arch
(arch 
)
[L. arcus, a bow]
An anatomical structure having a curved or bowlike outline.
SEE: arcus.
abdominothoracic a.Costal margin
alveolar a.The arch of the alveolar process of either jaw (maxillary and mand ibular).
aortic a.1In embryology, any of a series of six pairs of vessels that develop in the embryo and connect the aortic sac with the dorsal aorta. During the fifth to seventh weeks of gestation, the arches undergo transformation, some persisting as functional vessels, others persisting as rudimentary structures, and some disappearing entirely.2In anatomy, the termination of the ascending aorta. It begins at the level of the second costal cartilage, turns posterolaterally to the left, and terminates inferiorly as the thoracic aorta. It gives three branches: brachiocephalic trunk, left common carotid, and left subclavian.
axillary a.An anomalous muscular slip across the axilla, between the pectoralis major and latissimus dorsi muscles.
branchial a.In the embryo, any of five pairs of arched structures that form the lateral and ventral walls of the pharynx. In humans, the branchial arches are more properly called pharyngeal arches. There are five arches, each containing an arterial branch and a cranial nerve; thus structures derived from each arch are easily traced to their origin by their innervation. The arches are partially separated from one another externally by branchial (pharyngeal) clefts and internally by branchial (pharyngeal) pouches. The arches are important in the formation of structures of the face and neck. SYN: pharyngeal arch.
carotid a.The third aortic arch, which gives rise to the common carotid artery.
coracoacromial a.An umbrella-like complex superior to the lateral shoulder, composed of the undersurface of the acromion and the coracoacromial ligament.
deep crural a.A band of fibers arching in front of the sheath of femoral vessels. It is the downward extension of the transversalis fascia.SYN: Thompson ligament.
deep palmar a.An arch formed in the palm by the communicating branch of the ulnar and the radial artery.
dental a.The arch formed by the alveolar process and teeth in each jaw (maxillary and mand ibular). SYN: arcus dentalis.
a. of foot Any of the four vaulted structures in the foot: the internal (medial) longitudinal, the outer (lateral) longitudinal, and two transverse.
SEE: pillars of the fauces.
SEE: pillars of the fauces.
hemal a.1In lower vertebrates, any of the extensions from the lateral areas of the caudal vertebrae that fuse to enclose the caudal artery and vein. In humans these are represented by the costal processes of the vertebrae.2An arch formed by the body and dorsal processes of a vertebra.
hyoid a.The second branchial (pharyngeal) arch, which gives rise to the styloid process, the stylohyoid ligament, and the lesser cornu of the hyoid bone.
inferior tarsal a.The arch of the median palpebral artery that supplies the lower eyelid.
longitudinal a.The anteroposterior arch of the foot. The medial portion is formed by the calcaneus, talus, navicular, the three cuneiform bones, and the first three metatarsals; the lateral portion is formed by the calcaneus, cuboid, and the fourth and fifth metatarsals.
mand ibular a.1The composite structural arch of natural dentition and supporting tissues of the mand ible (lower jaw).2The residual bony ridge after teeth have been lost from the mand ible (lower jaw).
maxillary a.1The composite structural arch of the natural dentition and supporting tissues of the upper jaw (maxilla).2The residual bony ridge after teeth have been lost from the maxilla (upper jaw).
nasal a.An arch formed by the nasal bones and by the nasal processes of the maxilla.
neural a.The arch formed by the posterior projection of a vertebra that, with the body, encloses the vertebral foramen. SYN: vertebral arch.
palatine a.Either of two archlike folds of mucous membrane (glossopalatine and pharyngopalatine arches) that form the lateral margins of faucial and pharyngeal isthmuses. They are continuous above with the soft palate.
SEE: pillars of the fauces.
SEE: pillars of the fauces.
SEE: deep palmar arch; superficial palmar arch.
SEE: pillars of the fauces.
plantar a.The arch formed by the external plantar artery and the deep branch of the dorsalis pedis artery.
pubic a.The arch formed by the rami of the ischia and pubic bones. It forms the anterior portion of the pelvic outlet.
pulmonary a.The fifth aortic arch on the left side. It becomes the pulmonary artery.
superciliary a.An arch of the frontal bone lying just above the orbit, subjacent to the eyebrow, and directly above the supraorbital notch. SYN: superciliary ridge.
superficial palmar a.An arch in the palm forming the termination of the ulnar artery.
superior tarsal a.The arch of the median palpebral artery that supplies the upper eyelid.
supraorbital a.A bony arch formed by the upper margin of the orbit.
SEE: inferior tarsal arch; superior tarsal arch.
thyrohyoid a.The third branchial (“pharyngeal”) arch; it gives rise to the greater cornu of the hyoid bone.
transverse a.The transverse arch of the foot formed by the navicular, cuboid, cuneiform, and metatarsal bones.
zygomatic a.The formation, on each side of the cheeks, of the zygomatic process of each malar bone articulating with the zygomatic process of the temporal bone.