Posterior forearm and dorsum of the hand Flashcards
what is the origin and insertion of anconeus
lateral epicondyle of humerus to olecranon of ulna
what is the function of anconeus
extension of elbow
what is the nerve supply of anconeus
radial nerve (C7-C8 (T1))
is anconeus part of the posterior compartment of the arm
may be considered as part of posterior compartment of forearm but lies on posterior surface of elbow
is brachioradialis part of the posterior compartment of the forearm
may be considered as part of the posterior compartment of the forearm but lies on lateral surface of the forearm
what is the origin and insertion of brachioradialis
distal humerus (supra-epicondylar ridge) to radius proximal to styloid process
what is the function of brachioradialis
flexion of elbow, especially when forearm is in the semi-prone position
what is the innervation of brachioradialis
radial nerve (C5,C6,C7) (before division into deep and superficial)
brachioradialis crosses the ____ surface of the elbow
anterior
anconeus crosses the ____ surface of the elbow
posterior
where is the common extensor origin
lateral epicondyle of the humerus
what is the function of the muscles in the posterior compartment of the forearm
extensors of the digits and wrist and adductor of the thumb and supinator
what is the main nerve of the posterior compartment of the forearm
radial nerve
what is the origin and insertion of extensor carpi radialis longus
distal humerus (supra-epicondylar ridge) to base of 2nd metacarpal
what is the function of extensor carpi radialis longus
wrist extension and abduction
what is the innervation of extensor carpi radialis longus
radial nerve (C6,C7) pre-division
what is the origin and insertion of extensor carpi radialis brevis
lateral epicondyle of humerus to base of 3rd metacarpal
what is the function of extensor carpi radialis brevis
wrist extension and abduction
what is the innervation of extensor carpi radialis brevis
radial nerve (C7,C8) posterior interosseous branch
extensor carpi radialis longus and brevis act with what muscle to abduct the wrist
flexor carpi radialis
the radial nerve divides to give what
superficial sensory branch and a deeper motor branch
what are the muscles supplied by the radial nerve before it divides
triceps brachii
anconeus
brachioradialis
extensor carpi radialis longus
what is the origin and insertion of extensor carpi ulnaris
lateral epicondyle of humerus (small slip from ulna) to base of 5th metacarpal
what is the function of extensor carpi ulnaris
wrist extension and adduction
what is the innervation of extensor carpi ulnaris
radial nerve (posterior interosseous) (C7, C8)
extensor carpi ulnaris acts with what muscle to adduct the wrist
flexor carpi ulnaris
what is the origin and insertion of extensor digitorum
lateral epicondyle of humerus to dorsal expansion of digits 2-5 (not thumb)
what is the function of extensor digitorum
extension of principally MCP but also PIP and DIP of digits 2-5
extends wrist
what is the innervation of extensor digitorum
radial nerve (posterior interosseous) (C7, C8)
as it nears the wrist extensor digitorum forms what
4 tendons - one for each finger
what holds the tendons of extensor digitorum against the distal forearm
extensor retinaculum
what is the origin and insertion of extensor digiti minimi
lateral epicondyle of the humerus to dorsal expansion of 5th digit
what is the function of extensor digiti minimi
MCP PIP DIP extension of little finger
wrist extension
what is the innervation of extensor digiti minimi
radial nerve (posterior interosseous branch) (C7, C8)
why do we have an extra extensor for the little finger
support medial side of the hand against a surface when performing precision movements with the thumb and index finger e.g. writing
what is the origin and insertion of extensor indicis
posterior surface of ulna (and interosseous membrane) to dorsal expansion of digit 2 (index finger)
what is the function of extensor indicis
MCP PIP DIP extension of index finger
wrist extension
what is the innervation of extensor indicis
radial nerve (posterior interosseous branch) (C7,C8)
extensor indicis is deep/superficial
deep
why do we have an extra extensor for the index finger
used in conjunction with the thumb for fine precision movements
what 2 fingers have extra extensors since there is only one extensor for the digits
index and little finger
what is the origin and insertion of extensor pollicis longus
ulna and interosseous membrane to base of distal phalanx of thumb
what is the functino of extensor pollicis longus
CMC, MCP, IP extension of thumb
extends wrist
what is the innervation of extensor pollicis longus
radial nerve (posterior interosseous) (C7, C8)
what plane does extension of the thumb occur in
same plane as palm with thumb moving away from the palm
what is the origin and insertion of extensor pollicis brevis
radius and interosseous membrane to base of proximal phalanx of thumb
what is the function of extensor pollicis brevis
CMC and MCP thumb joint extension
extends wrist
what is the innervation of extensor pollicis brevis
radial nerve (posterior interosseous) (C7,C8)
extensor pollicis brevis and longus both contribute to the borders or what
anatomical snuffbox
what is the origin and insertion of abductor pollicis longus
radius, interosseous membrane and ulna to base of 1st metacarpal
what is the function of abductor pollicis longus
abducts thumb and extends it at CMC joint
extends wrist
what is the innervation of abductor pollicis longus
radial nerve (posterior interosseous) (C7,C8)
the thumb is abducted in what plane
away from the plane of the palm
where is the smaller abductor of the thumb
in the thenar eminence
what muscles does the thumb have and why
2 flexors
2 extensors
2 abductors
1 adductor
- important role in creating different types of grip
what is the origin and insertion of supinator
crest of ulna, lateral epicondyle of humerus, radial collateral and annular ligament of radius to lateral radius (proximal 3rd)
what is the function of supinator
supination of forearm (rotates radius)
what is the innervation of supinator
radial nerve (deep/posterior interosseous) (C7,C8)
what is the deepest muscle in the posterior compartment of the forearm
supinator
what is the most powerful muscle for supination
biceps brachii
what nerves contribute to supination
musculocutaneous - biceps brachii
radial - supinator
the radial nerve passes between the lamina of what
supinator
describe the path of the deep branch of the radial nerve
emerges from supinator to form the posterior interosseous nerve that runs with posterior interosseous artery
describe the path of the superficial branch of the radial nerve
overlies part of brachioradialis before running through the roof of the anatomical snuffbox to supply skin of dorsum of hand
the flexor compartment is dominated by the ___ nerve and also contains the ____ nerve
median
ulnar
muscles of the extensor compartment are supplied by what
radial nerve
sensory to lateral side of dorsum of hand is supplied by what
superficial branch of radial nerve
the radial artery is a terminal branch of what
brachial artery
describe the path of the radial artery
supplies structures in the forearm, runs in the floor of the anatomical snuffbox and passes between the heads of adductor pollicis to enter the hand
what does the radial artery contribute in the hand
forms most of the deep palmar arch but will also anastomose with the ulnar artery as part of the deep and superficial arches
most of the muscles in the posterior compartment are supplied by the … except …
deep interosseous branch of the radial nerve except carpi radialis longus
the deep artery of the posterior compartment is the … which is a branch of the …. which is derived from the …
posterior interosseous artery which is a branch of the common interosseous artery which is dervied from the ulnar artery
does the dorsum of the hand have muscles
no - the dorsal interossei lie between the bones
the dorsum has a layer of skin and subcutaneous fat that contains
a dorsal venous arch and cutaneous nerves
how are the extensor tendons held to the wrist
extensor retinaculum
how are the extensor tendons protected during movement of the tendon
each tendon is inside a small synovial sheath
the roof of the anatomical snuffbox contains what
branches of the superficial branch of the radial nerve and cephalic vein
what forms the floor of the anatomical snuffbox
scaphoid, trapezium and base of 1st metacarpal
what is the medial border of the anatomical snuffbox
tendon of extensor pollicis longus
what is the lateral border of the anatomical snuffbox
tendons of extensor pollicis brevis and abductor pollicis longus
why is the anatomical snuffbox an area of interest
the radial artery runs across the bones of the floor and can be palpated as a pulse point
the dorsal venous arch is a communication between
cephalic vein (lateral side) and basilic vein (medial side)
is the dorsal venous arch always an arch
no - variation in vein patterns
what lies superficially in the roof of the snuffbox
cephalic vein and radial nerve
what lies deep in the floor of the anatomical snuffbox between the tendons
radial artery
what are the flexor and extensor retinacula
fascia that hold down tendons
what is the dorsal expansion
formed from connective tissue that allows the long flexors and short muscles of the hand to act on all 3 finger joints
the dorsal expansion provides attachment for what
some of the intrinsic muscles of the hand that attach to the digits e.g. the lumbricals
describe what the lumbricals do
they cross the anterior surface of the MCP joint so can flex it but because their tendon joins the expansion that wraps around the dorsum of the finger they can exert pull on the posterior surface of the PIP joint and can extend it
what order do the tendons cross the dorsum of the hand
lateral to medial
- abductor pollicis longus and extensor pollicis brevis
- extensor carpi radialis longus and brevis
- extensor pollicis longus
- extensor indicis and extensor digitorum
- extensor digiti minimi
- extensor carpi ulnaris
on the dorsum of the wrist what tendon crosses most medially
Extensor carpi ulnaris
on the dorsum of the wrist what tendon crosses most laterally
abductor pollicis longus and extensor pollicis brevis
on the dorsum of the wrist what tendon shares a synovial sheath with extensor digitorum
extensor indicis
on the dorsum of the wrist what tendon shares a synovial sheath with abductor pollicis longus
extensor pollicis brevis