development of diaphragm, skull, vertebrae & limbs (special embryology)

Development of Diaphragm

(Page 157)

Dr. Sherif Fahmy

Anatomy of Diaphragm

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Dr. Sherif Fahmy

Lower Aspect Inferior vena cava

Esophagus

Aorta

Rt. crusLt. crus

Central tendon

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DIAPHRAGMDIAPHRAGM It is developed from the following structures.It is developed from the following structures.

1-1- Septum transversum:Septum transversum: It lies firstly infront the neck It lies firstly infront the neck and forms central tendon.and forms central tendon.

2- 2- Cervical myotomes (C3,4,5):Cervical myotomes (C3,4,5): Forms the muscular Forms the muscular part around the central tendon and supplied by part around the central tendon and supplied by phrenic nervephrenic nerve..

3- 3- Pleuro-peritoneal membrane:Pleuro-peritoneal membrane: forms the postero-forms the postero-lateral parts of the diaphragm.lateral parts of the diaphragm.

4- 4- Meso-esophagus:Meso-esophagus: forms the median posterior forms the median posterior part.part.

5- 5- Mesoderm of thoracic wall:Mesoderm of thoracic wall: forms the periphery forms the periphery of diaphragm.of diaphragm.

6- 6- Mesoderm around aorta:Mesoderm around aorta: forms the crura.forms the crura. Dr. Sherif Fahmy

Bucco-pharyngeal membrane

Cloacal membrane

Cardiogenic area

Notochord

Septum transversumPericardium

Pleura

Pleuro-peritoneal membrane

PeritoneumIntra-embryonic ceolom

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Bucco-pharyngeal membrane

heart

Pericardium

Septum transversum

Pharynx

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Dr. Sherif Fahmy

CONGENITAL ANOMALIES

• 1- Congenital Hernia of Bochdalek: due to failure of formation of pleuro-peritoneal membrane.

• 2- Esophageal (Hiatus) Hernia: due to wide esophageal opening or short esophagus.

• 3- Parasternal hernia (of Morgagni): wide gap between sternal and costal origin of diaphragm.

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Dr. Sherif Fahmy

Development of Skull(Page 159)

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Development of SkullSkull is formed by 2 parts:1- Neurocranium.2- Viscerocranium.

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A- Neurocranium (Brain box)

Is divided into:I- Cartilagenous neurocranium which forms skull base. 2- Membranous neurocranium which skull cap.

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SKULL BASE

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Skull Vault

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B- Viscero-craniumIs divided into:1- Membranous viscero-cranium.2- Cartilagenous viscero-cranium

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Pharyngeal Arches

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Maxillary & Mandibular processes of 1st Pharyngeal Arch

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Skull Vault & Viscerocranium

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Anomalies of Skull

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Acrania

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Craniosynostosis

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Scaphocephaly

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Oxycephaly

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Development of Vertebral Column

(page 161)

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Stages of Vertebral Column Development

1- First stage: represented by notochord.2- Second stage: Sclerotomes surround the notochord. Formation of vertebral body from upper ½ of one sclerotome and lower ½ of the previous one.3- Third stage: Transformation of mesenchymal bodies into cartilage.4- Fourth stage: Ossification of vertebral bodies. Dr. Sherif Fahmy

Differentiation of a Somite

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CentrumNotochord

Dorsal processes

Lateral proces

Costal process

Formation of processes

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Chondrification of a Vertebra

Chondrification center

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Ossification of a Vertebra

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Steps of vertebral formation:Formation of centrum:It is formed by fusion of sclerotomes of both sides.Formation of processes:1- Dorsal process: forms lamina and spine.2- Lateral process: forms transverse process.3- Costal process: forms:- Anterior boundary of foramen transversium in cervical vertebra.- Ribs in thoracic region.-Fuse with transverse process in lumbar vertebra.-Forms anterior part of lateral mass of sacrum.

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Anomalies of Vertebrae

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Development of The Limbs

(Page 165)

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Development of Limbs• Limb buds appear at the end of 4th

week as outpoketing from ventro-lateral aspect of body.

• Each bud is composed of a core of mesoderm which is covered by ectoderm.

• At 7th week, upper limb rotates 90 degree laterally while lower limb rotates 90 degree medially.

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Development of the Limbs

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Dr. Sherif Fahmy

LIMB DEVELOPMENT

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Dr. Sherif Fahmy

LIMB DEVELOPMENT

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Anomalies of Limbs• Amelia: Absence of a limb.• Phocomelia: Hand or foot are attached to

the body.• Polydactyly: Presence of extra-finger.• Syndactyly: Fusion between 2 fingers.

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PhocomeliaDr. Sherif Fahmy

Polydactyly

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ClubfootDr. Sherif Fahmy

Lobster hand

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SyndactylyDr. Sherif Fahmy

Dr. Sherif Fahmy