10.4 - Posterior Forearm And Dorsal Hand

Front 1

How do the forearm bones move?

Back 1

radial pivots about the ulna, allowing supination and pronation

Front 2

olecranon vs. coranoid process

Back 2

olecranon - posterior (point of elbow

coranoid process - anterior

Front 3

walls of trochlear notch

Back 3

olecranon
coranoid process

Front 4

articulation of the ulna and humerus - action

Back 4

flexion, extension of the elbow joint

Front 5

tuberosity of the ulna

Back 5

inferior to the coronoid process

where tendon of the brachialis muscle attaches

Front 6

radial notch - location

Back 6

lateral side of the coronoid process in the ulna

Front 7

ulnar notch - location

Back 7

medial distal end of radius

Front 8

location of radial styloid process, tuberosity

Back 8

tuberosity - proximal
styloid process - distal.

Front 9

apex

Back 9

formed by a section of the 
sharp interosseous border of 
the radius or ulna that 
connects to the thin, fibrous 
interosseous membrane of the forearm 

Front 10

where do fractures of the radius and ulna usually occur?

Back 10

middle third of the bones

Front 11

fracture of the distal end of the radius - most common in what group of people

Back 11

people >50 years age, women (b/c osteoporosis)

Front 12

what is the most common fracture of the forearm?

Back 12

Colles fracture: A complete transverse fracture of the distal 2 cm of the radiu

distal fragment is displaced dorsally, broken into pieces
caused by forced dorsiflexion of the hand.
ulnar styloid process is often broken off.
radius shortens - so ulnar tuberosity extends further than radial tuberosity (colles fracture causes radius to shorten)

aka dinner fork deformity - b/c posterior bending of the distal fragment of the radius

Front 13

fracture of the olecranon

Back 13

"fractured elbow"
caused by:  fall on the elbow combined with sudden powerful contraction of the triceps 

Front 14

antebrachial fascia

Back 14

deep to the skin in the forearm.

thickens posteriorly over the distal ends of the radius and ulna to form a transverse band, 
the extensor retinaculum, which retains the extensor tendons in position 
also forms an anterior thickening, which is continuous with the extensor retinaculum; some 
authors identify it as the palmar carpal ligament 

Front 15

Medial and lateral epicondyles, supraepicondylar ridges

Back 15

distal humerus

attachment sites for flexors and extensors of the fingers and wrist

Front 16

medial epicondyle and supraepicondylar ridge

Back 16

attachment for forearm flexors

Front 17

lateral epicondyle and supraepicondylar ridge

Back 17

attachment for forearm extensors

Front 18

flexors and pronators of the forearm are innervated mainly by the..

Back 18

median nerve (except flexor carpi ulnaris and 1/2 flexor digitorum profundus - ulnar nerve)

Front 19

extensors and supinators of the forearm are ALL innervated by the...

Back 19

radial nerve

Front 20

brachioradialis

Back 20

flexor of forearm - but located in the posterior (extensor) compartment! supplied by radial nerve

Front 21

3 functional groups of extensor forearm muscles.

Back 21

1. Muscles that extend and
abduct or adduct the hand at 
the wrist joint: 
- extensor carpi  radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris 

2. Muscles that extend the
 medial four fingers: 
- extensor digitorum, extensor indicis,
extensor digiti minimi 

3. Muscles that extend or  abduct the thumb: 
- abductor pollicis longus,
extensor pollicis brevis,
extensor pollicis longus 

Front 22

Extensor tendons

Back 22

held in place by extensor retinaculum
covered with synovial tendon sheaths as they pass over dorsum of wrist, through the osseofibrous tunnels of the extensor retinaculum

Front 23

brachioradialis

Back 23

lateral border of the cubital fossa

Front 24

the only 2 muscles of the posterior compartment that do not cross, and therefore cannot act at the wrist

Back 24

brachioradialis
supinator

Front 25

extensor carpi radialis longus

Back 25

partly overlapped by the brachioradialis (posterior to the brachioradialis)

its tendon is crossed by the abductor pollicis brevis and extensor pollics brevis

- impt for clenching fist

Front 26

Extensor carpi radialis brevis

Back 26

shorter than ECRL
attaches adjacent to ECRL in hand (attaches to base of 3rd metacarpal, ECRL atts to 2nd metacarpal)

covered by ECRL as it passes distally

Front 27

extensor digitorum

Back 27

principal extensor of the medial 4 fingers

its 4 tendons + tendon of the extensor indicis join, pass under the extensor retinaculum

Front 28

Intertendinous connections - link adjacent extensor digitorum tendons, proximal to knuckles (metacarpophalangeal joints)

Back 28

restricts independent extension of fingers

cannot fully flex finger if others are fully extended

Front 29

extensor expansions (digital or dorsal expansion or hood)

Back 29

= 4 extensor digitorum tendons flattened... On the distal ends of the metacarpals and along the phalanges

- triangular, tendinous 
aponeurosis that wraps around the dorsum and sides of a head of the 
metacarpal and proximal phalanx 

Front 30

how do flexor digitorum tendons form the extensor expansionss?

Back 30

In forming the extensor expansion, each flexor digitorum tendon divides into: 
• median band that passes to the base of the middle phalanx 
• two lateral bands that pass to the base of the distal phalanx