The Forearm

Front 1

What are the segmental Dermatone innervations from shoulder to hand?

Back 1

C4, C5, C6 (thumb), C7, C8 (pinky), T1, T2, T3 (armpit)

Front 2

Wrist: radiocarpal joint

Back 2

articulation bw distal radius, articular disc, and proximal carpals,
-synovial joint: ellipsoid/condyloid
-ulna DOES NOT directly participate nor does pisiform

Front 3

Name of the fascia and membrane?

Back 3

Antebrachial fascia and interosseous membrane (binds U & R together)

Front 4

Pronator Teres
A=
NN=

Back 4

Starts at common flexor tendon and inserts into proximal shaft of ulna
A=pronate and flex forearm at elbow
NN=Meidan n.

Front 5

Flexor carpi radialis
A=
NN=

Back 5

Starts at common flexor tendon and inserts into 2nd/3rd metacarpal bones
A=flex and abduct hand
NN=Median n.

Front 6

Palmaris Longus
A=
NN=

Back 6

**absent in 14% of population
starts at common flexor tendon and inserts into palmar aponeurosis
A=flex hand at wrist, tenses palmar aponeurosis
NN= Median N.

Front 7

Flexar Carpi Ulnaris
A=
NN=

Back 7

Starts at common flexor tendon and inserts into pisiform
A=flex and adduct hand at wrist
NN=Ulnar N.

Front 8

Flexor digitorum superficialis
A=
NN=

Back 8

Humeroulnar head starts at medial epicondyle, radial head from sup radius and they insert into middle phalanges of II-V (tendon splits in two)
A=flex middle and prox phalanges
NN=Median N.

Front 9

Flexor digitorum profundus
A=
NN=

Back 9

starts at the prox ulna/interosseous membrane and inserts under FDS onto distal phalanges of II-V
A=flex distal phalanges II-V
NN=Lateral-median n.
medial-ulnar n.

Front 10

Pronator Quadratus
A=
NN=

Back 10

starts from medial surface of ulna and inserts into lateral border of radius
A=pronate forearm and bind R/U
NN= Median N.

Front 11

Brachioradialis
A=
NN=

Back 11

starts at supracondylar ridge of humerus and inserts into distal radius (before styloid process)
A=flex forearm at elbow (drink)
NN=Radial N.

Front 12

Extensor Carpi radialis longus & brevis
A=
NN=

Back 12

Start at lateral ridge of humerus and insert into base of 2nd metacarpal
A= extend and abduct hand
NN=longus-radial n.
brevis-radial n. deep branch

Front 13

Extensor carpi ulnaris
A=
NN=

Back 13

One head comes from lateral epicondyle and the other from the posterior border of ulna and they insert into 5th metacarpal
A=extend and adduct hand
NN=radial n.deep branch

Front 14

Extensor digitorum (minimi + idicis)
A=
NN=

Back 14

Starts at lateral epicondyle and inserts into II-V digit
A=extend distal, middle, and prox phalanges of II-V
NN= radial n. deep branch

Front 15

Supinator
A=
NN=

Back 15

starts from lateral epicondyle, radial ligament, and ulnar crest and inserts into lateral, post, and anterior proximal of radius
A=supinate
NN=radial n of deep branch

Front 16

abductor pollicis longus
A=
NN=

Back 16

starts at posterior of ulna, radius and interosseous membrane and inserts into base of 1st metacarpal bone
A= abduct pollex
NN= radial n. deep branch

Front 17

Extensor pollicis longus
A=
NN=

Back 17

starts at posterior ulna and inserts into base of distal phalanx of the thumb
A= extend distal thumb phalanx and carpometacarpal joint
NN= Radial n deep branch

Front 18

Extensor pollicis brevis
A=
NN=

Back 18

starts from posterior radius and inserts into base of prox phalanx of thumb
A= extend proximal phalanx of thumb and carpometacarpal joint
NN= Radial n. deep branch

Front 19

Extension fracture of the distal radius=

Back 19

"Dinner fork deformity"
"Colles fracture"
-falling on outstretched pronated hands
-90% of distal radius fractures
-complete transverse fracture often comminuted
-distal fragment is displaced posteriorly (dorsal displacement of hand)
-ulnar styloid process may also be avulsed
-risk of injury to median n. (mimics carpal tunnel syndrome)

Front 20

Pronator syndrome

Back 20

-Median n. compressed b/w ulnar and humeral heads of pronator teres m.; trauma, muscle hypertrophy, fibrous hands
-symptoms present after provacative test
-pronation against resistance
-pain in forearm, paresthesia of hand

Front 21

Fracture & avulsion of medial epicondyle=

Back 21

Direct blow to medial elbow, fall with severe abduction of extended elbow (strong ulnar collateral ligament)
-HIGH risk of ulnar n. injury
-motor and sensory loss
-Claw hand deformity (when making a fist)

Front 22

"Claw hand"

Back 22

-difficulty making a fist
-cannot flex DIP joints (distal-interphalangeal) digits I-IV
-Hyper-extension of MP joings (metapharangeal)

Front 23

Supracondylar fracture (distal humerus)

Back 23

-falling onto outstretched hand
-distal shaft fragment displaced posteriorly (limb shortening)
-risk of brachial a. laceration (ischemic contracture (volkmann's)
-Risk of medan n. damage
-motor and sensory loss
-"hand of benediction (when making a fist)

Front 24

Radial N. Injury

Back 24

"wrist drop"
-inability to extend wrist & fingers (MP, PIP, DIP joints)
-Wrist remains partly flexed due to unopposed flexor tone and gravity
-Damage to radial n. usually at humerus mid shaft (radial groove)

Front 25

Repetitive stress elbow injuries
Lateral:
Medial:

Back 25

-Lateral epicondylitis-"tennis elbow" repetitive forced extension
-Medial epicondylitis-"golfers elbow" repetitive forced flexion

Front 26

Ischemic contracture
"Volkmann contracture"

Back 26

Ischemia of elbow and forearm:
-sudden brachial a. occlusion/laceration
-compartment syndrome may occlude
-necrotic tissue replaced by scar tissue (fibrous non-elastic)
-Muscles permanently shortened