Lacrimal Gland

 👁️ Lacrimal Gland: Overview

• A serous, exocrine gland that produces the aqueous layer of the tear film

• Located in the superolateral part of the orbit (above the eyeball)

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📍 Location & Structure

• Found in the lacrimal fossa of the frontal bone

• Lies in the upper outer quadrant of the orbit

• Divided into two parts by the levator palpebrae superioris aponeurosis:

  1. Orbital lobe – larger, located in the lacrimal fossa

  2. Palpebral lobe – smaller, lies below the aponeurosis

👉 Both lobes are continuous but separated anatomically.

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🧬 Function of the Lacrimal Gland

• Secretes the aqueous (watery) layer of the tear film, which:

  • Provides oxygen and nutrients to the cornea

  • Washes away debris and microbes

  • Contains lysozyme, lactoferrin, and IgA for immune defense

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🧠 Innervation

Type	Nerve	Function
Sensory	CN V₁ (Ophthalmic - lacrimal nerve)	Sensory innervation
Parasympathetic	CN VII (via greater petrosal nerve → pterygopalatine ganglion)	Stimulates tear production
Sympathetic	From superior cervical ganglion (via deep petrosal nerve)	Vasoconstriction (modulates flow)

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🩸 Blood Supply & Lymphatics

• Arterial supply: Lacrimal artery (branch of the ophthalmic artery)

• Venous drainage: Lacrimal vein → superior ophthalmic vein

• Lymphatic drainage: Preauricular (parotid) lymph nodes

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🔁 Tear Drainage Pathway (for full context):

1. Tears flow across the eye surface (medially)

2. Drain through the lacrimal puncta (upper & lower eyelids)

3. Enter canaliculi → lacrimal sac

4. Flow into nasolacrimal duct

5. Drain into the inferior meatus of the nose
   👉 (why your nose runs when you cry)

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🧾 Clinical Relevance

• Dry eye (keratoconjunctivitis sicca): Decreased aqueous production

• Lacrimal gland tumor: Can cause painless swelling of the upper eyelid

• Dacryoadenitis: Inflammation/infection of the lacrimal gland (e.g., mumps, EBV)

• Sjogren’s syndrome: Autoimmune destruction of lacrimal (and salivary) glands