **imp** - anastomosis in the hand

Answer 82

**superficial palmar arch**: ulnar artery & superficial branch of radial artery - *think superficial has a U for ulnar* **deep palmar arch**: radial artery & deep branch of ulnar artery *anastomosis of the ulnar and radial arteries gives these 2 arches*

Question 83

what are the 2 branches of the superficial palmar arch?

Answer 83

3 **common palmar digital arteries** → divide into **proper palmar digital arteries** → supply medial 4 fingers

Question 84

3 branches of the deep palmar arch

Answer 84

3 **palmar metacarpal arteries** → join **common palmar digital arteries** from superficial arch also gives rise to **princeps pollicis artery** (supplies thumb) & and **radialis indicis artery** (supplies lateral side of the index finger)

Question 85

which nerve has no motor function in the hand (only sensory function)?

Answer 85

radial nerve

Question 86

anastomosis around elbow joint **imp** - what arteries are involved

Answer 86

**brachial artery branches**: superior & inferior ulnar collateral artery **deep brachial artery branches (profunda brachii)**: radial and medial collateral artery **radial artery branch**: radial recurrent artery **ulnar artery**: anterior & posterior ulnar recurrent artery - **common interosseous artery** (branch of ulnar): interosseous recurrent artery *for own knowledge*: arteries come from above (descending branches) → come from **brachial** & deep brachial (**profunda brachii**) arteries arteries come from below (ascending arteries) → come from **radial** & **ulnar** arteries

Question 87

Allen's test

Answer 87

clinical test used to check if adequate blood flow to the hand, particularly through **superficial & deep palmar arches** (supplied by radial & ulnar arteries) - used before drawing blood or placing a catheter in the radial artery to make sure that the ulnar artery can still supply enough blood *basically patient squeezes and u take turns compressing each artery and patient opening hand to see if blood is returning fast enough (hand going back to normal color)*

Question 88

what are the 7 main **fascial spaces of the hand**? what is their surgical importance?

Answer 88

1. Thenar space 2. Midpalmar space 3. Hypothenar space 4. Pulp space (*of fingers*) 5. Dorsal subcutaneous space 6. Dorsal subaponeurotic space 7. Parona's space (*technically in distal forearm, but connected*) *3 mighty hands push deep* **surgical importance**: may become infected and distended with pus

Question 89

pulp spaces of fingers + boundaries (anterior & posterior)

Answer 89

on the distal palmar side (*like at the top of the finger on the front side of hand*) - have a bunch of **fibrous septa** that go from deep fascia to periosteum (outer lining of bone) - *they go vertically* **anterior**: skin & superficial fascia **posterior**: distal 2/3 of distal phalanx - dictate direction & extent of infections in the hand and fingers

Question 90

what is the **anatomical snuffbox**, what are the boundaries and contents?

Answer 90

**anatomical snuffbox**: triangular depression right below the thumb and above the styloid process of radius **boundaries**: medially (on top) is the **tendon of extensor pollicis longus** and laterally (below) is tendons of **extensor pollicis brevis & abductor pollicis longus** on the floor (proximally) are **scaphoid & trapezium bones** and the **radial styloid process** **contents**: radial artery and cephalic vein

Question 91

what is the structure/attachments of the **palmar aponeurosis**?

Answer 91

at apex, bordered by the **flexor retinaculum** and receives insertion of **palmaris longus tendon** at the base, splits into 4 slips that then divide into 2 bands (*1 that goes superficial to the skin & 1 that goes deep to the root of the finger*) and then they finally fuse with the **fibrous flexor sheath** (it goes across the knuckles region almost but on the palm side)

Question 92

clinical conditions: felon & whitlow

Answer 92

**felon**: deep bacterial infection of the pulp space — usually of the thumb or index finger - *have to create lateral incision to drain all the septum spaces* **whitlow**: viral infection of finger caused by herpes virus, on nail bed or top of finger *dont drain this surgically!*

Question 93

boundaries + contents of the thenar space (deep + superficial)

Answer 93

**contents**: 1st lumbrical lies deep to **long flexor tendons to the index finger** lies superficial (in front of) **adductor pollicis muscle**

Question 94

boundaries + contents of the midpalmar space (deep + superficial)

Answer 94

**contents**: 2nd, 3rd, 4th lumbrical muscles lies posterior (behind) to the **long flexor tendons to middle, ring, & little fingers** lies superficial (in front of) **interosseous muscles, 3rd, 4th, 5th metacarpal bones**

Question 95

drainage of midpalmar & thenar space infections (incision sites) + why important

Answer 95

**midpalmar space**: incision in 3rd or 4th web space (*middle or ring finger*) web space is like when you open your fingers and it looks like fish webbed fingers **thenar space**: incision site on lateral part of palm- b/w 1st & 2nd metacarpals *drainage imp b/c these spaces communicate w/ forearm & web spaces = infection can spread rapidly if not drained*

Question 96

what vein connects the cephalic and basilic veins? where is it located?

Answer 96

**median cubital vein** in the **cubital fossa** - cephalic runs on the lateral side & basilic runs on the medial side

Question 97

what veins does **dorsal venous arch** of hand receive blood from & where does it drain into?

Answer 97

receives from **dorsal metacarpal and digital veins** ultimately drains into **cephalic & basilic veins**, at its lateral and medial ends, respectively

Question 98

course of the **cephalic vein**

Answer 98

begins from **lateral end of dorsal venous arch** → ascends on the lateral side of wrist & forearm → travels along **anterolateral side of biceps brachii** → enters **deltopectoral groove** (b/w deltoid & pectoralis major) → pierces **clavopectoral fascia** → drains into **axillary vein**

Question 99

course of the **basilic vein**

Answer 99

begins from **medial end of dorsal venous arch** → ascends on **medial side** of wrist & forearm → continues along **anteromedial side of biceps** → at mid arm, pierces **deep fascia** to become a **deep vein** → joins **brachial veins** to form **axillary vein**

Question 100

where are the brachial plexus **roots, trunks, & divisions** located? what about the **cords & branches**?

Answer 100

**roots, trunks, & divisions**: in the posterior triangle of neck **cords & branches**: in the axilla

Question 101

klumpke's palsy is mainly what nerve damaged?

Answer 101

ulnar nerve *result is clawed hand*

Question 102

sensory innervation of musculocutaneous nerve

Answer 102

lateral part of forearm via **lateral cutaneous nerve of forearm**

Question 103

why is median's nerve called "laborer's nerve"?

Answer 103

manual laborers use grip, precision, and finger flexion a lot which all depend heavily on the **median nerve** - *motor supplies forearm muscles for flexion and thenar muscles*

Question 104

what happens if median nerve is damaged in **supracondylar fracture of the humerus**?

Answer 104

- flexion of wrist gone - adducted hand due to **paralysis of flexor carpi radialis** - forearm kept supine bc of **loss of pronators** **benedict's hand**: when asked to make a fist, cant flex index, middle, and thumb properly - pointing index finger

Question 105

what happens if median nerve is damaged at the **wrist**? (carpal tunnel syndrome)

Answer 105

- forearm alr supplied so mainly affects hand - **thenar eminence** gone = **ape hand deformity**

Question 106

ulnar nerve injury at elbow vs. wrist

Answer 106

elbow **flexor carpi ulnaris & half of flexor digitorum profundus** = weak flexion of ring & little fingers wrist most **intrinsic muscles** - hypothenar, interossei, medial 2 lumbricals, adductor pollicis = hand stays stuck in **claw hand deformity** and **forment sign** (cant pinch properly)

Question 107

guyon tunnel syndrome

Answer 107

compression of ulnar nerve in guyon tunnel = weakness of intrinsic muscles of hand & lack of sensation in medial 1 and 1/2 fingers

Question 108

bones that make the **wrist joint** (radiocarpal joint)

Answer 108

- distal end of radius - scaphoid, lunate, triquetral carpal bones - articular disc (below ulna)

Question 109

what type of joint is the wrist joint?

Answer 109

**synovial ellipsoid joint** - has oval shaped surface on one bone and shallow, oval depression on other bone allows movements in 2 directions but no rotations (wrist circling is on the radioulnar joint)

Question 110

wrist joint capsule

Answer 110

covers the wrist joint above the radius and ulna & before the proximal carpal bones - protects the joints & holds fluid *not flexor retinaculum, this is much more deep while flexor reticulum is much more superficial*

Question 111

ligaments of the wrist joint (dorsal & palmar)

Answer 111

**dorsal**: - dorsal radiocarpal ligament - radial collateral ligament - ulnar collateral ligament **palmar**: - palmar radiocarpal ligament - palmar ulnocarpal ligament

Question 112

nerve supply of the wrist joint

Answer 112

anterior interosseous nerve & the deep branch of the radial nerve

Question 113

4 movements of the wrist joint

Answer 113

1. **flexion**: flexor carpi radialis, flexor carpi ulnaris 2. **extension**: extensor carpi radialis longus & brevis, extensor carpi ulnaris 3. **abduction (radial deviation)**: abductor pollicis longus, FCR, ECRL, ECRB 4. **adduction (ulnar deviation)**: ECU, FCU (ulnaris)

Question 114

6 joints of the hand

Answer 114

1. wrist joint 2. inter carpal (*b/w carpal bones*) 2. carpometacarpal (*b/w carpal & metacarpal bones*) 3. inter metacarpal joints (*b/w the metacarpals*) 4. metacarpophalangeal joints (*b/w the metacarpal & phalanges - permit movement in 2 planes, knuckles*) 5. interphalangeal joints (*b/w the phalanges, permit flexion-extension only*)

Question 115

what is dupuytren's contracture?

Answer 115

progressive thickening & shortening of **palmar fascia**, causing flexion deformities of the fingers, most common affecting the ring & little fingers

Question 116

trigger finger (stenosing tenosynovitis)

Answer 116

finger locked in flexed position (like trigger position when holding a gun) due to inflammation & narrowing of tendon sheath

Question 117

boxer's fracture

Answer 117

fracture of neck of 5th metacarpal bones, typically resulting from punching a hard object

Question 118

which muscles in hand does the **median nerve** supply?

Answer 118

LOAF L - lumbricals (1st & 2nd) O A F - thenar muscles (opponens, abductor, flexor pollicis) *thats it, everything else in hand by ulnar nerve*