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.

• 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 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.

• 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.

• Development of the Heart

  • While the arterial system develops mainly from the aortic arches, the venous system arises from three bilateral veins during weeks four through eight of human development.
  • The human arterial system originates from the aortic arches and from the dorsal aortae starting from week four of human development.
  • Aortic arch 1 almost completely regresses except to form the maxillary arteries.
  • Aortic arch 2 also completely regresses except to form the stapedial arteries.
  • The definitive formation of the arterial system arise from aortic arches 3, 4 and 6, while aortic arch 5 completely regresses.

• Parts of a Vertebra

  • A vertebra consists of two parts: an anterior segment, or the vertebral body; and a posterior part, or the vertebral (neural) arch.
  • The posterior vertebral or neural arch that encloses the spinal cord.
  • The vertebral arch is formed from two, short, thick processes called pediments that extend posteriorly from the lateral sides of the vertebral body, before joining together at the midline with the laminae.
  • A single spinous process projects backwards and downwards from the center of the vertebral arch and it serves as a major attachment point for muscles and ligaments of the back.

• The Aorta and Its Branches

  • The aorta is the largest artery in the body and is divided into 3 parts: the ascending aorta, arch of the aorta, and descending aorta.
  • The aorta is divided into three parts: the ascending aorta, where the aorta initially leaves the heart and points superiorly toward the head; the arch of the aorta where the aorta changes direction; and the descending aorta where the aorta points inferiorly toward the feet.
  • The arch of the aorta has three branches: the brachiocephalic artery, which itself divides into right common carotid artery and the right subclavian artery, the left common carotid artery, and the left subclavian artery.
  • The aorta has three parts: the ascending, the arch and the descending.