Forearm Flashcards
Which epicondyle is the common extensor origin, which is the common flexor origin?
common extensor origin - lateral epicondyle common flexor origin - medial epicondyle
what is the principle function of the radius?
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
the principle attachment of the FA is through the …
ulna (olecranon fits into capitulum, olecranon fossa)
describe the deep fascia of the FA
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
extensor retinaculum
extends obliquely across the posterior radiocarpal jt from the anterior border of the DR to the triqeutrum and pisiform bones
flexor retinaculum
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
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)
what muscle of the anterior FA does the median n pierce?
pronator teres
what are the 5 muscles of the superior anterior compartment of the FA?
1) pronator teres (median)
2) flexor carpi radialis (median)
3) Palmaris Longus (median)
4) FDP (lat - median, medial - ulnar)
5) flexor carpi ulnaris (ulnar)
what are the 3 deep anterior compartment of the FA muscles?
1) FDS (median)
2) flexor pollicis longus (median - anterior interosseous)
3) pronator quadratus (median - anterior interossesous)
what are the 7 superficial posterior compartment of the FA muscles?
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
what are the 5 deep posterior compartment of the FA muscles?
1) supinator
2) APL
3) EPB
4) EPL
5) extensor indicis
what is the origin of all superficial anterior compartment of the FA muscles?
MEDIAL EPICONDYLE (common flexor origin)
what are the 2 muscles of pronation, what compartment of the arm are they found in?
anterior
pronator quadratus (deep)
pronator teres (superficial)
what are the 2 muscles of supination, what compartment of the FA are they found in?
posterior
Supinator
Biceps Brachii!
what are the lateral and medial borders of the anatomical snuffbox?
lateral: APL, EPB
medial: EPL
what are the 4 components of the anatomical snuffbox region?
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
where and into what does the brachial artery terminate?
terminates at the cubital fossa, into the radial and ulnar arteries.
describe the course of the radial artery.
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)
describe the course of the ulnar artery.
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
what is common interosseous a, where does it split and into what
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
what is the general course of the anterior interosseous a?
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
what is the general course of the posterior interosseous a?
passes immediately deep to the interosseous mem to supply the posterior FA btw the superficial and deep groups of muscles
describe the general course of the median n in the FA, and what branches it gives off
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
