Cumulative week 4

What are the primary sacral landmarks used for diagnosis?

Sacral base,sacral sulci,inferior lateral angles(ILAs),posterior superior iliac spines (PSIS), and the L5 vertebra

Where are the sacral sulci located and what do they represent?

Slightly medial and superior to the PSIS; their depth reflects the anterior or posterior position of the sacral base

What does a deep sacral sulcus indicate?

The sacral base on that side is more anterior

What does a shallow sacral sulcus indicate?

The sacral base on that side is more posterior

What does a posterior and inferior ILA indicate?

The sacrum is extended on that side

What is the normal lumbosacral angle(Ferguson’s angle)?

Approximately 25–35 degrees between the horizontal plane and the sacral base

How does an increased lumbosacral angle affect the spine?

It increases anterior shear forces and lumbosacral strain

What motion occurs around the superior transverse sacral axis?

Respiratory and craniosacral motion

What happens to the sacral base during inhalation?

It moves posteriorly and superiorly

What happens to the sacral base during exhalation?

It moves anteriorly and inferiorly

What motion occurs around the middle transverse sacral axis?

Postural motion including sacral nutation and counternutation during forward and backward bending

What motion occurs around the inferior transverse sacral axis?

Gait-related innominate motion on the sacrum

What are physiologic sacral dysfunctions?

Restrictions within normal motion ranges including forward torsions, forward rotations, and bilateral sacral flexions

What are non-physiologic sacral dysfunctions?

Restrictions outside normal motion ranges including backward torsions, backward rotations, unilateral shears, and bilateral sacral extensions

Which sacral dysfunctions should be treated first?

Non-physiologic dysfunctions

What is the purpose of the prone static sacral exam?

To assess L5 position, sacral sulci symmetry, and ILA symmetry

What does a positive lumbosacral spring test indicate?

A non-physiologic dysfunction with an extended sacral base and restricted springing

What does a negative lumbosacral spring test indicate?

A physiologic dysfunction with normal springing motion

What is the relationship between deep sulcus and ILA in sacral torsions?

They are found on opposite sides

What is the relationship between deep sulcus and ILA in unilateral sacral dysfunctions?

They are found on the same side

What axis is involved in bilateral sacral dysfunctions?

The middle transverse axis

What axis is involved in sacral torsions and rotations?

An oblique axis

What is the rule of L5 in sacral diagnosis?

L5 rotates opposite the sacrum in torsions and the same direction in rotations

How does L5 sidebending relate to the oblique axis?

L5 sidebends toward the side of the oblique axis

How can sacral torsions be diagnosed if only an L5 diagnosis is given?

Determine whether L5 is neutral or non-neutral, identify axis by sidebending, use opposite rotation for the sacrum, and determine forward versus backward torsion based on lumbar mechanics

What are the three transverse sacral axes and their levels?

Superior transverse axis through S2 attachment of dura, middle transverse axis through S2 vertebral body, inferior transverse axis through S3

What motion occurs around the superior transverse sacral axis?

Primary respiratory motion and gross respiratory sacral motion

What motion occurs around the middle transverse sacral axis?

Sacral motion on the pelvis including bilateral sacral flexion and extension

What motion occurs around the inferior transverse sacral axis?

Innominate motion relative to the sacrum during gait

How is the oblique sacral axis oriented?

From the superior SI joint on one side to the inferior SI joint on the opposite side

What motions occur around the oblique sacral axes?

Sacral torsions and sacral rotations

How are sacral torsions named?

By the direction of sacral rotation relative to the oblique axis

What defines a sacral torsion biomechanically?

The sacrum rotates in the opposite direction of L5

What defines a sacral rotation biomechanically?

The sacrum and L5 rotate in the same direction

What are the L5 rules for sacral torsions?

L5 rotation is opposite sacral rotation,sidebending is toward the oblique axis, and Type I corresponds to forward torsions while Type II corresponds to backward torsions

What is sacral nutation?

Anterior movement of the sacral base relative to the ilia

What is sacral counternutation?

Posterior movement of the sacral base relative to the ilia

What characterizes physiologic sacral dysfunctions?

The sacrum is restricted in a forward direction such as bilateral sacral flexion or forward torsions and rotations

What characterizes nonphysiologic sacral dysfunctions?

The sacrum is restricted in a backward direction such as bilateral sacral extension, backward torsions, backward rotations, or unilateral shears

Which sacral dysfunctions should be treated first?

Nonphysiologic sacral dysfunctions

What is the purpose of the spring test?

To determine whether the sacrum is stuck in a forward or backward position

What does a positive spring test indicate?

The sacrum is stuck posteriorly indicating a nonphysiologic dysfunction

What does a negative spring test indicate?

Normal anterior springing consistent with a physiologic dysfunction

What is the purpose of the sphinx test?

To distinguish forward versus backward sacral dysfunctions during lumbar extension

What does a positive sphinx test indicate?

Asymmetry worsens with extension indicating a backward dysfunction

What does a negative sphinx test indicate?

Asymmetry improves with extension indicating a forward dysfunction

How is the seated flexion test interpreted?

The side whose PSIS moves first and farthest is the positive side

How does the seated flexion test relate to sacral axes?

The axis lies on the side opposite the positive seated flexion finding

What does a deep sacral sulcus represent?

The sacral base on that side is more anterior relative to the opposite side

What does a shallow sacral sulcus represent?

The sacral base on that side is more posterior relative to the opposite side

What does an anterior ILA indicate?

The sacrum is flexed on that side

What does a posterior ILA indicate?

The sacrum is extended on that side

How are sulci and ILAs interpreted clinically?

They are relative findings and must be compared bilaterally to determine asymmetry

What is the relationship between sulci and ILAs in sacral torsions?

The deep sulcus and posterior ILA are found on opposite sides

What is the relationship between sulci and ILAs in unilateral sacral dysfunctions?

The deep sulcus and posterior ILA are found on the same side

What information is required to make a full sacral diagnosis?

Direction of dysfunction(forward or backward), axis location, and relative sulcus and ILA findings

What does a Right on Right sacral torsion represent?

A forward sacral torsion rotating right on a right oblique axis

What does a Left on Right sacral torsion represent?

A backward sacral torsion rotating left on a right oblique axis

Why is sacral motion considered relative?

Because palpatory findings are based on side-to-side comparisons rather than absolute positions

What is the key principle for accurate sacral diagnosis?

Determine forward versus backward motion,identify the axis,and then apply palpatory findings logically

What is the primary pharmacologic action of adrenergic antagonists?

They block adrenergic receptors and prevent norepinephrine and epinephrine from activating target tissues

What are the two major classes of adrenergic antagonists?

Alpha-adrenergic antagonists (alpha blockers) and beta-adrenergic antagonists (beta blockers)

How do alpha blockers lower blood pressure?

By relaxing arterial and venous smooth muscle, decreasing peripheral vascular resistance and venous return

What receptors are blocked by nonselective alpha blockers?

Both α1 and α2 adrenergic receptors

What are examples of nonselective alpha blockers?

Phenoxybenzamine and phentolamine

How does phenoxybenzamine differ mechanistically from phentolamine?

Phenoxybenzamine is an irreversible alpha antagonist, while phentolamine is a reversible competitive antagonist

What is the primary clinical use of phenoxybenzamine?

Presurgical management of hypertension and sweating in pheochromocytoma

Why do nonselective alpha blockers cause marked tachycardia?

Alpha2 blockade increases norepinephrine release and vasodilation triggers reflex sympathetic activation

What is epinephrine reversal?

Alpha blockade converts epinephrin’s pressor response into a depressor response due to unopposed β2-mediated vasodilation

Why does phenylephrine not show epinephrine reversal?

It lacks β2 activity so its pressor effect is suppressed but not reversed

What are selectiveα1blockers commonly used for?

Add-on treatment of hypertension and relief of urinary symptoms due to benign prostatic hyperplasia

What drugs are quinazoline α1 blockers?

Prazosin, terazosin, and doxazosin

What is the first-dose effect associated with α1 blockers?

Severe orthostatic hypotension, syncope, dizziness, and tachycardia

Why are α1 blockers recommended to be taken at bedtime initially?

To reduce the risk of orthostatic hypotension during the first doses

Which α1 blockers are selective for α1A receptors in the prostate?

Tamsulosin, silodosin, and alfuzosin

Why are α1A-selective blockers preferred for BPH?

They improve urinary flow with less effect on systemic blood pressure

What is intraoperative floppy iris syndrome and what causes it?

Poor iris dilation during cataract surgery caused by α1 blockade of the iris dilator muscle

What is yohimbine and how does it act?

A competitive α2 antagonist that increases sympathetic outflow

Why does yohimbine increase blood pressure and heart rate?

Blockade of presynaptic α2 receptors increases norepinephrine release

What defines beta blockers pharmacologically?

They antagonize β-adrenergic receptors and inhibit sympathetic cardiac effects

What receptors are blocked by nonselective beta blockers?

Both β1 and β2 adrenergic receptors

What are the primary cardiovascular effects of beta blockers?

Decreased heart rate,decreased contractility, slowed AV conduction, and reduced cardiac output

How do beta blockers lower blood pressure chronically?

By reducing cardiac output and suppressing renin release from the kidney

Why can beta blockers cause bronchoconstriction?

β2 blockade increases airway resistance, especially in asthma and COPD

How do beta blockers affect hypoglycemia awareness?

They mask adrenergic warning signs such as tremor and tachycardia

What is the major risk of abrupt beta blocker withdrawal?

Rebound hypertension, angina, myocardial infarction, and arrhythmias

What beta blocker properties may provide additional benefits?

Partial agonism, α1 blockade, nitric oxide production, calcium channel blockade, and antioxidant effects

What are common therapeutic uses of beta blockers?

Hypertension, angina, myocardial infarction, heart failure, arrhythmias, migraine prophylaxis, and performance anxiety

Which beta blocker is commonly used in pregnancy-related hypertension?

Labetalol

Why are lipophilic beta blockers associated with CNS effects?

They cross the blood-brain barrier and can cause fatigue, depression, and insomnia

What is the unifying mechanism behind beta blocker therapeutic effects?

Inhibition of sympathetic nervous system stimulation of β-adrenergic receptors

What are the major functional components of the spinal cord?

Central gray matter containing neuronal cell bodies and synapses, and peripheral white matter containing ascending and descending tracts

At what vertebral level does the adult spinal cord typically end?

At approximately the L1 vertebral level

What sensory modalities are carried by the dorsal columns?

Fine touch, vibration, and proprioception

Where do dorsal column fibers decussate?

In the brainstem

What sensory modalities are carried by the spinothalamic tracts?

Pain, temperature, and crude touch

Where do spinothalamic fibers cross?

Within one to two spinal levels after entering the cord

What is the primary function of the corticospinal tract?

Voluntary motor control

Where do most corticospinal fibers decussate?

In the medulla before descending as the lateral corticospinal tract

What constellation of findings suggests myelopathy?

Gait disturbance, spasticity, weakness, hyperreflexia, bladder or bowel dysfunction, and a sensory level