A2 The Head Deep Structures

Question 1

Define the cavities & regions of the head

Answer 1

• Sinuses
• Nasal cavity
• Oral cavity

Question 2

Explain the boundaries of the oral cavity

Answer 2

Bounded by lips, cheeks, hard & soft palates & tongue

Question 3

Explain the boundaries of the nasal cavity

Answer 3

Extends from nostrils to the choanal opening
Divided into two halves by the nasal septum

Question 4

Describe the muscles of the tongue including their attachments, actions and innovation

Answer 4

Genioglossus: along floor of mouth, protrudes tongue cranially
Geniohyoideus: from incisive to hyoid, draws tongue cranially when swallowing
Mylohyoideus: from mandible to basihyoid bone, draws tongue cranially
Hyoglossus: origin at basihyoid to tongue, draws tongue caudally
Sternohyoideus: sternum to hyoid, pulls hyoid & tongue caudally
Styloglossus: origin at stylohyoid to tongue, elevates tongue

Hypoglossal nerve (CN Xll)

Question 5

Describe the structure & function of the hyoid apparatus

Answer 5

Provide attachment for the tongue and larynx to the skull
Prevent food entering the trachea

Tympanonyoid articulation
Stylonyoid bone
Epihyoid bone
Ceratohyoid bone
Basihyoid bone
Thyrohyoid bone
Epiglottic cartilage
Thyroid cartilage
Cricoid cartilage

Question 6

Describe the muscles of mastication including their attachments, actions & innovation

Answer 6

Temporalis m.
o: occupies temporal fossa
i: coronoid process of mandible
a: closes & retracts lower jaw
n: trigeminal nerve (CN V)

Master m.
o: ventral border of zygomatic arch
i: ventral-medial surface of mandible
a: lateral & rotational movement
n: trigeminal nerve (CN V)

Pterygoid m.
o: palatine & sphenoid bones
i: medial surface of mandible
a: closes jaw & moves mandible laterally
n: trigeminal nerve (CN V)

Digastricus m.
o: ventral border of mandible
i: occipital bone
a: opens jaw
n: rostral-trigeminal nerve (CN V), caudal - facial nerve (CN Vll)