Biology 122 Spring, 2008

Laboratory 20

Face, muscles of facial expression, parotid gland and anterior scalp

OBJECTIVES

At the end of this laboratory you should:

1. Know the names of the major muscles of facial expression and understand the deficits that would occur if each or all of the muscles were paralyzed. You should know the following muscles:

frontalis, orbicularis oculi (orbital and palpebral parts), levator labii superiorus, zygomaticus major, levator anguli oris, orbicularis oris, buccinator, depressor anguli oris, mentalis.

2. Be able to describe the course, relationships and distribution of the facial nerve and its branches distal to the stylomastoid foramen.

4. Know the distribution of the three main sensory branches of the trigeminal nerve (supraorbital, infraorbital and mentalis) and the areas that would be anesthetized if these nerves or their main branches in the face were blocked or lesioned.

5. Know the structure, position and relationships of the parotid gland and duct.

6. Know the course and distribution of the facial artery and its main branches and the superficial temporal artery.

7. The structure of the scalp, its organization into layers and the relationship of the epicranial aponeurosis to the scalping plane and periostium. Know the sensory innervation via branches of the trigeminal nerve and rami of cervical nerves (greater and lesser occipital nerves). Know the extensive blood supply by branches of the internal carotid and external carotid arteries.

PRELAB PREPARATION

1. Read those parts of your textbook dealing with the muscles of facial expression, the peripheral distribution of the trigeminal and facial nerves and the scalp (pp. 933-957).