ForeArm Flashcards
The deep fascia of the forearm is the
antebrachial fascia
the antebrachial fascia is strengthened by
bicipital aponeurosis
the antebrachial fascia forms a ____ _________ which gives origin to:
strong aponeurosis
a. flexor capri ulnaris
b. extensor capri ulnaris
c. flexor digitorum profundus
antebrachial forms 2 bands in the wrist called
flexor retinaculum
entensor retinaculum
definition and site of cubital fossa
triangular hollow in front of elbow
cubital fossa- boundaries
base
lateral
medial
base - passes through two epicondyles of humerus
lateral - brachio-radialis muscle
medial - pronator teres muscle
cubital fossa boundaries
apex
floor
apex - meeting of brachio-radialis overlapping pronator teres
floor- brachialis and supinator
roof of cubital fossa is formed by
superficial fascia and skin
deep fascia
superficial fascia and skin contains
- parts of cephalic & basilic veins & median cubital vein (connects them)
- anterior branches of lateral and medial cutaneous nerves
- supra-trochlear lymph nodes (in upper roof)
deep fascia is reinforced/strengthened by
bicipital aponeurosis
contents of cubital fossa
- Medial Nerve
- termination of brachial artery and beginning of ulnar and radial arteries:
- Brachial artery lies in middle of cubital fossa
- tendon of biceps
- Radial nerve and beginning of its posterior interosseous branch
2TMBR
the ulnar artery and radial artery leave the cubital fossa by
ulnar - passing between two heads of pronator teres
radial- descend through apex
tendon of biceps in cubital fossa is inserted into
radial tuberosity
the radial/posterior interosseous branch leaves the cubital fossa by
piercing the supinator muscle
the bicipital aponeurosis
separates median cubital vein from median nerve and brachial artery
superficial group muscles of forearm
4 superficial muscles -
- pronator teres
- flexor capri radialis
- palmaris longus
- flexor capri ulnaris
1 deep muscle
1. flexor digitorum superficialis
deep group muscles of forearm
2 superficial muscles
- flexor pollicis longus
- flexor digitorum profundus
1 deep muscle
1. pronator quadratus muscle
common flexor origin - superficial group of muscles
medial epicondyle of humerus
common nerve supply - superficial group of muscles
medial nerve
except flexor carpi ulnaris - ulnar nerve
common action - superficial group of muscles
- flexion of wrist (except pronator teres)
2. weak flexion of elbow
pronator teres origin
two heads
1. humeral head - more superficial and larger head. arises from common flexor origin
- ulnar head - smaller & deeper. arises from coronoid process of ulna
pronator teres insertion
pronator tuberosity on shaft of radius
action of pronator teres
- powerful pronation of forearm (at radio-ulnar joints)
2. weak flexion of elbow
relations of pronator teres
median nerve enters forearm between its two heads
ulnar artery passes deep to two heads of muscle
flexor capri radialis muscle origin
common flexor origin - medial epicondyle of humerus
flexor capri radialis insertion
passes through flexor retinaculum to insert into palmar surfaces of 2nd and 3rd metacarpal bone
flexor capri action
common action:
- flexion of wrist (except pronator teres)
- weak flexion of elbow
+ abducts hand
palmaris longus muscle origin
common flexor origin - medial epicondyle of humerus
palmaris longus muscle insertion
passes flexor retinaculum to insert into apex of palmar aponeurosis
palmaris longus muscle action
common action + makes palmar aponeurosis tense to give protection to structures in palm of hand
flexor capri ulnaris muscle origin
2 heads
humeral - common flexor
ulnar- olecranion process of ulna by aponeurosis
flexor capri ulnaris insertion
pisiform bone (right above palm on wrist)
flexor capti ulnaris action
common flexor
+ abducts hand
flexor digitorum superficialis origin
2 heads
humero-ulnar head - common flexor + coranoid process of ulna
radial - anterior oblique line of radius
flexor digitorum superficialis insertion
4 tendons divide into 2 strips each.
2 strips are inserted on shaft of middle phalanx
flexor digitorum superficialis action
common action +
flexes metacarpo-phalangeal and proximal inter-phalangeal joints of medial 4 fingers
Deep group muscles common nerve supply
anterior interosseous branch of median nerve
EXCEPT
medial half of flexor digitorum profundus which is supplied by ulnar nerve
flexor digitorum profundus muscle origin
- shaft of ulna
2. interosseous membrane (b/w radius & ulna)
flexor digitorum profundus insertion
ends in 4 tendons that insert into distal phalanx
flexor digitorum profundus action
flexes all joints of medial 4 fingers and wrist
flexor pollicis longus muscle origin
- shaft of radius below anterior oblique line
2. interosseous membrane
flexor pollicis longus insertion
phalanx of thumb
flexor pollicis longus muscle action
flexes all joints of thumb & wrist
the 8 tendons of flexor digitorum superficialis and profundus are surrounded by
common flexor synovial sheath (ulnar bursa)
tendon of flexor pollicis longus is surrounded by its synovial sheath (radial bursa)
pronator quadratus muscle origin
oblique ridge on shaft of ulna
DEEPEST MUSCLE ON FOREARM
pronator quadratus muscle insertion
shaft of radius
pronator quadratus action
pronates forarm at radio-ulnar joints
muscles of the back of the forearm are
extensors
superficial group - muscles of back of forearm
5EAB
- Brachio-radialis
- extensor capri radialis longus
- extensor capri radialis brevis
- extensor digitorum
- extensor digiti minimi
- extensor capri ulnaris
- anconeus
common extensor origin for superficial group of muscles (back of forearm)
lateral epicondyle of humerus
except brachioradialis, extensor capri radialis longus and anconeus
brachioradialis origin
upper 2/3 lateral supracondylar ridge of humerus
lateral intermuscular septum of arm
brachioradialis insertion
lower end of radius above styloid process
brachioradialis nerve supply
radial nerve
action of brachioradialis
- puts forearm in midprone position
2. flexes elbow joint
extensor carpi radialis longus origin
- lower 1/3 lateral supracondylar ridge of humerus
2. lateral intermuscular septum of arm
extensor carpi radialis longus insertion
by long flat tendon into base of 2nd metacarpal bone
extensor carpi radialis nerve supply
radial nerve
action of extensor carpi radialis longus
extends and abducts wrist
extensor carpi radialis brevis origin
common extensor origin
extensor carpi radialis brevis insertion
base of 3rd metacarpal bone
extensor carpi radialis brevis nerve supply
branch from posterior interosseous nerve
extensor carpi radialis brevis action
same as extensor carpi radialis longus
extensor digitorum origin
common extensor origin
extensor digitorum insertion
reaches phalanges of medial four fingers then each tendon joins extensor expansion of corresponding finger
extensor digitorum action
- extends metacarpo-phalangeal and interphalangeal joints of medial 4 fingers
- assists in extension of wrist
extensor expansion definition
strong triangular sheet that covers proximal phalanx of each of medial 4 fingers.
Receives extensor tendons of digits and tendons of lumbricals and interossei
structure of extesor expansion
thick middle part formed by:
1 of 4 tendons of extensor digitorum
tendon of little finger is joined by tendon of digiti minimi
tendon of index is joined by tendon of etensor indicis
two margins formed by tendons of lumbricals and interossei
extensor expansion attachment
approaches proximal interphalangeal joint then divide into intermediate (attached to middle phalanx) part and 2 collateral parts (attached to terminal phalanx)
extensor digiti minimi origin
common extensor origin
extensor digiti minimi insertion
extensor expansion of little finger
extensor digiti minimi action
- extends little finger
2. assists in extension of wrist
extensor carpi ulnaris origin
- common extension origin
2. ulna by aponeurosis
extensor carpi ulnaris insertion
base of 5th metacarpal bone
action of extensor carpi ulnaris
extends and adducts wrist
anconeus origin
lateral epicondyle of humerus by seperate tendon
anconeus insertion
back of olecranon process of ulna
anconeus action
assists triceps in extending elbow
the anconeus is considered the ______ because _____
4th head of triceps
has same action
covered expansion from triceps tendon
takes nerve supply from radial nerve as it runs in spiral groove
deep group muscles of back of arm
- supinator
- extensor pollicis brevis
- abductor pollicis longus
- extensor pollicis longus
- extensor indicis
common nerve of the deep extensors
posterior interosseous branch of radial nerve
supinator origin
surrounds upper third of shaft of radius
- supinator crest and fossa of ulna
- lateral epicondyle of humerus, lateral collateral ligament of elbow and annular ligament
supinator insertion
radius above oblique lines
supinator action
supinates the forearm at radio-ulnar joints
supinator important relations
pierced by posterior interosseous nerve which splits it into 2 layers
abductor pollicis longus origin
- shaft of ulna below anconeus
- interosseous membrane
- radius just below supinator insertion
abductor pollicis longus insertion
first metacarpal bone (thumb)
action of abductor pollicis longus
- abducts thumb
- helps abduct wrist
- can flex wrist which helps when median and ulnar nerve become paralyzed
extensor pollicis brevis origin
shaft of radius below origin of abductor pollicis longus
extensor pollicis brevis insertion
proximal phalanx of thumb
extensor pollicis brevis action
extends metacarpo-phalangeal and carpo-metacarpal joints of thumb
extensor pollicis longus origin
shaft of ulna under origin of abductor pollices
extensor pollicis longus insertion
distal phalanx of thumb
extensor pollicis longus action
extends all joints of thumb
extensor indicis origin
shaft of ulna under extensor pollicis longus
interosseous membrane
extensor indicis insertion
joins tendon of extensor digitorum going to index finger to form extensor expansion of index
extensor indicis action
- extends index finder
2. helps in extending wrist