The dorsal column–medial lemniscus pathway (DCML) (also known as the posterior column-medial lemniscus pathway (PCML) is the major
sensory pathway of the
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...
that conveys
sensations of
fine touch,
vibration
Vibration () is a mechanical phenomenon whereby oscillations occur about an equilibrium point. Vibration may be deterministic if the oscillations can be characterised precisely (e.g. the periodic motion of a pendulum), or random if the os ...
,
two-point discrimination, and
proprioception
Proprioception ( ) is the sense of self-movement, force, and body position.
Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of propri ...
(body position) from the skin and joints. It transmits this information to the
somatosensory cortex
The somatosensory system, or somatic sensory system is a subset of the sensory nervous system. The main functions of the somatosensory system are the perception of external stimuli, the perception of internal stimuli, and the regulation of bod ...
of the
postcentral gyrus
In neuroanatomy, the postcentral gyrus is a prominent gyrus in the lateral parietal lobe of the human brain. It is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch. Like other sensory area ...
in the
parietal lobe
The parietal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus.
The parietal lobe integra ...
of the brain.
[O'Sullivan, S. B., & Schmitz, T. J. (2007). Physical Rehabilitation (5th Edition ed.). Philadelphia: F.A. Davis Company.] The pathway receives information from sensory receptors throughout the body, and carries this in the
gracile fasciculus and the
cuneate fasciculus, tracts that make up the white matter
dorsal columns (also known as the posterior
funiculi) of the spinal cord. At the level of the
medulla oblongata
The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...
, the fibers of the tracts
decussate
Decussation is used in biological contexts to describe a crossing (due to the shape of the Roman numeral for ten, an uppercase 'X' (), ). In Latin anatomical terms, the form is used, e.g. .
Similarly, the anatomical term chiasma is named aft ...
and are continued in the
medial lemniscus
The medial lemniscus, also known as Reil's band or Reil's ribbon (for German anatomist Johann Christian Reil), is a large ascending bundle of heavily myelinated axons that decussate in the brainstem
The brainstem (or brain stem) is the pos ...
, on to the
thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...
and relayed from there through the
internal capsule
The internal capsule is a paired white matter structure, as a two-way nerve tract, tract, carrying afferent nerve fiber, ascending and efferent nerve fiber, descending axon, fibers, to and from the cerebral cortex. The internal capsule is situate ...
and transmitted to the somatosensory cortex. The name dorsal-column medial lemniscus comes from the two structures that carry the sensory information: the dorsal columns of the
spinal cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...
, and the medial lemniscus in the
brainstem
The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...
.
There are three groupings of neurons that are involved in the pathway:
first-order neurons,
second-order neuron
Second-order may refer to:
Mathematics
* Second order approximation, an approximation that includes quadratic terms
* Second-order arithmetic, an axiomatization allowing quantification of sets of numbers
* Second-order differential equation, a d ...
s, and
third-order neurons. The first-order neurons are
sensory neuron
Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded receptor potentials. This process is called sensory transduc ...
s located in the
dorsal root ganglia
A dorsal root ganglion (or spinal ganglion; also known as a posterior root ganglion) is a cluster of neurons (a ganglion) in a dorsal root of a spinal nerve. The cell bodies of sensory neurons known as first-order neurons are located in the dors ...
, that send their
afferent fibers through the two dorsal columns.
The first-order
axon
An axon (from Greek ἄξων ''áxōn'', axis) or nerve fiber (or nerve fibre: see American and British English spelling differences#-re, -er, spelling differences) is a long, slender cellular extensions, projection of a nerve cell, or neuron, ...
s
make contact with second-order neurons of the
dorsal column nuclei (the
gracile nucleus and the
cuneate nucleus) in the lower
medulla. The second-order neurons send their axons to the
thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...
. The third-order neurons are in the
ventral posterolateral nucleus
The ventral posterolateral nucleus (VPL) is one of the subdivisions of the ventral posterior nucleus in the ventral nuclear group of the thalamus. It relays sensory information from the second-order neurons of the neospinothalamic tract and me ...
in the thalamus and fibres from these ascend to the postcentral gyrus.
Sensory information from the upper half of the body is received at the
cervical level of the spinal cord and carried in the cuneate tract, and information from the lower body is received at the
lumbar
In tetrapod anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm (anatomy), diaphragm and the sacrum.
Naming and location
The lumbar region is sometimes referred to as the lowe ...
level and carried in the gracile tract. The gracile tract is medial to the more lateral cuneate tract.
The axons of second-order neurons of the gracile and cuneate nuclei are known as the
internal arcuate fibers and when they cross over the midline, at the
sensory decussation in the medulla, they form the medial lemniscus which connects with the thalamus; the axons synapse on neurons in the ventral posterolateral nucleus which then send axons to the postcentral gyrus in the parietal lobe. All of the axons in the DCML pathway are rapidly conducting, large,
myelin
Myelin Sheath ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be lik ...
ated fibers.
Structure

The DCML pathway is made up of the axons of first, second, and third-order
sensory neuron
Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded receptor potentials. This process is called sensory transduc ...
s, beginning in the
dorsal root ganglia
A dorsal root ganglion (or spinal ganglion; also known as a posterior root ganglion) is a cluster of neurons (a ganglion) in a dorsal root of a spinal nerve. The cell bodies of sensory neurons known as first-order neurons are located in the dors ...
. The axons from the
first-order neurons form the ascending tracts of the gracile fasciculus, and the cuneate fasciculus (the
dorsal columns) which synapse on the second-order neurons in the
gracile nucleus and the
cuneate nucleus known together as the
dorsal column nuclei; axons from these neurons ascend as the
internal arcuate fibers; the fibers cross over at the
sensory decussation and form the
medial lemniscus
The medial lemniscus, also known as Reil's band or Reil's ribbon (for German anatomist Johann Christian Reil), is a large ascending bundle of heavily myelinated axons that decussate in the brainstem
The brainstem (or brain stem) is the pos ...
which connects with the
thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...
; the axons synapse on neurons in the
ventral nuclear group
The ventral nuclear group is a collection of nuclei on the ventral side of the thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of th ...
which then send axons to the
postcentral gyrus
In neuroanatomy, the postcentral gyrus is a prominent gyrus in the lateral parietal lobe of the human brain. It is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch. Like other sensory area ...
in the
parietal lobe
The parietal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus.
The parietal lobe integra ...
.
The gracile fasciculus carries sensory information from the lower half of the body entering the spinal cord at the lumbar level. The cuneate fasciculus carries sensory information from the upper half of the body (upper limbs, trunk, and neck) entering the spinal cord at the cervical level.
The gracile fasciculus is wedge-shaped on transverse section and lies next to the posterior median septum. Its base is at the surface of the spinal cord, and its apex directed toward the posterior gray commissure. The gracile fasciculus increases in size from inferior to superior.
The cuneate fasciculus is triangular on transverse section, and lies between the gracile fasciculus and the posterior column, its base corresponding with the surface of the spinal cord.
Its fibers, larger than those of the gracile fasciculus, are mostly derived from the same source, viz., the posterior nerve roots.
Some ascend for only a short distance in the tract, and, entering the gray matter, come into close relationship with the cells of the dorsal nucleus, while others can be traced as far as the medulla oblongata, where they end in the gracile nucleus and cuneate nucleus.
The two ascending tracts meet at the level of the
sixth thoracic vertebra (T6). Ascending tracts typically have three levels of neurons, namely
first-order,
second-order, and
third-order neurons, that relay information from the physical point of reception to the actual point of interpretation in the brain.
First-order neurons
Periphery and spinal cord

When an
action potential
An action potential (also known as a nerve impulse or "spike" when in a neuron) is a series of quick changes in voltage across a cell membrane. An action potential occurs when the membrane potential of a specific Cell (biology), cell rapidly ri ...
is generated by a
mechanoreceptor
A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are located on sensory neurons that convert mechanical pressure into action potential, electrical signals tha ...
in the
tissue, the action potential will travel along the peripheral axon of the first-order neuron. The first-order neuron is
pseudounipolar in shape with its
body in the
dorsal root ganglion
A dorsal root ganglion (or spinal ganglion; also known as a posterior root ganglion) is a cluster of neurons (a ganglion) in a dorsal root of a spinal nerve. The cell bodies of sensory neurons known as first-order neurons are located in the do ...
. The action signal will continue along the central axon of the neuron through the
posterior root, into the
posterior horn, and up the
posterior column of the
spinal cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...
.
Axons from the lower body enter the posterior column below the level of
T6 and travel in the midline section of the column called the gracile fasciculus.
Axons from the upper body enter at or above T6 and travel up the posterior column on the outside of the gracile fasciculus in a more
lateral
Lateral is a geometric term of location which may also refer to:
Biology and healthcare
* Lateral (anatomy), a term of location meaning "towards the side"
* Lateral cricoarytenoid muscle, an intrinsic muscle of the larynx
* Lateral release ( ...
section called the cuneate fasciculus. These fasciculi are in an area of white matter, the posterior funiculus (a
funiculus) that lies between the
posterolateral and the
posterior median sulcus. They are separated by a partition of
glial cells
Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (the brain and the spinal cord) and in the peripheral nervous system that do not produce electrical impulses. The neuroglia make up ...
which places them on either side of the posterior intermediate sulcus.
The column reaches the junction between the spinal cord and the
medulla oblongata
The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...
, where lower body axons in the gracile fasciculus connect (
synapse
In the nervous system, a synapse is a structure that allows a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending o ...
) with neurons in the
gracile nucleus, and upper body axons in the cuneate fasciculus synapse with neurons in the
cuneate nucleus.
First-order neurons secrete
substance P
Substance P (SP) is an undecapeptide (a peptide composed of a chain of 11 amino acid residues) and a type of neuropeptide, belonging to the tachykinin family of neuropeptides. It acts as a neurotransmitter and a neuromodulator. Substance P ...
in the dorsal horn as a chemical mediator of pain signaling. The dorsal horn of the spinal cord transmits pain and non-noxious signals from the periphery to the spinal cord itself. Adenosine is another local molecule that modulates dorsal horn pain transmission
Second-order neurons
Brainstem
The neurons in these two nuclei (the
dorsal column nuclei) are second-order neurons.
Their axons cross over to the other side of the medulla and are now named as the
internal arcuate fibers, that form the
medial lemniscus
The medial lemniscus, also known as Reil's band or Reil's ribbon (for German anatomist Johann Christian Reil), is a large ascending bundle of heavily myelinated axons that decussate in the brainstem
The brainstem (or brain stem) is the pos ...
on each side. This crossing over is known as the
sensory decussation.
At the medulla, the medial lemniscus is orientated perpendicular to the way the fibres travelled in their tracts in the posterior column. For example, in the column,
lower limb
Lower may refer to:
*Lower (album), ''Lower'' (album), 2025 album by Benjamin Booker
*Lower (surname)
*Lower Township, New Jersey
*Lower Receiver (firearms)
*Lower Wick Gloucestershire, England
See also
*Nizhny
{{Disambiguation ...
is medial,
upper limb
The upper Limb (anatomy), limbs or upper extremities are the forelimbs of an upright posture, upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digit (anatomy), digits, including all the musc ...
is more lateral. At the medial lemniscus, axons from the leg are more ventral, and axons from the arm are more dorsal. Fibres from the
trigeminal nerve
In neuroanatomy, the trigeminal nerve (literal translation, lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for Sense, sensation in the face and motor functions ...
(supplying the
head
A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...
) come in dorsal to the arm fibres, and travel up the lemniscus too.
The medial lemniscus rotates 90 degrees at the
pons
The pons (from Latin , "bridge") is part of the brainstem that in humans and other mammals, lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum.
The pons is also called the pons Varolii ("bridge of ...
. The secondary axons from neurons giving sensation to the head, stay at around the same place, while the leg axons move outwards.
The axons travel up the rest of the brainstem, and synapse at the
thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...
(at the
ventral posterolateral nucleus
The ventral posterolateral nucleus (VPL) is one of the subdivisions of the ventral posterior nucleus in the ventral nuclear group of the thalamus. It relays sensory information from the second-order neurons of the neospinothalamic tract and me ...
for sensation from the neck, trunk, and extremities, and at the
ventral posteromedial nucleus for sensation from the head).
Third-order neurons
Thalamus to cortex
Axons from the third-order neurons in the
ventral posterior nucleus in the thalamus, ascend the posterior limb of the
internal capsule
The internal capsule is a paired white matter structure, as a two-way nerve tract, tract, carrying afferent nerve fiber, ascending and efferent nerve fiber, descending axon, fibers, to and from the cerebral cortex. The internal capsule is situate ...
. Those originating from the head and the leg swap their relative positions. The axons synapse in the
primary somatosensory cortex
In neuroanatomy, the primary somatosensory cortex is located in the postcentral gyrus of the brain's parietal lobe, and is part of the somatosensory system. It was initially defined from surface stimulation studies of Wilder Penfield, and parallel ...
, with lower body sensation most medial (e.g., the paracentral lobule) and upper body more lateral.
Function
Discriminative sensation is well developed in the fingers of
human
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...
s and allows the detection of fine textures. It also allows for the ability known as
haptic perception
Haptic perception ( "palpable", ''haptikόs'' "suitable for touch") means literally the ability "to grasp something", and is also known as stereognosis. Perception in this case is achieved through the active exploration of surfaces and objects by a ...
(stereognosis), to determine what an unknown object is, using the hands without visual or audio input.
Fine touch is detected by
cutaneous receptor
A cutaneous receptor is a sensory receptor found in the skin that provides information about temperature, touch (including vibration and pain), spatial orientation,pressure (stretching or squeezing), and metabolic circumstances (including those i ...
s called
tactile corpuscle
Tactile corpuscles or Meissner's corpuscles are a type of mechanoreceptor discovered by anatomist Georg Meissner (1829–1905) and Rudolf Wagner. This corpuscle is a type of nerve ending in the skin that is responsible for sensitivity to pressur ...
s that lie in the
dermis
The dermis or corium is a layer of skin between the epidermis (skin), epidermis (with which it makes up the cutis (anatomy), cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from s ...
of the
skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other animal coverings, such as the arthropod exoskeleton, have different ...
close to the
epidermis
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermal layer provides a barrier to infection from environmental pathogens and regulates the ...
. When these structures are stimulated by slight pressure, an
action potential
An action potential (also known as a nerve impulse or "spike" when in a neuron) is a series of quick changes in voltage across a cell membrane. An action potential occurs when the membrane potential of a specific Cell (biology), cell rapidly ri ...
is started. Alternatively, proprioceptive
muscle spindles
Muscle spindles are stretch receptors within the body of a skeletal muscle that primarily detect changes in the length of the muscle. They convey length information to the central nervous system via afferent nerve fibers. This information can be ...
and other skin surface touch
mechanoreceptors such as
Merkel cells,
bulbous corpuscle
The bulbous corpuscle, Ruffini ending or Ruffini corpuscle is a slowly adapting mechanoreceptor
A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are locat ...
s,
lamellar corpuscles, and hair follicle receptors (peritrichial endings) may involve the first neuron in this pathway.
The sensory neurons in this pathway are
pseudounipolar, meaning that they have a single process emanating from the cell body with two distinct branches: one peripheral branch that functions somewhat like a
dendrite
A dendrite (from Ancient Greek language, Greek δένδρον ''déndron'', "tree") or dendron is a branched cytoplasmic process that extends from a nerve cell that propagates the neurotransmission, electrochemical stimulation received from oth ...
of a typical neuron by receiving input (although it should ''not'' be confused with a true dendrite), and one central branch that functions like a typical axon by carrying information to other neurons (again, both branches are actually part of one axon).
Clinical significance
Damage to the dorsal column-medial lemniscus pathway below the crossing point of its fibers results in loss of vibration and joint sense (proprioception) on the
same side of the body as the lesion. Damage above the crossing point result a loss of vibration and joint sense on the
opposite side of the body to the lesion. The pathway is tested with
Romberg's test.
Damage to either of the dorsal column tracts can result in the permanent loss of sensation in the limbs. See
Brown-Séquard syndrome.
Additional information
The cuneate fasciculus, fasciculus cuneatus, cuneate tract, tract of Burdach, was named for
Karl Friedrich Burdach. The gracile fasciculus, the tract of Goll, was named after Swiss neuroanatomist
Friedrich Goll (1829–1903).
See also
*
Spinothalamic tract
The spinothalamic tract is a nerve tract in the anterolateral system in the spinal cord. This tract is an ascending sensory pathway to the thalamus. From the ventral posterolateral nucleus in the thalamus, sensory information is relayed upwar ...
(Anterolateral system)
References
External links
*
{{DEFAULTSORT:Posterior column-medial lemniscus pathway
Spinal cord tracts
Sensory systems
Thalamus