Surface Markings Of The Back

Bony Landmarks.—In order to identify any particular spinous process it is customary to count from the prominence caused by the seventh cervical and first thoracic; of these the latter is the more prominent. The root of the spine of the scapula is on a level with the tip of the spinous process of the third thoracic vertebra, and the inferior angle with that of the seventh. The highest point of the iliac crest is on a level with the spinous process of the fourth lumbar, and the posterior superior iliac spine with that of the second sacral.


Fig. 91212– Diagram showing the relation of the medulla spinalis to the dorsal surface of the trunk. The bones are outlined in red.
 
Level of body ofNo. of nerve.Level of tip of spine ofLevel of body ofNo. of nerve.Level of tip of spine of

C.1C.1
T.8T.97 T.
22
9108

31 C.10119
342
1210
45311L. 111
564
2
675123

86
412
7T. 17
5
T. 121 T.
S. 1
23
L. 12
342
3
453
41 L.
564
5
675
C. 1
786L. 2

The transverse process of the atlas is about 1 cm. below and in front of the apex of the mastoid process. The transverse process of the sixth cervical vertebra is opposite the cricoid cartilage; below it is the transverse process of the seventh and occasionally a cervical rib.


Fig. 91213– Sagittal section of vertebral canal to show the lower end of the medulla spinalis and the flum terminale. (Testut.) Li, Lv. First and fifth lumbar vertebra. S\??\ Second sacral vertebra. 1. Dura mater. 2. Lower part of subarachnoid cavity. 3. Lower extremity of medulla spinalis. 4. Filum terminale internum, and 5. Filum terminale externum. 6. Attachment of filum terminale to first segment of cooccyx.
 


Fig. 91214– Scheme showing the relations of the regions of attachment of the spinal nerves to the vertebral spinous processes. (After Reid.)
 
 
Medulla Spinalis.—The position of the lower end of the medulla spinalis varies slightly with the movements of the vertebral column, but, in the adult, in the upright posture it is usually at the level of the spinous process of the second lumbar vertebra (Fig. 91212); at birth it lies at the level of the fourth lumbar.
  The subdural and subarachnoid cavities end below opposite the spinous process of the third sacral vertebra (Fig. 91213).
 
Spinal Nerves (Fig. 91214).—The table on page 1305, after Macalister, shows the relations which the places of attachment of the nerves to the medulla spinalis present to the bodies and spinous processes of the vertebræ.

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 Gray's Anatomy
 
 1. Embriology
 
 2. Osteology
menuVertebral Column
menuSkull
menuCranial Bones
menuFacial Bones
menuExtremities
 
 3. Arthrology
menuTrunk Articulations
menuUpper Extremity Articulations
menuPelvis Articulations
menuLower Extremity Articulations
 
 4. Myology
menuMuscles of the Head
menuMuscles of the Trunk
menuMuscles of the Upper Extremity
menuMuscles of the Lower Extremity
 
 5. Angiology
menuThoracic Cavity
 
 6. The Arteries
menuArteries of the Head and Neck
menuArteries of the Upper Extremity
menuArteries of the Trunk
menuArteries of the Lower Extremity
 
 7. The Veins
menuSystemic Veins
 
 8. The Lymphatic System
 
 9. Neurology
menuBrain or Encephalon
menuCranial Nerves
menuSpinal Nerves
menuSympathetic Nerves
 
 10. The Organs of the Senses and the Common Integument
menuThe Peripheral Organs of the Special Senses
 
 11. Splanchnology
menuThe Respiratory Apparatus
menuThe Digestive Apparatus
menuThe Urogenital Apparatus
menuThe Ductless Glands
 
 12. Surface Anatomy and Surface Markings
 
menuMuscle Tables
 
 Quizzes
menu1. Introduction
menu2. Head & Face
menu3. Neck
menu4. Torso
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