The mandibular and hyoid arch

Hyoid arch

The second pharyngeal arch or hyoid arch assists in forming the side and front of the neck.-Skeletal elements:From the cartilage of the second arch arises*Stapes,*Styloid process,*Stylohyoid ligament, and...

es grow more rapidly than those behind them, with the result that the latter become, to a certain extent, telescoped within the former, and a deep depression, the cervical sinus, is formed on either side of the neck

Neck

The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...

.

This sinus is bounded in front by the hyoid arch

Hyoid arch

The second pharyngeal arch or hyoid arch assists in forming the side and front of the neck.-Skeletal elements:From the cartilage of the second arch arises*Stapes,*Styloid process,*Stylohyoid ligament, and...

, and behind by the thoracic wall

Thoracic wall

The thoracic wall is the boundary of the thoracic cavity.The bony portion is known as the thoracic cage. However, the wall also includes muscle, skin, and fascia....

; it is ultimately obliterated by the fusion of its walls.