The pharyngeal arches, also known as visceral arches'','' are structures seen in the

embryonic development An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...

s that are recognisable precursors for many structures. In

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

, the arches are known as the

branchial arches Branchial arches, or gill arches, are a series of bony "loops" present in fish, which support the gills. As gills are the primitive condition of vertebrates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arc ...

, or gill arches. In the

human embryo Human embryonic development, or human embryogenesis, is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of de ...

, the arches are first seen during the fourth week of

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped *Photographi ...

. They appear as a series of outpouchings of

mesoderm The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.Langman's Medical E ...

on both sides of the developing

pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...

. The vasculature of the pharyngeal arches is known as the

aortic arches The aortic arches or pharyngeal arch arteries (previously referred to as branchial arches in human embryos) are a series of six paired embryological vascular structures which give rise to the great arteries of the neck and head. They are ventral ...

. In fish, the branchial arches support the

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

Structure

In vertebrates, the pharyngeal arches are derived from all three

germ layers A germ layer is a primary layer of cells that forms during embryonic development. The three germ layers in vertebrates are particularly pronounced; however, all eumetazoans (animals that are sister taxa to the sponges) produce two or three pri ...

(the primary layers of cells that form during embryogenesis).

Neural crest cells Neural crest cells are a temporary group of cells unique to vertebrates that arise from the embryonic ectoderm germ layer, and in turn give rise to a diverse cell lineage—including melanocytes, craniofacial cartilage and bone, smooth muscle, Per ...

enter these arches where they contribute to features of the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

and

facial skeleton The facial skeleton comprises the ''facial bones'' that may attach to build a portion of the skull. The remainder of the skull is the braincase. In human anatomy and development, the facial skeleton is sometimes called the ''membranous viscerocr ...

such as bone and cartilage. However, the existence of pharyngeal structures before neural crest cells evolved is indicated by the existence of neural crest-independent mechanisms of pharyngeal arch development. The first, most anterior

pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arch ...

gives rise to the oral jaw. The second arch becomes the

hyoid The hyoid bone (lingual bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies between the base of the mandible and the third cervical vertebra. ...

and jaw support. In fish, the other posterior arches contribute to the branchial skeleton, which support the gills; in tetrapods the anterior arches develop into components of the ear, tonsils, and thymus. The genetic and developmental basis of pharyngeal arch development is well characterized. It has been shown that

Hox gene Hox genes, a subset of homeobox genes, are a group of related genes that specify regions of the body plan of an embryo along the head-tail axis of animals. Hox proteins encode and specify the characteristics of 'position', ensuring that the cor ...

s and other developmental genes such as '' DLX'' are important for patterning the anterior/posterior and dorsal/ventral axes of the branchial arches. Some fish species have a second set of jaws in their throat, known as

pharyngeal jaws Pharyngeal jaws are a "second set" of jaws contained within an animal's throat, or pharynx, distinct from the primary or oral jaws. They are believed to have originated as modified gill arches, in much the same way as oral jaws. Originally hypo ...

, which develop using the same genetic pathways involved in oral jaw formation. During human and all

, a series of pharyngeal arch pairs form in the developing

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

. These project forward from the back of the embryo toward the front of the face and neck. Each arch develops its own artery, nerve that controls a distinct muscle group, and skeletal tissue. The arches are numbered from 1 to 6, with 1 being the arch closest to the head of the embryo, and arch 5 existing only transiently. These grow and join in the ventral midline. The first arch, as the first to form, separates the mouth pit or

stomodeum The stomodeum, also called stomatodeum or stomatodaeum, is a depression between the brain and the pericardium in an embryo, and is the precursor to the mouth and the anterior lobe of the pituitary gland. Development The mouth is developed partly ...

from the

pericardium The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong connective tissue (fibrous pericardium), and an inner layer made of ...

. By differential growth the neck elongates and new arches form, so the pharynx has six arches ultimately. Each pharyngeal arch has a

cartilaginous Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck and ...

stick, a

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

component that differentiates from the cartilaginous tissue, an artery, and a

cranial nerve Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and ...

. Each of these is surrounded by

mesenchyme Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood or bone. The interactions between mesenchyme and epithelium help to form nearly every o ...

. Arches do not develop simultaneously but instead possess a "staggered" development. Pharyngeal pouches form on the

endodermal Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and mesoderm (middle layer). Cells migrating inward along the archenteron form the inner layer of the gastru ...

side between the arches, and

pharyngeal groove A pharyngeal groove (or branchial groove, or pharyngeal cleft) is made up of ectoderm unlike its counterpart the pharyngeal pouch on the endodermal side. The first pharyngeal groove produces the external auditory meatus (ear canal). The rest (2, ...

s (or clefts) form from the lateral

ectodermal The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from t ...

surface of the

neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

region to separate the arches. In fish the pouches line up with the clefts, and these thin segments become

s. In mammals the

endoderm Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and mesoderm (middle layer). Cells migrating inward along the archenteron form the inner layer of the gast ...

and

ectoderm The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from t ...

not only remain intact but also continue to be separated by a

layer. The development of the pharyngeal arches provides a useful landmark with which to establish the precise stage of embryonic development. Their formation and development corresponds to

Carnegie stages In embryology, Carnegie stages are a standardized system of 23 stages used to provide a unified developmental chronology of the vertebrate embryo. The stages are delineated through the development of structures, not by size or the number of days o ...

10 to 16 in

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

, and

Hamburger–Hamilton stages In developmental biology, the Hamburger–Hamilton stages (HH) are a series of 46 chronological stages in chicken, chick development, starting from laying of the egg and ending with a newly hatched chick. It is named for its creators, Viktor Hambu ...

14 to 28 in the

chicken The chicken (''Gallus gallus domesticus'') is a domesticated junglefowl species, with attributes of wild species such as the grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster or cock is a term for an adult m ...

. Although there are six pharyngeal arches, in humans the fifth arch exists only transiently during

embryogenesis An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...

First arch

The first pharyngeal arch also mandibular arch (corresponding to the first branchial arch or gill arch of

), is the first of six pharyngeal arches that develops during the fourth week of

.William J. Larsen (2001). Human embryology. Edinburgh: Churchill Livingstone. It is located between the

and the

first pharyngeal groove In the embryonic development of vertebrates, pharyngeal pouches form on the endodermal side between the pharyngeal arches. The pharyngeal grooves (or clefts) form the lateral ectodermal surface of the neck region to separate the arches. The pouch ...

Processes

This arch divides into a maxillary process and a

mandibular process The mandibular prominence is an embryological structure which gives rise to the lower portion of the face. The mandible and lower lip derive from it. The mesenchymal cells within the mandibular prominence condense to form Meckel's cartilage. It i ...

, giving rise to structures including the

bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...

s of the lower two-thirds of the face and the jaw. The maxillary process becomes the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

(or upper jaw, although there are large differences among animals), and

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 sepa ...

while the mandibular process becomes the

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...

or lower jaw. This arch also gives rise to the

muscles of mastication There are four classical muscles of mastication. During mastication, three muscles of mastication (''musculi masticatorii'') are responsible for adduction of the jaw, and one (the lateral pterygoid) helps to abduct it. All four move the jaw late ...

Meckel's cartilage

Meckel's cartilage In humans, the cartilaginous bar of the mandibular arch is formed by what are known as Meckel's cartilages (right and left) also known as Meckelian cartilages; above this the incus and malleus are developed. Meckel's cartilage arises from the first ...

forms in the

of the mandibular process and eventually regresses to form the

incus The ''incus'' (plural incudes) or anvil is a bone in the middle ear. The anvil-shaped small bone is one of three ossicles in the middle ear. The ''incus'' receives vibrations from the ''malleus'', to which it is connected laterally, and transmit ...

and

malleus The malleus, or hammer, is a hammer-shaped small bone or ossicle of the middle ear. It connects with the incus, and is attached to the inner surface of the eardrum. The word is Latin for 'hammer' or 'mallet'. It transmits the sound vibrations fro ...

of the

middle ear The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear). The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the ...

, the anterior ligament of the malleus and the

sphenomandibular ligament The sphenomandibular ligament (internal lateral ligament) is one of the three ligaments of the temporomandibular joint. It is situated medially to - and generally separate from - the articular capsule of the joint. Superiorly, it is attached to the ...

. The

or lower jaw forms by perichondral

ossification Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

using Meckel's cartilage as a 'template', but the maxillary does ''not'' arise from direct ossification of Meckel's cartilage.

Derivatives

The skeletal elements and muscles are derived from mesoderm of the pharyngeal arches. Skeletal *

and

of the

and

spine of sphenoid bone The sphenoidal spine (Latin: "''spina angularis''") is a downwardly directed process at the apex of the great wings of the sphenoid bone that serves as the origin of the sphenomandibular ligament. Additional images File:Spine of sphenoid bone.p ...

palatine bone In anatomy, the palatine bones () are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxillae, they comprise the hard palate. (''Palate'' is derived from the Latin ''pa ...

squamous part of temporal bone The squamous part of temporal bone, or temporal squama, forms the front and upper part of the temporal bone, and is scale-like, thin, and translucent. Surfaces Its outer surface is smooth and convex; it affords attachment to the temporal muscle ...

anterior ligament of malleus The ligaments of malleus are three ligaments that attach the malleus in the middle ear. They are the anterior, lateral and superior ligaments. The anterior ligament of the malleus also known as Casserio's ligament is a fibrous band that extends ...

Muscles *

(chewing) **

masseter In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it ...

** medial and

lateral pterygoid muscle The lateral pterygoid muscle (or external pterygoid muscle) is a muscle of mastication. It has two heads. It lies superior to the medial pterygoid muscle. It is supplied by pterygoid branches of the maxillary artery, and the lateral pterygoid ner ...

s **

temporalis In anatomy, the temporalis muscle, also known as the temporal muscle, is one of the muscles of mastication (chewing). It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomatic a ...

mylohyoid muscle The mylohyoid muscle or diaphragma oris is a paired muscle of the neck. It runs from the mandible to the hyoid bone, forming the floor of the oral cavity of the mouth. It is named after its two attachments near the molar teeth. It forms the floor ...

digastric muscle The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a small muscle located under the jaw. The term "digastric muscle" refers to this specific muscle. However, other muscles that have two separate muscle bellie ...

, anterior belly *

tensor veli palatini muscle The tensor veli palatini muscle (tensor palati or tensor muscle of the velum palatinum) is a broad, thin, ribbon-like muscle in the head that tenses the soft palate. Structure The tensor veli palatini is found anterior-lateral to the levator ve ...

tensor tympani muscle The tensor tympani is a muscle within the middle ear, located in the bony canal above the bony part of the auditory tube, and connects to the malleus bone. Its role is to dampen loud sounds, such as those produced from chewing, shouting, or thunde ...

Other

Mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...

and glands of the

anterior two thirds of the tongue The tongue is a muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper surfa ...

are derived from

and

of the arch.

Nerve supply

The mandibular and maxillary branches of the

trigeminal nerve In neuroanatomy, the trigeminal nerve ( lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for sensation in the face and motor functions such as biting and chewin ...

(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 The chorda tympani is a branch of the facial nerve that originates from the taste buds in the front of the tongue, runs through the middle ear, and carries taste messages to the brain. It joins the facial nerve (cranial nerve VII) inside the facia ...

(branch of facial nerve) is the pre-trematic nerve. This double innervation is reflected in the nerve supply of anterior two-thirds of

tongue The tongue is a muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper surfa ...

which is derived from the first arch.

Blood supply

The artery of the first arch is the first

aortic arch The aortic arch, arch of the aorta, or transverse aortic arch () is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea. Structure The aorta begins a ...

,McMinn, R., 1994. ''Last's anatomy: Regional and applied (9th ed).'' which partially persists as the

maxillary artery The maxillary artery supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible. Structure The maxillary artery, the larger of the two terminal branches of the external carotid artery ...

Second arch

The second pharyngeal arch or hyoid arch, is the second of fifth pharyngeal arches that develops in fetal life during the fourth week of development and assists in forming the side and front of the

Reichert's cartilage

Cartilage in the second pharyngeal arch is referred to as Reichert's cartilage and contributes to many structures in the fully developed adult. In contrast to the

of the

first pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arch ...

it does not constitute a continuous element, and instead is composed of two distinct cartilaginous segments joined by a faint layer of

. Dorsal ends of Reichert's cartilage

ossify Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in th ...

during development to form the

stapes The ''stapes'' or stirrup is a bone in the middle ear of humans and other animals which is involved in the conduction of sound vibrations to the inner ear. This bone is connected to the oval window by its annular ligament, which allows the foot ...

of the

before being incorporated into the middle ear cavity, while the ventral portion ossifies to form the lesser cornu and upper part of the body of the

hyoid bone The hyoid bone (lingual bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies between the base of the mandible and the third cervical vertebr ...

. Caudal to what will eventually become the

, Reichert's cartilage also forms the styloid process of the

temporal bone The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears. Th ...

. The cartilage between the

and styloid process will not remain as development continues, but its

perichondrium The perichondrium (from Greek el, περί, peri, around, label=none and el, χόνδρος, chondros, cartilage, label=none) is a layer of dense irregular connective tissue that surrounds the cartilage of developing bone. It consists of two sep ...

will eventually form the

stylohyoid ligament The stylohyoid ligament is a ligament that connects the hyoid bone to the temporal styloid process (of the temporal bone of the skull). Structure The stylohyoid ligament connects the lesser horn of hyoid bone to the styloid process of the ...

Derivatives

Skeletal From the cartilage of the second arch arises *

Stapes The ''stapes'' or stirrup is a bone in the middle ear of humans and other animals which is involved in the conduction of sound vibrations to the inner ear. This bone is connected to the oval window by its annular ligament, which allows the foot ...

, *

Temporal styloid process The temporal styloid process is a slender bony process of the temporal bone extending downward and forward from the undersurface of the temporal bone just below the ear. The styloid process gives attachments to several muscles, and ligaments. Stru ...

, *

Stylohyoid ligament The stylohyoid ligament is a ligament that connects the hyoid bone to the temporal styloid process (of the temporal bone of the skull). Structure The stylohyoid ligament connects the lesser horn of hyoid bone to the styloid process of the ...

, and *

Lesser cornu The hyoid bone (lingual bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies between the base of the mandible and the third cervical vertebra ...

of the

. Muscles *

Facial muscles The facial muscles are a group of striated skeletal muscles supplied by the facial nerve (cranial nerve VII) that, among other things, control facial expression. These muscles are also called mimetic muscles. They are only found in mammals, alth ...

Occipitofrontalis The occipitofrontalis muscle (epicranius muscle) is a muscle which covers parts of the skull. It consists of two parts or bellies: the occipital belly, near the occipital bone, and the frontal belly, near the frontal bone. It is supplied by the ...

muscle *

Platysma The platysma muscle is a superficial muscle of the human neck that overlaps the sternocleidomastoid. It covers the anterior surface of the neck superficially. When it contracts, it produces a slight wrinkling of the neck, and a "bowstring" effect ...

Stylohyoid The stylohyoid muscle is a slender muscle, lying anterior and superior of the posterior belly of the digastric muscle. It is one of the suprahyoid muscles. It shares this muscle's innervation by the facial nerve, and functions to draw the hyoid ...

muscle *Posterior belly of

Stapedius The stapedius is the smallest skeletal muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes or strirrup bone of the middle ear. Structure The stapedius emerges from ...

muscle *Auricular muscles

Nerve supply

Facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of tas ...

(CN VII)

Blood supply

The artery of the second arch is the second

, which gives origin to the

stapedial artery In human anatomy, the stapedial branch of posterior auricular artery, or stapedial artery for short, is a small artery supplying the stapedius muscle in the inner ear. Structure In humans In humans, the stapedial artery is normally present in the ...

in some mammals but atrophies in humans.

Muscles derived from the pharyngeal arches

Pharyngeal muscles or Branchial muscles are

striated muscle Striations means a series of ridges, furrows or linear marks, and is used in several ways: * Glacial striation * Striation (fatigue), in material * Striation (geology), a ''striation'' as a result of a geological fault * Striation Valley, in Ant ...

s of the head and neck. Unlike

skeletal muscles Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle ...

that developmentally come from

somites The somites (outdated term: primitive segments) are a set of bilaterally paired blocks of paraxial mesoderm that form in the embryonic stage of somitogenesis, along the head-to-tail axis in segmented animals. In vertebrates, somites subdivide i ...

, pharyngeal muscles are developmentally formed from the pharyngeal arches. Most of the skeletal musculature supplied by the cranial nerves (

special visceral efferent Special visceral efferent fibers (SVE) are the efferent nerve fibers that provide motor innervation to the muscles of the pharyngeal arches in humans, and the branchial arches in fish. Some sources prefer the term "branchiomotor" or "branchial eff ...

) is pharyngeal. Exceptions include, but are not limited to, the

extraocular muscles The extraocular muscles (extrinsic ocular muscles), are the seven extrinsic muscles of the human eye. Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye and the ot ...

and some of the muscles of the tongue. These exceptions receive

general somatic efferent The general (spinal) somatic efferent neurons (GSE, somatomotor, or somatic motor fibers), arise from motor neuron cell bodies in the ventral horns of the gray matter within the spinal cord. They exit the spinal cord through the ventral roots, carr ...

innervation.

First arch

All of the

pharyngeal muscles The pharyngeal muscles are a group of muscles that form the pharynx, which is posterior to the oral cavity, determining the shape of its lumen, and affecting its sound properties as the primary resonating cavity. The pharyngeal muscles (involunta ...

that come from the first pharyngeal arch are innervated by the mandibular divisions of the

. These muscles include all the

, the anterior belly of the

digastric The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a small muscle located under the jaw. The term "digastric muscle" refers to this specific muscle. However, other muscles that have two separate muscle bellie ...

, the mylohyoid,

tensor tympani The tensor tympani is a muscle within the middle ear, located in the bony canal above the bony part of the auditory tube, and connects to the malleus bone. Its role is to dampen loud sounds, such as those produced from chewing, shouting, or thunde ...

, and

tensor veli palatini The tensor veli palatini muscle (tensor palati or tensor muscle of the velum palatinum) is a broad, thin, ribbon-like muscle in the head that tenses the soft palate. Structure The tensor veli palatini is found anterior-lateral to the levator ve ...

Second arch

All of the pharyngeal muscles of the second pharyngeal arch are innervated by the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of tas ...

. These muscles include the

muscles of facial expression The facial muscles are a group of striated skeletal muscles supplied by the facial nerve (cranial nerve VII) that, among other things, control facial expression. These muscles are also called mimetic muscles. They are only found in mammals, al ...

, the posterior belly of the

, the

stylohyoid The stylohyoid muscle is a slender muscle, lying anterior and superior of the posterior belly of the digastric muscle. It is one of the suprahyoid muscles. It shares this muscle's innervation by the facial nerve, and functions to draw the hyoid ...

muscle, the auricular muscle and the

stapedius The stapedius is the smallest skeletal muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes or strirrup bone of the middle ear. Structure The stapedius emerges from ...

muscle of the middle ear.

Third arch

There is only one muscle of the third pharyngeal arch, the

stylopharyngeus The stylopharyngeus is a muscle in the head that stretches between the temporal styloid process and the pharynx. Structure The stylopharyngeus is a long, slender muscle, cylindrical above, flattened below. It arises from the medial side of the ...

. The stylopharyngeus and other structures from the third pharyngeal arch are all innervated by the

glossopharyngeal nerve The glossopharyngeal nerve (), also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper Medulla oblongata, medulla, just anterior (closer to the nose) to t ...

Fourth and sixth arches

All the pharyngeal muscles of the fourth and sixth arches are innervated by the superior laryngeal and the recurrent laryngeal branches of the

vagus nerve The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right ...

. These muscles include all the muscles of the palate (exception of the

which is innervated by the

), all the muscles of the pharynx (except

which is innervated by the

), and all the muscles of the larynx.

In humans

Amniotes have five arches, numbered 1 to 5. Older literature reports the fifth arch as the sixth arch, the fifth being absent. More is known about the fate of the first arch than the remaining four. The first three contribute to structures above the larynx, whereas the last two contribute to the

larynx The larynx (), commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about ...

and

trachea The trachea, also known as the windpipe, is a Cartilage, cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends ...

. The

recurrent laryngeal nerve The recurrent laryngeal nerve (RLN) is a branch of the vagus nerve (cranial nerve X) that supplies all the intrinsic muscles of the larynx, with the exception of the cricothyroid muscles. There are two recurrent laryngeal nerves, right and le ...

s are produced from the nerve of arch 5, and the laryngeal cartilages from arches 4 and 5. The superior laryngeal branch of the vagus nerve arises from arch 4. Its arteries, which project between the nerves of the fourth and fifth arches, become the left-side arch of the aorta and the right

subclavian artery In human anatomy, the subclavian arteries are paired major arteries of the upper thorax, below the clavicle. They receive blood from the aortic arch. The left subclavian artery supplies blood to the left arm and the right subclavian artery supplie ...

. On the right side, the artery of arch 5 is obliterated while, on the left side, the artery persists as the

ductus arteriosus The ''ductus arteriosus'', also called the ''ductus Botalli'', named after the Italian physiologist Leonardo Botallo, is a blood vessel in the developing fetus connecting the trunk of the pulmonary artery to the proximal descending aorta. It allo ...

; circulatory changes immediately following birth cause the vessel to close down, leaving a remnant, the

ligamentum arteriosum The ligamentum arteriosum (arterial ligament), also known as the Ligament of Botallo or Harvey's ligament, is a small ligament attaching the aorta to the pulmonary artery. It serves no function in adults but is the remnant of the ductus arteriosus ...

. During growth, these arteries descend into their ultimate positions in the chest, creating the elongated recurrent paths.

References

External links

* {{Authority control Vertebrate anatomy Pharyngeal arches Animal developmental biology

Structure

First arch

Processes

Meckel's cartilage

Derivatives

Nerve supply

Blood supply

Second arch

Reichert's cartilage

Derivatives

Nerve supply

Blood supply

Muscles derived from the pharyngeal arches

First arch

Second arch

Third arch

Fourth and sixth arches

In humans

See also

References

External links