Gross anatomy, terms of direction, and sections/planes

1
Gross anatomy, terms of direction, and
sections/planes
2
Gross anatomy(See W, pp. 5-10)
3
Two Major Divisions of Nervous System
4
An overview of major structures of the CNS

• Brain (encephalon)
• Cerebrum (telencephalon), with basal ganglia deep
  inside
• Diencephalon (between brain)
• Brain stem
• Midbrain
• Pons
• Medulla oblongata
• Cerebellum
• Spinal cord

Note skull and foramen magnum
5
Two types of cells make up the nervous system

• Neurons (nerve cells)
• Transmit information, usually as nerve impulses
• Communicate with each other, to transmit messages
  throughout the body

• Satellite cells
• Facilitate neurons, but do not transmit nerve
  impulses

6
Terms of direction(See especially W, pp.10-14,
as well asWA, pp. 13-14)
This is information already introduced in your
Anatomical Bases class, so it should be familiar
to you
7
Terms of Direction Overview

• Terms of direction denote relative position of
  one neurological structure to another
• Two systems of higher, lower, more forward, more
  backward
• System referenced to person standing in 3-D space
• Superior / inferior anterior / posterior
• System referenced to anatomical neuraxis, which
  is straight in many animals, and curved in
  humans.
• Rostral / caudal ventral / dorsal
• A system of closer to the midline, farther from
  the midline
• Medial / lateral
• A system of how close to the point of connection
  with the body
• Proximal / distal

8
First system of higher, lower, more forward,
more backward

• System referenced to human in anatomical position
  in 3D space
• Superior / inferior anterior / posterior

Posterior
Superior
Anterior
6- Superior 2- Inferior 1- Anterior 5- Posterior
When referring to structures of the head as
superior to other structures, the terms cranial
or cephalic are sometimes used as terms of
direction
Inferior

• Human anatomical position Body erect, hands at
  side, palms facing outward

9
First system of higher, lower, more forward,
more backwardExamples

• The brain is superior to the spinal cord
• The brain is cephalic to the spinal cord
• The brain is cranial to the spinal cord
• The spinal cord is inferior to the brain
• The brain stem is anterior to the cerebellum
• The cerebellum is posterior to the brain stem

10
Second system of higher, lower, more forward,
more backward
System referenced to anatomical neuraxis, which
is straight in many animals, and curved in
humans. rostral/ caudal ventral / dorsal
The human anatomical neuraxis starts as a
straight tube (called the neural tube). During
development it bends/curves almost 90 degrees at
the juncture of the brainstem and diencephalon

1- early human embryo neurological system,
straight like the salamanders
2- human embryo neurological system- 3 weeks
curved neuraxis!
3-mature human major curve remains near juncture
of brainstem and diencephalon neuraxis
mushrooms out around curve
Human anatomical neuraxis brain and spinal cord
11
Second system of higher, lower, more forward,
more backwardExamples

• The front part of the cerebrum is rostral to the
  spinal cord
• The spinal cord is caudal to the front part of
  the cerebrum
• The brain stem is ventral to the cerebellum the
  lower part of the cerebrum is ventral to the
  upper part of the cerebrum
• The cerebellum is dorsal to the brainstem the
  upper part of the cerebral is dorsal to the lower
  part of the cerebrum

12
Compare the two systems of higher, lower, more
forward, more backward

• The neuraxis bends around the junction between
  the midbrain and diencephalon, so.
• At the level of the spinal cord and brainstem
• Anteriorventral
• Posteriordorsal
• Superiorrostral
• Inferiorcaudal
• At the level of the diencephalon and the
  telencephalon
• Inferiorventral
• Superiordorsal

Posterior
Anterior
Rostral
Superior
Inferior
13
System of closer to the midline, farther from
the midline
Anterior view of brain
Medial/ lateral

Posterior
Superior
Anterior
medial
lateral
lateral
Inferior
Lateral view of brain
Medial view of brain
14
System of how close to the point of connection
with the body
Proximal nearer to the point where the structure
connects to the body vs. Distal farther from
the point where the structure connects to the body

Posterior
Superior
Anterior
Inferior
Example The shoulder is more proximal to the
body than the fingers. The fingers are more
distal from the body than the shoulder.
Shoulders more proximal, fingers more distal
15
Sections/PlanesA cut through the body, or a
part of it, is called a section the resulting
cut surface is called a plane
16
Sections/Planes

• First system based on slices through 3-D space
• Horizontal section/plane (A)
• Coronal section/plane (B)
• Sagittal section/plane (C)

Posterior
Superior
Anterior
A
C
B
Inferior
17
Sections/Planes First System (Continued)
C. Midsagittal (also called medial) C.
Parasagittal
B. Coronal
A. Horizontal
18
Sections/Planes Second system

• Second system based on slices at right angles to
  longitudinal axis of the structure
• Transverse section/plane
• Remember that the longitudinal neuraxis is curved

19
Compare the two systems of sections/planes

• The neuraxis bends around the junction between
  the midbrain and diencephalon, so.
• At the level of the spinal cord and lower
  brainstem
• Horizontaltransverse
• Near the bend (upper brainstem and diencephalon)
• Transverse has no analog in the 3-D system of
  sections/planes
• Rostral to the diencephalon
• Coronal transverse and is also called a frontal
  section/plane