21.The Orbit and Eyeball

The Face

Skeleton

Paired facial bones include:-

Unpaired facial bones include:-

Identify the parts of the mandible labelled above.

Muscles

Muscles of the face share four main characteristics :

• They are generally subcutaneous

• They are arranged around the orifices of the face, thus acting as sphincters and dilators

• They are innervated by facial nerve

• They are embryologically derived from the 2 nd branchial arch

Blood Vessels

The face receives a rich blood supply from both internal and external carotid arteries through various arteries:

Artery	Source	Region
Facial Artery	External carotid	Mandibular, maxillary, zygomatic and nasal parts
Supratrochlear Supraorbital	Opthalmic- internal carotid	Forehead

Zygomatico-facial Zygomatico- temporal Infraorbital	Maxillary - External carotid	Side of face, upper jaw
Mental	Maxillary – External carotid	Lower jaw

The veins accompany the arteries and intimately join the external and internal jugular veins

Lymphatics

• From the lower lip and chin – submental nodes

• From the forehead and cheeks – Submandibular nodes

• Around the ear – Pre –auricular nodes

Innervation

Sensory innervations is derived from the divisions of the trigeminal nerve

Forehead- Ophthalmic

Maxillary region – Maxillary

Mandibular region and anterior to the ear – Mandibular

Motor innervation is provided by branches of the facial nerve

CHAPTER 21 : The Orbit and Eyeball