Download Ulnar nerve

fossa Cubital
Has:
* floor .
* roof :
- Skin
- superficial fasica
- deep fascia ( include bicipital aponeurosis )
Structures within the roof :
-cephalic and basilic veins
-and between them median cubital vein
-medial cutaneous nerve of the forearm.
-lateral cutaneous nerve of the forearm ( the end of musculocutaneous
nerve ).
* boundaries .
* contents : ( from medial to lateral )
- median nerve
- brachial artery and its terminal branches ( ulnar and radial arteries).
- bicipital tendon
- branches of the radial nerve :
superficial branch
deep branch ( posterior interosseous nerve ).
Forearm
divided by the bones ( redius and ulna ) and interosseous membrane into :
1) anterior ( flexor ) compartment
flexor : because the main action for all muscles is flexion
Common origin : medial epicondyle of humerus
2) posterior ( extensor ) compartment
Common origin : lateral epicondyle of humerus
law (1) :
any tendon passing in front of any joint has an action of flexion.
and any tendon passing behind any joint has an action of extension.
law (2) :
any muscle its name is radialis has an action of abduction.
and any muscle its name is ulnaris has an action of adduction at the rest
joint.
Anterior compartment of forearm :
muscles arranged in 3 layers (superficial-intermediate-deep ).
( in some references two layers - superficial and deep ).
1) superficial layer :
*pronator teres
*palmaris longus
*flexor carpi radialis
*flexor carpi ulnaris
2)intermediate layer:
*flexor digitorum superficialis ( deeper to the superficial layer ) : it lies
deep to the superficial layer, but because of it's name it may considered to
be in the superficial layer.
2) deep layer :
*flexor digitorum profundus
*flexor pollicis longus
*pronator quadratus
*The common origin of anterior compartment muscles is the medial
opicondyle of the humerus :
- some muscles originate just from the medial epicondyle.
-others have more than one origin, such as :
1-pronator teres : originates from medial epicondyle and have ulnar origin
2-flexor digitorum superficialis : originates from medial epicondyle
+Ulna + Radius ( anterior oblique line of shaft of the radius ).
*nerve supply for the anterior compartment of the forearm : ( 2 nerves )
1.median nerve
2.ulnar nerve ( one and a half muscles )
. flexor carpi ulnaris
. medial half of flexor digitorum profundus ( 2 tendons-for little and
ring fingers )
while lateral half ( 2 tendons-for middle and index fingers )
innervated by median nerve ( anterior interosseous nerve ).
( 2 nerves- 2 halves- 2 fingers for each half )
Ulnar nerve injury affects little and ring fingers
Median nerve injury affects index and middle fingers.
These muscles are in name-function relationship.for example :
-flexor digitorum superficialis
*attached to 4 digits
*action : flexion of digits and all joints that passes in front of them
*ends as 2 slips on the edge of the middle phalanx .so it does not flex the
distal phalanx.
-flexor digitorum profundus
*continues as one tendon and ends at the base of the distal phalanx .so it
flexes all the joints of the hand.
-flexor carpi ulnaris :
*flexion of the wrist joint
*adduction to the wrist joint
-flexor carpi radials :
*flexion of the wrist joint
*abduction to the wrist joint
Muscles of superficial layer
1)Pronator teres :
Origion : humeral head-medail epicondyle of humerus
:Ulnal head-medail side of coronoid tubercle of ulna
Insertion : middle of the lateral side of the radius
Nerve supply : median nerve
Action : -pronation
-flexion of the forearm ( crossing the elbow )
2)Flexor carpi radialis :
Origin : medial epicondyle of humerus
Insertion : base of second and third metacarpal bones ( in some
references-the second metacarpal-but the both are correct )
Nerve supply : median nerve
Action : flexion and abduction
3)Palmaris longus
Origin : medial epicondyle of humerus
Insertion : -felxor ratinaculum
-apex of the palmar aponeurosis ( palmar aponeurpsis is
triangular in shape, and it's a part of deep fascia of the hand ).
Nerve supply : median nerve.
Action : flexion
-sometimes this muscle is absent, so it's function achieved by other
muscles ( flexors ).
- this muscle is used in surgery as constructive surgery ( it's
tendon used for another muscle ).
4)Flexor carpi ulnaris :
Origin : *humeral head : medial epicondyle
*ulnar head : medial aspect of olecranon process and posterior broder
of the ulna ( ulnar nerve passes between these 2 heads )
Insertion : ( wide insertion ) *pisiform
*hook of hamate
* base of 5th metacarpal bone
Nerve supply : ulnar nerve
-You can feel the tendon for this muscle beside pisiform.
5)Flexor digitorum superficialis :
Origin ( wide origin ) :
*medial epicondyle of humerus
*medial broder of coronoid process of ulna
*radial head-oblique line of the anterior surface of the shaft
-has 4 tendons lie in 2 levels :
*level to the index and little fingers
*other level to the middle and ring fingers
Insertion : 2 slips on the edges of the middle phalanx
( the profundus tendon passes between the 2 slips to reach distal phalanx)
Nerve supply : median nerve
Action : flexion for all joints that the tendons pass in front of them -- to
the middle phalanx
Muscles of deep layer
1)Flexor pollicis longus :
Origin : *anterior surface of shaft of the radius
*interosseous membrane
Insertion : base of the distal phalanx of the thumb
Nerve supply : anterior interosseous branch of median nerve ( called like
this because it passes anterior interosseous membrane and innervate deep
group muscles).
2)Flexor digitorum profundus:
Origin ( wide origin ) : *anteromedial surface of the shaft of the ulna
*interosseous membrane
Insertion : distal phalanges of medial four fingers ( pass between 2 slips
of tendons of flexor digitorum superficialis )
nerve supply : *medial half ( ulnar half ) : ulnar nerve
*lateral half : median nerve ( anterior interosseous of median nerve )
Action : flexion for distal phalanx and all joints that pass in front of
them include wrist joint.
3)Pronator quadratus :
Origin : anterior surface of the ulna
Insertion : anterior surface of the radius in the lower third of the shaft
Nerve supply : anterior interosseoeus of the median nerve
Action : pronation
Arteries
*bracial artery terminates at the level of the neck of radius in the cubital
fossa and gives two branches :
-ulnar artery ( larger ).
-radial artery ( smaller ).
Ulnar artery
*( beginning )
it begins in the cubital fossa at the level of the neck of the radius
*( course )
-ulnar artery passes deep to the two heads of pronator teres ( while the
median nerve passes between the two heads ).
-then the ulnar artery passes obliquely and at the junction between upper
third and lower two thirds of the forearm combined with the ulnar nerve.
-then the ulnar artery and ulnar nerve continue under the cover of the
flexor carpi ulnaris and laterally to the flexor digitorum profundus.
-Below, it becomes superficial and lies between the tendons of the flexor
carpi ulnaris and the tendons of the flexor digitorum superficialis
Notice that nerves are more peripheral.
-ulnar artery and nerve descend dowmward until passing anterior to the
flexor retinaculun lateral to the pisiform bone.
There are two arches in the palm of the hand :
1) superficial palmar arch :
-made by ulnar artery
- anostomosing with the superficial palmar branch of the radial artery
2) deep palmar arch :
-made by the radial artery
-completed by branch from ulnar artery.
These arches give digital arteries to the fingers.
*( End of the ulnar artery )
It forms the superficial palmar arch in the hand.
*( Branches of ulnar artery )
1)common interosseous artery
*anterior interosseous artery
passes anterior to the interosseous membrane (with anterior
interosseous nerve )
*posterior interosseous artery
penetrate the interosseous membrane and pass to the posterior
compartment , with the deep branch of radial nerve (posterior
interosseous nerve).
2 )ulnar recurrent artery with anterior and posterior branches that take
part in the arterial anastomosis around the elbow joint
( anterior and posterior ulnar recurrent join with superior and inferior
ulnar collateral on the medial side).
3)two small carpal arteries which supply the wrist.
4) muscular branches .
Ulnar pulse
*In front of the flexor retinaculum, it lies just lateral to the pisiform bone
and is covered only by skin and fascia (site for taking ulnar pulse).
* the ulnar pulse is weak due to :
- below the ulnar artery there are muscles and soft tissue .
- covered by skin , superficial fascia , and part of deep fascia
Radial artery
*( beginning )
it's begins in the cubital fossa at the level of the neck of the radius
*( course )
-it passes obliquely to the radius and converges with branch of radail
nerve ( nerve is lateral to artery ).
-the artery and nerve descend on the lateral side under the cover of
brachioradialis muscle. and resting on the deep muscles of the forearm (
e.g flexor pollicis longus ).
-leave the forearm by winding posteriorly around the lateral aspect of the
wrist.
then the radail artery deviates laterally and pass beneath the tendon of
brachioradialis to the snuff box.
Snuff box
Floor : scaphoid and trapezium crapal bones
Boundaries : *abductor pollicis longus.
*extensor pollicis longus.
Roof : superficial branch of radail nerve ( it ends as cutaneous nervesensory to the lateral two thirds of the dorsum of the hand ).
Content :radial artery (so snuff box is the site for taking the radial pulse).
*( end of the radial artery )
It's forms the deep palmar arch in the hand.
*( branches )
1-Muscular branches to neighboring muscles
2-radial recurrent artery, which takes part in the arterial anastomosis
around the elbow joint
3-Superficial palmar branch, which arises just above the wrist enters the
palm of the hand, and frequently joins the ulnar artery to form the
superficial palmar arch
4-carpal branch to the carpal bones and joints
Radial pulse
*in the distal part of the forearm ( lower 7 cm ), the radial artery passes
directly on the radius ( bone ) under the cover of skin so we can palpate
the pulsation.
*here, the artery has the tendon of brachioradialis on its lateral side and
the tendon of flexor carpi radialis on its medial side (site for taking the
radial pulse).
*the radial pulse indicates to the beat of the heart ( normal heart rate 7090 beats per minute ).
*how to check the radial pulse ?
-put 3 fingers on the radial artery ( you know the site ).
*we use the 3 fingers because their arteries have connections so you take
the pulse of the artery not of your fingers, while the thumb arteries have
no connections.
Medain nerve
* Origion : -medial root from the medial cord
-lateral root from the lateral cord
*( course )
-passes to the lateral side of the third part of axillary artery.
-descend on the lateral side of brachial artery
-at the level of insertion of coracobrachialis it crosses in front of the
brachial artery and becomes medial to it.
-continue at the middle side until reach the cubital fossa ( the most
medial structure of the cubital fossa ).
-then it passes between the two heads of pronator teres and gives
anterior interosseous branch.
-the median nerve descends ( as a sandwich ) between flexor digitorum
superficialis and flexor digitorum profundus. ( so it is protected ).
-at the wrist joint it gives palmar branch of median nerve to the skin of
the lateral two thirds of the palm
-the median nerve passes under the flexor retinaculum in the carpal
tunnel, then to the hand.
-At the wrist, the median nerve emerges from the lateral border of the
flexor digitorum superficialis muscle and lies behind the tendon of the
palmaris longus
( take care of this point if you want to be a surgeon ).
*( branches )
*no branches in the arm .but may be injured at the supra-trochlear level.
-it passes between the two heads of pronator teres and gives anterior
interosseous branch.
-the median nerve innervates all superficial flexor muscles except flexor
carpi ulnaris ( innervated by ulnar nerve ).
-the anterior interosseous nerve innervates all deep mescles except medial
half of profundus ( innerated by ulnar nerve ).
-articular branches.
-palmar cutaneous branch.
-muscular branchs.
Ulnar nerve
*Origin : branch of medial cord
*( course )
-passes medially to third part of axillary artery and then medially to the
brachial artery.
-at level of insertion of coracobrachialis it penetrates the medial
intermuscular septum and becomes posteriorlly and passes behind the
medial epicondyle then between the two heads of flexor carpi ulnaris.
-then turns to the anterior compartment and continues with the ulnar
artery at the edge of the medial side under the cover of flexor carpi
ulnaris and separated by a small space from flexor digitorum superficialis
and profundus.
*( branches )
1-in the middle of the forearm it gives dorsal cutaneous branch to the
dorsum of the medial third of skin of the hand.
2-palmar cutaneous branch to the medial one third of palm.
3-dorsal posterior cutaneous branch distributed on the posterior surface
of the hand and fingers ( skin of the proximal phalanx .
Flexor retinaculum
-is a thickening of deep fascia
* Attachment
medially to the pisiform and hook of hamate,
laterally to the scaphoid , trapezium , and styloid process of radius.
*all structures pass to the hand under the flexor retinaculum, except six
structures pass superficial to it : ( 3 ulnar + 3 palmar )
1-ulnar nerve
2-ulnar artery
3-ulnar vein
4-palmar branch of ulnar nerve
5-palmar branch of median nerve
6-palmaris longus tendon
-It stretches across the front of the wrist and converts into an osteofascial
tunnel, the carpal tunnel for the passage of the median nerve and the
flexor tendons of the thumb and fingers