Carnegie stage 16

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Introduction

Facts

Week 6, 37 - 42 days, 8 - 11 mm

Gestational Age GA - week 8

Summary

Ectoderm: sensory placodes, lens pit, otocyst,nasal pits moved ventrally, fourth ventricle of brain
Mesoderm: heart prominence
Head: 1st, 2nd and 3rd pharyngeal arch, forebrain, eye, auricular hillocks
Body: heart, liver, umbilical cord, mesonephric ridge
Limb: upper and lower limb buds, hand plate, developing arm

Features

Eye showing retinal pigment, nasolacrimal groove, nasal pit, fourth ventricle of brain, umbilical cord, 1st and 2nd pharyngeal arches, cervical sinus, heart, developing arm with hand plate, foot plate
Identify: nasal pit, nasolacrimal groove, eye, 1st, 2nd and 3rd pharyngeal arches, 1st pharyngeal groove, maxillary and mandibular components of 1st pharyngeal arch, auricular hillocks, fourth ventricle of brain, heart prominence, upper limb bud, mesonephric ridge, lower limb bud, umbilical cord

Historic Papers: 1906 | 1908 | 1948 stages 15-18

Week:	1	2	3	4	5	6	7	8
Carnegie stage:	1 2 3 4	5 6	7 8 9	10 11 12 13	14 15	16 17	18 19	20 21 22 23

Carnegie Stages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | About Stages | Timeline

Kyoto Collection

View: This is a dorsolateral view of embryo. Amniotic membrane removed.

Image source: Embryology page Created: 19.03.1999

Head
Left lateral view	Left lateral view (labeled)
Ventral view of head region. Ventral view of head region (1 mm scale).

Central Nervous System

Cranial Nerves
Nerve Number	Name	Type	Origin	Function
CN I	Olfactory	sensory	telencephalon	smell placode
CN II	Optic	sensory	retinal ganglial cells	vision
CN III	Oculomotor	motor	anterior midbrain	extraocular muscles eye movements and pupil dilation (motor)
CN IV	Trochlear	motor	dorsal midbrain	extraocular muscles (superior oblique muscle)
CN V	Trigeminal	motor/sensory	pons	touch, mastication
CN VI	Abducent	motor	extraocular muscles	control eye movements (lateral rectus muscle)
CN VII	Facial	motor/sensory	pons	facial expression, taste (tongue anterior and central regions) regulate salivary production.
CN VIII	Acoustic	sensory	vestibular and cochlear nuclei	hearing, placode
CN IX	Glossopharyngeal	motor/sensory	medulla	swallowing and speech, taste (tongue posterior region)
CN X	Vagus	motor/sensory	medulla	larynx and pharynx muscles (speech and swallowing), regulates heartbeat, sweating, and peristalsis
CN XI	Accessory	motor	motor neurons	sternocleidomastoid and trapezius muscles
CN XII	Hypoglossal	motor	motor neurons	tongue muscles (speech, eating and other oral functions)

Right lateral view of the central nervous system of embryo at Carnegie stage 16. Scale bar is 1 mm

Movies

‎‎Embryo Stage 16

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‎‎Embryo CNS

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‎‎Embryo Stage 16

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‎‎Embryo Stage 16

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‎‎Embryo Stage 16

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‎‎Embryo Stage 16

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‎‎Embryo Stage 16

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‎‎Embryo Stage 16

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Image source: The Kyoto Collection images are reproduced with the permission of Prof. Kohei Shiota and Prof. Shigehito Yamada, Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan for educational purposes only and cannot be reproduced electronically or in writing without permission.

Scanning EM

Ventral view of head showing upper lip, maxilla and nasal region.

Image Source: Prof Virginia Diewert

Carnegie Collection

Carnegie Collection Embryos - Stage 16
Serial No.	Size (mm)	Grade	Fixative	Embedding Medium	Plane	Thinness (µm)	Stain	Year	Notes
163	E., 9.0 Ch., 35x35x20	Good	Formol	P	Transverse	20	Al. coch.	1899	Used by Bardeen and Lewis
221	E., 7.5 Ch., 40x33x33	Poor	Formalin	P	Sagittal	20	Al. coch.	1903	Macerated
383	E., 7.0 Ch., 15x15x15	Poor	Formalin	P	Transverse	10	Al. carm., H. & Congo red	1904
397	E., 8.0 Ch., 15x15x15	Poor	Formalin	P	Transverse	10	(Stain - Haematoxylin Eosin)	1907
422	E., 9.0 Ch., 30x30x30	Poor	Alc.	P	Transverse	40	Al. coch.	1910	Tubal. Partly macerated
559	E., 8.6 Ch., 20x15x12	Good	Formalin	P	Transverse	20	H. & Congo red	1911	Cyclopia. Formerly listed as stage 17
589	E., 11 Ch., 30x13x13	Poor	p	P	Sagittal	50	Al. coch.	1912
617	E., 7.0 Ch., 18x14x12	Good	Formalin	P	Transverse	15	Al. coch.	1912	Median in group
636	E., 10 Ch.,28x28x22	Poor	Formalin	P	Transverse	50	Al. coch.	1913	Macerated
651f	E., 7 Ch., 25x20x15	Poor	p	p	p	p	p	1913	Spina bifida
675	E., 10 Ch., 50x30x25	Poor	Formalin	P	Sagittal	100	Carmine	1915	Abnormal head and limbs
792	E., 8.0 Ch., 40x30x30	Good	Formalin	P	Transverse	20	Al. coch.	1913	Advanced
887	E, 9.0 Ch., 31x28x17	Good	Formalin	P	Transverse	40	Al. coch.	1914	Near next stage
1121	E., 11.8	Good	Corros. acetic	P	Coronal	40	Al. coch.	1915	Operative. Median in group
1197	E., 10.0 Ch., 23x19x15	Good	Formalin	C	Sagittal	20	(Stain - Haematoxylin Eosin), or. G.	1915	Advanced
1544	E., 7.2	Good	Zenker	P	Sagittal	20	Al. coch.	1916	Tubal. Mechanical injury
1836	E., 11.0	Good	Formalin	P	Transverse	20	(Stain - Haematoxylin Eosin)	1917	Most-advanced third
4677	E., 9.5 Ch., 48x36x30	Good	Formalin	P	Transverse	10	Al. coch.	1924	Median in group
5515	E., 12.0 Ch., 47x37x25	Good	Formalin	C-P	Transverse	10	(Stain - Haematoxylin Eosin)	1927	Near next stage
6054	E., 7,0 Ch., 21x17x12	Good	Formalin	C-P	Transverse	8	(Stain - Haematoxylin Eosin)	1930	Least-advanced third
6507	E., 9.0*	Excellent	Corros. acetic	C-P	Coronal	10 & 8	Al. coch.	p	Middle or most-advanced third
6509	E. 8.1*	Excellent	Corros. acetic	C-P	Coronal	10	Al. coch.	p	Least-adianced or middle third
6510	E., 10.1*	Excellent	Corros. acetic	C-P	Coronal	10	Al. coch.	p	Close to No. 6507. Ag added
6511	E, 8.1*	Good	Corros. acetic	C-P	Sagittal	10	Al. coch., iron H.	p	Surface injured by fixative. Most-advanced third
6512	E., 7.0*	Excellent	Corros. acetic	C-P	Transverse	10	Al. coch.	p	Least-advanced third. Borderline
6513	E., 7.2*	Good	Corros. acetic	C-P	Coronal	10	Al. coch.	p	Surface injured by fixative. Least advanced in group
6514	E, 9 0*	Poor	Corros. acetic	C-P	Sagittal	10	Al. coch.	p	Most-advanced third
6516	E., 10 5*	Good	Corros acetic	C-P	Sagittal	8	Al. coch.	p	Most-advanced third. Double left kidney and ureter
6517	E., 10.5*	Excellent	Corros. acetic	C-P	Transverse	8	Al. coch.	?	Close to No. 6516
6686	E., 11.0 Ch., l7x17xP	Poor	Formalin	C-P	Coronal	20	Al. coch.	1933	Tubal. Partly macerated
6750	E., 10.0	Good	Formalin	C-P	Transverse	10	H. & phlox.	1933	Tubal. Advanced
6909	E., 11.0	Good	Bouin	C-P	Coronal	10	(Stain - Haematoxylin Eosin)	1934	Tubal. Advanced
6931	E., 8.8 Ch., 3""x 33x16	Good	Formalin	C-P	Coronal	10	Al coch., phlox.	1934	Least-advanced third. Type specimen
6950	E.. 9 0 Ch., 3lx20x18	Good	Formalin	C-P	Transverse	10	(Stain - Haematoxylin Eosin)	1934	Tubal. Partly fragmented
7?15	E., 9.7	Exc	Bouin	C-P	Coronal	10	H. & phlox	1935	Operative. Less advanced
7629	E., 11.5 Ch., 31x31	Good	Formalin	C-P	Coronal	10	Al. coch., phlox	1939	Hysterectomy. Most advanced in group
7804	E., 9.5 Ch., 26x21x16	Good	Formalin	C-P	Transverse	10	(Stain - Haematoxylin Eosin)	1940	Least-advanced third
7897	E., 12.2 Ch., 31x24x23	Good	Formalin	C-P	Transverse	10	(Stain - Haematoxylin Eosin)	1941	Tubal. Advanced
8098	E., 10.0 Ch., 30	Good	Formalin	C-P	Coronal	6	(Stain - Haematoxylin Eosin)	1942	Tubal. Median in group
8112	E., 10.9	Excellent	Bouin	C-P	Coronal	8	(Stain - Haematoxylin Eosin)	1943	Most-advanced third
8179	E., 11.9 Ch., 23x18x17	Good	Formalin	C-P	Coronal	10	(Stain - Haematoxylin Eosin)	1943	Tubal
8436	E., 10.9 Ch., 13x15x1?	Good	Formalin	P	Coronal	10	Azan	1946	Advanced
8692	E., 10	Good	Bouin	P	Transverse	10	(Stain - Haematoxylin Eosin)	1949	Rubella. Medical abortion. Mechanically damaged
8697	E., 11.3	Poor	Formalin	C-P	Transverse	10	(Stain - Haematoxylin Eosin)	1949	Perhaps stage 17
8773	E, 11	Excellent	Bouin	P	Coronal	10	Azan	1950
8971	E., 10 Ch., 20.5x14.5x13.7	Poor	Formalin		Transverse	15	(Stain - Haematoxylin Eosin)	1932	Synophthalmia. Univ. Chicago No. H 1439
Template:CE9055	E., ca. 10	Excellent	Bouin	P	Transverse	20	Azan & Ag	1953	Damaged
9229	E, 9.5	Excellent	Formalin	P	Transverse	6	Ag & (Stain - Haematoxylin Eosin)	1954	Stage 15, 16, or 17? Mislaid
Abbreviations Size - E. is the greatest length of the embryo and Ch. is the mean diameter of the chorion. Grade - total grade of the specimen and includes both its original quality and the condition of the mounted sections. Embedding medium - paraffin (P) or a combination of celloidin and paraffin (C-P). Fixative - formalin (Formol), alcohol and formalin (Alc, formol), Bouin Bouin solution) Stain - ? - unknown or not determined.

iBook - Carnegie Embryos
	iTunes link \| iBook Store Description - Imagine the excitement of seeing this incredible early period of human development for the first time. Now consider that much of our initial understanding of human development is based upon study of historic embryo collections. You can now look at these historic images of the first 8 weeks after fertilisation and explore for yourself the changes that occur in human development during this key period. This current book is designed as an atlas of the Carnegie embryo stages with some brief notes and additional information covering the first 8 weeks of development. These images are from from the beginning of last century and are one of the earliest documented series of human embryos collected for basic research and medical education on development. I hope you enjoy learning about the amazing early events that begin to make and shape us. This is the second book in a series of educational releases from UNSW Embryology. Release: First Edition - Mar 12, 2012 ISBN 978-0-7334-3148-7 Print Length 82 Pages, 25.8 MB Language English. PDF Preview version 3.87 MB (Read the associated information, this is an edited educational preview version with many features not functioning). The current website also includes numerous embryo images from this textbook (see Embryonic Development and Carnegie Embryos).

Madrid Collection


Human Embryo CRL 10.2 mm (stage 16)	Human Embryo CRL 10.5 mm (stage 16)

Image source: The Madrid Collection images are reproduced with the permission of Prof. Rodríguez-Vázquez, Head, Embryology Institute of Complutense University of Madrid. Images are for educational purposes only and cannot be reproduced electronically or in writing without permission.

Madrid Collection Embryos
Carnegie Stage	Embryo	Days	CRL (mm)	Section thickness	Staining	Section plane
16	MAR 3	38	8	10	(Stain - Haematoxylin Eosin)-Azan	frontal
16	BOT9	39	9	10	(Stain - Haematoxylin Eosin)	transverse
16	CN 2	39	9.5	10	(Stain - Haematoxylin Eosin)	sagittal
16	FAUS 4	40	9.7	10	(Stain - Haematoxylin Eosin)	frontal
16	CA 2	40	10	10	(Stain - Haematoxylin Eosin)-Azan	transverse
16	FE 1	40	10.5	10	(Stain - Haematoxylin Eosin)	transverse

Hill Collection

Hill HH8

Stereo pair animation: right lateral animation | right lateral animation | left lateral animation

Hill HH5

Links: Hill Collection

Hinrichsen Collection

Hinrichsen collection Human Embryo ME34 (stage16). Left lateral view of the embryo.

Image source: The Hinrichsen Collection images are reproduced with the permission of Prof. Beate Brand-Saberi, Head, Department of Anatomy and Molecular Embryology, Ruhr-Universität Bochum. Images are for educational purposes only and cannot be reproduced electronically or in writing without permission.

Other Collection Embryos

No. BR, 9.75 mm G. L., 8.8 mm. Summarized by Tandler (1907)^[1], who, on the basis of the coital history, gave the age as the “38th day.” About stage 16.
9-mm embryo. The peripheral nervous system was described by Masy (1955)^[2] in this embryo of stage 16.
Huber No. 3, 10 mm. The nuclei of origin of the cranial nerves and the peripheral nervous system were described by Streeter (1908a,b).^[3]^[4] An advanced example of stage 16.
Wetzel (We) embryo, 10 mm. Discussed by v. Hayek (1934)^[5] in regard to age, which, based on the coital history, was given as the “40th day.” Probably about stage 16.
Carnegie No. 6516, 10.5 mm (corrected). Double ureters described by Wharton (1949).^[6]
No. H60, University of Missouri, 11 mm. Described briefly by Bonnot and Severs (1906).^[7] Probably belongs to stage 16.

Events

Hearing - otic vesicle wall thickens prior to appearance of the semicircular ducts.^[8] A utriculosaccular diverticulum and spiral ganglion appears. Auricular hillocks present (tragus, crus helicis, helix, and antitragus).
Vision - (37 days) Growth of the lens body results in a D-shaped lens cavity. Perilental blood vessels (tunica vasculosa lentis) are visible. Prior to the development of the eyelids, one small sulcus or groove forms above the eye (eyelid groove) and another below it.^[9]
smell - the vomeronasal groove appears.^[10] Stages Description
Cardiovascular
- Coronary circulation plexus acquires coronary sinus connection.^[11]
- Cerebral artery development of the middle cerebral artery first identified as small buds originating proximal to the anterior cerebral artery on the anterior division of the primitive internal carotid artery.^[12]
Endocrine^[13]
- Hypophysis - slight indication of the infundibular recess may be seen in some embryos (O'Rahilly 1973 a).
- Epiphysis - cellular migration in an external direction occurs in the pineal body during stages 16 and 17 (Stadium 2 of Turkewitsch 1933) (O'Rahilly 1968).
- Thymus - according to Norris (1938), "not until the primordium of the parathyroid [3] has been outlined can the remaining portion of the third pouch be recognized, by exclusion, as the primordium of the endodermal thymus".
- Parathyroids - parathyrogenic zones are closely related to the third and fourth aortic arches at 9 mm (Politzer and Hann 1935, unstaged embryo). Parathyroid 3 is identifiable on the anterior wall of the third pharyngeal pouch (Weller 1933, Fig. 17) and "does not arise from a dorsal lobule" of the pouch (Norris 1937). The "sudden appearance of well-differentiated clear chief cells in the early primordia of the parathyroids" at 9 mm was emphasized by Norris (1937).
- Thyroid - has lost its continuity with the pharynx and it consists of two lobes, an isthmus, and a remnant of the pedicle (Weller 1933).
- Adrenal Cortex. Another type of cell (C3) arises from the coelomic epithelium. Both C1 and C3 cells enter the suprarenal primordium. An "enormous immigration" of C2 cells occurs.^[14]
- Adrenal Medulla - cells of neural origin are migrating into the gland, separating the cortical cells into islands. Nerve fibres from the ganglia ac- company the M1 and M3 cells. The M2 cells remain in the ganglia and become sympathetic ganglion cells.^[14]
- Pancreas - dorsal pancreas and the ventral pancreas are contiguous.^[15]
meninges (spinal cord) - vertebral rudiments stand out more and more distinctly from the intermediate zone. Over the dorsal surface of the spinal cord the closure membrane is separating into a peripheral and denser body-wall portion and a deeper and looser portion. The latter becomes part of the meninx primitiva, and this can be identiﬁed everywhere about the cord. The meninx primitiva has broadened, and its cells are more scattered than in the previous age group. It is deepest ventral to the neural tube and in the lateral parts between adjacent ganglia. The ganglia have migrated so that their ventral tips lie at the level of origin of the ventral nerve root. The vascular channels now surround the spinal ganglia, and small vessels penetrate into the spinal cord. A frontal section through the ganglia shows extensions of the dense lateral concentrations of the vertebral canal, passing medially between each two adjacent ganglia to become continuous with the meninx adjacent to the cord. These extensions are the ﬁrst indications of the denticulate ligaments of the pia mater. These primordia of the dentate processes are also observed in transverse sections, forming a cellular concentration between the ventralateral part of the neural tube and the ventral part of the neural arch rudiments.^[16]