Biology 122 Spring, 2008

Laboratory 2

The Deep Musculature of the Back and Neck, and the Vertebral Canal and its Contents

OBJECTIVES

At the end of this laboratory you should:

1. Understand the position of the transversospinalis group muscles and how they differ from the other groups of back muscles (you do not have to know the individual muscles of this group).

2. Know the arrangement, innervation and the names of the major muscles associated with the posterior aspect of the neck, including the suboccipital muscles.

3. Have a detailed understanding of the vertebral canal, its openings (foramen magnum, intervertebral foramina), access points (interlaminar spaces, sacral hiatus), and contents (spinal cord, meninges, roots and rootlets of the spinal nerves, cauda equina, subarachnoid space, epidural space, vertebral venous plexus, and CSF).

4. Understand the gross structural characteristics of the meninges and their association with the spinal cord, spinal canal and spinal nerves and be able to define, identify and know the functional significance of the following parts: (filum terminale, denticulate ligaments, subarachnoid space, subdural space, dural root sleeves)

5. Know the landmarks that establish the approximate position of the termination of the spinal cord (L2), dural sac (S2), and vertebral canal (S4).

6. Know the position of the spinal cord, cauda equina and dorsal root (spinal) ganglia within the vertebral canal.

7. Understand the anatomy of the spinal cord including its position within the vertebral canal and the definition and significance of the following parts; spinal cord segments, conus medularis, cervical enlargement and lumbar enlargement. Understand the terms afferent and efferent and the names and designations of spinal nerve functional components (GSA, GVA, GSE, GVE). Be aware why the terms afferent and efferent are not strictly synonymous with the terms motor and sensory.

8. Be able to diagram and label a cross-section through the spinal cord showing the gray and white matter and the organization of the gray mater into dorsal, ventral and lateral (intermediolateral) columns or horns. Know what is meant by “spinal cord columns” (i.e. dorsal, lateral, ventral) and understand that they are composed of ascending and descending tracts.

9. Have a detailed understanding of a typical (e.g. thoracic) spinal nerve. Be able to define the term spinal nerve; know how many nerves there are and their regional designations, their association with spinal cord segments. The position of the segments within specific parts of the spinal canal should be appreciated and the relationship of spinal cord segments to dermatomes should be known.

10. Be able to diagram a typical spinal nerve and label its parts (dorsal and ventral roots, dorsal root ganglion, spinal nerve, dorsal primary ramus, ventral primary ramus, recurrent meningeal ramus) and its connections with the sympathetic chain and its ganglion via gray and white rami communicantes.

11. Know the origin, course and distribution of the arterial supply and venous drainage of the spinal cord.

PRELAB PREPARATION

1. Read the introductory chapter in M&D dealing with the nervous system (pp. 47-58). Concentrate on those parts covering motor neurons and sensory neurons and their association with the gray and white matter and ganglia (dorsal root and sympathetic chain) in the peripheral nervous system (PNS). Also, read the chapter on the vertebral canal and its contents (pp. 516-530). Understand the difference between a spinal and epidural block.

2. Review the vertebral column on an articulated skeleton with special attention to the spinous processes, lamina and pedicles in preparation for the laminectomy that will be part of this dissection.

SOME BASIC TERMS OF NEUROBIOLOGY THAT YOU SHOULD KNOW:

1. functional components 6. afferent and efferent
2. viscera and visceral 7. ramus and rami
3. soma and somatic 8. motor unit and motor unit size
4. axon and dendrite 9. pre- and postganglionic

5. synapse