Basic Anatomy

1. Basic Anatomy • Chris Rorden • Coordinates • Cortex • Brodmann Areas • Common Names • Talairach Coordinates • Best web site: • www.anatomy.usyd.edu.au/glossary/ • www.mricro.com

2. Relative Coordinates • On the globe we talk about North, South, East and West. • Lets explore the coordinates for the brain.

3. Multiple Choice • Which arrow points dorsally? • Red • Green • Blue • Red and Green • None of above

4. Multiple Choice • Which arrow points dorsally? • Red • Green • Blue • Red and Green • None of above

5. Orientation • Human anatomy described as if person is standing • If person is lying down, we would still say the head is superior to feet.

6. Orientation - animals • Cranialhead • Rostralbeak • Dorsalback • Caudaltail • Ventralbelly

7. Coordinates – Human • Human dorsal/ventral and rostral/caudal differ for brain and spine. • Head/Foot, Superior/Inferior, Anterior/Posterior not ambiguous. Dorsal Ventral Dorsal Ventral

8. Anatomy – Relative Directions lateral < medial > lateral Posterior <> Anterior Ventral/Dorsal aka Inferior/Superior aka Foot/Head Ventral <> Dorsal Anterior/Posterior aka Rostral/Caudal Posterior <> Anterior

9. coronal sagittal axial Coordinates - Anatomy • 3 Common Views of Brain: • Coronal (head on) • Sagittal (profile) • Axial (bird’s eye), aka Transverse. The book calls this ‘Horizontal’ but it is not horizontal when we are lying in a scanner.

10. Coronal • Corona: ‘crown’ a coronal plane is parallel to crown that passes from ear to ear • Coronal cut creates anterior, posterior portions

11. Sagittal • Sagittal – ‘arrow like’ • Sagittal cut divides object into left and right • sagittal suture looks like an arrow. top view

12. Transverse • Transverse: perpendicular to the long axis • These cuts are also referred to as Axial. Example: cucumber slices are transverse to long axis.

13. Oblique Slices • Slices that are not cut parallel to an orthogonal plane are called ‘oblique’. • The oblique blue slice is neither Coronal nor Axial. Cor Oblique Ax

14. Anatomy • Brain Planes Axis of left/right plane easy to define What is the axis for axial plane? ? ? ?

15. Bicommissural plane • Axis for axial plane is defined by anterior commissure (AC) and posterior commissure (PC). • Both are small regions that are clear to see on most scans. PC AC

16. Distance from midline • Medial – near sagittal midlineOptic chiasm C medial of eyes • Lateral – far from sag. MidlineEyes are lateral of optic chiasm • Ipsilateral – same sideDamage to A will cause blindness in ipsilateral eye • Contralateral –different sideDamage to D will lead to a contralateral field cut. • Note: after brain injury (lesions) we talk about contralesional and ipsilesionalDamage to visual cortex G leads to problems with contralesional vision.

17. Relative positions • Distance From Body • Proximal, Central: near center of body • Think ‘proximity’ • Shoulders are proximal parts of arms • Distal,peripheral: away from body • Think distant • Fingers are distal parts of the arms • Distance from Surface • Superficial, external: near surface • The bump bruised superficial tissue. • Profound, deep: far from surface • The car crash injured deep organs.

18. Neuron: Cell which is responsible for receiving, transmitting and synthesizing information • cell body: contains organelles for metabolism and a nucleus • Glial Cells: Support cells for Neurons

19. The cortex • Cortex – ‘Bark’ shell of brain ~80% of human brain ~20% of squirrel brain

20. The big folds • The folds of your brain are like a fingerprint – there are a few general patterns, with individual variability. • Two main folds • Central SulcusFissure of RolandoRolandic sulcus • Lateral sulcusSylvian fissure

21. Describing cortex location • Brodmann Areas (BAs, 1909) • Appearance of cortex under microscope • Not necessarily function • Arbitrary numbers are hard to remember

22. Brodmann Areas • Function does not necessarily follow appearance. • Some key areas: 44: Broca’s Area 22: Wernicke’s Area 17: V1 Primary Visual

23. Brodmann Areas (medial slice) • Note that gray matter is located in the longitudinal fissure (between the two hemispheres)

24. Squirrels vs humans • squirrel brain • Surface of human brain is grooved. • Surface of brain from many animals is flat. • If we completely flattened a squirrel brain, it would be the size of a stamp.

25. Cortical folding • Cortical folding increases surface area. • Ridges are called Gyri (singular = Gyrus) • Greek gyros = circle, hence a coil of brain cortex • Valleys are called Sulci (singular = Sulcus). • Latin = a groove. Gyri Sulci

26. Anatomy • Surface of human cortex and cerebellum is very folded • Flattened, each hemisphere 1100cm2 • Cerebellum is also 1100cm2 • Crumpled shape hides size of cortex • Compare Folded/Unfolded (from Marty Sereno) • Human • Chimpanzee • Monkey

27. Cortical Names • Much of cortex referred to by combination of coordinate+lobe+gyrus • E.G. Superior Temporal Gyrus (STG) • Middle Temporal Gyrus(MTG) • Lateral Occipital Gyrus (LOG)

28. Cortical names • Tip of an object called a ‘pole’ • Frontal Pole • Temporal Pole

29. Sulci names • Many of sulci referred to by combination of coordinate+lobe+sulcus • Superior temporal sulcus (STS) • Inferior frontal sulcus (IFS) • Precentral and postcentral sulciare just anterior and posterior to the central sulcus.

30. Brain function • Anatomy is interested with the structure of an organism. • Physiology is interested in the function of the structure. • We are still learning about brain function • Modern maps of brain function are primitive…

31. Brain function • Much of the primate cortex devoted to vision. • In some monkeys, up to 50% of neocortex is devoted to vision.

32. Brain function • Two striking features of human brain • Lots of cortex ‘left over’ (yellow)not devoted to specific task – we are flexible • Not much of the cortex is solely devoted to language.

33. A 1 B 2 4 3 C D