The thoracodorsal nerve is a

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...

present in humans and other animals, also known as the middle subscapular nerve or the long subscapular nerve. It supplies the

latissimus dorsi muscle The latissimus dorsi () is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline. The word latissimus dorsi (plural: ''latissimi dorsi'') comes from ...

Anatomy

Origin

The thoracodorsal nerve arises from the

posterior cord The posterior cord is a part of the brachial plexus The brachial plexus is a network of nerves (nerve plexus) formed by the anterior rami of the lower four Spinal nerve#Cervical nerves, cervical nerves and first Spinal nerve#Thoracic nerves, thor ...

of the

brachial plexus The brachial plexus is a network of nerves (nerve plexus) formed by the anterior rami of the lower four Spinal nerve#Cervical nerves, cervical nerves and first Spinal nerve#Thoracic nerves, thoracic nerve (cervical spinal nerve 5, C5, Cervical spi ...

. It is derived from their

ventral rami The ventral ramus (: rami) (Latin for 'branch') is the anterior division of a spinal nerve. The ventral rami supply the antero-lateral parts of the trunk and the limbs. They are mainly larger than the dorsal rami. Shortly after a spinal nerve ...

(in spite of the fact that the latissimus dorsi is found in the

back The human back, also called the dorsum (: dorsa), is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck. It is the surface of the body opposite from the chest and the abdomen. The vertebral c ...

) of cervical nerves C6-C8. It is derived from fibres of the posterior divisions of all three trunks of the brachial plexus.

Course

It passes inferior-ward anterior to the

subscapularis muscle The subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint. Structure The subscapularis is covered by a dense fasci ...

and subscapular vessels. It penetrates into the substance of the latissimus dorsi muscle near the lateral border of scapula. It follows the course of the subscapular artery, along the posterior wall of the

axilla The axilla (: axillae or axillas; also known as the armpit, underarm or oxter) is the area on the human body directly under the shoulder joint. It includes the axillary space, an anatomical space within the shoulder girdle between the arm a ...

to the

, in which it may be traced as far as the lower border of the muscle.

Distribution

The thoracodorsal nerve innervates the

on its deep surface.

Clinical significance

The latissimus dorsi is occasionally used for transplantation, and for augmentation of

systole Systole ( ) is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood. Its contrasting phase is diastole, the relaxed phase of the cardiac cycle when the chambers of the heart are refilling ...

cardiac failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF typically pre ...

. In these cases, the nerve supply is preserved, and transplanted with the muscle (for example, with facial reanimation). Posterior cord lesions can result in the loss of

adduction Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

of the

shoulder joint The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial joint, synovial ball-and-socket joint and functionally as a diarthrosis and m ...

, as innervation to latissimus dorsi is lost.

Additional images

File:Brachial plexus.svg, Brachial plexus File:Gray809.png, The right brachial plexus (infraclavicular portion) in the axillary fossa; viewed from below and in front. File:Brachial_plexus_color.svg, Brachial plexus with courses of spinal nerves shown

References

External links

Dissection Video of Superficial Back showing the Thoracodorsal Nerve
* - "The major subdivisions and terminal nerves of the brachial plexus."
Thoracodorsal Nerve
- BlueLink Anatomy - University of Michigan Medical School {{Authority control Nerves of the upper limb