65 Questions
What is the area of skin innervated by a single spinal nerve called?
Dermatome
Where is a collection of cell bodies in the CNS located?
Nucleus
What is the primary function of the anterior spinal artery in the spinal cord?
To supply gray matter
Which artery communicates with the anterior spinal artery at specific levels only?
Anterior segmental medullary artery
What is the term for a collection of cell bodies in the PNS?
Ganglion
In the cross-sectional view of the spinal cord, what are the two distinct areas visible?
Gray matter and white matter
During a lumbar puncture, where is cerebrospinal fluid withdrawn from?
Subarachnoid space
Which of the following best describes the blood supply to the spinal cord?
Branches of the vertebral arteries
Flexion of the vertebral column during anesthesia administration widens gaps between the vertebrae. Which region is most preferred for this action?
Lumbar region
Nerve cell bodies in the spinal cord are primarily found in which region?
Gray matter
Which region of the spinal cord is the origin of the most important medullary artery (Adamkiewicz)?
T8-L2
In anterior spinal artery syndrome, what structures are primarily damaged?
White matter of the spinal cord
What does a segmental loss in a dermatome or myotome indicate?
Injury to a specific spinal nerve
Where are the nerve cell bodies for sensory neurons located in the spinal cord?
Dorsal root ganglion
What is the key point about the venous drainage of the spinal cord?
It communicates both with venous sinuses of the brain and a venous plexus associated with the pelvis
What happens in a 'level loss' of sensation or muscle strength?
Loss starts at a specific dermatome and progresses segmentally
What radiographic image appearance is characteristic of a fracture of pars interarticularis?
A Scottie dog with a collar
Which spinal condition can result from repeated stress to the spine?
Spondylolysis
What is the defining feature of spondylolisthesis on radiographic imaging?
Decapitated dog representation
What ligament is important for preventing hyperextension of the vertebral column?
Anterior longitudinal ligament
Which structure limits flexion of the vertebral column?
Posterior longitudinal ligament
From where is cerebrospinal fluid withdrawn during a lumbar puncture?
Between the L3 and L4 or L4 and L5 vertebrae
What is the main difference between lumbar puncture and epidural anesthesia?
The anatomical layers penetrated
In spondylolisthesis, what is the specific abnormality that occurs?
Anterior displacement of a vertebra over the one beneath it
Which spinal cord segments are commonly affected in spondylolysis?
Lumbar
During a lumbar puncture, where does the needle typically enter the spinal canal?
Subarachnoid space
What is the main function of dorsal roots in the spinal cord?
Carry sensory information towards the spinal cord
Which term best describes the condition where the spinal cord is not in its normal position within the vertebral canal?
Tethered spinal cord
What is the primary difference in the pattern of symptoms between a L5 disc herniation and a disc impinging on the S1 nerve root?
Weakness in L5 disc herniation, numbness in S1 nerve root impingement
What is the main feature that distinguishes spondylolysis from spondylolisthesis? Spondylolysis is characterized by:
Presence of a stress fracture or defect in the pars interarticularis
In which region of the vertebral column does flexion and extension predominate?
Lumbar region
What is the primary purpose of a lumbar puncture procedure?
To withdraw cerebrospinal fluid
Which term best describes a congenital defect or stress fracture of the lamina presenting with no slippage of adjacent articulating vertebrae?
Spondylolysis
In which region of the vertebral column is rotation the primary movement?
Thoracic region
Which layer of back muscles contains the true back muscles that stabilize or move the axial skeleton?
Deep layer
Which back muscle is an exception to the general rule of being innervated by ventral rami of spinal nerves?
Trapezius
In which category are back muscles classified based on their embryological derivation?
Embryological classification
Which back muscle is part of the superficial layer and is primarily responsible for moving the upper extremity?
Latissimus dorsi
What is the main function of the splenius group of muscles within the deep layer of the back muscles?
Extend and rotate the head
Which group of muscles are considered the primary ones for extending the vertebral column?
Erector spinae group
Which muscle group primarily provides stabilization of the vertebral column and proprioceptive feedback?
Transversospinal group
Which nerves innervate the skin of the back according to the text?
Posterior rami
What is the function of the erector spinae group of muscles in controlling flexion against gravity?
Control extension against gravity
Which group of muscles in the deep layer of back muscles are responsible for small postural movements and stabilizing the vertebral column?
Transversospinal group
Which ligament connects adjacent laminae and forms part of the posterior wall of the vertebral canal?
Ligamentum flavum
What limits rotation by attaching the dens of the axis to the occipital bone?
Alar ligaments
If the transverse ligament of the atlas is ruptured, what structure could dislocate posteriorly, potentially compressing or transecting the spinal cord?
Dens of the axis
Which ligaments are covered posteriorly by the tectorial membrane as a continuation of the posterior longitudinal ligament?
Cruciate ligaments
What is a possible consequence if the dens dislocates posteriorly due to a ruptured transverse ligament of the atlas?
Compression of spinal cord
Which structure supports the weight of the head and attaches superiorly to the external occipital protuberance?
Ligamentum nuchae
Which part of the intervertebral disc cushions axial loads in the vertebral column?
Nucleus pulposus
In which region of the spine is there no disc between specific vertebrae?
Sacral
Which structure connects the bony parts of the vertebral column and consists of an outer layer of fibrocartilage and a gelatinous core?
Intervertebral disc
What type of joint exists between the vertebral bodies in the vertebral column?
Symphysis joint
Where is the most common location for herniated discs to occur?
Between L4 and L5 vertebrae
Which ligament is crucial for preventing hyperextension of the vertebral column?
Anterior longitudinal ligament
Which nerve is most likely to be compressed by a herniated disc between L4 and L5 vertebrae?
L5 nerve root
Where does the C8 nerve exit the vertebral column?
Superior to the T1 vertebra
Which spinal nerves pass superior to their corresponding vertebrae?
Cervical spinal nerves
What distinguishes a L5 disc herniation from a disc impinging on the S1 nerve root?
Pattern of pain, numbness, weakness, atrophy, and reflexes
What is the defining feature of spondylolysis?
Stress fracture of the lamina
Which ligament spans the tips of the spinous processes and acts as an attachment site for muscles and tendons in the back?
Supraspinous ligament
What is the main function of dorsal roots in the spinal cord?
Contain sensory nerve cell bodies
Where are nerve cell bodies for sensory neurons located in the spinal cord?
Dorsal root ganglia
What is the term for the area of skin innervated by a single spinal nerve?
Dermatome
Study Notes
Spinal Nerve Organization
- The spinal cord is divided into four segments: cervical, thoracic, lumbar, and sacral, which correspond to regions of the vertebral column.
- In the fully developed spinal cord, two distinct areas are visible in the cross-sectional view: gray matter and white matter.
- Collection of cell bodies in the CNS is called the nucleus, and in the PNS, it is called a ganglion.
- Collection of axons in the CNS is called a tract.
Dermatomes
- A dermatome is the area of skin innervated by a single spinal nerve, specifically the cutaneous branch.
- Dermatomes are important for understanding the distribution of sensation and pain in the body.
Blood Supply of the Spinal Cord
- The spinal cord is supplied by branches of the spinal artery.
- The posterior radicular artery communicates with the posterior spinal artery, while the anterior medullary artery communicates with the anterior spinal artery.
- The anterior spinal artery doesn't have enough flow to supply the entire length of the cord, and segmental contributions from anterior segmental medullary arteries boost flow.
- Blockage of the anterior spinal artery causes the anterior spinal artery syndrome.
Anterior Spinal Artery Syndrome
- Damage to the anterior spinal artery syndrome results in loss of sensation or muscle strength in a specific location that correlates with either a dermatome or a myotome.
- This is considered a segmental loss.
Venous Drainage
- The internal vertebral venous plexus communicates with both the venous sinuses of the brain and a venous plexus associated with the pelvis.
- The subarachnoid space of the spinal cord is continuous with the subarachnoid space of the brain.
Clinical Correlation
- Clinicians need to access the vertebral canal for various reasons, including administration of anesthesia and obtaining a sample of CSF.
- The region between L2 and S2 is favorable for accessing the vertebral canal because the spinal cord is not present.
Anatomy of the Spinal Cord
- The spinal cord is divided into four segments: cervical, thoracic, lumbar, and sacral, which correspond to regions of the vertebral column.
- In the fully developed spinal cord, two distinct areas are visible in the cross-sectional view: gray matter and white matter.
Sports Injuries
- Spondylolysis is a common sports injury in young kids, caused by repeated stress to the spine.
- Spondylolisthesis is a bilateral defect resulting in an anterior displacement of the L4 or L5 vertebral body and transverse process.
Ligaments
- The anterior longitudinal ligament is a continuous band found on the anterior aspect of the vertebral bodies, preventing hyperextension of the vertebral column.
- The posterior longitudinal ligament is a continuous band found on the posterior aspect of the vertebral bodies, limiting flexion of the vertebral column.
- The ligamentum flavum is a yellow ligament that connects adjacent laminae and forms part of the posterior wall of the vertebral canal.
Spinal Cord Organization
- The spinal cord can be divided into four segments: cervical, thoracic, lumbar, and sacral, which correspond to regions of the vertebral column.
- In the fully developed spinal cord, two distinct areas are visible in the cross-sectional view: gray matter and white matter.
- Gray matter contains cell bodies and dendrites, while white matter contains myelinated axons.
Back Muscles
- The muscles of the back are classified as extrinsic or intrinsic based on their embryological derivation.
- Extrinsic back muscles migrated into the back region and are innervated by ventral rami of spinal nerves.
- Intrinsic back muscles are the "true back muscles" that are innervated by dorsal rami of spinal nerves.
Facet Joints
- The vertebrae articulate with one another at the synovial facet (zygapophyseal) joints.
- The orientation of the facet joints is different in each region of the vertebral column to facilitate different types of movement.
Herniated Disc
- A "herniated or ruptured disc" is a common source of back pain.
- In this condition, the anulus fibrosus tears, and the nucleus pulposus protrudes through the torn area, compressing spinal nerve roots and causing back pain.
How Spinal Nerves Exit the Vertebral Column
- Spinal nerves exit the vertebral column through the intervertebral foramina.
- The cervical spinal nerves exit the vertebral column superior to their same numbered vertebra.
- The T1 nerve and below exit inferior to their corresponding vertebra.
Mortiz Block 4 Week 1
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