University:
Kentucky State University
Course:
BIO 301 | Human Anatomy
Academic year:

2023
Views:

225

Pages:

13
Author:

Arielle Armstrong

Atypical Ribs st 1 Rib Difficult to palpate it as it lies mostly under the clavicle. The anterior end of the first rib is larger than any other rib. The head has one facet only for articulation with the 1st thoracic vertebra. The lower surface is smooth. Particular features of the 1st rib Subclavius 2 origins 1st digitation of serratus anterior Scalenus anterior 2 insertions Scalenus medius Groove for subclavian vein 2 grooves Groove for subclavian artery and lower trunk of brachial plexus Pleura 2 membranes Suprapleural membrane 2nd rib much longer than the first, but has a very similar curvature. The body is not flattened horizontally like that of the first rib. The angle is slight, and situated close to the tubercle. The body is not twisted, so that both ends touch any plane surface upon which it may be laid; but there is a bend, with its convexity upward, similar to, though smaller than that found in the first rib. Its external surface is convex, and looks upward and a little outward; near the middle of it is a rough eminence for the origin of the lower part of the first and the whole of the second digitation of the Serratus anterior; behind and above this is attached the Scalenus posterior. The costal groove is poorly developed. th 10 rib It has a single articular facet on its head. Its tubercle is not eminent. 11th and 12th ribs 11th rib 12th rib Head One facet One facet Neck No neck No neck Tubercle No tubercle No tubercle Groove Faint No groove Articulation With T11 With T12 Sternum (Breast bone) Consists of: • Manubrium • Body • Xiphoid process Manubrium sterni ..1/2 Lies opposite T3-T4. It has the following features: • Upper border: • Suprasternal notch • 2 Clavicular notches • Lower border: • opposite the 2nd costal cartilage and T4. • Articulates with the body in the manubrio-sternal angle (angle of Louis). Manubrium sterni ..2/2 Lateral border: articulates with 1½ costal cartilages. Anterior surface: convex. Posterior surface: concave. Body and xiphoid process of the sternum Lies opposite T5-T8. Consists of 4 pieces (sternbrae) that fuse together at the age of puberty. Articulates half of the 2nd and 7th costal cartilages and costal cartilages 3-6. Xiphoid process lies opposite T9. T 10