Ulnar nerve

The ulnar nerve ( " Ulnar Nerve ") is a nerve of the brachial plexus ( Armgeflecht ). It has fibers that - and have in the 1st thoracic segment ( Th1) of the spinal cord from the medial cord of the brachial plexus coming -: - originate in the 8th cervical segment ( between the 7th cervical and 1st thoracic vertebra C8). In some mammals, it also refers fibers from the 2nd thoracic segment (Th2 - behind the second thoracic vertebra of the spinal canal outlet).

The ulnar nerve runs along the inside of the upper arm to the elbow bump. He breaks through the medial intermuscular septum. At the medial epicondyle of the humerus it is through the skin palpable and can in initiating a violent pain reaction in his sensitive innervation ( in Germany " funny bone ", " funny bone ", " musician bone ", " little mouse / Mausle " in Austria " narrisches leg ", " narrisches Band'l " or " tamisches Aderle " in Switzerland " fools leg ", " Surribei " or " Surrbeindli " ) cause. In addition, he draws elle each other on the forearm toward hand.

Motor branches

In the forearm, the nerve provides motor innervation to:

  • Flexor carpi ulnaris
  • Caput of the ulnar flexor digitorum profundus
  • Flexor digitorum superficialis ( excl. man, predators )

In the hands of the nerve innervates the muscles of the hypothenar eminence ( abductor digiti V, flexor digiti V brevis, musculus opponens digiti V ) and most short muscles of the metacarpal (musculi lumbricales III and IV, interossei, adductor pollicis and caput profundum of the flexor pollicis brevis ).

Function

The muscles supplied by the ulnar nerve are involved in flexion and ulnar deviation of the wrist, on the diffraction of the ring finger and little finger. They carry virtually alone, the spread of the long fingers (all fingers except the thumb ) and the closing of the long finger. Furthermore, the musculi bend lumbricales the phalanges of the fingers IV and V and stretch the middle and end links.

There are numerous variants of the innervation of the small hand muscles. In some people, some of the commonly supplied by the ulnar nerve hand muscles innervated by the median nerve, which then also according to their function has to share.

Sensory branches

Man

In humans, the nerve is ulnar approximately in the middle of the forearm or slightly below the sensory dorsal branch from whose terminal branches, the Nervi digital dorsal, the skin on the extensor side of elle -side half of the middle finger and the skin of the dorsum of the ring finger and little finger respectively between provide wrist to finger - middle joint. In isolated cases there may be a transition from the median nerve to the ulnar nerve, this is called Berrettini connection.

The slightly less outgoing sensitive ramus supplies the palmaris elle -side portion of the wrist flexor surface and the proximal hypothenar eminence.

Finally, the superficial branch supplies via its terminal branches the rest of the little finger, and on the Nervi palmar digital proprii the lean side skin of the little finger and the adjacent skin of the bending side ring finger.

Domestic mammals

In the domestic animals of the ulnar nerve releases the caudal antebrachial cutaneous nerve, which supplies the back of the forearm sensitive. Above the Carpal it divides into a dorsal ramus and ramus palmaris. The Ramus palmaris has connection to the median nerve. The two terminal branches of the ulnar nerve supply sensory skin's outer toe and deep structures of the forefoot.

Diseases

The ulnar nerve palsy is the most common peripheral nerve damage in humans. Depending on the location of the injury is called a Ulnarisrinnen syndrome or a Loge de Guyon syndrome.

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