Exam 4 Review:  Chapter 12:  Gross Anatomy of the Spinal Cord

vertebral column - The series of vertebrae forming the axis of the skeleton and protecting the spinal cord; divided into five groups by location: cervical, thoracic, lumbar, sacral and coccygeal groups.  aka. spinal column, spine.

 

vertebral canal = spinal canal - The passage formed by the vertebral foramen in the articulated successive vertebrae through which the spinal cord and its membranes pass.

 

denticulate ligament - A band of fibrous pia mater extending along the spinal cord on each side between the dorsal and ventral roots of the spinal nerves; it pierces the arachnoid and is attached to the dura mater at 21 points; this* stabilizes the spinal cord within the vertebral canal and decreases the likelihood of cord damage when physical trauma occurs.    (*The filum terminale has a similar function.).

 

spinal cord - The inferior portion of the Central Nervous System; the thick, whitish, cylindrical (slightly flattened dorso-ventrally) mass of nervous tissue that extends from the medulla oblongata down through the upper two-thirds of the spinal canal in the vertebral column to the upper lumbar region and from which the spinal nerves branch off to various parts of the body; the nervous tissue consists of nerve fibers and nerve cells, the latter being confined to the gray matter of the central portions of the cord, while the peripheral white matter is composed of nerve fibers only; the center of the cord is traversed by a slender canal connecting with the ventricles of the brain which contains cerebrospinal fluid.


cervical enlargement - An expansion in the mass and diameter of the spinal cord in the region of C3-4 - T1-2 where motor neurons located in prominent ventral horns supply the upper limb muscles and where there are large number of axons entering and leaving the spinal cord to innervate the upper extremity.

 

lumbar enlargement - An expansion in the mass and diameter of the spinal cord in the region of T10-12 - L1-2 where motor neurons located in prominent ventral horns supply the lower limb muscles and where there are large number of axons entering and leaving the spinal cord to innervate the lower extremity.

 

anterior median fissure = ventral median fissure - The groove along the anterior midline of the spinal cord that incompletely divides it into symmetrical halves; it increases the surface area of the spinal cord for exchange of nutrients and oxygen with the blood stream and the cerebrospinal fluid.

 

posterior median sulcus = dorsal median sulcus - The groove along the posterior midline of the spinal cord that incompletely divides it into symmetrical halves; it increases the surface area of the spinal cord for exchange of nutrients and oxygen with the blood stream and the cerebrospinal fluid.

 

conus medullaris - The short tapered end of the spinal cord which is found just inferior to the lumbar enlargement of the cord in the region of L1-2.

 

filum terminale - The slender threadlike prolongation of the spinal cord below the origin of the lumbar nerves and the last portion of the pia mater; this* stabilizes the spinal cord within the vertebral canal and decreases the likelihood of cord damage when physical trauma occurs.    (*The denticulate ligament has a similar function.)

 

cauda equina - The spinal nerve roots with a common covering of meninges which extend out from the end of the spinal cord and go down the spinal canal through the lower part of the spine canal in the region of the lower lumbar vertebrae, sacrum and coccyx; it looks somewhat like a "horse's tail."

List

11. Sequentially, the structures encountered when exiting the body posteriorly from the central canal of the spinal cord.

 

          (central canal) → (1) gray commissure → (2) white matter (fasiculus gracilis) → (3) pia mater → (subarachnoid space with CSF) → (4) arachnoid → (5) dura mater → (6) epidural space with adipose tissue → (7) spinous process of vertebral arch → (supraspinous ligament of superficial fascia) → (hypodermis) → (8) dermis → (9) epidermis

 

12. the protective coverings of the spinal cord from deep to superficial.

 

          (spinal cord) → (1) pia mater → (subarachnoid space with CSF) → (2) arachnoid → (3) dura mater

 

          [Note: in the broadest sense, protective coverings extend beyond the meninges:  → (4) epidural space with adipose tissue → (5) vertebral arch and body → (6) dermis and epidermis.]

 

Sketch and label

3. All the protective layers and barriers covering the spinal cord.

 

(1) pia mater → (2) arachnoid → (3) dura mater

 

4. The main features of the external anatomy of the spinal cord in a frontal view (not a cross-section).

 

 

5. The major features of the internal anatomy visible in a transverse section of the spinal cord.