Musculocutaneous nerve

The musculocutaneous nerve ( " muscle - skin - nerve" ) arises from the brachial plexus. It refers in humans fibers from the 5th - 7th Cervical segment (C5 - C7) of the spinal cord, in domestic animals from C6 - C8. In ungulates it connects the upper arm to the median nerve (so-called ansa axillaris ).

Course

The nerve passes after leaving the lateral cord ( brachial plexus ) distally on the lateral border of the pectoralis minor muscle and pierces the coracobrachialis. Later he draws between the musculus brachialis and biceps brachii distally toward the elbow, from where he to as sensitive cutaneous branch ( lateral antebrachial cutaneous nerve ) innervates the outer side of the forearm.

Muscular branches

The musculocutaneous nerve innervates the muscles on the ventral (front ) side of the upper arm, the flexors of the elbow joint are and / or cause an anteversion of the shoulder joint:

  • Biceps brachii
  • Musculus brachialis
  • Musculus coracobrachialis

Cutaneous branch

After delivery of the muscular branches of the nerve between the biceps brachii and brachialis muscle comes to the surface.

In humans, this cutaneous branch is referred to as lateral antebrachial cutaneous nerve. It innervates the spoke- side (radial ) part of the forearm sensitive.

In domestic mammals of the cutaneous branch is called the medial antebrachial cutaneous nerve. It innervates the skin on the medial forearm, in ungulates presented his innervation to the fetlock joint, thus also includes the dorsomedial part of the fore metatarsus.

Clinical aspects

Damage to the nerve resulting in a failure of the flexion of the elbow joint. Depending on how far above ( proximally of ) the injury is located, it is optionally in the failure of the musculus coracobrachialis and hence to a failure of the weak Nachvornziehens ( anteversion ) of the upper arm and the fixing of the head of the humerus at the shoulder joint. Moreover, it can in humans to the impairment of supination ( supination ) of the arm come. In animals, nerve damage manifests as mild gait disturbance.

In addition, the damage to the nerve leads to sensitivity losses in the skin area, which innervate sensitive.

A neurectomy of the nerve can be applied to functionless arm and contracture of the elbow joint.

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