Help with Evaluation Methods for the Nervous System - Anatomy
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At what level does one perform a lumbar puncture?
At what level does one perform a lumbar puncture?
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In human adults the spinal cord (caudal tip) usually ends at the level of L1/L2. Thus lumbar punctures are performed between the L3 and L4 vertebrae or between L4 and L5, so there is no risk of damage to the spinal cord.
In human adults the spinal cord (caudal tip) usually ends at the level of L1/L2. Thus lumbar punctures are performed between the L3 and L4 vertebrae or between L4 and L5, so there is no risk of damage to the spinal cord.
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A 62-year old man with a history of chicken pox as a child presents with a rash around his neck for the past two days. He recalls an intense burning pain in the same area a few days before the rash appeared. This is the first time he has experienced this and admits that his family physician has been pushing him to get the shingles vaccine. After doing some reading on shingles, the patient asks you “what spinal nerve is affected?”
A 62-year old man with a history of chicken pox as a child presents with a rash around his neck for the past two days. He recalls an intense burning pain in the same area a few days before the rash appeared. This is the first time he has experienced this and admits that his family physician has been pushing him to get the shingles vaccine. After doing some reading on shingles, the patient asks you “what spinal nerve is affected?”
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The affected dermatome is supplied by the spinal root C3.
This is a matter of simple memorization of dermatomes in the body. Each dermatome is innervated by a single spinal nerve, which is responsible for sensation in the area. The neck is supplied mostly by C3, with C4 and C5 supplying parts of the posterior neck.
C2 supplies the back of the skull. C6 supplies the lateral aspect of the arm and forearm. T2 supplies the upper chest and medial aspect of the arm. T4 is a common landmark dermatome as it supplies the nipples. Another landmark is T10, which supplies the umbilical cord.
The affected dermatome is supplied by the spinal root C3.
This is a matter of simple memorization of dermatomes in the body. Each dermatome is innervated by a single spinal nerve, which is responsible for sensation in the area. The neck is supplied mostly by C3, with C4 and C5 supplying parts of the posterior neck.
C2 supplies the back of the skull. C6 supplies the lateral aspect of the arm and forearm. T2 supplies the upper chest and medial aspect of the arm. T4 is a common landmark dermatome as it supplies the nipples. Another landmark is T10, which supplies the umbilical cord.
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A 65-year old nursing home resident is referred to you from her primary care physician, who is concerned that she may have a neurological deficit. As you proceed to test her cranial nerves, you note her blink reflex is absent (she doesn’t blink when you touch her cornea with a cotton swab). In order to figure out what is wrong, you ask her to make different facial expressions including shutting her eyes tightly, which she successfully does.
Now confident that you know which cranial nerve is involved, what other deficit do you expect to see in this patient?
A 65-year old nursing home resident is referred to you from her primary care physician, who is concerned that she may have a neurological deficit. As you proceed to test her cranial nerves, you note her blink reflex is absent (she doesn’t blink when you touch her cornea with a cotton swab). In order to figure out what is wrong, you ask her to make different facial expressions including shutting her eyes tightly, which she successfully does.
Now confident that you know which cranial nerve is involved, what other deficit do you expect to see in this patient?
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You suspect that the trigeminal nerve (CN V) is compromised and would expect there to be sensory deficits in the face.
To approach this problem, we need to think about a few things:
1. If the blink reflex is absent, what cranial nerves are involved?
The afferent part of the blink reflex is supplied by the trigeminal nerve (V), while the efferent action is from the facial nerve (VII).
2. The patient is able to make different facial expressions and shut her eyes tightly. Which cranial nerve is involved in facial expressions?
The facial nerve innervates muscles of facial expressions. The patient's ability perform these actions tells us the facial nerve is intact; thus, the trigeminal nerve must be the part of the blink reflex that is deficient.
3. What other function does the trigeminal nerve have?
The trigeminal nerve provides sensation to the face and scalp, and also innervates the muscles of mastication.
Absent gag reflex can be due to deficits in the glossopharyngeal nerve (IX, afferent portion) or vagus nerve (X, efferent portion). Lack of eye movement can be due to occulomotor (III), trochlear (IV), and/or abducens (VI) cranial nerves. Inability to turn the head is a result of sternocleidomastoid deficiency, which is innervated by the accessory nerve (XI). An impaired sense of smell suggests olfactory nerve (I) deficit.
You suspect that the trigeminal nerve (CN V) is compromised and would expect there to be sensory deficits in the face.
To approach this problem, we need to think about a few things:
1. If the blink reflex is absent, what cranial nerves are involved?
The afferent part of the blink reflex is supplied by the trigeminal nerve (V), while the efferent action is from the facial nerve (VII).
2. The patient is able to make different facial expressions and shut her eyes tightly. Which cranial nerve is involved in facial expressions?
The facial nerve innervates muscles of facial expressions. The patient's ability perform these actions tells us the facial nerve is intact; thus, the trigeminal nerve must be the part of the blink reflex that is deficient.
3. What other function does the trigeminal nerve have?
The trigeminal nerve provides sensation to the face and scalp, and also innervates the muscles of mastication.
Absent gag reflex can be due to deficits in the glossopharyngeal nerve (IX, afferent portion) or vagus nerve (X, efferent portion). Lack of eye movement can be due to occulomotor (III), trochlear (IV), and/or abducens (VI) cranial nerves. Inability to turn the head is a result of sternocleidomastoid deficiency, which is innervated by the accessory nerve (XI). An impaired sense of smell suggests olfactory nerve (I) deficit.
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A patient presenting with "Saturday night" palsy would have which of the following deficits?
A patient presenting with "Saturday night" palsy would have which of the following deficits?
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"Saturday night" palsy is a nickname for radial nerve paralysis. Because the wrist extensors are innervated by the radial nerve, this type of paralysis would prevent a person from being able to perform wrist extension. While the supinator is innervated by the radial nerve, the biceps brachii is also a supinator, so although supination may be weaker with radial nerve paralysis, it would not be absent.
"Saturday night" palsy is a nickname for radial nerve paralysis. Because the wrist extensors are innervated by the radial nerve, this type of paralysis would prevent a person from being able to perform wrist extension. While the supinator is innervated by the radial nerve, the biceps brachii is also a supinator, so although supination may be weaker with radial nerve paralysis, it would not be absent.
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You suspect that your patient has a C5 nerve root irritation. Which deep tendon reflex could help you rule in this diagnosis?
You suspect that your patient has a C5 nerve root irritation. Which deep tendon reflex could help you rule in this diagnosis?
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The biceps brachii is innervated by C5 and C6 nerve roots. So, in the presence of a C5 nerve root irritation, biceps tendon reflexes may be diminished. the triceps brachii is innervated by C7 and C8 nerve roots, and the lower extremity muscles are innervated by L2 through S2 nerve roots, so testing these muscles would not tell us anything about a C5 nerve irritation.
The biceps brachii is innervated by C5 and C6 nerve roots. So, in the presence of a C5 nerve root irritation, biceps tendon reflexes may be diminished. the triceps brachii is innervated by C7 and C8 nerve roots, and the lower extremity muscles are innervated by L2 through S2 nerve roots, so testing these muscles would not tell us anything about a C5 nerve irritation.
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The Romberg test examines function of which cranial nerve?
The Romberg test examines function of which cranial nerve?
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The Romberg test involves maintaining an upright stance with feet together, which tests the vestibular portion of the vestibulocochlear nerve. The accessory nerve controls shoulder girdle and neck movement, the olfactory nerve provides the sense of smell, the hypoglossal nerve controls tongue movement, the facial nerve controls the muscles of facial expression (amon other functions) and the trigeminal nerve controls the muscles of mastication (among other functions). Thus, the Romberg test would not test any of these functions
The Romberg test involves maintaining an upright stance with feet together, which tests the vestibular portion of the vestibulocochlear nerve. The accessory nerve controls shoulder girdle and neck movement, the olfactory nerve provides the sense of smell, the hypoglossal nerve controls tongue movement, the facial nerve controls the muscles of facial expression (amon other functions) and the trigeminal nerve controls the muscles of mastication (among other functions). Thus, the Romberg test would not test any of these functions
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Testing which of the following reflexes would not help you diagnose a suspected lumbosacral nerve root pathology?
Testing which of the following reflexes would not help you diagnose a suspected lumbosacral nerve root pathology?
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The triceps brachii deep tendon reflex tests the C7 and C8 nerve roots, so testing it would not provide any information about a lumbosacral nerve root pathology. The cremasteric reflex tests the T12 and L1 nerve roots, the Achilles deep tendon reflex tests the S1 and S2 nerve roots, the anal wink reflex tests the S2, S3, and S4 nerve roots, and the patellar deep tendon reflex tests the L3 and L4 nerve roots.
The triceps brachii deep tendon reflex tests the C7 and C8 nerve roots, so testing it would not provide any information about a lumbosacral nerve root pathology. The cremasteric reflex tests the T12 and L1 nerve roots, the Achilles deep tendon reflex tests the S1 and S2 nerve roots, the anal wink reflex tests the S2, S3, and S4 nerve roots, and the patellar deep tendon reflex tests the L3 and L4 nerve roots.
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A patient comes has a drooping eyelid (ptosis). Upon elevation of the eyelid, it is observed that the eye looks down and out, the pupil is dilated, and there is loss of accommodation.
Which cranial nerve is damaged?
A patient comes has a drooping eyelid (ptosis). Upon elevation of the eyelid, it is observed that the eye looks down and out, the pupil is dilated, and there is loss of accommodation.
Which cranial nerve is damaged?
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Cranial nerve (CN) III (oculomotor nerve) is responsible for certain eye movements. It innervates the following muscles: superior rectus, inferior rectus, medial rectus, and inferior oblique. It also functions in pupillary constriction, accommodation, and eyelid opening (via levator palpebrae). CN III is a motor nerve along with parasympathetic function. If there is injury to CN III these functions will be impaired leading to the presentation of the observations in the question stem.
Cranial nerve (CN) III (oculomotor nerve) is responsible for certain eye movements. It innervates the following muscles: superior rectus, inferior rectus, medial rectus, and inferior oblique. It also functions in pupillary constriction, accommodation, and eyelid opening (via levator palpebrae). CN III is a motor nerve along with parasympathetic function. If there is injury to CN III these functions will be impaired leading to the presentation of the observations in the question stem.
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If a person cannot feel pain on the dorsal side of his/her right hand along the outer part of the hand including the little finger he/she likely has damage to the .
If a person cannot feel pain on the dorsal side of his/her right hand along the outer part of the hand including the little finger he/she likely has damage to the .
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The ulnar nerves serves the dorsal and palmar surfaces of the hand from the midline of the ring finger over to the little finger (dorsal and palmar).
The ulnar nerves serves the dorsal and palmar surfaces of the hand from the midline of the ring finger over to the little finger (dorsal and palmar).
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Which of the following is the nerve root for the sciatic nerve?
Which of the following is the nerve root for the sciatic nerve?
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The sciatic nerve is a large nerve that runs through the buttocks and down the lower limb. The sciatic nerve innervates skin of the leg, and muscles in the posterior thigh, leg, and foot. The sciatic nerve is derived from spinal nerves L4-S3. The L4-S3 nerve root also supplies the tibial nerve.
L4-S1 is the nerve root for the superior gluteal nerve. Common fibular nerve is supplied by spinal nerves L4-S2. The obturator and femoral nerves are derived from L2-L4.
The sciatic nerve is a large nerve that runs through the buttocks and down the lower limb. The sciatic nerve innervates skin of the leg, and muscles in the posterior thigh, leg, and foot. The sciatic nerve is derived from spinal nerves L4-S3. The L4-S3 nerve root also supplies the tibial nerve.
L4-S1 is the nerve root for the superior gluteal nerve. Common fibular nerve is supplied by spinal nerves L4-S2. The obturator and femoral nerves are derived from L2-L4.
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Which of the following is the nerve root for the femoral nerve?
Which of the following is the nerve root for the femoral nerve?
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The femoral nerve is a nerve in the thigh that innervates the skin on the upper thigh and inner leg and shin. It also innervates the muscles that extend the knee (quadriceps). It is the largest branch of the lumbar plexus and derives from spinal nerves L2-L4. The obturator nerve is also supplied by spinal nerves L2-L4.
The sciatic nerve is derived from spinal nerves L4-S3. The L4-S3 nerve root also supplies the tibial nerve. L4-S1 is the nerve root for the superior gluteal nerve. Common fibular nerve is supplied by spinal nerves L4-S2.
The femoral nerve is a nerve in the thigh that innervates the skin on the upper thigh and inner leg and shin. It also innervates the muscles that extend the knee (quadriceps). It is the largest branch of the lumbar plexus and derives from spinal nerves L2-L4. The obturator nerve is also supplied by spinal nerves L2-L4.
The sciatic nerve is derived from spinal nerves L4-S3. The L4-S3 nerve root also supplies the tibial nerve. L4-S1 is the nerve root for the superior gluteal nerve. Common fibular nerve is supplied by spinal nerves L4-S2.
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Which nerve supplies the deltoid muscle?
Which nerve supplies the deltoid muscle?
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The axillary nerve supplies three muscles, the deltoid, teres minor, and the long head of the triceps. The deltoid is a muscle of the shoulder and teres minor is a muscle involved in the rotator cuff. The axillary nerve also supplies sensory information from the shoulder joint, and to the skin below the deltoid. The axillary nerve may be injured during an anterior dislocation of the shoulder joint or a fracture of the surgical neck of the humerus.
The axillary nerve supplies three muscles, the deltoid, teres minor, and the long head of the triceps. The deltoid is a muscle of the shoulder and teres minor is a muscle involved in the rotator cuff. The axillary nerve also supplies sensory information from the shoulder joint, and to the skin below the deltoid. The axillary nerve may be injured during an anterior dislocation of the shoulder joint or a fracture of the surgical neck of the humerus.
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Which nerve supplies the triceps brachii muscle?
Which nerve supplies the triceps brachii muscle?
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The radial nerve supplies the posterior portion of the upper limb. The radial nerve innervates the medial and lateral head of the triceps brachii muscle (the long head is supplied by the axillary nerve) and anconeus. The radial nerve originates from the brachial plexus and consists of fibers of nerves C5, C6, C7, C8, and T1.
The radial nerve supplies the posterior portion of the upper limb. The radial nerve innervates the medial and lateral head of the triceps brachii muscle (the long head is supplied by the axillary nerve) and anconeus. The radial nerve originates from the brachial plexus and consists of fibers of nerves C5, C6, C7, C8, and T1.
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The ankle jerk (Achilles) reflex tests which nerve root?
The ankle jerk (Achilles) reflex tests which nerve root?
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The ankle jerk (Achilles) reflex tests the nerve root S1, S2. Biceps reflex tests roots C5, C6. Brachioradialis tests C5, C6, C7. Triceps reflex tests C6, C7, C8 nerve roots. Patellar (knee jerk) reflex tests the L2, L3, L4 nerve roots. The hamstring reflex tests nerve roots L5 and S1.
The ankle jerk (Achilles) reflex tests the nerve root S1, S2. Biceps reflex tests roots C5, C6. Brachioradialis tests C5, C6, C7. Triceps reflex tests C6, C7, C8 nerve roots. Patellar (knee jerk) reflex tests the L2, L3, L4 nerve roots. The hamstring reflex tests nerve roots L5 and S1.
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The patellar (knee jerk) reflex tests which nerve root?
The patellar (knee jerk) reflex tests which nerve root?
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The ankle jerk (Achilles) reflex tests the nerve root S1, S2. Biceps reflex tests roots C5, C6. Brachioradialis reflex tests C5, C6, C7. Triceps reflex tests C6, C7, C8 nerve roots. Patellar (knee jerk) reflex tests the L2, L3, L4 nerve roots.
The ankle jerk (Achilles) reflex tests the nerve root S1, S2. Biceps reflex tests roots C5, C6. Brachioradialis reflex tests C5, C6, C7. Triceps reflex tests C6, C7, C8 nerve roots. Patellar (knee jerk) reflex tests the L2, L3, L4 nerve roots.
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Which cranial nerves (CN) are responsible for the pupillary light reflex?
Which cranial nerves (CN) are responsible for the pupillary light reflex?
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The pupillary light reflex and ocular accommodation reflex involves cranial nerve II for the sensory aspect and cranial nerve III for the motor application. The jaw jerk reflex uses cranial nerve V for both sensory and motor. The corneal (blink reflex) utilizes cranial nerve V for sensory and VII for motor. The gag reflex utilizes cranial nerve IX for sensory and X for motor.
The pupillary light reflex and ocular accommodation reflex involves cranial nerve II for the sensory aspect and cranial nerve III for the motor application. The jaw jerk reflex uses cranial nerve V for both sensory and motor. The corneal (blink reflex) utilizes cranial nerve V for sensory and VII for motor. The gag reflex utilizes cranial nerve IX for sensory and X for motor.
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Which cranial nerves are responsible for the gag reflex?
Which cranial nerves are responsible for the gag reflex?
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The gag reflex utilizes cranial nerve IX for sensory and X for motor. The pupillary light reflex and ocular accommodation involves cranial nerve II for the sensory aspect and cranial nerve three for the motor application. The jaw jerk reflex uses cranial nerve V for both sensory and motor. The corneal (blink reflex) utilizes cranial nerve V for sensory and VII for motor.
The gag reflex utilizes cranial nerve IX for sensory and X for motor. The pupillary light reflex and ocular accommodation involves cranial nerve II for the sensory aspect and cranial nerve three for the motor application. The jaw jerk reflex uses cranial nerve V for both sensory and motor. The corneal (blink reflex) utilizes cranial nerve V for sensory and VII for motor.
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A sudden, uncontrolled flinging movement of a limb can best be described by which of the following?
A sudden, uncontrolled flinging movement of a limb can best be described by which of the following?
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Hemiballism describes a sudden, uncontrolled flinging movement; this occurs if there is damage/destruction of subthalamic nuclei. Chorea is an abnormal, involuntary movement that can be seen in Huntington's disease; it occurs after destruction of the caudate nucleus. Dystonias are abnormal movements and are most often referred to as resting tremors of Parkinson's disease. Parkinsons disease results from a loss of dopamine from the substantia nigra.
Hemiballism describes a sudden, uncontrolled flinging movement; this occurs if there is damage/destruction of subthalamic nuclei. Chorea is an abnormal, involuntary movement that can be seen in Huntington's disease; it occurs after destruction of the caudate nucleus. Dystonias are abnormal movements and are most often referred to as resting tremors of Parkinson's disease. Parkinsons disease results from a loss of dopamine from the substantia nigra.
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The dermatome for the inguinal region is which of the following?
The dermatome for the inguinal region is which of the following?
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A dermatome is an area of skin supplied by a single spinal nerve. Along the thorax and abdomen the dermatomes are stacked like coins/discs, each layer supplied by a different spinal nerve. Along the arms and legs the pattern is different. Symptoms that follow a dermatome may indicate a pathology that involves the nerve root. There are a number of important dermatomes one being the inguinal region innervated by the L1 nerve root.
A dermatome is an area of skin supplied by a single spinal nerve. Along the thorax and abdomen the dermatomes are stacked like coins/discs, each layer supplied by a different spinal nerve. Along the arms and legs the pattern is different. Symptoms that follow a dermatome may indicate a pathology that involves the nerve root. There are a number of important dermatomes one being the inguinal region innervated by the L1 nerve root.
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Which of the following innervates the dermatome at the umbilicus?
Which of the following innervates the dermatome at the umbilicus?
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A dermatome is an area of skin supplied by a single spinal nerve. Along the thorax and abdomen the dermatomes are stacked like coins/discs, each layer supplied by a different spinal nerve. Along the arms and legs the pattern is different. Symptoms that follow a dermatome may indicate a pathology that involves the nerve root. There are a number of important dermatomes one being the layer of the umbilicus innervated by the T10 nerve root.
A dermatome is an area of skin supplied by a single spinal nerve. Along the thorax and abdomen the dermatomes are stacked like coins/discs, each layer supplied by a different spinal nerve. Along the arms and legs the pattern is different. Symptoms that follow a dermatome may indicate a pathology that involves the nerve root. There are a number of important dermatomes one being the layer of the umbilicus innervated by the T10 nerve root.
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