Anatomy of the Hand

What does the deep branch of the ulnar nerve supply? (5 things)

1. ALL minimi muscles 2. ALL interossei muscles 3. lumbricals 3&4 4. adductor pollicis 5. flexor pollicis brevis (deep head ONLY)

How is Dupuytren's contracture fixed? (3 ways)

1. Inject collagenase to eat up collagen 2. Stab at collagen fibers w/ a needle to weaken it 3. In severe cases, surgery to remove palmar aponeurosis is done.

The radial artery splits twice once it gets into the hand. What are these splits?

1. Radial artery (at the thumb) --> - radial artery - superficial palmar branch of radial artery 2. Radial artery (after 1st split) --> - radialis indicis artery - princeps pollicis artery

What does the adductor pollicis do and where is it located?

1. it adducts the thumb and also aides in thumb opposition 2. it originates at the 2nd and 3rd metacarpals and inserts at the thumb

What do the medial & lateral branches of the median nerve supply? (3 things)

1. lumbricals 1& 2 2. lateral 3.5 digits (sensory) 3. splits further into the common and proper palmar digital nerves

What does the superficial branch of the ulnar nerve supply? (2 things)

1. medial 1.5 digits 2. palmaris brevis *splits into the common and proper digital nerves of medial 1.5 digits)

What 4 important structures run superficial to the carpal tunnel/ flexor retinaculum fascia, but deep to the palmar carpal ligament?

1. palmer branch of median nerve 2. ulnar nerve 3. ulnar artery 4. palmaris longus tendon

How many palmar interossei muscles are there? Why does it have more/less than its dorsal counterpart?

3 has less because the middle finger doesn't have any - it IS the midline, so it can't go toward the midline.

How many dorsal interossei muscles are there?

4

Lumbricals help you: A) hold a cup of coffee B) make a spock sign C) give a high-five D) do push-ups

A) hold a cup of coffee why? finger FLEXION of metaphalangeal joints

What muscles comprise the hypothenar compartment?

Abductor digiti minimi flexor digiti minimi opponens digiti minimi

What function would you lose if your million dollar nerve was severed?

Could not oppose the thumb

Radialis Incidis runs where?

From base of thumb, up the 2nd digit (think, indicis runs up INDEX finger)

Princeps Pollicis artery runs where?

From base of thumb, up the thumb

The Ulnar Canal is sometimes called _________.

Guyon's canal

What two bones of the hand lie between the 3rd digit and wrist?

Lunate (proximal) and Capitate (distal)

Name the bond of the fingers from proximal to distal (there are 4).

Metacarpals, Proximal phalanx, Middle phalanx, Distal phalanx

The _______ ligament covers is an extension of the antebrachial fascia that covers and protects the carpal tunnel.

Palmar Carpal ligament

Timmy falls off his bike and holds his hands out to break his fall. His mom, a doctor, brings him to the ER because she suspects he may have fractured his __________.

Scaphoid bone

What are the four proximal bones of the hand, named medial to lateral?

Scaphoid, Lunate, Triquetrum, Pisiform

What is the mnemonic for remembering the bones of the hand?

So Long To Pinky Here Comes The Thumb

The flexor digitorum _______ has four tendon heads, two of which lie more superficial to the other two. Which ones are the more superficial ones?

Superficialis 3 & 4 (2 & 5 are deeper)

_____________ helps to lubricate the finger joint.

Synovial fluid in the synovial sheath

Name the bone that articulates with the 1st digit, or thumb.

Trapezium

What are the four distal bones of the hand, named medial to lateral?

Trapezium, Trapezoid, Capitate, Hamate

What is the function of the abductor pollicis brevis?

abduct the thumb - abduction of the thumb is where you move it to a 90 degree angle with your palm, such that it if your palm is facing the ceiling your thumb points straight upward also.

If you interlace your fingers with someone, the first step in this motion would be to _________ your fingers, or spread them apart. This action is made possible by the ________ muscle.

abduct your fingers dorsal interossei (D-A-B)

If you place you 2nd digit and thumb together to make an "OK" sign, you are partially ______ your thumb.

abducting

If you squeeze all of your fingers together, such that they are all touching, this action is called _________.

adduction

Name the joints of the fingers of the hand from proximal to distal (there are 4).

carpometacarpal metacarpopphalangeal proximal interphalangeal distal interphalangeal

Distal to the superficial palmar arch, we can find the ______________, and then, when the fingers split apart we can find the ___________.

common palmar digital arteries; proper palmar digital arteries

Ulnar Canal Syndrome can be caused by ______ and leads to ______ (symptoms).

compression of ulnar nerve (sometimes caused by fracture of hook of hamate bone) hypoesthesia (reduced sensation) in medial 1.5 digits weak intrinsic hand muscles

What causes Dupuytren's contracture? What anatomical structure is affected?

contracture of collagen fibers in the palmar aponeurosis

What nerve innervates adductor pollicis?

deep branch of the ulnar nerve

What nerve innervates the muscles of the hypothenar compartment?

deep branch of the ulnar nerve

The thumb is missing the _______ joint.

distal interphalangeal

Flexor digitorum profundus attaches to the ___________.

distal phalanx

If you hold your hands up in a "raise the roof" position, your hands are ________ .

dorsi-flex

If a mime on the street is pretending that he is inside an invisible box, he is repeatedly _______ his hands when he "feels" the sides of the box.

dorsi-flexing (is that a word?)

When you tell someone that they are a loser, complete with the L sign, you are _______ your thumb.

extending

T/F - If you look down at your hands while you are typing, Guyon's canal is closer to the thumb than the carpal tunnel.

false - Guyon's canal is toward your pinky. It is formed by the hamate and pisiform bones, which are over there.

T/F - When you give someone a thumbs-up, you are contracting your thenar muscle group.

false - your thumb is extended, so these muscles would be relaxed (because their function is flexion).

What are the symptoms of Dupuytren's contracture?

finger(s) drawn into permanent flexion (inward, like as if you were about to make a fist)

What is the function of the flexor pollicis brevis?

flex the thumb

The metacarpophalangeal joints are capable of these movements:

flex/extension abduct/adduct circumduction (digits 2-5)

if you curl your thumb in to your palm as if to make a fist, you are _______ your thumb.

flexing

What three muscles have tendons within the carpal tunnel?

flexor digitorum superficialis flexor digitorum profundus flexor pollicis longus

The thenar compartment of the hand contains which muscles?

flexor pollicis brevis abductor pollicis brevis opponens pollicis

The _______ is deep to the palmar carpal ligament.

flexor retinaculum

What fascial structure is the "roof" of the carpal tunnel?

flexor retinaculum

What bone in the hand articulates directly with the 4th and 5th digits?

hamate (and its hook)

Guyon's canal is made by two bones and a ligament, which are:

hamate bone, pisiform bone, flexor retinaculum

What two muscle groups comprise the interosseous/adductor muscle compartment?

interossei muscles and lumbricals

Is your thumb medial or lateral?

lateral

If you only bend your finger at the knuckle, and nowhere else, the ___________ muscles are working.

lumbricals they also aid in EXTENTION of the interphalangeal joints

What nerve is mainly affected in a patient with carpal tunnel syndrome?

median nerve

A baseball player comes in to the clinic with right upper extremity weakness. In addition to the weakness, he also can not form a fist - when he tries, his 2nd and 3rd digits do not move. What nerve may be affected in this patient?

median nerve - injury at the elbow (associated forearm problems - flexor digitorum superficialis can not do its job of flexing the fingers)

A 35 year old male patient comes in complaining of weakness in his left hand. Upon further examination, you notice an indent near his thumb, indicative of muscle wasting. What nerve could be affected in this patient?

median nerve - injury at the wrist

Flexor digitorum superficialis attaches to the __________.

middle phalanx

The adductor pollicis looks like a 7 because it has two heads. Listed lateral --> medial, they are called:

oblique head (lateral) transverse head (medial)

When you make a peace sign with your fingers, you are ______ your thumb.

opposing

What is the function of opponens pollicis? What does this movement look like?

opposition - when you touch your pinky and thumb together. also does a little bit of rotation

What are the names of the two interossei muscles?

palmar interossei dorsal interossei

If you palpate the medial side of your wrist crease, you can feel the _______ bone

pisiform

The flexor digitorum _____ passes through an opening in the ______ on its way to the fingers.

profundus, superficialis

In the forearm, the median nerve passes between the two heads of what muscle?

pronator teres

In the deep palmar arch, where does most of the blood supply come from?

radial artery

Blood supply to the scaphoid bone is sort of bizarre because the ______ artery enters on the distal side and then travels back more proximally through the bone. This puts the bone at great risk for ______ when it gets fractured.

radial; avascular necrosis

The median nerve splits into three subdivisions in the hand - what are they?

recurrent branch - supplies all of the thenar muscles medial & lateral branches - lumbricals 1 & 2, palmar cutaneous branch - supplies the skin of the palm

Two of the thenar muscles are innervated exclusively by the _______. They are _______ and _________.

recurrent branch of the median nerve abductor pollicis brevis; opponens pollicis

What nerve is often referred to as the "million dollar nerve?"

recurrent branch of the median nerve - because if you cut it in surgery you will be sued for a million dollars

If you place your hands together in a praying position, your thumb is _______.

repositioned

How do we treat patients with carpal tunnel syndrome?

rest, immobilization, drugs, physical therapy - stretching, etc sometimes surgery

What innervates the flexor pollicis brevis? What compartment/muscle group is it in?

superficial head = recurrent branch of median nerve **deep head = deep branch of the ulnar nerve** < weird in the thenar compartment - flex. poll. brevis is the only one NOT innervated by the median nerve.

A cool fact about lumbricals is that they originate on a _____, not a ______.

tendon (flex. dig. profundus) ; bone

Lumbricals 3 & 4 are innervated by:

the deep branch of the ulnar nerve.

What happens to the ulnar artery at the wrist?

the deep palmar branch of the ulnar artery splits off and dive deep down (eventually make the deep palmar arch). In the meantime, the regular ulnar artery continues forward to make the superficial palmar arch.

Which one is more superficial - the palmar or dorsal interosseous muscle?

the dorsal interossei is deeper than the palmar interossei

Lumbricals 1 & 2 are innervated by:

the median nerve.

What arteries come off of the deep palmar arch?

the palmar metacarpal arteries

Which digit is mostly likely to aid in the spread of infection and why?

the pinky - because the pinky's synovial sheath extends far down into the wrist, and connects to the COMMON FLEXOR SHEATH in the palm.

What happens to the radial artery at the thumb?

the superficial branch of the radial artery splits off at the thumb and goes to the superficial arch while the radial artery continues down and goes to the deep palmar arch

Where do all the thenar muscles go?

the thumb

What does the palmar aponeurosis do?

thick fascia that runs to the digits - protects the nerves and arteries underneath it

T/F - the median nerve is responsible for both sensory and motor functions in the hand

true

In the superficial palmar arch, where does most of the blood supply come from?

ulnar artery

Which two big arteries anastomose to form the superficial palmar arch?

ulnar artery superficial palmar branch of the radial artery

What 2 important structures pass through Guyon's canal?

ulnar nerve ulnar artery

If the same 95 year old lady had come into the clinic with her abnormally flexed 4th and 5th digits AND inability to make a fist, what nerve could she have compressed and where? What forearm muscles may be affected?

ulnar nerve - at the elbow (proximal) flexor carpi ulnaris, flexor digitalis profundus not working

A 95 year old lady comes in to the clinic with odd contraction in her 4th and 5th digits. She also mentions that she can not feel very well on that side. What nerve ma be compressed? What muscle is messed up?

ulnar nerve - injury near wrist. lumbricals 4 & 5