Anatomy, MBBS Second Year. This chapter is split into 4 topics and has
138 practice questions. The topics covered are listed below, followed by
10 free sample questions from the chapter.
Topics in this chapter
Autonomic targets and the sympathetic pathways36 questions
Horner's syndrome33 questions
Parasympathetic pathways, the ciliary ganglion and its lesion35 questions
Autonomic innervation of the lacrimal gland34 questions
Sample questions: HN 21. Autonomic innervation of the orbit
10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.
Q1. Which orbital structures receive autonomic innervation?
A. Only the extraocular muscles
B. The muscles (Muller's muscle, dilator pupillae, sphincter pupillae and ciliary muscle), the lacrimal gland and the arteries(correct answer)
C. Only the blood vessels
D. Only the lacrimal gland
Answer: B.Structures receiving autonomic innervation: (1) muscles — sympathetic to Muller's muscle and dilator pupillae, parasympathetic to sphincter pupillae and ciliary muscle; (2) the lacrimal gland — sympathetic (SCSG) and parasympathetic (VII nerve); (3) arteries — sympathetic (SCSG, internal carotid plexus).
Q2. Why is the sympathetic pathway to the orbit described as travelling with other nerves rather than forming its own named nerve?
A. Because the postganglionic fibres from the SCSG hitch-hike along the internal carotid plexus and then along the oculomotor, ophthalmic and nasociliary nerves to reach their targets(correct answer)
B. Because the fibres arise in the orbit
C. Because they travel in the short ciliary nerves only
D. Because they synapse in the ciliary ganglion
Answer: A.Sympathetic fibres from the SCSG run in the plexus around the internal carotid artery and are then distributed along existing nerves — the oculomotor nerve (to Muller's muscle) and the ophthalmic/nasociliary nerves (to the dilator pupillae) — rather than forming a separate sympathetic nerve.
Q3. Which statement about Horner's syndrome is correct?
A. It results from a lesion anywhere in the sympathetic pathway from the hypothalamus and reticular formation through T1 and the SCSG, producing incomplete ptosis, miosis, anhidrosis, enophthalmos and flushing of the face(correct answer)
B. It produces excessive sweating
C. It produces complete ptosis and mydriasis
D. It results from a lesion of the oculomotor nerve
Answer: A.Horner's syndrome follows a lesion in the sympathetic innervation — from the hypothalamus and reticular formation, through the descending fibres, T1 (ciliospinal centre) and the SCSG — giving incomplete ptosis (Muller's muscle), miosis (dilator pupillae), anhidrosis (sweat glands), enophthalmos and flushing of the face (vasodilation of blood vessels).
Q4. Which comparison of the short ciliary and long ciliary nerves is correct?
A. Long ciliary nerves arise from the ciliary ganglion
B. Short ciliary nerves carry only parasympathetic fibres
C. Short ciliary nerves arise from the ciliary ganglion (carrying sensory, parasympathetic and sympathetic fibres), while long ciliary nerves are branches of the nasociliary nerve carrying sympathetic and sensory fibres(correct answer)
D. Long ciliary nerves supply the ciliary muscle
Answer: C.Short ciliary nerves: from the ciliary ganglion (10 in number) carrying sensory (cornea/iris), parasympathetic (sphincter pupillae, ciliary muscle) and sympathetic (blood vessel) fibres. Long ciliary nerves: from the nasociliary nerve carrying sympathetic fibres to the dilator pupillae and sensory fibres (cornea/iris).
Q5. Which statement about the ciliary ganglion's roots and their distribution is correct?
A. The sensory root synapses in the ganglion
B. The sympathetic root synapses in the ganglion
C. Sensory root — nasociliary nerve (no synapse); parasympathetic root — oculomotor nerve via the nerve to the inferior oblique (synapses); sympathetic root — SCSG via the ICA plexus (no synapse); branches — 10 short ciliary nerves(correct answer)
D. All roots synapse in the ganglion
Answer: C.Ciliary ganglion roots: sensory (nasociliary — no synapse), parasympathetic (oculomotor via the nerve to the inferior oblique — synapses in the ganglion) and sympathetic (SCSG through the plexus around the ICA — no synapse); it gives 10 short ciliary nerves to the cornea and iris, sphincter pupillae and ciliary muscles, and blood vessels.
Q6. Which sequence describes the parasympathetic pathway to the lacrimal gland?
A. Facial nerve → ciliary ganglion → lacrimal gland
D. Superior salivatory nucleus → facial nerve → greater superficial petrosal nerve → joins the deep petrosal nerve → nerve of the pterygoid canal → pterygopalatine (sphenopalatine) ganglion → maxillary nerve → zygomatic nerve → zygomaticotemporal nerve → lacrimal nerve → lacrimal gland(correct answer)
Answer: D.Parasympathetic pathway to the lacrimal gland: superior salivatory nucleus → facial nerve → greater superficial petrosal nerve → joins the deep petrosal nerve → nerve of the pterygoid canal → pterygopalatine (sphenopalatine) ganglion → maxillary nerve → zygomatic nerve → zygomaticotemporal nerve → lacrimal nerve → lacrimal gland.
Q7. Which comparison of the parasympathetic and sympathetic routes to the lacrimal gland is correct?
A. The sympathetic fibres reach the gland via the zygomatic nerve
B. The sympathetic fibres synapse in the pterygopalatine ganglion
C. The parasympathetic fibres synapse in the pterygopalatine ganglion and reach the gland via the zygomatic and lacrimal nerves, while the sympathetic fibres come from the SCSG via the deep petrosal nerve and pass through the ganglion without synapsing(correct answer)
D. The parasympathetic fibres come from the SCSG
Answer: C.Parasympathetic: superior salivatory nucleus → facial nerve → greater superficial petrosal nerve → nerve of the pterygoid canal → pterygopalatine ganglion (synapse) → maxillary → zygomatic → zygomaticotemporal → lacrimal nerve. Sympathetic: SCSG → deep petrosal nerve (passes through the pterygopalatine ganglion without synapsing).
Q8. Which statement about the autonomic supply of the lacrimal gland is correct?
A. Its parasympathetic fibres travel with the oculomotor nerve
B. The parasympathetic supply is secretomotor (facial nerve via the greater superficial petrosal and Vidian nerves to the pterygopalatine ganglion), and the sympathetic supply comes from the SCSG via the deep petrosal nerve(correct answer)
C. Its fibres synapse in the ciliary ganglion
D. The lacrimal gland receives only sympathetic fibres
Answer: B.Lacrimal gland: parasympathetic (secretomotor) from the facial nerve via the greater superficial petrosal nerve and nerve of the pterygoid canal to the pterygopalatine ganglion, then via the maxillary, zygomatic, zygomaticotemporal and lacrimal nerves; sympathetic from the SCSG via the deep petrosal nerve.
Q9. Which statement summarises the autonomic innervation of the lacrimal gland?
A. The lacrimal gland is supplied only by the oculomotor nerve
B. It has no parasympathetic supply
C. Superior salivatory nucleus → facial nerve → greater superficial petrosal nerve → nerve of the pterygoid canal → pterygopalatine ganglion → maxillary → zygomatic → zygomaticotemporal → lacrimal nerve → gland (parasympathetic); SCSG → deep petrosal nerve (sympathetic); the gland also receives sensory fibres from the lacrimal nerve(correct answer)
D. Its fibres synapse in the ciliary ganglion
Answer: C.Autonomic innervation of the lacrimal gland: parasympathetic — superior salivatory nucleus → facial nerve → greater superficial petrosal nerve → joins the deep petrosal nerve → nerve of the pterygoid canal → pterygopalatine (sphenopalatine) ganglion → maxillary nerve → zygomatic nerve → zygomaticotemporal nerve → lacrimal nerve → lacrimal gland; sympathetic — SCSG via the deep petrosal nerve; sensory — lacrimal nerve.
Q10. Which statement about the autonomic nerves of the orbit as summarised in this lecture is correct?
A. All autonomic fibres of the orbit are sympathetic
B. Parasympathetic — oculomotor nerve via the nerve to the inferior oblique → ciliary ganglion → short ciliary nerves (sphincter pupillae, ciliary muscle); and facial nerve → greater superficial petrosal nerve → sphenopalatine ganglion (lacrimal gland). Sympathetic — from the ICA plexus along the long ciliary nerves (dilator pupillae), short ciliary nerves (blood vessels) and the branch of III to the levator (Muller's muscle)(correct answer)
C. Sympathetic fibres synapse in the ciliary ganglion
D. Parasympathetic fibres supply the dilator pupillae
Answer: B.Summary of autonomic nerves of the orbit. Parasympathetic: (1) oculomotor nerve → nerve to the inferior oblique → ciliary ganglion → short ciliary nerves → sphincter pupillae and ciliary muscle; (2) facial nerve → greater superficial petrosal nerve → sphenopalatine ganglion → lacrimal gland. Sympathetic: from the plexus around the internal carotid artery, distributed along (1) long ciliary nerves → dilator pupillae; (2) short ciliary nerves → blood vessels; (3) the branch of the III nerve to the levator palpebrae superioris → Muller's muscle.