ORBICULARIS OCULI

 ORBICULARIS OCULI

Orbicularis oculi is a muscle located in the orbital region of the face. 

PARTS:-

It consists of three parts. 

1. Orbital part

2. Palpebral part

3. Lacrimal part

ORBITAL PART:-

On and around the orbital margin. 

Origin

It arises from medial part of medial palpebral ligament, frontal process of maxilla and nasal part of frontal bone. 

Insertion

Concentric rings returns to the point of origin. 

Actions

Protects eye from bright light, wind and rain. 

Cause forceful closure of eyelids. 

PALPEBRAL PART:-

In the lids

Origin

Lateral part if medial palpebral ligament. 

Insertion

Lateral palpebral raphae. 

Action

Closes lids gently as in blinking and sleeping. 

LACRIMAL PART:-

Lateral and deep to the lacrimal sac. 

Origin

Lacrimal fascia and posterior lacrimal crest, forms sheath for lacrimal sac. 

Insertion

Pass laterally in front of tarsal plates of both the eyelids. 

Action

Dilates lacrimal sac for sucking of lacrimal fluid into the sac, directs lacrimal puncta into lacus lacrimalis, supports the lower lid.

DIAGRAM:-

INNERVATION:-

Orbicularis oculi is innervated by the zygomatic and temporal branch of facial nerve ( cranial nerve vii). 

BLOOD SUPPLY:-

Orbicularis oculi receives arterial blood from three branches of the external carotid artery. 

1. Maxillary

2. Superficial temporal

3. Facial arteries

The ophthalmic artery, a branch of the internal carotid artery, also supplies the muscle. 

APPLIED ANATOMY:-

1. CROW'S FEET:-

The contraction of entire orbicularis oculi draws the skin of forehead, temple, and cheek towards the lateral angle of the eye, Producing radiating skin folds from the lateral angle of the eye, which may be a permanent feature in some old people forming the so called crow's feet. 

2. ECTROPION:-

The paralysis of orbicularis oculi results in drooping of the lower eyelid ( ectropion) causing spilling of tear on the cheek ( epiphora ).