T10 dermatome and nerve root

Thoracic spinal root

Where is the T10 dermatome?

The T10 dermatome covers a band round the trunk at the umbilicus. Its ISNCSCI key sensory point is the tenth intercostal space, level with the umbilicus. ISNCSCI grades no key movement for T10. A disc rarely compresses T10; when one does, it is the T10/T11 disc.

T10 at a glance
Type	Thoracic spinal root
Key sensory point	The tenth intercostal space, level with the umbilicus
Key movement	None graded: the standard grades C5 to T1 and L2 to S1
Tendon reflex	None tests it on its own
Usual disc	T10/T11, rarely

Try in: Dermatome and Myotome Map Explorer →

T10 myotome: the muscles it supplies

T10 is a major root for 5 of the 7 muscles below and a minor root for the rest.

Muscles T10 supplies, and every root each takes
Muscle	From T10	All its roots
Intercostal muscles	Major	T1 to T11
Rectus abdominis	Major	T7 to T12
External oblique	Major	T7 to T12
Internal oblique	Major	T7 to L1
Transversus abdominis	Major	T7 to L1
Erector spinae	Minor	T1 to L5 in part
Multifidus	Minor	T1 to L5 in part

Erector spinae and multifidus: supplied segment by segment by the dorsal rami, so each root reaches only its own short stretch.

T10 and the tendon reflexes

No tendon reflex tests T10 on its own.

Why a disc rarely compresses T10

Each thoracic root leaves below its own vertebra and runs round the trunk as an intercostal nerve, which is why its dermatome is a band. A disc rarely presses on a thoracic root, since the ribs steady that part of the spine; shingles, which reactivates in one root’s ganglion, is the classic cause of pain in one band.

What a T10 root lesion does

Sensation. Numbness or tingling in the T10 band. Usually a smaller patch than the whole band, because T9 and T11 overlap it: Sherrington found in 1893 that cutting a single root in monkeys left no skin entirely without feeling.
Strength. Also weaker where T10 is a major supply: intercostal muscles, rectus abdominis, external oblique, internal oblique and transversus abdominis.
Reflexes. No tendon reflex depends on T10.

A teaching map. Root territories overlap and vary between people, and a root lesion is diagnosed by examination and imaging, not by a map. Numbness between the legs or around the anus, new bladder or bowel problems, or quickly spreading weakness need emergency care.

A way to remember T10

T10 at the belly butTEN.

Neighboring dermatomes

T9: a band round the trunk just above the umbilicus
T11: a band round the trunk below the umbilicus

Dermatome and Myotome Map Explorer, with T10 lit on a front and back body map
Every dermatome, with the disc levels and key movements side by side
Vertebral Column and Pelvis Explorer, the openings between the vertebrae that the roots leave through, in 3D
Reflex Arc Simulator, the loop a tendon reflex runs through the spinal cord
Muscles Worked by Exercise 3D Explorer, a whole body colored by root, in its root mode

Sources. Key sensory points and key movements: International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), American Spinal Injury Association, 2019 revision. Muscles: Aids to the Examination of the Peripheral Nervous System, Medical Research Council and the Guarantors of Brain, 5th ed. (2010), cross-checked with Kendall et al. (2005). Reflex roots: Walker (1990), Clinical Methods, 3rd ed., Table 72.1, and StatPearls, “Physiology, Deep Tendon Reflexes”; the main root as the MSD Manual’s “How to Assess Reflexes” names it. Overlap: Sherrington (1893), Phil Trans R Soc Lond B 184:641-763.