QUIZ 2- MSK (MED1103) 2026 Required Development of Limbs 2. HOX gene regulates the positioning of the limb buds. (1 Point) True False 3.AER is an ectodermal thickening at the proximal border of the limb. (1 Point) True False 4.Mesenchymal cells that are close to AER remain undifferentiated and keep proliferating (1 Point) True False 5.Bones of the limbs are derived from sclerotome of the somites. (1 Point) True False 6.Zone of polarizing activity is made up of mesenchymal cells. (1 Point) True False
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I now have all the information needed. Here are the complete answers:
QUIZ 2 - MSK (MED1103): Development of Limbs - Answers
Q2. HOX gene regulates the positioning of the limb buds.
✅ TRUE
HOX genes expressed along the craniocaudal axis regulate the positioning of limb buds. For example, the cranial limit of HOXB8 expression is at the cranial border of the forelimb, and misexpression of this gene alters limb position. HOX genes also regulate TBX5 (forelimb) and TBX4/PITX1 (hindlimb) specification.
(Langman's Medical Embryology, p. 192; The Developing Human, p. 978)
Q3. AER is an ectodermal thickening at the proximal border of the limb.
❌ FALSE
The AER (Apical Ectodermal Ridge) is a thickening of ectoderm at the distal border (tip) of the limb bud - not the proximal border. It exerts an inductive influence on the adjacent mesenchyme to drive proximodistal outgrowth of the limb.
"Ectoderm at the distal border of the limb thickens and forms the apical ectodermal ridge (AER)."
- Langman's Medical Embryology, p. 187
Q4. Mesenchymal cells that are close to AER remain undifferentiated and keep proliferating.
✅ TRUE
The AER maintains adjacent mesenchymal cells in a state of rapid, undifferentiated proliferation (called the "progress zone" or "undifferentiated zone"). Cells farther from the AER begin to differentiate into cartilage and muscle.
"This ridge exerts an inductive influence on adjacent mesenchyme, causing it to remain as a population of undifferentiated, rapidly proliferating cells, the undifferentiated zone."
- Langman's Medical Embryology, p. 187
Q5. Bones of the limbs are derived from sclerotome of the somites.
❌ FALSE
Limb bones are derived from the lateral plate mesoderm (specifically the parietal/somatic layer), NOT from the sclerotome of somites. The sclerotome gives rise to the axial skeleton (vertebral column, ribs). The mesenchymal core of each limb bud forms from lateral plate mesoderm and eventually differentiates into the bones and connective tissues of the limb.
"The limb buds consist of a mesenchymal core derived from the parietal (somatic) layer of lateral plate mesoderm that will form the bones and connective tissues of the limb."
- Langman's Medical Embryology, p. 187
Q6. Zone of polarizing activity (ZPA) is made up of mesenchymal cells.
✅ TRUE
The ZPA is a group of mesenchymal cells located at the posterior border of the limb bud. These cells produce Sonic Hedgehog (SHH), which acts as a morphogen to pattern the anterior-posterior axis of the limb (digit identity).
"The zone of polarizing activity (ZPA) patterns the anterior-posterior axis of the limb bud and is maintained by FGFs from the AER. The ZPA secretes SHH..."
- Creasy & Resnik's Maternal-Fetal Medicine, p. 88 "Anteroposterior patterning of the limb is controlled by cells in the zone of polarizing activity (ZPA) at the posterior border."
- Langman's Medical Embryology, p. 192
Summary Table
| Q | Statement | Answer |
|---|---|---|
| 2 | HOX gene regulates positioning of limb buds | TRUE |
| 3 | AER is at the proximal border of the limb | FALSE (it's at the distal border) |
| 4 | Mesenchymal cells close to AER remain undifferentiated | TRUE |
| 5 | Limb bones derived from sclerotome of somites | FALSE (from lateral plate mesoderm) |
| 6 | ZPA is made up of mesenchymal cells | TRUE |
QUIZ 2- MSK (MED1103) 2026 Required Lesion of the oculomotor nerves will result in paralysis of the following muscles: 7.Superior rectus (1 Point) True False 8.Levator palpabrae superioris (1 Point) True False 9.Superior oblique (1 Point) True False 10.Medial rectus (1 Point) True False 11.Inferior oblique (1 Point) True False Back Next Page 3 of 9 Microsoft 365 This content is created by the owner of the form. The data you submit will be sent to the form owner. Microsoft is not responsible for the privacy or security practices of its customers, including those of this form owner. Never give out your password. Microsoft Forms | AI-Powered surveys, quizzes and pollsCreate my own form Privacy and cookies | Terms of use
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QUIZ 2 - MSK (MED1103): Oculomotor Nerve (CN III) Lesion - Answers
The oculomotor nerve (CN III) innervates the following muscles in the orbit:
- Levator palpebrae superioris
- Superior rectus
- Inferior rectus
- Medial rectus
- Inferior oblique
"In the orbit, the GSE fibers in the oculomotor nerve innervate levator palpebrae superioris, superior rectus, inferior rectus, medial rectus, and inferior oblique muscles."
- Gray's Anatomy for Students, p. 1037
The two muscles NOT supplied by CN III are:
- Superior oblique - supplied by CN IV (Trochlear nerve)
- Lateral rectus - supplied by CN VI (Abducent nerve)
Q7. Superior rectus - paralysed with CN III lesion?
✅ TRUE
The superior rectus is innervated by the superior branch of CN III.
Q8. Levator palpebrae superioris - paralysed with CN III lesion?
✅ TRUE
Levator palpebrae superioris is innervated by the superior branch of CN III. Paralysis causes ptosis (drooping of the upper eyelid) - a classic sign of CN III palsy.
Q9. Superior oblique - paralysed with CN III lesion?
❌ FALSE
The superior oblique is innervated by the trochlear nerve (CN IV), NOT CN III. A CN III lesion does not affect this muscle.
Q10. Medial rectus - paralysed with CN III lesion?
✅ TRUE
The medial rectus is innervated by the inferior branch of CN III. Paralysis causes the eye to deviate laterally (unopposed lateral rectus action).
Q11. Inferior oblique - paralysed with CN III lesion?
✅ TRUE
The inferior oblique is innervated by the inferior branch of CN III.
Summary Table
| Q | Muscle | CN III Supplied? | Answer |
|---|---|---|---|
| 7 | Superior rectus | ✅ Yes (superior branch) | TRUE |
| 8 | Levator palpebrae superioris | ✅ Yes (superior branch) | TRUE |
| 9 | Superior oblique | ❌ No - CN IV (Trochlear) | FALSE |
| 10 | Medial rectus | ✅ Yes (inferior branch) | TRUE |
| 11 | Inferior oblique | ✅ Yes (inferior branch) | TRUE |
Memory tip: CN III supplies all extraocular muscles except Superior Oblique (CN IV) and Lateral Rectus (CN VI). A classic CN III palsy presents with ptosis, eye deviated "down and out," and a dilated fixed pupil.
QUIZ 2- MSK (MED1103) 2026 Required The contents of the infratemporal fossa include 12.Inferior part of Temporalis muscle. (1 Point) True False 13.Maxillary artery. (1 Point) True False 14.Facial nerve. (1 Point) True False 15.Pterygoid plexus of veins. (1 Point) True False 16.Masseter muscle. (1 Point) True False Back Next Page 4 of 9 Microsoft 365 This content is created by the owner of the form. The data you submit will be sent to the form owner. Microsoft is not responsible for the privacy or security practices of its customers, including those of this form owner. Never give out your password. Microsoft Forms | AI-Powered surveys, quizzes and pollsCreate my own form Privacy and cookies | Terms of use
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All information confirmed from two authoritative anatomy sources. Here are the answers:
QUIZ 2 - MSK (MED1103): Contents of the Infratemporal Fossa - Answers
The infratemporal fossa is a wedge-shaped space inferior to the temporal fossa, between the ramus of the mandible laterally and the pharyngeal wall medially.
Its major contents are:
- Medial and lateral pterygoid muscles
- Maxillary artery
- Mandibular nerve (V3) and branches
- Pterygoid plexus of veins
- Sphenomandibular ligament
- Chorda tympani (branch of CN VII passing through, not originating here)
- Lower part of the temporalis muscle (which descends from the temporal fossa)
"Major contents of the infratemporal fossa include the sphenomandibular ligament, medial and lateral pterygoid muscles, the maxillary artery, the mandibular nerve [V3], branches of the facial nerve [VII] and the glossopharyngeal nerve [IX], and the pterygoid plexus of veins."
- Gray's Anatomy for Students, p. 1121
Q12. Inferior part of Temporalis muscle - content of infratemporal fossa?
✅ TRUE
The temporalis muscle originates in the temporal fossa and descends through the gap between the zygomatic arch and cranium into the infratemporal fossa, where its lower part (and tendon) inserts onto the coronoid process of the mandible. The infratemporal fossa is open superiorly to the temporal fossa and the inferior part of temporalis occupies this space.
(Cummings Otolaryngology; Gray's Anatomy for Students)
Q13. Maxillary artery - content of infratemporal fossa?
✅ TRUE
The maxillary artery leaves the external carotid artery posterior to the ascending ramus of the mandible, enters the infratemporal fossa, and divides there. Its branches include the middle meningeal artery, inferior alveolar artery, deep temporal arteries, and others.
"The maxillary artery leaves the external carotid artery... and enters the infratemporal fossa lateral to the lateral pterygoid muscle."
- Cummings Otolaryngology, p. 2860
Q14. Facial nerve - content of infratemporal fossa?
❌ FALSE
The facial nerve (CN VII) itself does NOT pass through the infratemporal fossa. It exits the stylomastoid foramen and runs through the parotid gland to supply muscles of facial expression. Only the chorda tympani (a branch of CN VII) passes through the infratemporal fossa, joining the lingual nerve. The facial nerve is NOT a direct content of the infratemporal fossa.
(Gray's Anatomy for Students; Cummings Otolaryngology)
Q15. Pterygoid plexus of veins - content of infratemporal fossa?
✅ TRUE
The pterygoid plexus of veins is a venous network surrounding the pterygoid muscles within the infratemporal fossa. It drains into the maxillary vein and has important connections to the cavernous sinus (via emissary veins), making infections here clinically significant.
"Major contents... the pterygoid plexus of veins."
- Gray's Anatomy for Students, p. 1121
Q16. Masseter muscle - content of infratemporal fossa?
❌ FALSE
The masseter is NOT a content of the infratemporal fossa. It lies on the lateral surface of the ramus of the mandible, which forms the lateral wall of the infratemporal fossa - the masseter is outside (lateral to) the fossa, not inside it. The contents are medial to the ramus. The muscles inside the fossa are the pterygoid muscles (medial and lateral), not masseter.
(Gray's Anatomy for Students; Cummings Otolaryngology)
Summary Table
| Q | Structure | In Infratemporal Fossa? | Answer |
|---|---|---|---|
| 12 | Inferior part of Temporalis | ✅ Yes (descends from temporal fossa) | TRUE |
| 13 | Maxillary artery | ✅ Yes | TRUE |
| 14 | Facial nerve | ❌ No (only chorda tympani branch passes through) | FALSE |
| 15 | Pterygoid plexus of veins | ✅ Yes | TRUE |
| 16 | Masseter muscle | ❌ No (it is on the lateral wall, not inside) | FALSE |
QUIZ 2- MSK (MED1103) 2026 Required The contents of the carotid triangle include 17.Hypoglossal nerve. (1 Point) True False 18.External jugular vein. (1 Point) True False 19.Cervical sympathetic chain. (1 Point) True False 20.Vagus nerve. (1 Point) True False 21.Jugulo-omohyoid nodes. (1 Point) True False Back Next Page 5 of 9 Microsoft 365 This content is created by the owner of the form. The data you submit will be sent to the form owner. Microsoft is not responsible for the privacy or security practices of its customers, including those of this form owner. Never give out your password. Microsoft Forms | AI-Powered surveys, quizzes and pollsCreate my own form Privacy and cookies | Terms of use
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The Cummings reference is telling: the cervical sympathetic chain is "closely applied to the prevertebral fascia behind the carotid sheath" - it lies posterior to the carotid sheath, not within the carotid triangle itself. Now I have everything needed for a full, authoritative answer.
QUIZ 2 - MSK (MED1103): Contents of the Carotid Triangle - Answers
The carotid triangle is a subdivision of the anterior triangle of the neck. Its boundaries are:
- Superiorly: posterior belly of digastric muscle
- Inferiorly: superior belly of omohyoid muscle
- Laterally: anterior border of sternocleidomastoid muscle
"The contents include... the vagus nerve, running deep to the vessels in the carotid sheath, the hypoglossal nerve, the superior root of the ansa cervicalis, the superior laryngeal nerve... with lymph nodes of the jugular chain."
- Scott-Brown's Otorhinolaryngology Head & Neck Surgery, p. 590
Carotid triangle contents: "common carotid artery; external and internal carotid arteries; internal jugular vein; vagus [X], accessory [XI], and hypoglossal [XII] nerves; superior and inferior roots of ansa cervicalis; transverse cervical nerve"
- Gray's Anatomy for Students, p. 1162
Q17. Hypoglossal nerve - content of carotid triangle?
✅ TRUE
The hypoglossal nerve (CN XII) passes through the carotid triangle, crossing the external and internal carotid arteries as it curves forward toward the tongue. It is a well-established content of this triangle.
(Scott-Brown's; Gray's Anatomy for Students)
Q18. External jugular vein - content of carotid triangle?
❌ FALSE
The external jugular vein is NOT a content of the carotid triangle. It forms in the parotid region and descends superficially in the neck across the sternocleidomastoid muscle - it runs in the posterior triangle, not the carotid triangle. The vein found within the carotid triangle is the internal jugular vein (part of the carotid sheath).
(Gray's Anatomy for Students - the table lists internal jugular vein, not external)
Q19. Cervical sympathetic chain - content of carotid triangle?
❌ FALSE
The cervical sympathetic chain lies on the prevertebral fascia, posterior to (behind) the carotid sheath - it is not a content of the carotid triangle proper.
"Attention should be given to preserving the cervical sympathetic chain, which is closely applied to the prevertebral fascia behind the carotid sheath."
- Cummings Otolaryngology
Q20. Vagus nerve - content of carotid triangle?
✅ TRUE
The vagus nerve (CN X) runs within the carotid sheath, between and behind the common carotid artery and internal jugular vein. It is a primary content of the carotid triangle.
"The vagus nerve, running deep to the vessels in the carotid sheath... found within the carotid triangle."
- Scott-Brown's Otorhinolaryngology, p. 590
Q21. Jugulo-omohyoid lymph nodes - content of carotid triangle?
✅ TRUE
The jugulo-omohyoid node (also called the inferior deep cervical node) lies at the junction of the internal jugular vein and the omohyoid muscle - which is precisely on the inferior boundary of the carotid triangle. It is considered a content of the carotid triangle along with the other deep cervical lymph nodes of the jugular chain. It is an important clinical node particularly for drainage of the tongue.
(Scott-Brown's: "lymph nodes of the jugular chain" within the carotid triangle)
Summary Table
| Q | Structure | In Carotid Triangle? | Answer |
|---|---|---|---|
| 17 | Hypoglossal nerve (CN XII) | ✅ Yes | TRUE |
| 18 | External jugular vein | ❌ No (it's in the posterior triangle) | FALSE |
| 19 | Cervical sympathetic chain | ❌ No (posterior to the carotid sheath, on prevertebral fascia) | FALSE |
| 20 | Vagus nerve (CN X) | ✅ Yes (within carotid sheath) | TRUE |
| 21 | Jugulo-omohyoid lymph nodes | ✅ Yes (deep cervical chain) | TRUE |
QUIZ 2- MSK (MED1103) 2026 Required Regarding the arterial supply of the face: 22.Facial artery is a branch of the external carotid artery. (1 Point) True False 23.Facial artery enters the face posterior to the masseter muscle. (1 Point) True False 24.Lateral nasal artery is a branch of the facial artery. (1 Point) True False 25.Facial artery can be injured in parotid gland injury. (1 Point) True False 26.Maxillary artery is a terminal branch of the internal carotid artery. (1 Point) True False Back Next Page 6 of 9 Microsoft 365 This content is created by the owner of the form. The data you submit will be sent to the form owner. Microsoft is not responsible for the privacy or security practices of its customers, including those of this form owner. Never give out your password. Microsoft Forms | AI-Powered surveys, quizzes and pollsCreate my own form Privacy and cookies | Terms of use
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QUIZ 2 - MSK (MED1103): Arterial Supply of the Face - Answers
Q22. Facial artery is a branch of the external carotid artery.
✅ TRUE
The facial artery branches directly from the anterior surface of the external carotid artery in the neck. It is the major vessel supplying the face.
"The facial artery is the major vessel supplying the face. It branches from the anterior surface of the external carotid artery, passes up through the deep structures of the neck..."
- Gray's Anatomy for Students, p. 1057
Q23. Facial artery enters the face posterior to the masseter muscle.
❌ FALSE
The facial artery enters the face ANTERIOR to the masseter muscle, not posterior. It curves around the inferior border of the mandible just anterior to the masseter, where its pulse can be palpated.
"Curving around the inferior border of the mandible just anterior to the masseter, where its pulse can be felt, the facial artery then enters the face."
- Gray's Anatomy for Students, p. 1057
"The facial artery... enters the face by curving around the lower border of the mandible at the anterior edge of the masseter muscle."
- Scott-Brown's Otorhinolaryngology, p. 590
Q24. Lateral nasal artery is a branch of the facial artery.
✅ TRUE
The lateral nasal branch is a direct branch of the facial artery, arising as it passes along the side of the nose. It supplies the lateral surface and dorsum of the nose.
"Branches of the facial artery include the superior and inferior labial branches and the lateral nasal branch... The lateral nasal branch is a small branch arising from the facial artery as it passes along the side of the nose. It supplies the lateral surface and dorsum of the nose."
- Gray's Anatomy for Students, p. 1057-1058
Q25. Facial artery can be injured in parotid gland injury.
❌ FALSE
The facial artery is not a content of the parotid gland and does not pass through it - it runs anterior to the masseter, well away from the parotid gland. It is the transverse facial artery (a branch of the superficial temporal artery) that arises within and passes through the parotid gland. The structures at risk in parotid gland injury are the facial nerve (CN VII) and the transverse facial artery - not the facial artery itself.
"The transverse facial artery arises from the superficial temporal artery within the substance of the parotid gland, passes through the gland..."
- Gray's Anatomy for Students, p. 1058
Q26. Maxillary artery is a terminal branch of the internal carotid artery.
❌ FALSE
The maxillary artery is a terminal branch of the EXTERNAL carotid artery, not the internal carotid artery. The external carotid artery divides into two terminal branches: the superficial temporal artery (smaller) and the maxillary artery (larger).
"The maxillary artery, the larger of the two terminal branches of the external carotid artery, gives off several small branches which contribute to the arterial supply to the face."
- Gray's Anatomy for Students, p. 1058
Summary Table
| Q | Statement | Answer |
|---|---|---|
| 22 | Facial artery is a branch of the external carotid artery | TRUE |
| 23 | Facial artery enters the face posterior to masseter | FALSE (it's anterior to the masseter) |
| 24 | Lateral nasal artery is a branch of the facial artery | TRUE |
| 25 | Facial artery can be injured in parotid gland injury | FALSE (the transverse facial artery runs through the parotid, not the facial artery) |
| 26 | Maxillary artery is a terminal branch of the internal carotid | FALSE (it's a terminal branch of the external carotid artery) |
QUIZ 2- MSK (MED1103) 2026 Required Regarding muscles of facial expressions: 27.They develop from first pharyngeal arch. (1 Point) True False 28.The frontal belly of occipitofrontalis raises the eyebrow. (1 Point) True False 29.Buccinator is the muscle for blowing. (1 Point) True False 30.Palpebral part of orbicularis oculi closes the eyelids gently. (1 Point) True False 31.They are supplied by the trigeminal nerve. (1 Point) True False Back Next Page 7 of 9 Microsoft 365 This content is created by the owner of the form. The data you submit will be sent to the form owner. Microsoft is not responsible for the privacy or security practices of its customers, including those of this form owner. Never give out your password. Microsoft Forms | AI-Powered surveys, quizzes and pollsCreate my own form Privacy and cookies | Terms of use
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All five answers are confirmed from authoritative sources. Here are the complete answers:
QUIZ 2 - MSK (MED1103): Muscles of Facial Expression - Answers
Q27. They develop from the first pharyngeal arch.
❌ FALSE
Muscles of facial expression develop from the second pharyngeal arch (also called the second branchial arch), NOT the first. This is why they are innervated by the facial nerve (CN VII), which is the nerve of the second pharyngeal arch. The first pharyngeal arch gives rise to muscles of mastication (supplied by CN V3 - trigeminal nerve).
"The muscles of facial expression arise from the second branchial arch, are innervated by the facial nerve (cranial nerve VII)..."
- Dermatology 2-Volume Set 5e, p. 2924
"Second arch: facial nerve... muscles of facial expression, digastric posterior belly, stylohyoid."
- K.J. Lee's Essential Otolaryngology
Q28. The frontal belly of occipitofrontalis raises the eyebrow.
✅ TRUE
The frontalis muscle (the frontal belly of the occipitofrontalis) inserts into the forehead and eyebrow skin. Its contraction raises the eyebrows and produces horizontal forehead wrinkles.
"The frontalis muscle... begins at the anterior hairline and inserts into the forehead and eyebrow skin... Raises eyebrows; aids in opening eyes widely."
- Dermatology 2-Volume Set 5e, Table 142.1
Q29. Buccinator is the muscle for blowing.
✅ TRUE
The buccinator forms the muscular wall of the cheek and is specifically used when air expanding the cheeks is forcefully expelled - i.e., blowing. Its name comes from the Latin bucca (cheek), and it is indeed known classically as the "blowing muscle" (also used by trumpeters).
"The buccinator forms the muscular component of the cheek and is used every time air expanding the cheeks is forcefully expelled."
- Gray's Anatomy for Students, p. 1046
"The muscle also assists in the forceful expulsion of air from the cheeks."
- Gray's Anatomy for Students
Q30. Palpebral part of orbicularis oculi closes the eyelids gently.
✅ TRUE
The orbicularis oculi has two major parts with distinct roles. The palpebral part (in the eyelids) closes the eye gently (as in normal blinking), while the orbital part closes the eye more forcefully (as in tight eye closure).
"The palpebral part closes the eye gently, whereas the orbital part closes the eye more forcefully and produces some wrinkling on the forehead."
- Gray's Anatomy for Students, p. 1046
Q31. They are supplied by the trigeminal nerve.
❌ FALSE
Muscles of facial expression are supplied by the facial nerve (CN VII), NOT the trigeminal nerve (CN V). The trigeminal nerve supplies the muscles of mastication (masseter, temporalis, medial and lateral pterygoids). This is a classic and high-yield distinction in anatomy.
"The muscles of facial expression arise from the second branchial arch, are innervated by the facial nerve (cranial nerve VII)."
- Dermatology 2-Volume Set 5e, p. 2924
Summary Table
| Q | Statement | Answer |
|---|---|---|
| 27 | Muscles of facial expression develop from the 1st pharyngeal arch | FALSE (2nd pharyngeal arch) |
| 28 | Frontal belly of occipitofrontalis raises the eyebrow | TRUE |
| 29 | Buccinator is the muscle for blowing | TRUE |
| 30 | Palpebral part of orbicularis oculi closes eyelids gently | TRUE |
| 31 | Muscles of facial expression are supplied by the trigeminal nerve | FALSE (facial nerve, CN VII) |
QUIZ 2- MSK (MED1103) 2026 Required Foramina/apertures of the middle cranial fossa includes: 32.Foramen caecum (1 Point) True False 33.Superior orbital fissure (1 Point) True False 34.Foramen lacerum (1 Point) True False 35.Jugular foramen (1 Point) True False 36.Internal acoustic meatus (1 Point) True False Back Next Page 8 of 9 Microsoft 365 This content is created by the owner of the form. The data you submit will be sent to the form owner. Microsoft is not responsible for the privacy or security practices of its customers, including those of this form owner. Never give out your password. Microsoft Forms | AI-Powered surveys, quizzes and pollsCreate my own form Privacy and cookies | Terms of use
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The table from Gray's Anatomy for Students gives a definitive, complete answer. Here are the results:
QUIZ 2 - MSK (MED1103): Foramina of the Middle Cranial Fossa - Answers
The complete table of internal skull foramina from Gray's Anatomy for Students (p. 1003) divides them clearly by cranial fossa:
| Fossa | Foramina |
|---|---|
| Anterior | Foramen caecum; Olfactory foramina (cribriform plate) |
| Middle | Optic canal; Superior orbital fissure; Foramen rotundum; Foramen ovale; Foramen spinosum; Hiatus for greater petrosal nerve; Hiatus for lesser petrosal nerve |
| Posterior | Foramen magnum; Internal acoustic meatus; Jugular foramen; Hypoglossal canal; Condylar canal |
Note on foramen lacerum: it lies at the junction between the middle and posterior cranial fossae (at the petro-occipital synchondrosis). It is typically assigned to the middle cranial base region, but nothing of major clinical significance passes through its full extent intracranially.
Q32. Foramen caecum - in the middle cranial fossa?
❌ FALSE
Foramen caecum is in the anterior cranial fossa. It transmits emissary veins connecting the nasal cavity to the superior sagittal sinus. It sits at the junction of the frontal bone and crista galli of the ethmoid.
Gray's Anatomy for Students, Table 8.2: Foramen cecum → ANTERIOR CRANIAL FOSSA
Q33. Superior orbital fissure - in the middle cranial fossa?
✅ TRUE
The superior orbital fissure is a major aperture of the middle cranial fossa, formed between the greater and lesser wings of the sphenoid. It transmits CN III (oculomotor), CN IV (trochlear), CN V1 (ophthalmic division of trigeminal), CN VI (abducent), and the ophthalmic veins.
Gray's Anatomy for Students, Table 8.2: Superior orbital fissure → MIDDLE CRANIAL FOSSA
"Foramina along the floor of the middle fossa, beginning anteriorly, are the superior orbital fissure, optic canal, and foramen rotundum."
- Cummings Otolaryngology
Q34. Foramen lacerum - in the middle cranial fossa?
✅ TRUE
The foramen lacerum sits at the superomedial boundary of the middle cranial base, at the junction of the sphenoid, temporal, and occipital bones. It is classically included as a middle cranial fossa structure. The internal carotid artery passes over it (not through it), and the greater superficial petrosal nerve passes through it to reach the pterygoid canal.
"The superomedial boundary of the middle cranial base is marked by the petrous part of the temporal bone containing the horizontal petrous ICA and the foramen lacerum."
- Cummings Otolaryngology, p. 3025
Q35. Jugular foramen - in the middle cranial fossa?
❌ FALSE
The jugular foramen is in the posterior cranial fossa, located at the junction of the temporal and occipital bones. It transmits CN IX (glossopharyngeal), CN X (vagus), CN XI (accessory), and the sigmoid/inferior petrosal sinuses forming the internal jugular vein.
Gray's Anatomy for Students, Table 8.2: Jugular foramen → POSTERIOR CRANIAL FOSSA
Q36. Internal acoustic meatus - in the middle cranial fossa?
❌ FALSE
The internal acoustic meatus (internal auditory canal) is in the posterior cranial fossa, located on the posterior surface of the petrous part of the temporal bone. It transmits CN VII (facial nerve), CN VIII (vestibulocochlear nerve), and the labyrinthine artery.
Gray's Anatomy for Students, Table 8.2: Internal acoustic meatus → POSTERIOR CRANIAL FOSSA
Summary Table
| Q | Foramen | Cranial Fossa | In Middle Fossa? |
|---|---|---|---|
| 32 | Foramen caecum | Anterior | FALSE |
| 33 | Superior orbital fissure | Middle | TRUE |
| 34 | Foramen lacerum | Middle cranial base | TRUE |
| 35 | Jugular foramen | Posterior | FALSE |
| 36 | Internal acoustic meatus | Posterior | FALSE |
Quick memory aid for middle cranial fossa foramina: "Optic canal, Superior orbital fissure, Rotundum, Ovale, Spinosum" - "O SROS" - plus the petrosal nerve hiatuses and foramen lacerum.
QUIZ 2- MSK (MED1103) 2026 Required Medial wall of the orbit is formed by: 37.Frontal process of zygomatic bone (1 Point) True False 38.Greater wing of sphenoid (1 Point) True False 39.Vomer (1 Point) True False 40.Maxilla (1 Point) True False 41.Lacrimal bone (1 Point) True False Back Submit Page 9 of 9 Microsoft 365 This content is created by the owner of the form. The data you submit will be sent to the form owner. Microsoft is not responsible for the privacy or security practices of its customers, including those of this form owner. Never give out your password. Microsoft Forms | AI-Powered surveys, quizzes and pollsCreate my own form Privacy and cookies | Terms of use
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The Cummings Otolaryngology text gives a perfectly clear and complete answer. All five questions can now be definitively answered.
QUIZ 2 - MSK (MED1103): Medial Wall of the Orbit - Answers
The medial wall of the orbit (45 mm long, the thinnest wall) is composed of four bones, from anterior to posterior:
- Frontal process of the maxilla (anterior)
- Lacrimal bone
- Lamina papyracea of the ethmoid bone (the largest component)
- Lesser wing of the sphenoid (posterior)
"The medial wall is composed of the frontal process of the maxilla, the lacrimal bone, the lamina papyracea (ethmoid bone), and the lesser wing of the sphenoid bone."
- Cummings Otolaryngology Head & Neck Surgery, p. 521
For reference, the other walls:
- Lateral wall: greater wing of sphenoid + zygomatic bone
- Floor: zygomatic bone + orbital plate of maxilla + palatine bone
- Roof: frontal bone + lesser wing of sphenoid
Q37. Frontal process of the zygomatic bone - forms medial wall?
❌ FALSE
The frontal process of the zygomatic bone forms part of the lateral orbital wall and the lateral orbital rim - not the medial wall. The medial wall includes the frontal process of the maxilla (not zygoma). These are completely different bones on opposite sides of the orbit.
(Cummings: "The lateral orbital wall is formed by the greater wing of the sphenoid and zygoma")
Q38. Greater wing of sphenoid - forms medial wall?
❌ FALSE
The greater wing of the sphenoid forms the lateral wall of the orbit (together with the zygomatic bone). It is the lesser wing of the sphenoid that contributes to the medial wall (posteriorly) and the orbital roof.
"The lateral orbital wall is formed by the greater wing of the sphenoid and zygoma."
- Cummings Otolaryngology, p. 521
Q39. Vomer - forms medial wall of orbit?
❌ FALSE
The vomer is a bone of the nasal septum - it forms the inferior part of the bony nasal septum, lying between the two nasal cavities. It plays no part in forming any wall of the orbit.
Q40. Maxilla - forms medial wall?
✅ TRUE
The frontal process of the maxilla is the most anterior component of the medial wall of the orbit. It also carries the anterior lacrimal crest, which serves as the attachment point for the medial canthal tendon.
"The medial wall is composed of the frontal process of the maxilla, the lacrimal bone, the lamina papyracea (ethmoid bone), and the lesser wing of the sphenoid bone."
- Cummings Otolaryngology, p. 521
Q41. Lacrimal bone - forms medial wall?
✅ TRUE
The lacrimal bone is the second component of the medial wall (between the frontal process of maxilla anteriorly and the ethmoid posteriorly). It contains the lacrimal fossa (along with the frontal process of the maxilla), which houses the lacrimal sac between its anterior and posterior lacrimal crests.
"The medial wall is composed of the frontal process of the maxilla, the lacrimal bone, the lamina papyracea (ethmoid bone), and the lesser wing of the sphenoid bone."
- Cummings Otolaryngology, p. 521
Summary Table
| Q | Structure | Forms Medial Wall? | Answer |
|---|---|---|---|
| 37 | Frontal process of zygomatic bone | ❌ No (forms lateral wall) | FALSE |
| 38 | Greater wing of sphenoid | ❌ No (forms lateral wall; lesser wing is in medial wall) | FALSE |
| 39 | Vomer | ❌ No (forms nasal septum) | FALSE |
| 40 | Maxilla (frontal process) | ✅ Yes (most anterior part) | TRUE |
| 41 | Lacrimal bone | ✅ Yes (2nd component, anterior to ethmoid) | TRUE |
Memory aid for medial wall (anterior → posterior): "My Little Eye Sees" = Maxilla (frontal process) → Lacrimal bone → Ethmoid (lamina papyracea) → Sphenoid (lesser wing)
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