Pharyngeal Arches
Mesoderm of lateral wall of pharynx
Pharyngeal Arches I-VI
(rostro-caudal sequence)
V and VI not visible externally
Core of Mesoderm
Inner surface endoderm
Surface ectoderm
in humans V does not form/regresses rapidly
artery
nerve
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)