Two-point discrimination: Difference between revisions

Revision as of 23:47, 9 February 2025

The ability to discern two separate points of contact on the skin

Two-point discrimination is a measure of the ability to discern that two nearby objects touching the skin are truly two distinct points, not one. This ability varies across different areas of the body and is an important aspect of somatosensory perception.

Physiology

Two-point discrimination is primarily a function of the nervous system, particularly the somatosensory cortex in the brain. The density of nerve endings in the skin, such as Meissner's corpuscles and Merkel cells, influences the ability to distinguish between two points. Areas with higher nerve density, like the fingertips and lips, have a finer two-point discrimination threshold compared to areas with lower nerve density, such as the back.

Measurement

The two-point discrimination test is a common method used to assess the sensory function of the skin. During the test, two points are applied to the skin with a specific distance apart, and the subject is asked whether they feel one or two points. The smallest distance at which the subject can distinguish two points is recorded as the two-point discrimination threshold.

Clinical significance

Two-point discrimination is used in neurology to assess the integrity of the peripheral nervous system and the central nervous system. It can help diagnose conditions that affect sensory perception, such as peripheral neuropathy or spinal cord injury.

Factors affecting two-point discrimination

Several factors can influence two-point discrimination, including age, skin condition, and neurological disorders. For instance, aging can lead to a decline in sensory perception, increasing the two-point discrimination threshold.

Related pages

References

Kandel, E. R., Schwartz, J. H., & Jessell, T. M. (2000). Principles of Neural Science. McGraw-Hill.
Mountcastle, V. B. (2005). The Sensory Hand: Neural Mechanisms of Somatic Sensation. Harvard University Press.

@@ Line 1: / Line 1: @@
-'''Transverse cervical artery''' is an artery in the neck that supplies blood to the muscles in the front, middle, and back of the neck. It originates from the thyrocervical trunk, which is a branch of the subclavian artery. The transverse cervical artery is divided into two branches: the superficial branch and the deep branch. The superficial branch supplies blood to the trapezius muscle, while the deep branch (also known as the dorsal scapular artery) supplies blood to the rhomboid muscles.
+{{Short description|The ability to discern two separate points of contact on the skin}}
+{{Use dmy dates|date=October 2023}}
-== Anatomy ==
+[[File:Lawrence_1960_8.11.png|thumb|right|Diagram illustrating two-point discrimination]]
+[[File:2-point_orientation_discrimination_(2POD)_compared_to_traditional_two-point_discrimination_(2PD).jpg|thumb|right|Comparison of two-point orientation discrimination and traditional two-point discrimination]]
-The '''transverse cervical artery''' arises from the [[thyrocervical trunk]], which is a branch of the [[subclavian artery]]. It runs across the neck, passing beneath the [[sternocleidomastoid muscle]] and the [[levator scapulae muscle]], and then divides into a superficial branch and a deep branch.
+'''Two-point discrimination''' is a measure of the ability to discern that two nearby objects touching the skin are truly two distinct points, not one. This ability varies across different areas of the body and is an important aspect of [[somatosensory system|somatosensory perception]].
-=== Superficial Branch ===
+==Physiology==
+Two-point discrimination is primarily a function of the [[nervous system]], particularly the [[somatosensory cortex]] in the [[brain]]. The [[density]] of [[nerve endings]] in the skin, such as [[Meissner's corpuscles]] and [[Merkel cells]], influences the ability to distinguish between two points. Areas with higher nerve density, like the [[fingertips]] and [[lips]], have a finer two-point discrimination threshold compared to areas with lower nerve density, such as the [[back]].
-The superficial branch of the transverse cervical artery runs across the posterior triangle of the neck, supplying blood to the [[trapezius muscle]]. It also gives off branches to the [[levator scapulae muscle]] and the [[sternocleidomastoid muscle]].
+==Measurement==
+The two-point discrimination test is a common method used to assess the sensory function of the skin. During the test, two points are applied to the skin with a specific distance apart, and the subject is asked whether they feel one or two points. The smallest distance at which the subject can distinguish two points is recorded as the two-point discrimination threshold.
-=== Deep Branch ===
+==Clinical significance==
+Two-point discrimination is used in [[neurology]] to assess the integrity of the [[peripheral nervous system]] and the [[central nervous system]]. It can help diagnose conditions that affect sensory perception, such as [[peripheral neuropathy]] or [[spinal cord injury]].
-The deep branch of the transverse cervical artery, also known as the dorsal scapular artery, runs downward and laterally to supply blood to the [[rhomboid muscles]]. It also gives off branches to the [[levator scapulae muscle]].
+==Factors affecting two-point discrimination==
+Several factors can influence two-point discrimination, including age, [[skin condition]], and [[neurological disorders]]. For instance, aging can lead to a decline in sensory perception, increasing the two-point discrimination threshold.
-== Clinical Significance ==
+==Related pages==
+* [[Somatosensory system]]
+* [[Nerve ending]]
+* [[Sensory receptor]]
-The transverse cervical artery can be involved in various medical conditions. For example, it can be injured in neck trauma, leading to [[hemorrhage]]. It can also be involved in [[aneurysm]]s, [[arteriovenous malformation]]s, and [[carotid artery dissection]]s.
+==References==
+* Kandel, E. R., Schwartz, J. H., & Jessell, T. M. (2000). ''Principles of Neural Science''. McGraw-Hill.
+* Mountcastle, V. B. (2005). ''The Sensory Hand: Neural Mechanisms of Somatic Sensation''. Harvard University Press.
-== See Also ==
+[[Category:Neuroscience]]
+[[Category:Sensory system]]
-* [[Thyrocervical trunk]]
-* [[Subclavian artery]]
-* [[Trapezius muscle]]
-* [[Rhomboid muscles]]
-* [[Sternocleidomastoid muscle]]
-* [[Levator scapulae muscle]]
-[[Category:Anatomy]]
-[[Category:Arteries]]
-[[Category:Neck]]
-{{stub}}