SPINAL NERVE SEGMENT

PLEXUS

INNERVATION OF MUSCLE & VISCERIA

DERMATOME PATTERN

T1

BRACHIAL

Intercostals of Respective Level; Levatores Costarum;  Serratus Posterior & Superior; Semispinalis Thoracis; Pectoralis Major & Minor; Transversus Thoracis; Sometimes Pronator Teres; Flexor Digitorum Superficalis & Profundus; Interossei, Lumbricales; Flexor Pollicis Longus & Brevis; Opponens Pollicis; Abductor Pollicis Brevis;  Thyroid; Heart

Posteriorly from about the level of T1 the pattern traverses inferiorly across the spine of the scapula around and under the axilla anteriorly to the sternum at approximately the level of the 2nd and 3rd rib; Additionally it traverses from the sternum at the level of the 2nd or 3rd rib laterally to the anterior aspect of the shoulder and down the anterior medial aspect of the arm, forearm and terminates at the base of the thenar eminence.

T2

BRACHIAL

Transversus Thoracis; Intercostals of Respective Level; Levatores Costarum; Serratus Posterior Superior; Semispinalis Thoracis; Intrinsic Back Muscles; Heart, Heart Valves; Coronary Arteries

Posteriorly it traverses from T2 inferiorly beneath the inferior angle of the scapula at which time it ascends superiorly to the axilla and anteriorly above the nipple line to the sternum.

T3

NONE

Transversus Thoracis; Intercostals of Respective Level; Levatores Costarum; Serratus Posterior Superior; Semispinalis Thoracis; Intrinsic Back Muscles; Heart; Chest; Pleura; Bronchial Tubes; Lungs

Traverses from approximately the level of T3 inferiorly and lateral to the inferior angle of the scapula at which time it traverses superiorly and laterally around the thorax and terminates at the sternum just superior to the nipple line.

T4

NONE

Transversus Thoracis; Intercostals of Respective Level; Levatores Costarum; Semispinalis Thoracis; Intrinsic Back Muscles; Gall Bladder; Common Bile Duct;

Traverses from the level of T4 well beneath the scapula at approximately the level of the 7th rib; anteriorly it sweeps superiorly under the axilla and across the nipple line.

T5

NONE

Transversus Thoracis; Intercostals of Respective Level; Levatores Costarum; Semispinalis Thoracis; Stomach; Liver; Solar Plexus;

T5 traverses in a pattern slightly inferior to that referenced at T4 with its anterior translation across the inferior aspect of the breast and mastic cleft and terminating at the sternum.

T6

NONE

Transversus Thoracis: Intercostals of Respective Level: Levatores Costarum; Semispinalis Thoracis;  Stomach; Pancreas

T6 traverses from the 6th segment posteriorly along the course of the 6th or 7th rib anteriorly and terminates at the xiphoid process.

T7

NONE

Intercostals of Respective Levels; Levatores Costarum; Intrinsic Back Muscles; Transverse Abdominis; Rectus Abdominis; Pancreas; Spleen; Duodenum

The dermatome pain referral for the T7 spinal nerve traverses from the 7th segment, anteriorly along the 7th & 8th rib and terminates slightly inferior of the xiphoid process.

T8

NONE

Intercostals of Respective Levels;  Levatores Costarum; Intrinsic Back Muscles; External Obliques; Internal Obliques; Transverse Abdominis; Rectus Abdominis; Spleen

Traverses posteriorly from T8 to anteriorly at the mid epigastrium.

T9

NONE

Intercostals of Respective Levels; Levatores Costarum; Intrinsic Back Muscles; External Obliques; Internal Obliques; Transverse Abdominis; Rectus Abdominis; Adrenal Glands

Traverses posteriorly from T9 to anteriorly slightly above the umbilicus.

T10

NONE

Intercostals of Respective Levels:  Levatores Costarum; Serratus Posterior Inferior; Intrinsic Back Muscles; External Obliques; Internal Obliques; Transverse Abdominis; Rectus Abdominis; Kidneys; Adrenal Glands

Traverses posteriorly from T10 to anteriorly through the umbilicus.

T11

NONE

Intercostals of Respective Levels;  Levatores Costarum; Serratus Posterior Inferior; Intrinsic Back Muscles; External Obliques; Internal Obliques; Transverse Abdominis; Rectus Abdominis; Kidneys; Ureters

Traverses posteriorly from T11 to anteriorly slightly beneath the umbilicus.

T12

LUMBAR

Intercostals of Respective Levels;  Levatores Costarum; Serratus Posterior Inferior; Intrinsic Back Muscles; External Obliques; Internal Obliques; Transverse Abdominis; Rectus Abdominis; Pyramidalis; Small Intestine; Kidneys

Traverses posteriorly from T12 to anteriorly slightly above the pubis.