Pharyngeal Arches

Mesoderm of lateral wall of pharynx

Pharyngeal Arches I-VI
(rostro-caudal sequence)
Stage14_sem2l

V and VI not visible externally

Core of Mesoderm

Inner surface endoderm

Surface ectoderm

in humans V does not form/regresses rapidly

artery

nerve

Drawing-shows-the-pharyngeal-arches-cut-in-cross-section-2

Cartilage/muscle

1st pharyngeal arch (mandibular arch)

Blood and nerve supply:

Skeletal Derivatives:

Meckel's Cartilage

Muscles:

Tensor tympani

mylohyoid

Tensor veli palatini

Muscles of Mastication

Temporalis

Lateral pterygoid

Masseter

Medial Pterygoid

anterior belly of digastric

Maxillary artery

Maxillary + Mandibular br. of CN V

1st Pharyngeal Pouch
b/w 1st + 2nd arches

1st Pharyngeal Groove/Cleft
b/w 1st and 2nd arches

External Auditory Meatus

Middle ear + auditory tube (pharyngo-tympanic tube)

2nd Pharyngeal arch (hyoid)

Blood and Nerve Supply:

Skeletal Derivatives:

Muscles:

Hyoid + stapedial artery

CN VII (facial nerve)

Muscles of Facial Expression

Posterior belly of digastric

Stylohyoid

Stapedius

Procerus

Nasalis

Corrugator supersilii

Levator labii superioris alaeque nasi

Levator labii superioris

Orbicularis Oculi

Zygomaticus major

Zygomaticus minor

Depressor anguli oris

Depressor labii inferioris

Risorius

Levator anguli oris

Orbicularis oris

Levator palpebral superioris

Buccinator

Mentalis

Frontalis and galea aponeurotica

Platysma

Reichert's Cartilage

Styloid process

Stylohyoid ligament

Stapes (bone of mid. ear)

Lesser horn, upper body of hyoid bone

Sphenomandibular ligament

Tympanic ring

Incus + Malleus (middle ear bones)

3rd Pharyngeal arch

Muscles

Skeletal Derivatives

Blood and nerve supply

Internal carotid artery

Glossopharyngeal nerve (IX)

Stylopharyngeus

Greater horn +
Lower body of hyoid

2nd Pharyngeal groove/cleft
b/w 2nd + 3rd arches

2nd Pharyngeal pouch
b/w 2nd + 3rd arches

Supratonsillar fossa

Part of cervical sinus (temporary)

Palatine tonsil

IV-VI pharyngeal arches

Muscles

Skeletal derivatives

Blood and nerve supply

For VI arch: ductus arteriosus + proximal pulmonaries

For IV arch: Superior laryngeal branch of vagus (X) ) (sensory + motor) + pharyngeal branch (motor)

For IV arch: Proximal right subclavian + arch of aorta

For VI arch: Recurrent laryngeal branch of vagus (X) (sensory + motor)

All muscles of the larynx

All muscles of the pharynx and soft palate (except stylopharyngeus and tensor palati)

laryngeal cartilage

Cricoid cartilage

Arytenoid cartilage

Thyroid cartilage

Corniculate cartilage

Cuneiform cartilage

Clefts II-VI form the cervical sinus that is obliterated

Thin mesoderm b/w cleft 1 (ectoderm) and pouch one (endoderm) becomes tympanic mb (3 layers together)

3rd pharyngeal pouch b/w 3rd and 4th arches

4th pouch b/w 4th + 5th arches

Dorsal

Ventral

inferior parathyroid gland (parathyroid III)

Thymus

Dorsal

Ventral

superior parathyroid gland (parathyroid VI)

ultimobranchial body

parafollicular C cells (secrete calcitonin)