Anatomy of unlar nerve

BY: Azmat Ali KhanTrainee Technologist

AKUH Karachi12-08-2013

Ulnar nerve is one of the major terminal Branches of Brachial Plexus. It is the continuation of medial cord of brachial plexus which arises from the anterior Division of the lower Trunk.

Root Value: The fibers of ulnar nerve arise from the eight

cervical and first thorasic nerve, so the root value of ulnar nerve is C8 and T1.These (C8,T1) coordinate to form the lower trunk of brachial plexus.

Introduction of ulnar nerve:

Brachial plexus

Course From Cord to Axilla.

The Ulnar nerve runs between the Axillary artery and vein in the axilla.

Course from Axilla to Arm From the axilla it enters in the arm and

stays between the brachial artery and vein.

Cont:

Course from Arm to Elbow

The nerve runs inferior and posterior medial portion of humerus bone till it enters the cubital tunnel.

As the ulnar nerve exists the cubital tunnel, it courses between the two head of the flexor Carpi ulnaris and enters the anterior compartment of the forearm.

Shortly after exiting the cubital tunnel, the ulnar nerve gives off motor branches to the flexor Carpi ulnaris.

Cont:

It then lies on the anterior surface of the flexor digitorum profundus.

In the middle of the forearm at approximately 12 cm distal to the medial epicondyle, the ulnar nerve becomes the superficial and meets with the ulnar artery as it travels toward the wirst.

cont;

The nerve then descends through the medial forearm, giving off no further muscular branches untill after the wrist.

Five to eight centimeters proximal to the wrist, the dorsal ulnar sensory branch exits to supply sensation to the dorsal medial hand and dorsal fifth and medial fourth digits.

At the level of the ulnar styloid, the palmar cutaneous sensory branch originates to supply sensation to the proximal medial palm.

Ulnar nerve distribution

Ulnar nerve

Near the wrist the ulnar nerve rises superficial to the flexor carpi retinaculum and lies under the tendon of the flexor carpi ulnaris before its attachment to the pisiform.

The ulnar nerve the turns radial to the pisiform to lies in a tunnel known as Guyon’s canal within the canal, the ulnar nerve divides into motor and sensory branches.

Ulnar nerve distribution

Forearm: Flexor Carpi Ulnaris (C7, C8, T1) Flexor Digitorum Profundus III & IV (C7, C8) Thenar: Hypothenar Muscles (C8, T1) Adductor Pollicis (C8, T1) Flexor Pollicis Brevis (C8, T1) Fingers: Palmer Interosseous (C8, T1) Dorsal Interosseous (C8, T1) III & IV Lumbricles (C8, T1) Digiti Minimi: Abductor Digiti Minimi (Quinti) (C8, T1) Opponens Dgiti Minimi (C8-T1) Flexor Digiti Minimi. : ( C8-T1)

It gives supply to:

Palmar & dorsal interossei 3rd and 4th lumbricals

Ulnar motor response: ulnar motor study recording abductor digiti minimi (ADQ)stimulating wrist, below elbow and above elbow in the flexed elbow position.

Ulnar F response Ulnar sensory response: recording medial

half of ring finger, ulnar F5, dorsal cutaneous nerve (DUC).

NCS TEST

Motor normative data:

Sensory normative data:

Normal values

Latency ms Amplitude uV

Conduction velocity ms

3.5 2 35-40

Latency ms

Amplitude mv

C v ms F latency ms

3.3 5 53.6 32.0

Distal lat difference Ipsilateral (ms)

Contra lateral difference (ms)

1.4> 0.7 >

Latency difference

Peak lat difference (ms) sensory

Ulnar palmer (ms)

2.2> 0.4 >

The best thing about the future is that it comes one day at a time.

By Abraham Lincoln.

Quote:

Reference: Priston www.google.com http://www.mdguidelines.com/neuropathy

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