COMLEX Level 1 Practice Exam (Form 110)
Prep 2026/2027 – Questions with Verified
Answers, Detailed Rationales & Expert-
Reviewed Study Guide PDF (Latest Updated
Edition)
COMLEX LEVEL 1 PRACTICE EXAM — FORM 110
Questions | Verified Answers | Detailed EXPERT RATIONALE | 2026/2027
Edition
• This question practice exam mirrors the full COMLEX Level 1 blueprint,
featuring verified answers, detailed EXPERT RATIONALE, and expert-reviewed
content spanning all major tested domains — from basic sciences to
Osteopathic Manipulative Medicine.
• Study by attempting each question independently before reviewing the
correct answer; use the EXPERT RATIONALE to deepen conceptual
understanding, not just to memorize, and return to weak-area questions for
spaced repetition.
Q1. A 45-year-old man presents with sudden severe chest pain radiating to
the back. CT angiography reveals an aortic dissection beginning at the aortic
root. Which layer of the aorta is most directly disrupted in the pathogenesis
of this condition?
A. Tunica intima
B. Tunica adventitia
C. Tunica media
D. Vasa vasorum
E. Endothelium
Correct Answer: C. Tunica media
,EXPERT RATIONALE: Aortic dissection begins with a tear in the tunica intima,
allowing blood to enter and dissect through the tunica media. Cystic medial
necrosis — degeneration of elastic fibers and smooth muscle in the media — is the
predisposing lesion, seen in Marfan syndrome and chronic hypertension. The
media provides the structural integrity of the aortic wall; its disruption creates a
false lumen.
Q2. A surgeon performing a right hemicolectomy inadvertently injures a
tubular structure running along the right side of the pelvic brim near the
right gonadal vessels. Which structure was most likely damaged?
A. Right renal artery
B. Right lumbar lymphatic trunk
C. Right sympathetic trunk
D. Right iliac artery
E. Right ureter
Correct Answer: E. Right ureter
EXPERT RATIONALE: The right ureter runs retroperitoneally and crosses the right
common iliac artery at the pelvic brim. During right hemicolectomy it is at risk as it
lies medial to and near the gonadal vessels. The mnemonic "water under the
bridge" reminds us the ureter (water) passes under the gonadal vessels (bridge).
Failure to identify it before ligation can result in ureteric injury and hydronephrosis.
Q3. A 24-year-old man fractures the surgical neck of the humerus. He cannot
abduct his arm beyond 15 degrees. Which nerve is most likely damaged?
A. Radial nerve
B. Ulnar nerve
C. Musculocutaneous nerve
D. Median nerve
, E. Axillary nerve
Correct Answer: E. Axillary nerve
EXPERT RATIONALE: The axillary nerve winds around the surgical neck of the
humerus. It innervates the deltoid (primary abductor of the arm beyond 15°) and
teres minor, and provides cutaneous sensation to the regimental badge area
(lateral arm). The first 15° of abduction is performed by the supraspinatus,
innervated by the suprascapular nerve, which is not at risk here.
Q4. A 55-year-old man undergoes carotid endarterectomy. Postoperatively, he
develops hoarseness and difficulty swallowing. Which nerve was most likely
injured?
A. Hypoglossal nerve
B. Glossopharyngeal nerve
C. Accessory nerve
D. Facial nerve
E. Vagus nerve
Correct Answer: E. Vagus nerve
EXPERT RATIONALE: The recurrent laryngeal nerve — a branch of the vagus nerve
— innervates all intrinsic laryngeal muscles except the cricothyroid. Injury during
carotid surgery causes hoarseness (unilateral vocal cord paralysis) and dysphagia.
The hypoglossal nerve (CN XII), if injured, causes tongue deviation toward the side
of the lesion rather than hoarseness.
Q5. A newborn presents with cyanosis that worsens with feeding and
improves with crying. Physical exam reveals bilateral nasal obstruction.
Which of the following best describes the embryological basis?
A. Failure of first branchial cleft closure
B. Incomplete fusion of the maxillary processes
Prep 2026/2027 – Questions with Verified
Answers, Detailed Rationales & Expert-
Reviewed Study Guide PDF (Latest Updated
Edition)
COMLEX LEVEL 1 PRACTICE EXAM — FORM 110
Questions | Verified Answers | Detailed EXPERT RATIONALE | 2026/2027
Edition
• This question practice exam mirrors the full COMLEX Level 1 blueprint,
featuring verified answers, detailed EXPERT RATIONALE, and expert-reviewed
content spanning all major tested domains — from basic sciences to
Osteopathic Manipulative Medicine.
• Study by attempting each question independently before reviewing the
correct answer; use the EXPERT RATIONALE to deepen conceptual
understanding, not just to memorize, and return to weak-area questions for
spaced repetition.
Q1. A 45-year-old man presents with sudden severe chest pain radiating to
the back. CT angiography reveals an aortic dissection beginning at the aortic
root. Which layer of the aorta is most directly disrupted in the pathogenesis
of this condition?
A. Tunica intima
B. Tunica adventitia
C. Tunica media
D. Vasa vasorum
E. Endothelium
Correct Answer: C. Tunica media
,EXPERT RATIONALE: Aortic dissection begins with a tear in the tunica intima,
allowing blood to enter and dissect through the tunica media. Cystic medial
necrosis — degeneration of elastic fibers and smooth muscle in the media — is the
predisposing lesion, seen in Marfan syndrome and chronic hypertension. The
media provides the structural integrity of the aortic wall; its disruption creates a
false lumen.
Q2. A surgeon performing a right hemicolectomy inadvertently injures a
tubular structure running along the right side of the pelvic brim near the
right gonadal vessels. Which structure was most likely damaged?
A. Right renal artery
B. Right lumbar lymphatic trunk
C. Right sympathetic trunk
D. Right iliac artery
E. Right ureter
Correct Answer: E. Right ureter
EXPERT RATIONALE: The right ureter runs retroperitoneally and crosses the right
common iliac artery at the pelvic brim. During right hemicolectomy it is at risk as it
lies medial to and near the gonadal vessels. The mnemonic "water under the
bridge" reminds us the ureter (water) passes under the gonadal vessels (bridge).
Failure to identify it before ligation can result in ureteric injury and hydronephrosis.
Q3. A 24-year-old man fractures the surgical neck of the humerus. He cannot
abduct his arm beyond 15 degrees. Which nerve is most likely damaged?
A. Radial nerve
B. Ulnar nerve
C. Musculocutaneous nerve
D. Median nerve
, E. Axillary nerve
Correct Answer: E. Axillary nerve
EXPERT RATIONALE: The axillary nerve winds around the surgical neck of the
humerus. It innervates the deltoid (primary abductor of the arm beyond 15°) and
teres minor, and provides cutaneous sensation to the regimental badge area
(lateral arm). The first 15° of abduction is performed by the supraspinatus,
innervated by the suprascapular nerve, which is not at risk here.
Q4. A 55-year-old man undergoes carotid endarterectomy. Postoperatively, he
develops hoarseness and difficulty swallowing. Which nerve was most likely
injured?
A. Hypoglossal nerve
B. Glossopharyngeal nerve
C. Accessory nerve
D. Facial nerve
E. Vagus nerve
Correct Answer: E. Vagus nerve
EXPERT RATIONALE: The recurrent laryngeal nerve — a branch of the vagus nerve
— innervates all intrinsic laryngeal muscles except the cricothyroid. Injury during
carotid surgery causes hoarseness (unilateral vocal cord paralysis) and dysphagia.
The hypoglossal nerve (CN XII), if injured, causes tongue deviation toward the side
of the lesion rather than hoarseness.
Q5. A newborn presents with cyanosis that worsens with feeding and
improves with crying. Physical exam reveals bilateral nasal obstruction.
Which of the following best describes the embryological basis?
A. Failure of first branchial cleft closure
B. Incomplete fusion of the maxillary processes
