VAN 121: Veterinary Gross Anatomy-II (2+2)

Muscles of the palpebral region /eyelids

MUSCLES OF THE EYELIDS / PALPEBERAL REGION

They are

• Orbicularis oculi
• Corrugator supercilli
• Malaris
  • Levator buccalis
  • Depressor palpebrae inferioris
• Levator palpebrae superioris

Orbicularis oculi

• It is a well-developed, flat, elliptical sphincter muscle around the eyelids. The muscle fibres are chiefly attached to the skin and the palpebral ligament at the medial canthus.
• Action: To close the eyelids.
• Blood supply: Alar and frontal arteries.
• Nerve supply: Facial nerve.

Corrugator supercilli

• The place of this muscle is taken up in the ox by the lower part of the frontalis muscle around the upper eye-lid.
• Action: It raises the upper eye-lid and wrinkles the skin.
• Blood supply: Frontal arteries.
• Nerve supply: Facial nerve.

Malaris

• It is a broad muscle spreading below the lower eyelid over the buccinator and masseter. It is divisible into an anterior part levator buccalis and a posterior part the depressor palpebrae inferioris.
  • Levator buccalis
    • Origin: Facial part of lacrimal bone
    • Insertion: Buccal mucosae, ventral to the facial tuberosity.
    • Action: To raise the posterior part of the cheek.
    • Blood supply: Malar branch of external maxillary artery.
    • Nerve supply:  Superior buccal and sub zygomatic nerve.
  • Depressor palpebrae inferioris
    • Origin: Facial part of lacrimal bone.
    • Insertion:  Fascia of the dorsal border of the buccinator.
    • Action:  It is attached to the lower eye-lid. It depresses the lower eyelid.
    • Blood supply:   a branch from external maxillary artery.
    • Nerve supply: Superior buccal and sub zygomatic nerve.

Levator palpebrae superioris

• It is situated with in the orbit above dorsal rectus muscle.
• Origin: Pterygoid crest opposite to the optic foramen.
• Insertion: Upper eyelid.
• Action: To raise the upper eye-lid.
• Blood supply:  Ophthalmic artery.
• Nerve supply: Oculomotor nerve.