1
COMSAE PHASE 1 EXAM 2026/2027 |
COMPREHENSIVE MEDICAL SELF-ASSESSMENT
| 100 VERIFIED Q&A | DETAILED RATIONALES |
PASS GUARANTEED – A+ GRADED
SECTION 1: ANATOMY AND EMBRYOLOGY – Questions 1–10
Q1: Anatomy – Brachial Plexus
The student is reviewing the brachial plexus. Which nerve is most commonly injured in Erb-
Duchenne palsy?
A. Radial nerve
B. Median nerve
C. Upper trunk of the brachial plexus (C5–C6)
D. Lower trunk of the brachial plexus (C8–T1)
Correct Answer: C
Rationale: Erb-Duchenne palsy involves injury to the upper trunk of the brachial plexus (C5–C6),
often from shoulder dystocia or trauma. It presents with the “waiter’s tip” posture. Lower trunk
injury (Klumpke palsy) affects C8–T1 and causes claw hand. [100% CORRECT]
Q2: Embryology – Neural Tube Development
The student is reviewing embryology. The neural tube develops from which embryonic structure?
A. Endoderm
B. Mesoderm
C. Ectoderm
D. Neural crest cells
Correct Answer: C
Rationale: The neural tube develops from the ectoderm. Failure of neural tube closure can cause
anencephaly or spina bifida. Neural crest cells migrate to form peripheral nerves, melanocytes, and
other structures. [100% CORRECT]
Q3: Anatomy – Cranial Nerves
The student is reviewing cranial nerves. Which cranial nerve is responsible for lateral rectus muscle
function?
A. CN III
B. CN IV
C. CN VI
D. CN VII
Correct Answer: C
Rationale: CN VI (abducens) innervates the lateral rectus, which abducts the eye. CN III (oculomotor)
,2
innervates most extraocular muscles. CN IV (trochlear) innervates the superior oblique. CN VII
(facial) controls facial expression. [100% CORRECT]
Q4: Anatomy – Inguinal Canal
The student is reviewing the inguinal canal. Which structure passes through the deep inguinal ring?
A. Spermatic cord
B. Femoral nerve
C. Obturator nerve
D. Sciatic nerve
Correct Answer: A
Rationale: The spermatic cord in males (round ligament in females) passes through the deep
inguinal ring, inguinal canal, and superficial inguinal ring. The femoral nerve exits below the inguinal
ligament. [100% CORRECT]
Q5: Embryology – Aortic Arches
The student is reviewing aortic arches. The right subclavian artery is derived from which aortic arch?
A. 3rd
B. 4th
C. 5th
D. 6th
Correct Answer: B
Rationale: The 4th aortic arch forms the right subclavian artery and part of the aortic arch. The 3rd
forms the common carotid and proximal internal carotid. The 6th forms pulmonary arteries and
ductus arteriosus. [100% CORRECT]
Q6: Anatomy – Thorax
The student is reviewing thoracic anatomy. Which intercostal space is used for a thoracentesis to
avoid the neurovascular bundle?
A. Above the rib
B. Below the rib
C. At the rib
D. Any space
Correct Answer: A
Rationale: The neurovascular bundle runs along the inferior border of each rib. To avoid it, insert the
needle just above the rib. [100% CORRECT]
Q7: Embryology – Pharyngeal Pouches
The student is reviewing pharyngeal pouches. The thymus and parathyroid glands develop from
which pouch?
A. 1st
B. 2nd
, 3
C. 3rd
D. 4th
Correct Answer: C
Rationale: The 3rd pharyngeal pouch gives rise to the thymus and inferior parathyroid glands. The
4th pouch gives rise to the superior parathyroid and ultimobranchial body. [100% CORRECT]
Q8: Anatomy – Lower Extremity
The student is reviewing lower extremity anatomy. Which nerve is compressed in tarsal tunnel
syndrome?
A. Tibial nerve
B. Peroneal nerve
C. Femoral nerve
D. Sciatic nerve
Correct Answer: A
Rationale: Tarsal tunnel syndrome involves compression of the tibial nerve as it passes behind the
medial malleolus. [100% CORRECT]
Q9: Embryology – Heart Development
The student is reviewing heart development. The ventricular septum forms primarily from which
structure?
A. Septum primum
B. Septum secundum
C. Muscular interventricular septum
D. Endocardial cushions
Correct Answer: C
Rationale: The muscular interventricular septum grows upward from the ventricular floor and fuses
with the endocardial cushions and conotruncal septum. Failure leads to VSD. [100% CORRECT]
Q10: Anatomy – Abdomen
The student is reviewing abdominal anatomy. The artery of Adamkiewicz is a major radicular artery
supplying which region of the spinal cord?
A. Cervical
B. Upper thoracic
C. Lower thoracic and lumbar
D. Sacral
Correct Answer: C
Rationale: The artery of Adamkiewicz typically arises from the left intercostal or lumbar arteries and
supplies the lower two-thirds of the spinal cord. Injury can cause anterior spinal artery syndrome.
[100% CORRECT]
SECTION 2: PHYSIOLOGY – Questions 11–20
COMSAE PHASE 1 EXAM 2026/2027 |
COMPREHENSIVE MEDICAL SELF-ASSESSMENT
| 100 VERIFIED Q&A | DETAILED RATIONALES |
PASS GUARANTEED – A+ GRADED
SECTION 1: ANATOMY AND EMBRYOLOGY – Questions 1–10
Q1: Anatomy – Brachial Plexus
The student is reviewing the brachial plexus. Which nerve is most commonly injured in Erb-
Duchenne palsy?
A. Radial nerve
B. Median nerve
C. Upper trunk of the brachial plexus (C5–C6)
D. Lower trunk of the brachial plexus (C8–T1)
Correct Answer: C
Rationale: Erb-Duchenne palsy involves injury to the upper trunk of the brachial plexus (C5–C6),
often from shoulder dystocia or trauma. It presents with the “waiter’s tip” posture. Lower trunk
injury (Klumpke palsy) affects C8–T1 and causes claw hand. [100% CORRECT]
Q2: Embryology – Neural Tube Development
The student is reviewing embryology. The neural tube develops from which embryonic structure?
A. Endoderm
B. Mesoderm
C. Ectoderm
D. Neural crest cells
Correct Answer: C
Rationale: The neural tube develops from the ectoderm. Failure of neural tube closure can cause
anencephaly or spina bifida. Neural crest cells migrate to form peripheral nerves, melanocytes, and
other structures. [100% CORRECT]
Q3: Anatomy – Cranial Nerves
The student is reviewing cranial nerves. Which cranial nerve is responsible for lateral rectus muscle
function?
A. CN III
B. CN IV
C. CN VI
D. CN VII
Correct Answer: C
Rationale: CN VI (abducens) innervates the lateral rectus, which abducts the eye. CN III (oculomotor)
,2
innervates most extraocular muscles. CN IV (trochlear) innervates the superior oblique. CN VII
(facial) controls facial expression. [100% CORRECT]
Q4: Anatomy – Inguinal Canal
The student is reviewing the inguinal canal. Which structure passes through the deep inguinal ring?
A. Spermatic cord
B. Femoral nerve
C. Obturator nerve
D. Sciatic nerve
Correct Answer: A
Rationale: The spermatic cord in males (round ligament in females) passes through the deep
inguinal ring, inguinal canal, and superficial inguinal ring. The femoral nerve exits below the inguinal
ligament. [100% CORRECT]
Q5: Embryology – Aortic Arches
The student is reviewing aortic arches. The right subclavian artery is derived from which aortic arch?
A. 3rd
B. 4th
C. 5th
D. 6th
Correct Answer: B
Rationale: The 4th aortic arch forms the right subclavian artery and part of the aortic arch. The 3rd
forms the common carotid and proximal internal carotid. The 6th forms pulmonary arteries and
ductus arteriosus. [100% CORRECT]
Q6: Anatomy – Thorax
The student is reviewing thoracic anatomy. Which intercostal space is used for a thoracentesis to
avoid the neurovascular bundle?
A. Above the rib
B. Below the rib
C. At the rib
D. Any space
Correct Answer: A
Rationale: The neurovascular bundle runs along the inferior border of each rib. To avoid it, insert the
needle just above the rib. [100% CORRECT]
Q7: Embryology – Pharyngeal Pouches
The student is reviewing pharyngeal pouches. The thymus and parathyroid glands develop from
which pouch?
A. 1st
B. 2nd
, 3
C. 3rd
D. 4th
Correct Answer: C
Rationale: The 3rd pharyngeal pouch gives rise to the thymus and inferior parathyroid glands. The
4th pouch gives rise to the superior parathyroid and ultimobranchial body. [100% CORRECT]
Q8: Anatomy – Lower Extremity
The student is reviewing lower extremity anatomy. Which nerve is compressed in tarsal tunnel
syndrome?
A. Tibial nerve
B. Peroneal nerve
C. Femoral nerve
D. Sciatic nerve
Correct Answer: A
Rationale: Tarsal tunnel syndrome involves compression of the tibial nerve as it passes behind the
medial malleolus. [100% CORRECT]
Q9: Embryology – Heart Development
The student is reviewing heart development. The ventricular septum forms primarily from which
structure?
A. Septum primum
B. Septum secundum
C. Muscular interventricular septum
D. Endocardial cushions
Correct Answer: C
Rationale: The muscular interventricular septum grows upward from the ventricular floor and fuses
with the endocardial cushions and conotruncal septum. Failure leads to VSD. [100% CORRECT]
Q10: Anatomy – Abdomen
The student is reviewing abdominal anatomy. The artery of Adamkiewicz is a major radicular artery
supplying which region of the spinal cord?
A. Cervical
B. Upper thoracic
C. Lower thoracic and lumbar
D. Sacral
Correct Answer: C
Rationale: The artery of Adamkiewicz typically arises from the left intercostal or lumbar arteries and
supplies the lower two-thirds of the spinal cord. Injury can cause anterior spinal artery syndrome.
[100% CORRECT]
SECTION 2: PHYSIOLOGY – Questions 11–20
