Cortical area · one in each half of the brain
Pars triangularis
Also called Brodmann area 45, Triangular part of the inferior frontal gyrus
The triangle-shaped front of Broca's area: fetching words and their meanings.
The pars triangularis is the front part of Broca's area, named for its triangle shape. It helps you search your memory for the right word and choose between competing options. It also helps you understand and build complex sentences, and it joins in when you work out what words mean.
Where it is
In the lower frontal lobe, between the pars opercularis behind it and the pars orbitalis in front. It is the front half of Broca's area.
What it does
Choosing the right word
It helps you pick the best word when several could fit, like choosing between "cup", "mug" and "glass".
Word meanings
It works with the temporal lobe to pull up what words mean.
Word fluency
It is key when you try to list as many words starting with one letter as you can in a minute, a quick test doctors often use.
Complex sentences
It helps you follow long sentences, keeping track of who did what to whom.
Think of it as a librarian: when you need a word, it searches the shelves of memory and hands you the best one.
Works with
- Pars opercularisIts neighbor behind handles speech sounds and structure, while it handles meaning and word choice.
- Middle temporal gyrusThis temporal region stores much of our knowledge of word meanings, which it retrieves on demand.
- Inferior fronto-occipital fasciculusThis long fiber cable connects it to the back of the brain, supporting a pathway for meaning.
- Uncinate fasciculusThis hook-shaped bundle links the lower frontal lobe to the front of the temporal lobe, where names and concepts are stored.
- Dorsolateral prefrontal cortexIt works with this neighbor above to keep a sentence in mind while working out its meaning.
When it goes wrong
Word-finding trouble
Damage here can make it hard to find words, so speech is full of pauses, vague words like "thing" and roundabout descriptions.
Part of Broca's aphasia
Together with the pars opercularis, damage here is part of the classic picture of slow, effortful, simplified speech after a left-sided stroke.
For learning only, not medical advice. If you have a health concern, talk to a doctor.
Surprising facts
- Its shape varies from person to person: a small groove usually splits it into front and back parts, and some people have an extra groove at its front edge.
Where the name comes from
Latin for "the triangular part". Two branches of the side groove of the brain cut into this area, leaving a wedge that looks like a triangle.
Quick quiz
3 questions. Your answers are saved and come back in your daily review.
Which of these is a job of the pars triangularis?
Show the answer
Choosing the right word. It helps you pick the best word when several could fit, like choosing between "cup", "mug" and "glass".
Choosing the right word. It helps you pick the best word when several could fit, like choosing between "cup", "mug" and "glass".
The pars triangularis is part of which larger structure?
Show the answer
Broca's area. It belongs to Broca's area.
Broca's area. It belongs to Broca's area.
Which part fits this description? "Like a librarian: when you need a word, it searches the shelves of memory and hands you the best one."
Show the answer
Pars triangularis. It is the pars triangularis. The triangle-shaped front of Broca's area: fetching words and their meanings.
Pars triangularis. It is the pars triangularis. The triangle-shaped front of Broca's area: fetching words and their meanings.
These parts now come back in your daily review, just before you would forget them.
Practice it and its neighbors in 3DSources
- Pars triangularis, Radiopaedia
- The differing roles of the frontal cortex in fluency tests, Brain (Oxford Academic)
- Neuroanatomy, Broca Area, StatPearls, NCBI Bookshelf
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Explore the pars triangularis in 3D
Turn it around, zoom inside and see how it connects to the rest of the brain, then test yourself with quick quizzes.
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