Anatomy: Posterior Forearm

Front 1

What nerve innervates the muscles of the posterior compartment of the forearm?

Back 1

Radial

Front 2

Where do the extensor tendons of the forearm have their origin?

Back 2

Radial side (lateral epicondyle)

Front 3

A thickening of the antebrachial fascia in the distal forearm that binds down the extensor tendons as they pass onto the dorsum of the hand

Back 3

Extensor retinaculum

Front 4

Where does the radial nerve travel in the forearm?

Back 4

passes from below the brachioradialis muscle and over the extensor retinaculum to supply cutaneous innervation to the dorsum of the hand.

Front 5

Where should you test for radial innervation on the hand?

Back 5

The dorsum of the hand at the base of the thumb

Front 6

What is the function of the brachioradialis?

Back 6

Flexes the forearm

Front 7

What artery passes through the anatomical snuff box?

Back 7

Radial

Front 8

What makes up the snuff box?

Back 8

EPL, EPB, APL

Front 9

What is the function of the abductor pollicis longus?

Back 9

Abducts thumb

Front 10

What is the function of the Extensor pollicis brevis?

Back 10

Extends proximal phalanx of thumb

Front 11

What is the function of the Extensor pollicis longus?

Back 11

Extends distal phalynx of thumb

Front 12

What is the function of the extensor carpi radialis longus and the extensor carpi radialis brevis?

Back 12

Extend and aBduct hand

Front 13

What is the function of the extensor digitorum?

Back 13

Extend hand and medial 4 digits

Front 14

What is the function of the extensor carpi ulnaris?

Back 14

Extends and adducts hand

Front 15

What is the function of the extensor digiti minimi?

Back 15

Extends 5th digit

Front 16

What specific nerve supplies the deep muscles of the posterior forearm compartment?

Back 16

Posterior interosseous branch of the radial nerve

Front 17

What is the function of the supinator?

Back 17

Supinates the forearm

Front 18

What is the function of the extensor indicis?

Back 18

Extends digit #2

Front 19

What layers of muscle does the deep branch of the radial nerve pass between?

Back 19

Supinator

Front 20

What are the two outcropping muscles?

Back 20

Abductor Pollicis Longus
Extensor Pollicis Brevis

Front 21

What is the posterior interosseous nerve a continuation of?

Back 21

The deep branch of the radial nerve

Front 22

What gives rise to the posterior interosseous artery?

Back 22

Common interosseous artery

Front 23

What are all interossei muscles innervated by in the hand?

Back 23

Ulnar

Front 24

How many dorsal interossei are there?

Back 24

4

Front 25

What is the function of the dorsal interossei?

Back 25

abduct the fingers (thumb and pinky have own abductors)

Front 26

What do DABS and PADS flex and what do they extend?

Back 26

Flex Metacarpophalangeal joint and exted the two distal phalanges

Front 27

What insert into the extensor hood?

Back 27

Lumbrical and iterossei from the palm

Front 28

What side of the metacarpal are the lumbricals on?

Back 28

radial

Front 29

What is the fibrous band that form osseofibrous canals with palmar surface of phalanges to hold tendons of the flexor digitorum superficialis and profundus?

Back 29

Fibrous digital (tendon) sheaths

Front 30

What are small bands that carry BV from sheaths to tendons?

Back 30

Vincula tendineae

Front 31

Damage to what nerve would cause the "Hand of benediction?"

Back 31

Median

Front 32

What muscles are paralyzed in the hand of benediction?

Back 32

Thenar and 1st and 2nd lumbricles

Front 33

What muscle function in the hand is lost when the median nerve is damaged?

Back 33

Thumb opposition and loss of flexion at 2nd and 3rd finger DIP and PIP joints and weakened flexion of the MP joints of the 2nd and 3rd finger

Front 34

What would a patient present like with a damage to the median nerve? (hand)

Back 34

When asked to make a fist, the index and middle fingers tend to lag behind the ring and little fingers

Front 35

What would cause "claw hand?"

Back 35

Ulnar nerve injury in the elbow region

Front 36

What is the patient unable to do with ulnar nerve injury in the elbow?

Back 36

Unable to flex the little and ring fingers at the DIP joints

Front 37

What muscles would be affected with an ulnar injury in the elbow region?

Back 37

Flexor digitorum profundus (half), 3rd and 4th lumbricles and interossei

Front 38

What would happen with distal ulnar nerve damage? (motor)

Back 38

Loss of flexion at 4th and 5th MP joint (hyperextension of joint) – no innervation of 3rd and 4th lumbricals by the ulnar nerve
Inability to extend the IP joints when attempting to straighten the fingers – loss of innervation of the 3rd and 4th lumbricals and interossei by the ulnar nerve

Front 39

Would a pt be able to flex 4th and 5th DIP joints in a distal ulnar nerve palsy?

Back 39

Yes. FDP innervation by the ulnar nerve is intact

Front 40

What would happen with distal ulnar nerve damage? (Sensory)

Back 40

Hypoesthesia and paresthesia in little finger and ulnar half of ring finger – loss of sensory innervation by ulnar nerve

Front 41

What is "wrist drop?"

Back 41

When the writs is flexed; inability to extend the hand at the wrist due to unopposed flexor muscles

Front 42

When would wrist drop occur?

Back 42

Damage to the radial nerve, especially above the elbow

Front 43

Why does damage to the radial nerve cause wrist drop?

Back 43

Radial nerve supplies extensor muscles of the forearm

Front 44

What is not possible due to a raidal nerve damage above the elbow?

Back 44

Cannot extend the wrist or extend the fingers at the MP joint

Front 45

Where would paresthesia occur in the hand due to a medial nerve injury?

Back 45

lateral three and a half fingers

Front 46

Why is there no loss or abnormal sensation in the palm of the hand during a median nerve injury?

Back 46

The are is innervated by the palmar cutaneous branch of the median nerve before the median nerve passes through the carpal tunnel

Front 47

Why would there be loss of coordination and strength in the thumb, difficulty gripping things, during median nerve injury?

Back 47

thenar muscles weak due to loss of innervation by median nerve (recurrent branch)

Front 48

Why would there be weakened flexion of 2nd and 3rd MP joints in a median nerve injury?

Back 48

Loss of innervation of the 1st and 2nd lumbricales

Front 49

What is the Phalen test and what would the result be in someone with carpal tunnel syndrome?

Back 49

compression of the median nerve in the carpal tunnel produces abnormal sensations in the lateral three and one-half digits, +

Front 50

What is nursemaid's elbow or pulled elbow?

Back 50

The head of the radius is pulled out of the anular ligament, resulting in a subluxation or dislocation of the radial head

Front 51

What results when avulsion of the extensor tendon from the distal phalanx when the extensor tendon is contracted and the distal phalanx is forcibly flexed?

Back 51

Mallet or Baseball finger

Front 52

What does a mallet finger look like?

Back 52

The distal phalanx is held in a flexed position because of the unopposed action of the flexor digitorum profundus

Front 53

Where does ulnar nerve injury usually occur?

Back 53

where the nerve passes posterior to the medial epicondyle of the humerus

Front 54

What is compression of the ulnar nerve at the elbow called?

Back 54

Cubital tunnel syndrome

Front 55

What would occur with any lesion to the ulnar nerve superior to the medial epicondyle?

Back 55

Paresthesia of the median part of the dorsum of the hand

Front 56

What would an injury to the ulnar nerve in the distal part of the forearm cause? (sensory wise)

Back 56

denervation of most intrinsic hand muscles

Front 57

When an attempt is made to flex the wrist joint with a distal forearm ulnar injury, what happens?

Back 57

Hand is drawn to the lateral side by the FCR (supplied by the median nerve) because the balance is not provided by the FCU