First branchial arch
Encyclopedia
The first branchial arch, also called the first pharyngeal arch and mandibular arch, is the first of six branchial arch
es that develops in fetal life during the fourth week of development. It is located between the stomodeum
and the first pharyngeal groove.
and a mandibular process, giving rise to structures including the bone
s of the lower two-thirds of the face and the jaw. The maxillary process becomes the maxilla (or upper jaw), and palate
while the mandibular process becomes the lower jaw. This arch also gives rise to the muscles of mastication.
forms in the mesoderm of the mandibular process and eventually regresses to form the incus
and malleus
of the middle ear
; the anterior ligament of the malleus and the sphenomandibular ligament
. The mandible or lower jaw forms by perichondral ossification
using Meckel's cartilage as a 'template', but the mandible does not arise from direct ossification of Meckel's cartilage.
Derivatives of the first arch:
and glands of the anterior two thirds of the tongue are derived from ectoderm
and endoderm
of the arch.
(CN V) innervate the structures derived from the corresponding processes of the first arch. In some lower animals ,each arch is supplied by two cranial nerves.The nerve of the arch itself runs along the cranial side of the arch and is called post-trematic nerve of the arch.Each arch also receives a branch from the nerve of the succeeding arch called the pre-trematic nerve which runs along the caudal border of the arch.In human embryo,a double innervation is seen only in the first pharyngeal arch.The mandibular nerve is the post-trematic nerve of the first arch and chorda tympani
(branch of facial nerve) is the pre-trematic nerve.This double innervation is reflected in the nerve supply of anterior two-thirds of tongue which is derived from the first arch.
Branchial arch
In the development of vertebrate animals, the pharyngeal arches are anlage for a multitude of structures. In humans, they develop during the fourth week in utero as a series of mesodermal outpouchings on the left and right sides of the developing pharynx...
es that develops in fetal life during the fourth week of development. It is located between the stomodeum
Stomodeum
The stomodeum, also called stomatodeum or stomatodaeum, is a depression between the brain and the pericardium in an embryo, and is the precursor of the mouth and the anterior lobe of the pituitary gland.-Structure:...
and the first pharyngeal groove.
Processes
This arch divides into a maxillary processMaxillary process
Maxillary process can refer to:* An alternate name for the maxillary prominence * The maxillary process of inferior nasal concha...
and a mandibular process, giving rise to structures including the bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
s of the lower two-thirds of the face and the jaw. The maxillary process becomes the maxilla (or upper jaw), and palate
Palate
The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...
while the mandibular process becomes the lower jaw. This arch also gives rise to the muscles of mastication.
Meckel's cartilage
Meckel's cartilageMeckel's cartilage
The cartilaginous bar of the mandibular arch is formed by what are known as Meckel’s cartilages also known as Meckelian cartilages; above this the incus and malleus are developed....
forms in the mesoderm of the mandibular process and eventually regresses to form the incus
Incus
The incus or anvil is the anvil-shaped small bone or ossicle in themiddle ear. It connects the malleus to the stapes. It was first described by Alessandro Achillini of Bologna.The incus transmits sound vibrations from the malleus to the stapes....
and malleus
Malleus
The malleus or hammer is a hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum...
of the middle ear
Middle ear
The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear has...
; the anterior ligament of the malleus and the sphenomandibular ligament
Sphenomandibular ligament
The sphenomandibular ligament is a flat, thin band which is attached above to the spina angularis of the sphenoid bone, and, becoming broader as it descends, is fixed to the lingula of the mandibular foramen...
. The mandible or lower jaw forms by perichondral ossification
Ossification
Ossification is the process of laying down new bone material by cells called osteoblasts. It is synonymous with bone tissue formation...
using Meckel's cartilage as a 'template', but the mandible does not arise from direct ossification of Meckel's cartilage.
Derivatives
The skeletal elements and muscles are detrived from mesoderm of the pharyngeal arches.Derivatives of the first arch:
Skeletal elements
- MalleusMalleusThe malleus or hammer is a hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum...
& IncusIncusThe incus or anvil is the anvil-shaped small bone or ossicle in themiddle ear. It connects the malleus to the stapes. It was first described by Alessandro Achillini of Bologna.The incus transmits sound vibrations from the malleus to the stapes....
of the middle ear - maxillaMaxillaThe maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
& mandible - spine of sphenoid bone
- Sphenomandibular ligamentSphenomandibular ligamentThe sphenomandibular ligament is a flat, thin band which is attached above to the spina angularis of the sphenoid bone, and, becoming broader as it descends, is fixed to the lingula of the mandibular foramen...
- palatine bonePalatine boneThe palatine bone is a bone in many species of the animal kingdom, commonly termed the palatum .-Human anatomy:...
- squamous part of temporal boneTemporal boneThe temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebrum.The temporal bone supports that part of the face known as the temple.-Parts:The temporal bone consists of four parts:* Squama temporalis...
- Anterior ligament of malleusAnterior ligament of malleusThe Anterior ligament of the malleus is a fibrous band that extends from the neck of the malleus just above its anterior process to the anterior wall of the tympanic cavity close to the petrotympanic fissure. Some of the fibers also pass through the fissure to the spine of sphenoid bone....
Muscles
- Muscles of masticationMuscles of masticationDuring mastication, four muscles of mastication are responsible for adduction and lateral motion of the jaw. Other muscles, usually associated with the hyoid such as the sternohyomastoid, are responsible for opening the jaw.-Muscles:*The masseter...
(chewing)- Masseter
- medial & lateral PterygoidPterygoidPterygoid can refer to:* Pterygoid processes of the sphenoid bone** The Lateral pterygoid plate by it* a muscle such as Lateral pterygoid muscle or Medial pterygoid muscle* a branch of the Mandibular nerve...
muscles - Temporalis muscles
- Mylohyoid muscleMylohyoid muscleThe mylohyoid muscle is a muscle running from the mandible to the hyoid bone, forming the floor of the oral cavity. It is named for its two attachments, with the prefix "mylo" coming from the Greek word for "molar". These muscles are mesodermal in origin...
- Digastric muscleDigastric muscleThe digastric muscle is a small muscle located under the jaw. so digastric muscles are muscle fibers in ligament of treitz ,omohyoid , occipitofrontalis....
, anterior belly - Tensor palati muscle
- Tensor tympani muscle
Other derivatives
Mucous membraneMucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
and glands of the anterior two thirds of the tongue are derived from ectoderm
Ectoderm
The "ectoderm" is one of the three primary germ cell layers in the very early embryo. The other two layers are the mesoderm and endoderm , with the ectoderm as the most exterior layer...
and endoderm
Endoderm
Endoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and mesoderm , with the endoderm as the intermost layer...
of the arch.
Nerve supply
The mandibular and maxillary branches of the trigeminal nerveTrigeminal nerve
The trigeminal nerve contains both sensory and motor fibres. It is responsible for sensation in the face and certain motor functions such as biting, chewing, and swallowing. Sensory information from the face and body is processed by parallel pathways in the central nervous system...
(CN V) innervate the structures derived from the corresponding processes of the first arch. In some lower animals ,each arch is supplied by two cranial nerves.The nerve of the arch itself runs along the cranial side of the arch and is called post-trematic nerve of the arch.Each arch also receives a branch from the nerve of the succeeding arch called the pre-trematic nerve which runs along the caudal border of the arch.In human embryo,a double innervation is seen only in the first pharyngeal arch.The mandibular nerve is the post-trematic nerve of the first arch and chorda tympani
Chorda tympani
The chorda tympani is a nerve that branches from the facial nerve inside the facial canal, just before the facial nerve exits the skull via the Stylomastoid foramen...
(branch of facial nerve) is the pre-trematic nerve.This double innervation is reflected in the nerve supply of anterior two-thirds of tongue which is derived from the first arch.
Blood supply
The artery of the first arch is the first aortic arch, which partially persists as the maxillary artery.External links
- Overview at University of Newcastle
- Overview at Howard UniversityHoward UniversityHoward University is a federally chartered, non-profit, private, coeducational, nonsectarian, historically black university located in Washington, D.C., United States...
- Mnemonic:First branchial arch