64 - Transpyloric plane

An upper transverse line also known as Addison's Plane, located halfway between the jugular notch and the upper border of the pubic symphysis. It is also said to lie roughly a hand's breadth beneath the xiphoid process of the human sternum. The plane in most cases cuts through the pylorus of the stomach, the tips of the ninth costal cartilages and the lower border of the first lumbar vertebra.

 The transpyloric plane is clinically notable because it passes through several important abdominal structures. These include:

1. lumbar vertebra 1 and hence passes just before the end of the spinal cord in adults. 
2. the fundus of the gallbladder 
3. the neck of the pancreas 
4. the pancreatic body 
5. the origin of the superior mesenteric artery from the abdominal aorta and 
6. termination of the superior mesenteric vein at the hepatic portal vein 
7. the left and right colic flexure  
8. hilum of the kidney on the left  
9. upper pole of the kidney on the right 
10. the root of the transverse mesocolon 
11. duodenojejunal flexure 
12. the 1st part of the duodenum 
13. the upper part of conus medullaris 
14. the spleen 
15. the pylorus of the stomach which will lie at this level approximately 5 cm to the right of the midline.

p.s: I want the readers to note that the image depicted above shows the transpyloric plane to be passing through the hilum of both kidneys, which infact is not true. The transpyloric plane actually passes through the upper pole of right kidney and the hilum of left kidney as mentioned in the description below the image. The cause of the error is probably because the artist depicted both the kidneys at equal height rather than the actual fact that the right kidney is inferior to the left kidney due to the liver above.

63 - Scalene Muscles

The scalene muscles are a group of three pairs of muscles in the lateral neck, namely the scalenus anterior, scalenus medius, and scalenus posterior. They are innervated by the spinal nerves C4-C6.

 The Scalenus anterior (Scalenus anticus), also known as anterior scalene muscle, lies deeply at the side of the neck, behind the Sternocleidomastoideus. It arises from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebræ, and descending, almost vertically, is inserted by a narrow, flat tendon into the scalene tubercle on the inner border of the first rib, and into the ridge on the upper surface of the rib in front of the subclavian groove. It can be involved in certain forms of Thoracic outlet syndrome.

 The Scalenus medius, the largest and longest of the three scalene muscles, arises from the posterior tubercles of the transverse processes of the lower six cervical vertebræ. It descendes along the side of the vertebral column to insert by a broad attachment into the upper surface of the first rib, between the tubercle and the subclavian groove. The brachial plexus and the subclavian artery pass anterior to it. Because it elevates the upper ribs, the middle scalene muscle is also one of the accessory muscles of respiration. The

Scalenus posterior (Scalenus posticus), the smallest and most deeply seated of the three Scaleni, arises, by two or three separate tendons, from the posterior tubercles of the transverse processes of the lower two or three cervical vertebræ, and is inserted by a thin tendon into the outer surface of the second rib, behind the attachment of the Scalenus anterior. It is occasionally blended with the Scalenus medius.