14 Spinal Cord and Spinal Nerves

Question 1

What is the epidural space?

Answer 1

The epidural space is external to the dura mater and contains areolar CT, adipose CT, and blood vessels.
In the brain, the epidural space is a potential space except where it forms the dural venous sinuses.

Question 2

What type of cell body is found in the anterior horn?

Answer 2

cell bodies of somatic motor neurons

Question 3

What type of cell body is found in the posterior horn?

Answer 3

cell bodies of interneurons and axons of sensory neurons

Question 4

What are the four major plexuses?

Answer 4

cervical
brachial
lumbar
sacral

Question 5

Describe the cervical plexus

Answer 5

-primarily formed by the anterior rami of spinal nerves C1-C4
-deep on right side of neck, innervates anterior neck muscles, skin of neck, portions of head and shoulders, phrenic nerve (diaphragm) formed from C4 plus C4&C5

Question 6

Describe the brachial plexus

Answer 6

-formed by the anterior rami of C5-T1
-innervates upper limb and pectoral girdle
-contains five major terminal branches: axillary nerve, median nerve, musculocutaneous nerve, radial nerve, ulnar nerve

Question 7

Describe the lumbar plexus

Answer 7

-formed from the anterior rami of L1-L4
-innervates thigh, abdominal wall, external genitalia
-femoral nerve supplies anterior thigh muscle and sartorius

Question 8

Describe the sacral plexus

Answer 8

-formed from the anterior rami of L4-S4
-innervates gluteal region, pelvis, perineum, posterior thigh, almost all leg and foot
-nerves include: sciatic (largest/longest nerve in the body), tibial, common fibular, deep fibular, superficial fibular

Question 9

What is the sensory function of the posterior funiculus-medial lemniscal pathway?

Answer 9

-to sense the environment
-tactile receptors of skin or conscious proprioceptors w/in joints
-signal posterior funiculus to
-tertiary neuron in thalamus to
-primary somatosensory cortex of cerebrum

Question 10

What is the sensory function of the anterolateral pathway (spinothalamic tract)?

Answer 10

-sense things that require a reaction
-somatosensory receptors of skin and mucus membranes, crude touch/pressure/temp
-signal via anterior or lateral funiculus to
-tertiary neuron in thalamus to
-primary somatosensory cortex

Question 11

What is the sensory function of the spinocerebellar pathway?

Answer 11

-subconscious proprioceptive information regarding posture
-signal vial spinocerebellar tract w/in lateral funiculus to
-the cerebellum (fine motor control)