Exercise Fifteen Anatomy and Physiology

what are the similarities between the arrangement of the meningeal layers around the spinal cord and the brain.

a)The basic organization of the three meningeal layers- dura mater, arachnoid mater, pia mater- is similar b)The subarachnoid space filled with cerebrospinal fluid is present around the brain and spinal cord

what are the differences between the arrangement of the meningeal layers around the spinal cord and the brain.

a. The brain is surrounded by an outer and inner dural layer; the spinal cord is surrounded by only one dural layer, which is a continuation of the inner layer around the brain. b. Around the spinal cord, the epidural space is a true space, which is usually filled with fat tissue, blood vessels, and nerves. Around the brain, the epidural space is lacking, or represented only as a potential space. c. The spinal dura mater and arachnoid mater extend beyond the termination of the spinal cord. As a result, the subarachnoid space ends as a blind fluid filled sac. d. The spinal pia mater has two special structures - the filum terminale and the denticulate ligaments - that secure the spinal cord in its position. Similar structures are not associated with the cranial pia mater.

Define Spinal Nerve Plexus

Complex network of ventral rami of adjacent spinal nerves where they branch and reunite to produce the peripheral nerves

Define Conus Medullaris

Cone-shaped ending of the spinal cord

Define Cauda Equina

Extention of the roots of the inferior spinal nerves as they descend within the vertebral canal, below the end of the spinal cord, until they exit at the appropriate level

Define Filum Terminale

Thin Strand of Pia Mater that extends from the tip of the Conus Medullaris to the coccyx, helps secure the spinal cords position

Define Cervical and lumbar enlargements

expanded areas of the spinal cord in those regions and mark the origin of the nerves that supply the upper and lower extremities, respectively