Chapter 1: Back and Autonomic Nervous System Flashcards
During week 4, sclerotome cells of the somites (mesoderm) migrate medially to surround what stuctures?
spinal cord and notochord
How many cervical, thoracic, lumbar, sacral, and coccygeal vertebrae are there?
7 cervical, 12 thoracic, 5 lumbar, and fused 5 sacral, and 3-4 coccygeal.
Zygapophyseal joints are classified as what type of joints?
synovial joints
What structure of the vertebra allows for exit of the spinal nerves?
intervertebral foramina
How is each intervertebral disk numbered?
by the vertebral body above the disk
What is each intervertebral disk composed of?
anulus fibrosus
nucleus pulposus
Anulus fibrosus? Also what is it composed of?
consists of the outer concentric rings of fibrocartilage and fibrous connective tissue
Nucleus pulposus?
an inner soft, elastic, compressible material that functions as a shock absorber for external forces placed on the vertebral column
Where is herniation of the nucleus pulposus common?
posterolateral direction
Anterior longitudinal ligament of the vertebral column?
forms a broad band of fibers that connects the anterior surfaces of the bodies of the vertebrae between the cervical and sacral regions.
prevents hyperextension of the vertebrae and is involved in “whiplash” accidents
Posterior longitudinal ligament of the spinal column?
connects the posterior surfaces of vertebral bodies and is located in the vertebral canal
limit flexion of the vertebral column
What does the vertebral (foramen) canal house?
spinal cord
The nucleus pulposus may herniate through what structure and lead to what?
herniate through the anulus fibrosus
herniated nucleus pulposus may. compress the spinal nerve roots, resulting in pain along the involved spinal nerve (sciatica)
What area of the spinal cord does herniation of the nucleus pulposus typically occur? (What levels)
lower cervical (C5/C6 or C6/C7) or lower lumbar (L4/L5 or L5/S1) parts of the vertebral column
Herniated disk will usually compress what spinal nerve roots? (herniated nucleus pulposus)
the nerve roots one number below involved disk (e.g herniation of L4 disk will compress the L5 roots)
What are the boundaries of the intervertebral foramina?
anterior: bodies of the vertebrae and intervertebral disks
posterior: zygapophyseal joint and articular processes
superior and inferior: pedicles of the vertbrae
Dura mater?
cylindrical covering of connective tissue forming a dural sac
Where do the dura mater and dural sac terminate in the spinal cord?
inferiorly at the second sacral vertebra level
Describe the arachnoid.
delicate membrane which completely lines the inner surface of the dura mater and dural sac
Where does arachnoid terminate in the spinal cord?
terminates at the second sacral vertebra
What is pia mater?
tightly attached to surface of the spinal cord and provides a delicate covering of the cord
Where does the spinal cord with the covering of the pia mater terminate?
at the L1 or L2 vertebral levels in the adult
What are the 2 specializations of the pia mater?
denticulate ligaments and filum terminale
What are the denticulate ligaments?
bilateral thickenings of pia mater that run continuously on the lateral sides of the midpoint of the cord
separate the ventral and dorsal roots of the spinal nerves and anchor to the dura mater
What is the filum terminale?
a continuation of the pia mater distal to the lower end of the spinal cord and is part of the cauda equina which is composed of ventral and dorsal roots of lumbar and sacral nerves that extend below the inferior limit of the spinal cord
The internal vertebral venous plexus is valveless and connects what structures?
veins of the pelvis, abdomen, and thorax