Dissection of left orbit from an anterior approach

Inferior lacrimal part of orbicularis oculi muscle

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Image #53-2

Dissection of left orbit from an anterior approach

Inferior lacrimal part of orbicularis oculi muscle

The muscle fibers have been separated to show their inward extension toward the lacrimal fascia. This portion of the orbicularis muscle together with its counterpart in the upper eyelid is known as Horner's muscle. The underlying orbital septum (18) is not as distinctly membranous here as it is in the upper part of the orbit.

1. Infratrochlear nerve
2. Middle palpebral artery
3. Orbital septum
4. Origin of superior part of orbicularis oculi muscle
5. Medial palpebral ligament
6. Nasomaxillary suture
7. Origin of inferior part of orbicularis oculi muscle
8. Artery in periosteum
9. Lateral nasal cartilage
10. Deep vein (unnamed)
11. Medial horn of aponeurosis of levator palpebrae superioris muscle
12. Medial part of superior tarsalis muscle (Müller's muscle, composed here of connective tissue with no evident smooth muscle fibers)
13. Superior tarsus
14. Upper pointer: Superior lacrimal duct Lower pointer: Position of lacrimal puncta
15. Medial ocular angle (medial canthus)
16. Lacrimal part orbicularis. oculi muscle
17. Middle palpebral artery
18. Orbital septum
19. Infraorbital margin