1. Pharyngeal cleft
   1. Ectodermal in origin
   2. 4 cleft persist
   3. At last 1 st cleft persist & forms EXTERNAL ACOUSTIC MEATUS
   4. Cervical sinus is filled with connective tissue & disappears, if persist known as cervical sinus.
2. Pharyngeal pouches
   1. 1 st pouch
      1. Tubo- Tympanic Recess forms Auditory tube & Middle ear cavity
   2. 2 nd pouch
      1. Palatine Tonsil
   3. 3 rd pouch
      1. Doral part : Parathyroid III
      2. Ventral part : Thymus
   4. 4 th pouch
      1. Dorsal part : parathyroid IV
      2. Ventral part : Lat. Thyroid
   5. 5th pouch
      1. Persist : ultimo branchial body
      2. Caudal pharyngeal complex —> ‘C’ cells of thyroid —> Calcitonin secretion
3. Development of face
   1. Face starts developing from the 4 th week of IUL
      1. Face is dominated by the frontal prominence of the overhanging forebrain.
      2. On both sides of frontal prominence are
         1. 1. Medial Nasal process 2. Lateral nasal process
      3. a. Maxillary processes grow to crowd the nasal processes closer together. b. Nasomedial processes grow quickly, pushing the frontal prominence, then fuse with the maxillary processes to complete the arch of upper jaw. c. Nasomedial process give rise to philtrum of lip
         1. Cleft: Cleft lip : failure of fusion of medial nasal process with maxillary process
      4. Oro optic groove is formed by fusion of maxillary process & nasal process
         1. If unfused then oblique facial cleft is formed
      5. Parts of palate Frontonasal process : Median part of upper lip Premaxilla : Primitive palate ( From FNP) maxillary process soft palate ( ms)—> 4 th pharyngeal arch
         1. Cleft: 1. B/L Cleft palate : failure of fusion of Premaxilla & palatal process 2. U/L Cleft palate : Non fusion of 1 palatal process of maxilla with premaxilla 3. Midline cleft : failure of fusion of palatal process 4.Bifid Uvula : Teratogenic drugs like phenytoin
4. Pharyngeal arches
   1. 1 st arch
      1. Muscles
         1. 4 muscles of mastication 1. Temporalis 2. Masseter 3. Medial pterygoid 4. Lateral pterygoid
         2. 4 other muscles 1. Mylohyoid 2. Ant. Belly of Digastric 3. Tensor tympani 4. Tensor veli palatini
            1. Mnemonic: MAT2
      2. Cartilage aka Meckel’s cartilage ( 5M)
         1. 1. Malleus & Incus 2. Malleolar ligament ( ant) 3. Mandibulo- sphenoid lig. 4. Maxilla( part) 5. Mandible( part)
      3. Artery
         1. Maxillary artery ( disappears)
            1. Inf. Alveolar artery
      4. Nerve
         1. Maxillary & Mandibular Division of V3
      5. Clinical
         1. Deformity 1. Treacher collin Syndrome 2. Pierre Robbin Syndrome
   2. 2 nd arch
      1. Muscles
         1. Facial muscles 1. Stylohyoid ms 2. Stapedius 3. Post. Belly of digastric 4. Platysma 5. Facial expression
            1. Mnemonic: SPF
      2. Cartilage aka Reichert’s cartilage
         1. 1. Stapes 2. Styloid process 3. Stylohyoid ligament 4. Smaller cornu of Hyoid 5. Sup. 1/2 body of Hyoid
      3. Artery
         1. Hyoid artery & stapedial artery both disappears
      4. Nerve
         1. Seventh cranial N ( facial nerve)
   3. 3 rd arch
      1. Muscle
         1. Stylopharyngeus
      2. Cartilage
         1. 1. Greater cornu of hyoid 2. Lower 1/2 of body of hyoid
      3. Artery
         1. Proximal part : common carotid artery distal part : Internal carotid artery New growth : External carotid artery
      4. Nerve
         1. Glossopharyngeal Nerve
   4. 4 th Arch
      1. Muscle
         1. Pharyngeal constrictors levator veli palatini Cricothyroid
            1. Note: All muscle of palate except TENSOR PALATINI All muscle of pharynx except STYLOPHARYNGEUS
      2. Cartilage
         1. 4th & 6th arch combines & forms laryngeal cartilage
      3. Artery
         1. 1. Arch of aorta 2. Rt. Subclavian artery
      4. Nerve
         1. Superior laryngeal nerve
   5. 5 th Arch
      1. Disappears
   6. 6 th Arch
      1. Muscle
         1. All muscles of Larynx, except cricothyroid
      2. Cartilage
         1. Combines with 4 th arch & forms laryngeal cartilage
      3. Artery
         1. Ductus arteriosus: disappears Normally if persist k/s patent ductus arteriosus
      4. Nerve
         1. Recurrent laryngeal nerve
5. Pharyngeal apparatus
   1. Near pharynx so called pharyngeal apparatus
   2. Pharyngeal apparatus consist of 3 layers
      1. Endoderm
         1. Endoderm outbulging b/w 2 arches k/a pouch
         2. 4 pouch persists
      2. Ectoderm
         1. Ectodermal indipping b/w 2 arches k/s cleft
         2. 4 cleft persists
      3. Mesoderm
         1. 6 Thickening gives 6 arches
         2. 5 th arch disappear
         3. 5 arch persist
   3. 6 mesoderm , 5 persist called 5 pharyngeal arches
      1. Within each arch 4 elements develop
         1. 1. Phr. Nerve 2. Phr. Muscle 3. Phr. Cartilage 4. Phr. Artery
6. Parts of embryo : Head bulge somites stoma ( mouth): cavity ( pharynx) cardiac bulge
7. Development of tongue
   1. Development of tongue from pharyngeal arches 1-4 & the occipital somites
      1. Embryonic precursor
         1. Adult structure
         2. Innervations
         3. Intermediate structure
      2. Pharyngeal arch 1
         1. Overgrown by lateral lingual swelling
         2. Mucosa of ant 2/3 rd of tongue
         3. Lingual nerve: General sensation
         4. Chorda tympani : special sensation ( taste)
         5. Median tongue bud
         6. Lateral lingual swelling
      3. Pharyngeal arch 2
         1. Overgrown by other structures
         2. Copula
      4. Pharyngeal arch 3
         1. Mucosa of post. 1/3 rd including circumvallate papilla
         2. Glossopharyngeal nerve
         3. Ventral part of hypopharyngeal eminence
      5. Pharyngeal arch 4
         1. Mucosa of small dorsal region of tongue
         2. Superior laryngeal nerve ( vagus)
         3. Dorsal part of hypo pharyngeal eminence
      6. Occipital somites
         1. Intrinsic muscles of tongue, palatoglossus muscle
         2. Hypoglossal nerve ( main) pharyngeal plexus
         3. Myoblasts
8. Development of Thyroid
   1. First endocrine gland to develop in IUL
   2. Developed from floor of pharynx ( area of developing tongue) , beigns as diverticulum at dorsum of tongue.
   3. Thyroid diverticulum elongates to form thyroglossal duct.
      1. Elongates downward infront of hyoid & thyroid cartilage , & divides in 2 parts
         1. Congenital Anomalies: 1. Thyroid agenesis : Failure of its formation 2. Lingual thyroid : failure of thyoid descend 3. Aberrant thyroid ( Retrosternal goiter): over- descend of thyroid gland in the thorax. 4. Thyroglossal cyst: persistance of a part of thyroglossal duct
   4. Ultimobrachial body gives parafollicular cells to TG
9. Lots of ‘M’
10. Lot’s of ‘S’