Anatomy Flashcards
Vignette: A 45-year-old man presents with a recent injury to his abdomen. You suspect nerve damage affecting his abdominal wall muscles. Which nerve originating from T12 innervates muscles of the abdominal wall?
A) Ilioinguinal
B) Subcostal
C) Genitofemoral
D) Femoral
Correct Answer: B) Subcostal
Explanation:
A) Ilioinguinal: Innervates internal oblique and transversus abdominis, but originates from L1.
B) Subcostal: Correct. Innervates muscles of the abdominal wall and originates from T12.
C) Genitofemoral: Innervates genital branch: male cremasteric muscle, but originates from L1 and L2.
D) Femoral: Innervates iliacus, pectineus, and muscles in the anterior compartment of the thigh, originates from L2-L4.
Vignette: A patient complains of numbness on her medial thigh. You suspect nerve damage. Which nerve could be compromised?
A) Subcostal
B) Ilioinguinal
C) Lateral cutaneous nerve of the thigh
D) Obturator
Correct Answer: D) Obturator
Explanation:
A) Subcostal: Provides sensory function to the skin over the hip.
B) Ilioinguinal: Sensory function in upper medial thigh, but also skin over either the root of the penis and anterior scrotum or the mons pubis and labium majus.
C) Lateral cutaneous nerve of the thigh: Sensory function to skin on anterior and lateral thigh to the knee.
D) Obturator: Correct. Provides sensory function to skin on the medial aspect of the thigh.
Memory Tool: “Obturator is the ‘Medial Mate’ for your thigh.”
Reference Citation: Modified from Drake RL, Vogl AW, Mitchell AWM: Gray’s Anatomy for Students, Philadelphia, 2005, Churchill Livingstone. (Table 75.4)
Rationale: A grasp of sensory functions of the lumbosacral plexus branches is essential for identifying possible sites of nerve damage.
Vignette: A 30-year-old man has difficulty in movements that would normally engage the pectineus muscle. Which nerves could be responsible for this?
A) Obturator
B) Femoral
C) Ilioinguinal
D) Both A and B
Explanation:
A) Obturator: Innervates pectineus and originates from L2-L4.
B) Femoral: Also innervates pectineus and originates from L2-L4.
C) Ilioinguinal: Innervates internal oblique and transversus abdominis and originates from L1.
D) Both A and B: Correct. Both the obturator and femoral nerves innervate the pectineus muscle.
Memory Tool: “OF Pectineus: Obturator and Femoral make it move.”
Reference Citation: Modified from Drake RL, Vogl AW, Mitchell AWM: Gray’s Anatomy for Students, Philadelphia, 2005, Churchill Livingstone. (Table 75.4)
Rationale: Knowing which nerves innervate specific muscles aids in the precise diagnosis of neuromuscular issues.
Vignette: A 29-year-old female patient presents with a lesion affecting spinal nerves in the lumbar region. She shows no sensory symptoms in the anterior and lateral thigh down to the knee. Which nerve is likely unaffected?
A) Femoral
B) Ilioinguinal
C) Lateral cutaneous nerve of the thigh
D) Obturator
Correct Answer: C) Lateral cutaneous nerve of the thigh
Explanation:
A) Femoral: Provides sensory function to the skin on the anterior thigh and medial surface of the leg, originating from L2-L4.
B) Ilioinguinal: Provides sensory function to the skin in upper medial thigh, originating from L1.
C) Lateral cutaneous nerve of the thigh: Correct. Provides sensory function to the skin on the anterior and lateral thigh down to the knee, originating from L2 and L3.
D) Obturator: Provides sensory function to skin on the medial aspect of the thigh, originating from L2-L4.
Memory Tool: “If the lateral thigh feels fine, look to L2 and L3, darling!”
Reference Citation: Modified from Drake RL, Vogl AW, Mitchell AWM: Gray’s Anatomy for Students, Philadelphia, 2005, Churchill Livingstone. (Table 75.4)
Rationale: Understanding the spinal segments responsible for each branch of the lumbosacral plexus is crucial for proper diagnosis when spinal injuries occur.
Vignette: A patient shows weakness in the muscles of the internal oblique and transversus abdominis. Which nerve is most likely affected?
A) Ilioinguinal
B) Obturator
C) Femoral
D) Subcostal
Correct Answer: A) Ilioinguinal
Explanation:
A) Ilioinguinal: Correct. Innervates internal oblique and transversus abdominis, originating from L1.
B) Obturator: Innervates obturator externus, pectineus, and muscles in the medial compartment of the thigh, originating from L2-L4.
C) Femoral: Innervates iliacus, pectineus, and muscles in the anterior compartment of the thigh, originating from L2-L4.
D) Subcostal: Innervates muscles of the abdominal wall, originating from T12.
Memory Tool: “For Internal and Transversus, ILIO-inguinal is a must!”
Reference Citation: Modified from Drake RL, Vogl AW, Mitchell AWM: Gray’s Anatomy for Students, Philadelphia, 2005, Churchill Livingstone. (Table 75.4)
Rationale: Identifying nerves responsible for specific muscle innervation is important for diagnosing and treating muscle weakness.
Vignette: A 60-year-old male patient complains of numbness over his hip area. Which nerve is likely to be involved?
A) Subcostal
B) Genitofemoral
C) Iliohypogastric
D) Femoral
Correct Answer: A) Subcostal
Explanation:
A) Subcostal: Correct. Provides sensory function to the skin over the hip, originating from T12.
B) Genitofemoral: Provides sensory function to the skin of the anterior scrotum or skin of the mons pubis and labium majus, originating from L1 and L2.
C) Iliohypogastric: Provides sensory function to the posterolateral gluteal skin and skin in the pubic region, originating from L1.
D) Femoral: Provides sensory function to the skin on the anterior thigh and medial surface of the leg, originating from L2-L4.
Memory Tool: “Subcostal for the hip; think ‘hip sub’!”
Reference Citation: Modified from Drake RL, Vogl AW, Mitchell AWM: Gray’s Anatomy for Students, Philadelphia, 2005, Churchill Livingstone. (Table 75.4)
Rationale: Sensory function in different areas can indicate the health of specific nerves, which is vital for diagnosis.
Vignette: A 40-year-old female patient reports numbness in the skin over her mons pubis and labium majus. Which nerve should you consider as possibly compromised?
A) Iliohypogastric
B) Ilioinguinal
C) Genitofemoral
D) Subcostal
Correct Answer: C) Genitofemoral
Explanation:
A) Iliohypogastric: Provides sensory function to the posterolateral gluteal skin and skin in the pubic region, originating from L1.
B) Ilioinguinal: Provides sensory function to skin in upper medial thigh and the skin over either the root of the penis and anterior scrotum or the mons pubis and labium majus, but it’s not exclusive to these regions.
C) Genitofemoral: Correct. Provides sensory function to the skin of the mons pubis and labium majus, originating from L1 and L2.
D) Subcostal: Provides sensory function to the skin over the hip, originating from T12.
Memory Tool: “Genitofemoral: Genital regions get priority, darling!”
Reference Citation: Modified from Drake RL, Vogl AW, Mitchell AWM: Gray’s Anatomy for Students, Philadelphia, 2005, Churchill Livingstone. (Table 75.4)
Rationale: Properly diagnosing which nerves are likely compromised based on sensory symptoms is key in effective treatment planning.
Vignette: During a routine check-up, you observe that a patient does not have any loss of motor function but reports sensory loss on the anterior and lateral thigh to the knee. Which nerve is likely affected?
A) Iliohypogastric
B) Femoral
C) Obturator
D) Lateral cutaneous nerve of the thigh
Correct Answer: D) Lateral cutaneous nerve of the thigh
Explanation:
A) Iliohypogastric: Affects the internal oblique and transversus abdominis, originating from L1.
B) Femoral: Affects the iliacus, pectineus, and muscles in the anterior compartment of the thigh, originating from L2-L4.
C) Obturator: Affects the obturator externus, pectineus, and muscles in the medial compartment of the thigh, originating from L2-L4.
D) Lateral cutaneous nerve of the thigh: Correct. This nerve has no motor function but provides sensory function to the skin on the anterior and lateral thigh down to the knee, originating from L2 and L3.
Memory Tool: “Lateral cutaneous nerve keeps your thigh feeling alive, but doesn’t make it move!”
Reference Citation: Modified from Drake RL, Vogl AW, Mitchell AWM: Gray’s Anatomy for Students, Philadelphia, 2005, Churchill Livingstone. (Table 75.4)
Rationale: It’s essential to know which nerves serve exclusively sensory functions when diagnosing patients who exhibit specific types of sensory loss but no motor dysfunction.
Vignette: A 35-year-old male athlete presents with isolated muscle weakness affecting his medial thigh compartment. Which nerve would you suspect to be compromised?
A) Femoral
B) Obturator
C) Genitofemoral
D) Iliohypogastric
orrect Answer: B) Obturator
Explanation:
A) Femoral: Innervates the iliacus, pectineus, and muscles in the anterior compartment of the thigh, originating from L2-L4.
B) Obturator: Correct. Innervates the obturator externus, pectineus, and muscles in the medial compartment of the thigh, originating from L2-L4.
C) Genitofemoral: Innervates the male cremasteric muscle, originating from L1 and L2.
D) Iliohypogastric: Innervates the internal oblique and transversus abdominis, originating from L1.
Memory Tool: “Medial thigh muscle mess? Obturator is your best guess!”
Reference Citation: Modified from Drake RL, Vogl AW, Mitchell AWM: Gray’s Anatomy for Students, Philadelphia, 2005, Churchill Livingstone. (Table 75.4)
Rationale: Knowing which nerve affects the muscles in the medial thigh compartment is essential for diagnosis, especially in athletes where precise muscle function is critical.
Vignette: A patient with a spinal injury at the T12 level complains of sensory loss. Which area is most likely to be affected?
A) Skin over the hip
B) Skin on the anterior thigh
C) Posterolateral gluteal skin
D) Skin on medial aspect of the thigh
Correct Answer: A) Skin over the hip
Explanation:
A) Skin over the hip: Correct. The subcostal nerve originates from the anterior ramus of T12 and provides sensory function to the skin over the hip.
B) Skin on the anterior thigh: The femoral nerve provides this function and originates from L2-L4.
C) Posterolateral gluteal skin: The iliohypogastric nerve provides this function and originates from L1.
D) Skin on medial aspect of the thigh: The obturator nerve provides this function and originates from L2-L4.
Memory Tool: “T12 takes care of the hips, so don’t let it slip!”
Reference Citation: Modified from Drake RL, Vogl AW, Mitchell AWM: Gray’s Anatomy for Students, Philadelphia, 2005, Churchill Livingstone. (Table 75.4)
Rationale: For patients with spinal injuries, understanding which spinal segment affects which sensory region is crucial for accurate diagnosis and treatment planning.
Clinical Vignette:
A 45-year-old male patient is undergoing an abdominal surgery. During the procedure, which nerve should be carefully preserved to maintain sensation to the anterior abdominal wall and pubis?
Multiple Choice Options:
A. Pudendal Nerve
B. Iliohypogastric Nerve
C. Genitofemoral Nerve
D. Nervi erigentes
Correct Answer:
B. Iliohypogastric Nerve
In-depth Explanation for All Answer Choices:
A. The pudendal nerve primarily supplies the perineum, scrotum, and controls the urinary and anal sphincters.
B. The iliohypogastric nerve originates from L1 and supplies the anterior abdominal wall and pubis.
C. The genitofemoral nerve supplies the cremaster muscle and anterior scrotum, and the anterior thigh.
D. The nervi erigentes supply parasympathetic fibers from the sacral cord to the pelvic viscera.
Memory Tool:
Remember Iliohypogastric as “Ilio-Hypo-Gastric” - Ilio for iliac, Hypo for below, and Gastric for stomach area - collectively covering the anterior abdominal wall and pubis.
Reference Citation:
Table 109.2, Somatic and Autonomic Nerves of the Pelvis
Rationale for Importance:
Understanding nerve anatomy is crucial for surgeries to avoid nerve damage and preserve functions like sensation and motor control.
Clinical Vignette:
A 28-year-old male comes to the clinic with numbness in his anterior thigh. Which nerve could be compromised?
Multiple Choice Options:
A. Ilioinguinal Nerve
B. Posterior Femoral Cutaneous Nerve
C. Genitofemoral Nerve
D. Lateral Cutaneous Femoral Nerve
Correct Answer:
C. Genitofemoral Nerve
In-depth Explanation for All Answer Choices:
A. The ilioinguinal nerve primarily supplies the anterior scrotum.
B. The posterior femoral cutaneous nerve supplies the perineum and posterior scrotum.
C. The femoral branch of the genitofemoral nerve supplies the anterior thigh.
D. The lateral cutaneous femoral nerve supplies the lateral thigh.
Memory Tool:
Genitofemoral nerve splits into two: “Genito” for genital and “Femoral” for thigh.
Reference Citation:
Table 109.2, Somatic and Autonomic Nerves of the Pelvis
Rationale for Importance:
Assessing numbness requires precise understanding of nerve distribution to identify possible neuropathy.
Clinical Vignette:
A 65-year-old male with a history of chronic constipation reports difficulty in controlling bowel movements. Which nerve is most likely implicated in maintaining anal sphincter tone?
Multiple Choice Options:
A. Pudendal Nerve
B. Pelvic Somatic Efferents
C. Nervi erigentes
D. Ilioinguinal Nerve
Correct Answer:
A. Pudendal Nerve
In-depth Explanation for All Answer Choices:
A. The pudendal nerve controls the urinary and anal sphincters, and also provides sensation to the perineum, scrotum, and penis.
B. Pelvic somatic efferents supply motor control to the levator ani and striated urethral sphincter, but not the anal sphincter.
C. The nervi erigentes primarily supply parasympathetic fibers to the pelvic viscera.
D. The ilioinguinal nerve supplies the anterior scrotum.
Memory Tool:
Pudendal sounds like “Poo-dendal.” Think of “poo” when you think of anal sphincter control.
Reference Citation:
Table 109.2, Somatic and Autonomic Nerves of the Pelvis
Rationale for Importance:
Understanding the role of the pudendal nerve is essential in managing conditions like incontinence.
Clinical Vignette:
A 42-year-old female cyclist reports pain and numbness along her lateral thigh. Which nerve is most likely involved?
Multiple Choice Options:
A. Genitofemoral Nerve
B. Lateral Cutaneous Femoral Nerve
C. Ilioinguinal Nerve
D. Posterior Femoral Cutaneous Nerve
Correct Answer:
B. Lateral Cutaneous Femoral Nerve
In-depth Explanation for All Answer Choices:
A. Genitofemoral nerve affects the anterior thigh, not lateral.
B. Lateral cutaneous femoral nerve supplies the lateral thigh.
C. Ilioinguinal nerve affects the anterior scrotum.
D. Posterior femoral cutaneous nerve affects the perineum and posterior scrotum.
Memory Tool:
Lateral Cutaneous Femoral (LCF) Nerve: LCF for “Laterally Causes Feelings” in the thigh.
Reference Citation:
Table 109.2, Somatic and Autonomic Nerves of the Pelvis
Rationale for Importance:
Accurate diagnosis of lateral thigh pain in cyclists can guide management and prevent further nerve injury.
Clinical Vignette:
A 55-year-old male patient with post-prostatectomy incontinence is being evaluated for treatment options. Which nerve is primarily responsible for controlling the striated urethral sphincter?
Multiple Choice Options:
A. Ilioinguinal Nerve
B. Pelvic Somatic Efferents
C. Pudendal Nerve
D. Nervi erigentes
Correct Answer:
B. Pelvic Somatic Efferents
In-depth Explanation for All Answer Choices:
A. The ilioinguinal nerve primarily supplies the anterior scrotum.
B. Pelvic somatic efferents supply the motor control to the levator ani and the striated urethral sphincter.
C. The pudendal nerve controls the urinary and anal sphincters but is not primarily responsible for the striated urethral sphincter.
D. The nervi erigentes supply parasympathetic fibers to the pelvic viscera but not the urethral sphincter.
Memory Tool:
Pelvic Somatic Efferents: “Somatic” for body (urethral sphincter) and “Efferents” for outgoing (motor control).
Reference Citation:
Table 109.2, Somatic and Autonomic Nerves of the Pelvis
Rationale for Importance:
For management of post-prostatectomy incontinence, knowing which nerve controls the striated urethral sphincter is crucial for targeted treatment options.
