Forearm

Question 1

Which epicondyle is the common extensor origin, which is the common flexor origin?

Answer 1

common extensor origin - lateral epicondyle common flexor origin - medial epicondyle

Question 2

what is the principle function of the radius?

Answer 2

principle bone of the wrist. transmits F, i.e. during pushups, to the ulna via fibers of the interosseous mem radius twists at the elbow joint; has no strong articulation w the elbow. this gives us the ability to pronate and supinate

Question 3

the principle attachment of the FA is through the …

Answer 3

ulna (olecranon fits into capitulum, olecranon fossa)

Question 4

describe the deep fascia of the FA

Answer 4

deep faschia of the FA = antebrachial fascia - a continuation of the brachial fascia of the arm - distally, it will thicken and form the flexor and extensor retinacula

Question 5

extensor retinaculum

Answer 5

extends obliquely across the posterior radiocarpal jt from the anterior border of the DR to the triqeutrum and pisiform bones

Question 6

flexor retinaculum

Answer 6

aka the transverse carpal ligament - attached medially to the pisiform and hook of hamate, and laterally to the trapezium and scaphoid bones of the wrist - lies deep to extensor retinaculum - forms CT and canal of Guyon

Question 7

Answer 7

1) Extensor retinaculum (continous with the palmar carpal ligament)
2) Flexor retinaculum (i.e. transverse carpal ligament)

(Both are the distal continuation - thickening - of the antebrachial fascia)

Question 8

what muscle of the anterior FA does the median n pierce?

Answer 8

pronator teres

Question 9

what are the 5 muscles of the superior anterior compartment of the FA?

Answer 9

1) pronator teres (median)
2) flexor carpi radialis (median)
3) Palmaris Longus (median)
4) FDP (lat - median, medial - ulnar)
5) flexor carpi ulnaris (ulnar)

Question 10

what are the 3 deep anterior compartment of the FA muscles?

Answer 10

1) FDS (median)
2) flexor pollicis longus (median - anterior interosseous)
3) pronator quadratus (median - anterior interossesous)

Question 11

what are the 7 superficial posterior compartment of the FA muscles?

Answer 11

1) Brachioradialis (better seen anteriorly, but still innervated by radial n)
2) extensor carpi radius longus
3) extensor carpi radius brevis
4) extensor digitorum
5) extensor digiti minimi
6) extensor carpi ulnaris
7) anconeus

Question 12

what are the 5 deep posterior compartment of the FA muscles?

Answer 12

1) supinator
2) APL
3) EPB
4) EPL
5) extensor indicis

Question 13

what is the origin of all superficial anterior compartment of the FA muscles?

Answer 13

MEDIAL EPICONDYLE (common flexor origin)

Question 14

what are the 2 muscles of pronation, what compartment of the arm are they found in?

Answer 14

anterior

pronator quadratus (deep)

pronator teres (superficial)

Question 15

what are the 2 muscles of supination, what compartment of the FA are they found in?

Answer 15

posterior

Supinator

Biceps Brachii!

Question 16

what are the lateral and medial borders of the anatomical snuffbox?

Answer 16

lateral: APL, EPB
medial: EPL

Question 17

what are the 4 components of the anatomical snuffbox region?

Answer 17

1) radial artery runs thru the floor
2) branches of the superficial radial n run through the roof
3) styloid process of the radius can be palpated distally
4) scaphoid and trapezium

Question 18

where and into what does the brachial artery terminate?

Answer 18

terminates at the cubital fossa, into the radial and ulnar arteries.

Question 19

describe the course of the radial artery.

Answer 19

it extends from the neck of the radius to the medial side of the styloid process.

• it lies deep to the brachioradialis muscle, but becomes superficial in the distal 1/3 of the arm (site of radial pulse)

Question 20

describe the course of the ulnar artery.

Answer 20

extends from the neck of the radius to the flexor retinaculum on the medial edge of the wrist

• runs deep to the superficial flexors of the FA
• runs w the ulnar nerve in distal 1/2 of the FA, and enters the hand via the canal of Guyon w the ulnar n
• can be palpated just lateral to the tendon of the FCU
• gives off the common interosseous a in the cubital fossa

Question 21

what is common interosseous a, where does it split and into what

Answer 21

the common interosseous a is a trunk that splits off the ulnar a at the cubital fossa, where is almost immediately divides into the anterior and posterior interosseous arteries

Question 22

what is the general course of the anterior interosseous a?

Answer 22

travels down the FA, superficial to the interosseous mem

• pierces the interosseous mem distally to anastamose w the posterior interosseous a
• continues under the pronator quadratus m to the palmar carpal network

Question 23

what is the general course of the posterior interosseous a?

Answer 23

passes immediately deep to the interosseous mem to supply the posterior FA btw the superficial and deep groups of muscles

Question 24

describe the general course of the median n in the FA, and what branches it gives off

Answer 24

enters the FA btw the heads of the pronator teres m, where it gives off the anterior interosseous branch

• lies deep to the FDS muscle as it continues distally (btw FDS and flexor carpi radialis)
• becomes superficial in the distal FA
• passes deep and medial to the palmaris longus m, where it enters the CT deep to the flexor retinaculum

Question 25

describe the general course of the ulnar n in the FA

Answer 25

enters the FA behind the medial epicondyle, and pierces the FCU m

• continues deep to FDS, travels w ulnar a to the wrist where it enters the hand via canal of Guyon (deep to palmar carpal ligament but superficial to flexor retinaculum)

Question 26

where does the radial n divide, and into what branches

Answer 26

radial n divides into the superficial and deep (posterior interosseous) branches btw the brachialis and brachioradialis mm

• superficial branch runs deep to the brachioradialis muscle just lateral to radial a; crosses along the roof of the anatomical snuffbox
• deep branch, or posterior interosseous n, passes THRU the supinator muscle to innervate the posterior FA extensor mm