S. End of internal jugular vein.
T. Bracheo-cephalic artery.
U U*. Roots of common carotid arteries.
V. Thyroid body.
W. Thyroid cartilage.
X. Hyoid bone.
Y. Hyo-glossus muscle.
Z. Upper maxillary bone.
2. Inferior maxillary branch of fifth cerebral nerve.
3. Digastric muscle cut.