Temporal plane
Planum temporale
The flat triangular area on the hidden upper surface of the superior temporal gyrus, behind the transverse temporal gyri.
At a glance
- English
- Temporal plane
- Latin (TA2)
- Planum temporale
- System
- Brain and spinal cord
- Region
- Head
- Side
- Paired, left and right
About the temporal plane
The planum temporale, or temporal plane, lies on the upper surface of the superior temporal gyrus, the face that forms the floor of the lateral sulcus and is hidden from view until the sulcus is opened. It is a roughly triangular stretch of cortex behind the transverse temporal gyrus of Heschl, separated from it by the transverse temporal sulcus. It extends back to the end of the lateral sulcus, where the cortex may continue up as a posterior ascending ramus into the parietal operculum. In front of Heschl's gyrus lies the corresponding area called the planum polare.
The planum temporale is the best known example of size difference between the hemispheres. In most right-handed people it is clearly larger on the left. This led to the idea that it is a structural basis for the dominance of the left hemisphere for language, though the relation with handedness and language side is not exact.
Its cortex is auditory association cortex, mostly Brodmann area 22 together with the back part of area 42, next to the primary auditory cortex of Heschl's gyrus. It takes part in the early analysis of complex sounds, including the timing and sequence of speech sounds, music, and the position and movement of sound sources. On the left it forms part of Wernicke's area and acts as a link between heard speech and the motor system that produces it, which is why it is active during both listening and silent speech.
Reduced or reversed asymmetry of the planum temporale has been described in developmental dyslexia, in stuttering and in schizophrenia, where it has been linked with auditory hallucinations. People with absolute pitch tend to show a stronger leftward asymmetry. Damage to the left planum contributes to the comprehension and repetition problems of fluent aphasias.
Function and supply
- Function
- Auditory association cortex that analyses complex and speech sounds and their location; on the left it forms part of Wernicke's area, linking heard speech with speech production.
- Blood supply
- Posterior temporal branches of the middle cerebral artery.
Anthromica
See the temporal plane where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
