File:Human embryonic shoulder girdle 01.jpg

Human Embryonic Shoulder Girdle

Drawing of a model of the right shoulder girdle of the 17mm. (Robinson) embryo, viewed from behind.

The sternal segment (S.S.) has been cut coronally to expose the interior, and the acromial segment has been cut horizontally for the same purpose.

The black area in each is bone, the dotted area surrounding the bone is precartilage, and the area surrounding this is perichondrium.

Above the junction of the two segments, two circles and a black dot are seen; the circles represent supraclavicular nerves, the black dot represents the cephalic vein.

The scapula has been purposely shortened.

Legend

• Ac. pr. - acromion process
• A. S. - acromial segment of clavicle
• C. Al. - clei-do-mastoid
• C. Cl. I. - coraco-clavicular ligament
• C. pr. - coracoid process
• T. - trapezius muscle
• P.M. - pectoralis major
• St. MI. - sterno-miastoid
• S. S. - sternal segment of clavicle

17mm CRL (Robinson) embryo

• difficult to estimate the amount of shrinkage in this historic material.
• Week 7 Stage 18 CRL 13 - 17 (Somites 44 - 48)

Original file name: FIG.1. Drawing of a model of the right shoulder girdle of the 17mm. (Robinson) embryo, viewed from behind. (figure scaled and background cleared, above text modified from figure legend)

Reference

Fawcett The Development and Ossification of the Human Clavicle. J Anat Physiol: 1913, 47(Pt 2);225-34 PMID:17232952 | PMC1289013

J Anat Physiol. 1913 Jan;47(Pt 2):225-34. The Development and Ossification of the Human Clavicle. Fawcett. University of Bristol.

<pubmed>17232952</pubmed>