The Origin of the Ulnar nerve:

The brachial plexus is a network of nerve fibers, running from the spine, formed by the ventral rami of the lower four

cervical and first thoracic nerve roots (C5-

C8, T1). It proceeds through the neck, the axilla, and into the arm. It is a network of nerves passing through the cervico-axillary canal to reach axilla and supplies

brachium, antebrachium and hand.

The brachial plexus is responsible for cutaneous and muscular innervation of the entire upper limb.

The ulnar nerve originates from the C8-T1 nerve roots (and occasionally carries C7 fibres)

which form part of the medial cord of

the brachial plexus .

course of Ulnar nerve:

-In the Axilla:

it descends on the medial side of the 3rd part

of axillary artery between it and axillary

vein

-In the Arm:it descends on the medial

side of brachial artery down to the insertion of

coracobrachialis muscle,Pierces the medial intermusular septum at the arcade of Struthers ~ 8cm from medial epicondyle

and lies with triceps .Travels on back of

medial epicondyle; vulnerable in fractures

Runs with superior ulnar collateral artery to reach post. compartment of the

arm in front of medial head of triceps.

-At the Elbow:it reaches the

back of med.epicondyle

to enter the forearm between 2 heads of flexor carpi ulnaris(and

here it is accompanied by

sup.ulnar collateral a. and post. branch of inferior ulnar

collateral arteries).

: -In the Forearm

after passing between 2 heads of flexor carpi ulnaris,

it descends vertically infront of med. side of flexor digitorm

profunds covered by the flexor carpi

ulnaris.

-In the Hand:it enters the palm

of the hand by passing in front of med. part of flexor

retinaculum between

pisiform(medially) and the ulnar

artery(laterally)& finally ends by dividing into

superficial and deep branches.

Branches of Ulnar Nerve :

-Just past the Elbow: The nerve

gives branches

to the Flexor Carpi

Ulnaris and the medial

half of the Flexor

digitorum profundus

.

-In the Forearm:

The Ulnar Nerve divides

into Dorsal and palmer cutaneous branches.

 

-The Palmer cutaneous

branch of the Ulnar Nerve

provides sensation to the palm of

the hand. The Finger sensation is provided by

the superficial branch.

-The Dorsal cutaneous branch of the Ulnar

Nerve gives innervation

to the medial dorsal

aspect of the hand and

the one and a Half Fingers.

-In the Hand:

The Nerve further

divides into superficial and deep branches.

The superficial

branch of the Ulnar nerve divides into

Palmer digital nerves after it passes under and supplies the Palmaris

brevis muscle.

The Deep branch of the Ulnar nerve

innervates the three

hypothenar muscles , the medial two

lumbricals , the seven interossei , the adductor

pollicis and the deep head of flexor pollicis

brevis.

Ulnar Nerve Entrapment: The Ulnar Nerve

can become pinched in different locations.

 1 -Thoracic outlet

syndrome. 2-cubital tunnel

syndrome. 3-Ulnar Tunnel

syndrome.

The Cubital Tunnel syndrome:

causes of Ulnar Nerve entrapment around the cubital

tunnel:  

1-Cubitus Valgus:  

Deformity in which the elbow is turned outward

2 -A spur on the Medial Epicondyle

Symptoms of the cubital tunnel syndrome:

1-Pain, tingling and numbness in the small and ring fingers.

2-Weakness of the muscles in the hand.

3-claw hand deformity if compression below the elbow due to flexion of the fingers by a functional profundus muscle for the 4th and 5th fingers.

claw hand deformity

The diagnosis of cubital tunnel syndrome:

is made after a thorough history and examination. X-rays or other tests

may be ordered if there is a concern of something abnormal pressing on the nerve. Nerve tests, called EMGs, can

help to determine the extent and location of nerve compression.

Treatment of Cubital Tunnel Syndrome:

1-Anti-inflammatory medications.

2-Splinting the elbow, especially at night.

3-Padding the elbow for work activities.

4-Physical therapy.“If these simple treatments fail, surgery may be

necessary to remove the pressure from the ulnar ”nerve .

: Guyon's canal syndrome

 Guyon's canal syndrome, sometimes called Guyon's

tunnel syndrome, is a common nerve compression affecting the ulnar nerve as it passes

through a tunnel in the wrist called Guyon's canal.

Symptoms of the Guyon`s canal syndrome:

1 -Feeling of pins and needles in the ring and little fingers.

2 -May progress to a burning pain in the wrist and hand.

3-Decreased sensation in the ring and little fingers.

N.B :One common cause of this syndrome is from pressure of bicycle handlebars seen with avid cyclists , Another is from hard, repetitive

compression against a desk surface while using a computer mouse.

Treatment of Cubital Guyon`s canal Syndrome:

1- Initial line of treatment is with anti-inflammatory drugs or cortisone injections .

2 -Massage therapy.

3-  acupuncture. 

4-  physical therapy.

5- chiropractic and osteopathic care.

If these options do not produce the desired results, some doctors may recommend working with surgical

option.

Surface Anatomy of the Ulnar nerve:

The surface marking of the nerve is along a line from the medial bicipital groove behind coracobrachialis to the point behind the medial epicondyle of the humerus where it is readily palpable.

The ulnar nerve runs from the groove between the medial epicondyle and olecranon process above to the radial or outer side of the pisiform bone below. It lies to the ulnar side of the ulnar artery in the lower half of the forearm

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