ABSTRACT
The lacrimal gland:
is situated anterolaterally in the roof of the orbit
measures 5 × 12 × 20 mm
has two parts: a larger orbital part in the lacrimal fossa of the orbital roof and a smaller palpebral part lying below the aponeurosis of levator palpebrae superioris:
– the palpebral part is one-third the size of the orbital part
– the two parts of the gland are continuous with one another and do not lie within a definitive capsule
secretes the aqueous component of tears, with those produced by the orbital part passing through the palpebral part before release via 9–12 small ducts into the conjunctival sac
removal of the palpebral part leads to the gland becoming non-secreting
receives parasympathetic secretomotor supply:
– derived from the superior salivatory nucleus of the seventh cranial nerve
– reaches the pterygopalatine ganglion through the nervus intermedius and its greater petrosal branch
– post-ganglionic fibres run in the zygomaticotemporal and then lacrimal nerves
also receives sympathetic and sensory innervation
arterial supply is via the lacrimal artery, from the ophthalmic artery
venous drainage is into the ophthalmic vein
lymphatic drainage joins that of the conjunctiva and passes into the superficial parotid nodes
lobulated tubuloacinar structure:
– smaller ducts are lined by a monolayer of low columnar or cuboidal epithelium, larger ducts by a bilayer
– both parts have myoepithelial cells at their periphery
– secretory cells have basally located nuclei
– most secretory cells are of the serous type but some mucus-producing cells are also present
forms from a series of ectodermal buds that grow superolaterally from the superior fornix of the conjunctiva into the underlying mesenchyme. Development of levator palpebrae superioris muscle divides the gland into lacrimal and orbital parts.
