Pharyngeal Apparatus Lecture 2 PDF

Pharyngeal Apparatus, Face and Neck-I PHARYNGEAL APPARATUS MOHD ASIM KHAN [email protected] Drawings by:...

Pharyngeal Apparatus, Face and Neck-I PHARYNGEAL APPARATUS MOHD ASIM KHAN [email protected] Drawings by: ADDITIONAL RESOURCE Is Medical Student, Al Samir Campus (KKU-KSA) (Reproduced with permission from the author) https://www.youtube.com/watch?v=fp3Z_Y--0jo (Pharyngeal arches, tongue, thymus, and thyroid) LEARNING OBJECTIVES ▪ At the end of this lecture, the students should be able to: 1. Enumerate the components of the pharyngeal apparatus 2. Define pharyngeal arches, and give their number and source of development 3. Discuss the nerves of the pharyngeal arches 4. Define the components of the pharyngeal arches, and give the derivatives of these components in each pharyngeal arch 5. Describe pharyngeal clefts (grooves), pouches and membranes and enumerate their derivatives  PHARYNGEAL APPARATUS (BRANCHIAL APPARATUS) - Consists of the following: 1. Pharyngeal arches TELL Branchial: Greek, Gill Brachial: Relating to the arm The old term for pharyngeal arches is branchial arches 2. Pharyngeal pouches because they somewhat resemble the gills [branchia] of a fish 3. Pharyngeal grooves 4. Pharyngeal membranes Tsun - Contribute to the formation of the face and neck Plane for reference B Primitive pharynx after the formation of the pharyngeal arches Reference A : Netter’s Atlas of Human Embryology, By Cochard, 1st edition Reference B: Textbook of Clinical Embryology By Vishram Singh  Pharyngeal arches cut in cross section PHARYNGEAL ARCHES (BRANCHIAL ARCHES) Reference: Medical Embryology By Langman, 13th Edition ▪ Consists of a mesenchymal core (mesoderm and neural crest cells) a To ▪ Covered on the outside with ectoderm and lined on the inside with endoderm endoderm …………………………………………………………………………….. Reference: Before we are Born- Essentials of Embryology and Birth Defects, By Moore, 8th Edition * Each pharyngeal arch contains: ▪ Arterial component: - Aortic arch artery (Pharyngeal arch artery) Diagram-1 ▪ Skeletal component: - Cartilaginous rod that forms the skeletal of the arch ▪ Muscular component: - Primordium of the muscles in the head and neck ▪ Nerve component: - Supplies the mucosa and muscles derived from each arch …………………………………………………………………………….. Diagram-2 Pharyngeal arch arteries  SALIENT FEATURES OF VARIOUS COMPONENTS OF THE PHARYNGEAL APPARATUS I and Pharyngeal Arches - Five in number (1,2,3,4,6) [FIFTH PHARYNGEAL ARCH DEGENERATES IN HUMANS) - Present in the lateral wall and floor of the primitive pharynx Pharyngeal Clefts - Four in number (1,2,3,4) (=Pharyngeal Grooves) - Present externally between the arches and are lined by ectoderm s if Primitive pharynx after the formation of the pharyngeal arches Reference A : Netter’s Atlas of Human Embryology, By Cochard, 1st edition Reference B: Textbook of Clinical Embryology By Vishram Singh  SALIENT FEATURES OF VARIOUS COMPONENTS OF THE PHARYNGEAL APPARATUS Pharyngeal Pouches - Four in number (1,2,3,4) - Located internally between the two pharyngeal arches - Lined by endoderm 51 if Pharyngeal Membranes - Four in number (1,2,3,4) - Located between the two adjacent arches where pharyngeal cleft and pouches are opposed to each other membrang Primitive pharynx after the formation of the pharyngeal arches Reference A : Netter’s Atlas of Human Embryology, By Cochard, 1st edition Reference B : Textbook of Clinical Embryology By Vishram Singh  MNEMONIC DEVICE FOR PHARYNGEAL GROOVE (CLEFT) AND PHARYNGEAL POUCH Primitive pharynx after the formation of the pharyngeal arches Reference A: Textbook of Clinical Embryology By Vishram Singh Reference B: Netter’s Atlas of Human Embryology, By Cochard, 1st edition PHARYNGEAL GROOVE = Girl’s (Abaya) PHARYNGEAL CLEFT = Clothes Abaya is the outer (external) layer of clothes worn by muslim females Pharyngeal groove (cleft) is present externally between the pharyngeal arches Copyright (©) – Dr. Mohd Asim Khan- King Khalid University, Abha, KSA  PHARYNGEAL ARCHES AND THEIR NERVES PHARYNGEAL ARCH NERVE First arch (Mandibular arch) Trigeminal nerve 5ᵗʰcranialnerve ▪ Maxillary process of first arch: Maxillary nerve (Trigeminal nerve, V2) Second arch (Hyoid Arch) 8 ▪ Mandibular process of first arch: Mandibular nerve (Trigeminal nerve, V3) Facial nerve (CN VII) 7 Third arch Glossopharyngeal nerve (CN IX) 9 Fourth arch Superior laryngeal branch of vagus nerve (CN X) Sixth arch Recurrent laryngeal branch of vagus nerve (CN X) First pharyngeal arch D The first pharyngeal arch consists of a maxillary process (prominence) and a mandibular process (prominence), which can cause some confusion in numbering of the arches Reference A: Human Embryology, By Inderbir Singh, 11th edition Reference B: Netter’s Atlas of Human Embryology, By Cochard, 1st edition  MNEMONIC DEVICE FOR PHARYNGEAL ARCHES AND THEIR NERVES FIVE PHARYNGEAL (1,2,3,4,6) ARCHES BUT FIFTH ARCH DEGENERATES PHARYNGEAL ARCH CRANIAL NERVE CRANIAL NERVE NUMBER MNEMONIC DEVICE 7-2= 5 First arch (Mandibular arch) Trigeminal nerve SECONDS (7 ALPHABETS) V 7+2= 9 2 5 Second arch (Hyoid Arch) Facial nerve VII 2+5=7 2 7 5 Third arch Glossopharyngeal nerve 1X 7+2=9 Fourth arch Vagus nerve X 4 4+6=10 Sixth arch Vagus nerve X 6 Copyright (©) – Dr. Mohd Asim Khan- King Khalid University, Abha, KSA  STRUCTURES DERIVED FROM PHARYNGEAL ARCH COMPONENTS ARCH MUSCLES SKELETAL STRUCTURES LIGAMENTS First 1. Muscles of mastication ▪ Meckel’s cartilage 1. Anterior ligament of malleus 2. Sphenomandibular ligament (Mandibular) 2. Mylohyoid 1. Malleus 3. Anterior belly of digastric 2. Incus 4. Tensor tympani 1. Premaxilla 2. Maxilla 3. Temporal (part) 5. Tensor veli palatini 4. Zygomatic 5. Mandible Muscles derived from first pharyngeal arch Adult derivatives of the first pharyngeal arch cartilage and ligament Reference: Color Atlas of Clinical Embryology, By Moore, 2nd Edition  STRUCTURES DERIVED FROM PHARYNGEAL ARCH COMPONENTS ARCH MUSCLES SKELETAL STRUCTURES LIGAMENTS Second 1. Muscles of facial expression ▪ Reichert’s cartilage ▪ Reichert’s cartilage (Hyoid) 2. Stapedius 1. Stapes 1. Stylohyoid ligament 3. Stylohyoid 2. Styloid process of the temporal bone 4. Posterior belly of digastric 3. Lesser cornu (horn) of hyoid bone 4. Upper part of body of hyoid bone o O Muscles derived from second pharyngeal arch Adult derivatives of the second pharyngeal arch cartilage Reference: Color Atlas of Clinical Embryology, By Moore, 2nd Edition Reference: Medical Embryology by Langman, 9th Edition  STRUCTURES DERIVED FROM PHARYNGEAL ARCH COMPONENTS ARCH MUSCLES SKELETAL STRUCTURES Third Stylopharyngeus 1. Greater cornu (horn) of hyoid bone 2. Lower part of body of hyoid bone iIw6 Muscle derived from third pharyngeal arch Adult derivatives of the third pharyngeal arch cartilage Reference: Color Atlas of Clinical Embryology, By Moore, 2nd Edition Reference: Medical Embryology by Langman, 9th Edition  STRUCTURES DERIVED FROM PHARYNGEAL ARCH COMPONENTS ARCH MUSCLES SKELETAL STRUCTURES Fourth and Sixth 1. Cricothyroid 1. Thyroid cartilage 2. Levator veli palatini 2. Cricoid cartilage 3. Constrictors of pharynx 3. Arytenoid cartilage 4. Intrinsic muscles of larynx 4. Corniculate cartilage 5. Striated muscles of esophagus 5. Cuneiform cartilage g Reference: Color Atlas of Clinical Embryology, By Moore, 2nd Edition  PHARYNGEAL POUCHES endoderm that lines the foregut Evagination: Outpouching or protrusion of a layer or part 1. Evaginations of endoderm 2. Four pairs of pharyngeal pouches (1, 2, 3, 4) in human embryo 3. The fifth pair of pharyngeal pouch is rudimentary or absent 0 Primitive pharynx after the formation of the pharyngeal arches Development of the pharyngeal pouches Reference A: Textbook of Clinical Embryology By Vishram Singh Reference B: Medical Embryology By Langman, 13th Edition  FIRST PHARYNGEAL POUCH * Gives rise to the tubotympanic recess 1. The cavity of the tubotympanic recess gives rise to the tympanic cavity (middle ear cavity) and the mastoid antrum 2. The connection of the tubotympanic recess with the pharynx forms the pharyngotympanic tube (auditory tube or eustachian tube) a Horizontal section at 5 weeks (A) and 6 weeks (B) of the embryo showing pharyngeal apparatus Adult derivatives of first pharyngeal pouch Reference A: Before we are Born- Essentials of Embryology and Birth Defects, By Moore, 8th Edition Reference B: Netter’s Atlas of Human Embryology, By Cochard, 1st edition  FIRST PHARYNGEAL POUCH 1. The tubotympanic recess comes in contact with the epithelial lining of the first pharyngeal cleft, the future external auditory meatus first cleft 2. The first pharyngeal membrane contributes to the formation of the tympanic membrane (ear drum) Adult derivatives of first pharyngeal pouch and first pharyngeal membrane Reference A : Medical Embryology By Langman, 13th Edition Reference B: Before we are Born- Essentials of Embryology and Birth Defects, By Moore, 8th Edition  SECOND PHARYNGEAL POUCH 1. Forms palatine tonsils and tonsillar fossa (tonsillar sinus) IS Adult derivatives of second pharyngeal pouch Reference A: Medical Embryology By Langman, 13th Edition Reference B: Before we are Born- Essentials of Embryology and Birth Defects, By Moore, 8th Edition  THIRD AND FOURTH PHARYNGEAL POUCHES 0 Retrieved from: w https://thyroidutah.com/parathyroid-disorders.php Embryo at 4 or 5 weeks In PHARYNGEAL POUCH STRUCTURES DERIVED THIRD 1. Inferior parathyroid gland 2. Thymus FOURTH 1. Superior parathyroid gland 2. Ultimobranchial body Reference: Netter’s Atlas of Human Embryology, By Cochard, 1st edition  PHARYNGEAL GROOVE (PHARYNGEAL CLEFT) 1. Invaginations of ectoderm located between each pharyngeal arch 2. Four pairs of pharyngeal grooves (1, 2, 3, 4) in human embryo during 4th and 5th week Invagination: The condition of being folded inward Pharyngeal Pouches: Evaginations of endoderm Pharyngeal Grooves: Invaginations of ectoderm Pharyngeal grooves Primitive pharynx after the formation of the pharyngeal arches Reference A : Netter’s Atlas of Human Embryology, By Cochard, 1st edition Reference B : Textbook of Clinical Embryology By Vishram Singh  FIRST PHARYNGEAL GROOVE (FIRST PHARYNGEAL CLEFT) 1. The first pair of pharyngeal grooves contributes to the adult structures, external acoustic meatus (ear canal) 2. The other grooves lie in a slit-like depression, the cervical sinus that sinks below the 62,3 4 surface and disappears Adult derivatives of first pharyngeal groove, A and B Primitive pharynx after the formation of the pharyngeal arches Reference A: Before we are Born- Essentials of Embryology and Birth Defects, By Moore, 8th Edition Reference B: Textbook of Clinical Embryology By Vishram Singh  PHARYNGEAL MEMBRANES 1. Formed where the endoderm of the pharyngeal pouches contacts the ectoderm of the pharyngeal grooves 2. Four pairs of pharyngeal membranes (1, 2, 3, 4) 3. First pair of pharyngeal membrane forms the definitive structure: ▪Tympanic membrane 4. The remaining pharyngeal membranes disappear Site of the tympanic membrane formation THANKS Is Primitive pharynx after the formation of the pharyngeal arches Reference A: Textbook of Clinical Embryology By Vishram Singh Adult derivatives of first pharyngeal membrane Reference B: Before we are Born- Essentials of Embryology and Birth Defects, By Moore, 8th Edition