Forearm and Wrist Flashcards
describe the 3 borders of the radius
anterior
posterior - distinct only in middle third of the bone
interosseous border - sharp and site for where the radius and ulna link
what roughening is found on the lateral surface of the radius
oval roughening for attachment of pronator teres
what is there to easily distinguish between the posterior and anterior surface o the radius
large dorsal tubercle
what is found on the distal medial aspect of the radius
ulnar notch
what is found on the lateral aspect of the distal head of the radius
diamond shaped and has a radial styloid process
describe the three borders of the ulna
anterior - smooth, except distally
posterior - sharp and palpable
interosseous - joins ulna and radius
what is found at the distal end of the ulna
ulnar styloid process
what covers the distal head of the ulna
ulnar styloid process
describe the distal radio-ulnar joint
occurs between head of ulna and ulnar notch on the radius - has fibrous articular disc to separate it from the wrist joint
this joint allows the distal end of the radius to move anteromedially over the ulna in pronation
describe the process of pronation vs supination
occurs only in the forearm - distal end of the radius moves over the ulna
during pronation what holds the bones together
anular ligamento of the radius at the promixal radio-ulnar joint
interosseous membrane along the length of the bones
articular disc at the distal radio-ulnar joint
what two muscles allow pronation
pronator teres and pronator quadratus fond in the anterior compartment of the arm
contraction = pull distal end of the radius over the ulna = pronation
what are the routes of pronator muscle attachments
pronator teres - medial epicondyle on the humerus to lateral surface of the radius midway along the shaft
pronator quadratura - extends between anterior surfaces at the distal end of the radius and ulna
what muscles supinate the forearm
muscles in the posterior compartment of the forearm and the biceps
how does the biceps brachii cause supination
largest of the supinators
works best when the elbow is flexed
what is the anconeus muscle
proximal posterior compartment of the forearm from lateral epicondyle to lateral surface of proximal ulna
which two forearm muscles form the cubital fossa
brachioradialis which originates form the lateral supra-epicondylar ridge
pronator teres mussen and flexors originating from the medial epicondyle
what are the major constituents of the cubital fossa from lateral to medial
the tendon of the biceps brachii
the brachial artery
median nerve
describe the parameters of the cubital fossa triangle
base is line between lateral and medial epicondyles
floor covered by brachialis
pronator teres on the medial aspect and brachioradialis from the lateral side
what does the brachial artery bifurcate into
ulnar and radial artery (radial is thumb side when supinated)
what does the radial and ulnar artery supply
radial = posterior aspect of forearm ulnar = anterior
what happens distally to he radial and ulnar arteries
anastomose to form the deep and superficial palmar arch
what are the nerves that occupy the anterior compartment of the forearm
median nerve
ulnar nerve
superficial branch of the radial nerve
describe the route and innervation of the median nerve
innervates all muscles anteriorly except flexor carpi ulnas and medial part of the flexor digitorum profundus
travels in the forearm deep to the flexor digitorum superficials muscle. enters pan of hand via the carpel tunnel
describe the route and innervation of the ulnar nerve in the anterior compartment of the forearm
innervates flexor carpi ulnas and medial part of flexor digitorum profundus (ring and little fingers)
where is the ulnar artery compared to the ulnar nerve
ulnar artery is lateral to the nerve in the distal two thirds of the forearms
describe the route and innervation of the superficial radial branch of the radial nerve
anterior compartment - sensory
travels deeps to the brachioradialis in association with the radial artery
innervates skin on the posterolateral side of the hand
which nerve innervates the posterior compartment of the forearm
radial nerve (mainly deep branch)
what happens to the deep radial nerve
becomes posterior interosseous nerve after emerging between the two heads of the supinator muscles in the posterior compartment of the forearm
describe what the radial nerve innervates in different areas
innervates the brachiradialis and extensor carpi radialis longus
the deep branch innervates the extensor carpi radialis bravis
BEST - brachioradialis, extensors, supinator, triceps
what does the posterior interosseous muscle innervate
all remaining muscles of the forearm posterior compartment (does not travel through carpel tunnel)
where do all flexors of the forearm originate
medial epicondyle
what 3 muscles occupy the superficial layer of the forearm (anterior compartment)
flexor carpi ulnaris
palmris longus
flexor carpi radialis
(pronator teres)
what is the role of the flexor carpi ulnaris
most medial of sup layer
humeral and ulnar head which inserts into pisiform bone in wrist
most powerful flexor of forearm and adductor of wrist
innervated by the ulnar nerve
what is the structure and role of the palmaris longus
(absent in 15% of population)
lies between flexor carpi longus and ulnaris
inserts into flexor retinaculum
accessory flexor of wrist and innervated by median nerve
what is the role of the flexor carpi radialis
lateral to palmar is longus - large tendon medial distal anterior forearm
inserts into metacarpals 2 and 3
flex and abduct the wrist
innervated by median nerve
which muscle occupies the intermediate layer of the anterior forearm
flexor digitorum superficialis
what is the structure role of the flexor digitorum superficials
two heads which form 4 tendons pass through carpel tunnel and into 4 fingers
flexes the metacarpophalangeal joint and proximal interphalangeal joint of each finger and flexes wrist
innervated by median nerve (just deep to this muscle)
which muscles occupy the deep layer of the anterior compartment of the forearm
flexor digitorum profundus
flexor pollicis longus
what is the structure and role of the flexor digitourm profundus
deep to the FDS - gives rise to four tendons which go through carpal tunnel into 4 fingers - insert into distal phalanx
innervated by: lateral half (index and middle) - anterior interosseous nerve (branch of median) medial half (little and ring) ulnar nerve
flexes wrist and metacarpophalangeal joints and proximal and distal interphalangeal joints
what is the structure and role of the flexor pollicis longus
forms single large tendon which goes into the thumb - attaches to base of the distal phalanx
flexes thumb
innervated by anterior interosseous nerve
where to the majority of extensors of the forearm originate from and what innervates them
lateral epicondyle
all innervated by the radial nerve
what are the muscles of the superficial layer of the posterior compartment of the forearm
brachioradialis extensor carpi radialis longus extensor carpi radialis brevis extensor digitorum extensor digiti minimi extensor carpi ulnaris
what are the muscles of the deep layer of the posterior compartment of the forearm
abductor pollicus longus
extensor pollicus brevis
extensor pollicus longus
extensor indics
what is the structure and role of the brachioradialis
not an extensor
from lateral supraepicondylar ridge to lateral side of ulnar styloid process
accessory flexor of the elbow, innervated by the radial nerve
what is the structure and role of the extensor carpi radialis longus
deep to brachioradialis - from lateral epicondyle to dorsal surface of base of metacarpal 2 - extends and abducts wrist
what is the structure and role of the extensor carpi radialis brevis
lies deep to longus and inserts into adjacent dorsal surfaces of metacarpals 2 and 3
extends and abducts wrist
what is the structure and role of the extensor digitorum
major extensor of the 4 fingers
dorsal surface of hand - tendons insert via extensor hood into middle and distal phalanges
what is the structure and role of the extensor digit minimi
accessory extensor of little finger (medial to extensor digitorum)
what is the structure and role of the extensor carpi ulnaris
medial to minimi - inserts into medial side of base of metacarpal 5 - extends and adducts wrist
what is the structure and role of the abductor pollicus longus
emerges between extensor digitiurm and extensor carpi radialis brevis to form tendon which passes into thumb and inter laterally to base of metacarpal 1
abduct thumb at metacarpal 1 and trapezium bone
what is the structure and role of the extensor pollicis brevis
same emergence at abductor pollicis longus
inserts into thumb over metacarpal 1 and on dorsal surface at base of proximal phalanx
extends the metapophalangeal and carpometacarpel joints of the thumb
what is the structure and role of the extensor pollicis longus
inserts into dorsal surface of distal phalanx of thumb
extends all joints of the thumb
what is the structure and role of the extensor indices
accessory extensor fo the index finger - inserts into extensor hood of the index finger with extensor digitorum
what holds the tendons of the extensor muscles together
extensor retinaculum
what is the anatomical snuffbox
triangular depression on anterolateral aspect of thumb by extensor tendons
what are the borders of the anatomical snuffbox
lateral = abductor pollicis longus and extensor pollicis brevis
medial = extensor politic longus
floor = scaphoid and trapezium (distal ends of extensor carpi radialis longus and extensor carpi radialis brevis)
what vessels pass through the anatomical snuff box
radial artery
terminal branche of the superficial branch of the radial nerve
origin of the cephalic vein
