mandibular arch

Examples of mandibular arch in the following topics:

• Fourth Week of Development

  • During the fourth week of development, the first pharyngeal arch, also called the mandibular arch, is the first of six pharyngeal arches that begins to develop.
  • A schematic of a developing fetus with the first, second, and third arches labeled.

• Development of the Cardiovascular System

  • The aortic arches—or pharyngeal arch arteries—are a series of six, paired, embryological vascular structures that give rise to several major arteries .
  • It passes through the ring of the stapes and divides into supraorbital, infraorbital, and mandibular branches that follow the three divisions of the trigeminal nerve.
  • The infraorbital and mandibular branches arise from a common stem, the terminal part of which anastomoses with the external carotid.
  • The common stem of the infraorbital and mandibular branches passes between the two roots of the auriculotemporal nerve and becomes the middle meningeal artery.
  • The third aortic arch constitutes the commencement of the internal carotid artery, and is named the carotid arch.

• Arches, Vaults, and Domes

  • This is sometimes referred to as arch action.
  • As the forces in the arch are carried to the ground, the arch will push outward at the base; this is called thrust.
  • Circular arches, also referred to as rounded arches, were commonly employed by the builders of ancient, heavy masonry arches.
  • The advantage of using a pointed arch rather than a circular arch is that the arch action in a pointed arch produces less thrust at the base.
  • Of any arch type, the parabolic arch produces the most thrust at the base, but can span the largest areas.

• Arch of the Aorta

  • The arch of the aorta follows the ascending aorta and begins at the level of the second sternocostal articulation of the right side.
  • The arch of the aorta, or the transverse aortic arch, is continuous with the upper border of the ascending aorta and begins at the level of the upper border of the second sternocostal articulation of the right side.
  • Three vessels come out of the aortic arch: the brachiocephalic artery, the left common carotid artery, and the left subclavian artery.
  • In approximately 20% of individuals, the left common carotid artery arises from the brachiocephalic artery rather than the aortic arch, and in approximately 7% of individuals the left subclavian artery also arises here.
  • This diagram shows the arch of the aorta and its branches.

• Arches and Domes

  • As the forces in an arch are carried toward the ground, the arch will push outward at the base (called thrust).
  • As the height of the arch decreases, the outward thrust increases.
  • The most common true arch configurations are the fixed arch, the two-hinged arch and the three-hinged arch.
  • The two-hinged arch is most often used to bridge long spans.
  • This type of arch has pinned connections at the base.

• Arches of the Feet

  • The arches of the foot are formed by the tarsal and metatarsal bones.
  • The longitudinal arch of the foot can be broken down into several smaller arches.
  • The main arches are the antero-posterior arches, which may, for descriptive purposes, be regarded as divisible into two types—a medial and a lateral.
  • In contrast, the lateral longitudinal arch is very low.
  • In addition to the longitudinal arches, the foot presents a series of transverse arches.

• Trigeminal (V) Nerve

  • It is derived from the fact that each nerve, one on each side of the pons, has three major branches: the ophthalmic nerve (V1 in the illustration below), the maxillary nerve (V2), and the mandibular nerve (V3) .
  • The mandibular nerve has both sensory and motor functions.
  • The motor component of the mandibular division (V3) of the trigeminal nerve controls the movement of eight muscles, including the four muscles of mastication: the masseter, the temporal, and the medial and lateral pterygoids.
  • The ophthalmic nerve branch (V1) innervates the bright red area, the maxillary nerve branch (V2) innervates the light red area, and the mandibular nerve branch (V3) innervates the yellow area.

• Dislocated Mandible

  • A dislocated mandible or jaw occurs at the temporomandibular joint: the mandibular condyles and the temporal bone fail to align correctly.
  • This joint is located where the mandibular condyles and the temporal bone meet.
  • The muscles that are affected during anterior jaw dislocation are the masseter and temporalis, which pull up on the mandible, and the lateral pterygoid, which relaxes the mandibular condyle.
  • This dislocation will push the jaw back, affecting the alignment of the mandibular condyle and mastoid.

• Roman Architecture under the Republic

  • An arch is a pure compression form.
  • As the forces in the arch are carried to the ground, the arch will push outward at the base, called thrust.
  • Multiple arches can be used together to create a vault.
  • Roman aqueducts are another iconic use of the arch.
  • The arches that make up an aqueduct provided support without requiring the amount of building material necessary for arches supported by solid walls.

• Flatfoot and Clawfoot

  • Flatfoot and crowfoot are medical conditions that appear as flat and high arches, respectively.
  • The appearance of flat feet is normal and common in infants, partly due to "baby fat" which masks the developing arch, and partly because the arch has not yet fully developed.
  • Flat arches in children usually become proper arches and high arches while the child progresses through adolescence and into adulthood.
  • A high arch is the opposite of a flat foot, and somewhat less common.
  • High arch in foot of a person with a hereditary neuropathy.