1 --- 2 title: "General Anatomy and Musculoskeletal System (THIEME Atlas of" 3 isbn: "9781626237186" 4 block: 1 5 total_blocks: 3 6 next_block: ./9781626237186_block2.md 7 pages: "19-238" 8 --- 9 10 11 12 13 ## A General Anatomy 14 15 16

1	Human Phylogeny and Ontogeny	2
2	Overview of the Human Body	22
3	Surface Anatomy of the Body, Landmarks, and Reference Lines	26
4	The Bones and Joints	40
5	The Muscles	56
6	The Vessels	64
7	The Lymphatic System and Glands	70
8	General Neuroanatomy	74

17 18 19 20 21 ## 1.1 Human Phylogeny 22 23 24 ## A Brief overview of human phylogenetic development 25 26 To better understand the evolution of the human body, it is helpful to trace its phylogenetic development. Humans and their closest relatives belong to the phylum Chordata, which includes approximately 50,000 species. It consists of two subphyla: 27 28 Invertebrata: the tunicates (Tunicata) and chordates without a true skull (Acraniata or Cephalochordata) 29 30 Vertebrata: the vertebrates (animals that have a vertebral column) 31 32 Although some members of the chordate phylum differ markedly from one another in appearance, they are distinguished from all other animals by characteristic morphological structures that are present at some time during the life of the animal, if only during embryonic development (see G). Invertebrate chordates, such as the cephalochordates and their best-known species, the lancelet (Branchiostoma lanceolatum) are considered the model of a primitive vertebrate by virtue of their organization. They provide clues to the basic structure of the vertebrate body and thus are important in understanding the general organization of vertebrate organisms (see D). 33 34 All the members of present-day vertebrate classes (jawless fish, cartilaginous fish, bony fish, amphibians, reptiles, birds, and mammals) have a number of characteristic features in common (see H), including a row of vertebrae arranged in a vertebral column, which gives the subphylum its name (Vertebrata). The evolution of an amniotic egg (i.e., the development of the embryo within a fixed shell inside a fluid-filled amniotic cavity) was a critical evolutionary breakthrough that helped the vertebrates to survive on land. This reproductive adapta-tion enabled the terrestrial vertebrates (reptiles, birds, and mammals) to live out their life cycles entirely on land and sever the final ties with their marine origin. When we compare the embryos of different verte-brate classes, we observe a number of morphological and functional similarities, including the formation of branchial arches (see B). 35 36 Mammals comprise three major groups: monotremes (egg-laying mammals), marsupials (mammals with pouches), and placentals (mammals with a placenta). The placental mammals, which include humans, have a number of characteristic features (see I), including a tendency to invest much greater energy in the care and rearing of their young. Placental mammals complete their embryonic development inside the uterus and are connected to the mother by a placenta. Humans belong to the mammalian order of primates, whose earliest members were presumably small tree-dwelling mammals [... Output truncated due to length. 1617 tokens/6148 characters removed ...]