AMIA ARCHIVE • View topic

Last edited by Dead on Fri, Jul 06 2012, 17:26 PM, edited 4 times in total.

~ Basic anatomy manual ~
by Lucius Blackwater

Introduction

In this shortened edition I will focus on basic humanoid anatomy. Even though this is a simple
and short overview, do not underestimate the importance of knowing these body parts and
their locations at any moment given. When operating, time isa crucial factor and there will be
no time for consulting this manual. The human body is the entire structure of a human organism,
and consists of a head, neck, torso, two arms and two legs. The organ systems of the body
include the musculoskeletal system, cardiovascular system, digestive system, endocrine
system, integumentary system, urinary system, lymphatic system, immune system, respiratory
system, nervous system and reproductive system.

Musculoskeletal system

There are two different skeletal types: the exoskeleton, which is the stable outer shell of an
organism, and the endoskeleton, which forms the support structure inside the body. In this
part of the manual I shall give my undivided attention to the endoskeleton, or to be more
precise the endoskeleton of a human for I consider it to be the very basic knowledge any
scholar requires in order to conduct any further research concerning anatomy.

An average human body consists of 206 bones. Do note that this number may vary, as some
individuals may have more or fewer bones than this owing to anatomical variations. The most
common variations include additional (i.e. supernumerary) cervical ribs or lumbar vertebra.
Also, let it be noted that the number of bones in the human body varies due to age, thus at
birth, a newborn baby has over 300 bones, whereas on average an adult human has 206
bones. In this manualI will not speak of every single bone, but I will rather mention 24 basic
and most important bones and bone groups, which will be divided in two segments: the axial
skeleton and the appendicular skeleton. Bones are rigid organs that form part of the
endoskeleton of vertebrates. They function to move, support, and protect the various organs
of the body, produce red and white blood cells and store minerals. Skeletal system of the
human body weights only 15-20% of the total bodymass, which implies that, compared to
their weight, bones are extraordinary tough organs.
1. The hard outer layer of bones is composed of compact bone tissue. This tissue gives bones
their smooth, white, and solid appearance, and accounts for 80% of the total bone mass of an
adult skeleton. Compact bone may also be referred to as dense bone.
2. Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow
in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total
body mass of humans.

-------------------------------------------------------------------------------------------------------------------------------------

-------------------------------------------------------------------------------------------------------------------------------------

The axial skeleton

The axial skeleton consists of the 80 bones along the central axis of the human body. Even
though it is usually divided into six segments, for easier understanding I have simplified it and
divided it into three segments: the skull, vertebral column and thorax (chest).

-------------------------------------------------------------------------------------------------------------------------------------

The skull

1. Cranium: The functions of the cranium are to encloses the brain and protect the organs of
sight, hearing and balance. Cranium consists of two basic parts: the neurocranium and the
viscerocranium. The neurocranium (or braincase) is a protective vault surrounding the brain
and brain stem. The viscerocranium (also known as facial skeleton) is formed by the bones supporting
the face.

2. Mandible: The mandible or jawbone orms the lower jaw. Its role is to hold the lower teeth
in place. The mandible is the largest and strongest bone of the face.

-------------------------------------------------------------------------------------------------------------------------------------

Vertebral column
Main function: Protection of the spinal cord.

1. Cervical vertrebrae: Cervical vertebrae (also known as C-spine) are those vertebrae
immediately inferior to the skull. Its role is to support the globe of the skull and allow the
movements such as turning the head or nodding.

2. Thoracic vertebrae: This part of the vertebral column consists of 12 segments. It is also
known as T-spine. The role of T-spine is to support thorax and allow rib attachment.

3. Lumbar vertebrae: L-spine is the largest segments of the movable part of the vertebral
column. The 5 segments have the role of supporting the abdomen.

4. Sacrum: Or the S-spine is a large triangular bone in the base of the vertebral column. The
sacrum is what connects the upper body with the lower body at the sacroiliac joint, which is
also where your body weight is transmitted to the pelvic girdle.

-------------------------------------------------------------------------------------------------------------------------------------

Thorax

1. Sternum: The sternum or breastbone is a long flat bony plate shaped like a capital "T" located in the
center of the thorax. The sternum connects with the ribs forming the front of the rib cage. Without the
sternum there would be a big hole in the front of the human chest. It also articulates with the
clavicles. The sternum plays an important role in protecting the heart, lungs and major blood vessels
from damage.

2. Ribs: Ribs are the long curved bones which form the rib cage. They serve to protect the lungs,
heart, and other internal organs of the thorax. Humans have 24 ribs (12 pairs). The first seven sets of
ribs, known as "true ribs", are directly attached to the sternum. The following five sets are known as
"false ribs", three of these sharing a common cartilaginous connection to the sternum, while the last
two are termed floating ribs or vertebral ribs. They are attached to the vertebrae only, and not to the
sternum or cartilage coming off of the sternum. Some people are missing one of the two pairs of
floating ribs, while others have a third pair.

-------------------------------------------------------------------------------------------------------------------------------------

Last edited by Dead on Thu, Jul 19 2012, 1:02 AM, edited 1 time in total.

The appendicular skeleton

The appendicular skeleton is composed of 126 bones in the human body. The word appendicular is the
adjective of the noun appendage, which itself means a part that is joined to something larger. Do note
that each bone described in this section comes in pair in humans. Thus the appendicular skeleton
consists of four extremities - two arms and two legs.

Also this is a good time to mention the term - anatomical position. It is important for the
students of anatomy to understand this for the terminology in anatomy and medicine is aligned to this.
In the Anatomical Position, the body is assumed to be standing, the feet together, the arms to the
side, and the head and eyes and palms of the hands facing forwards. To ensure consistency of
description it is important to keep the anatomical position constantly in mind.

Anatomical Position

-------------------------------------------------------------------------------------------------------------------------------------

Arm

Scapula: The scapula, omo, or shoulder blade, is the bone that connects
the humerus (upper arm bone) with the clavicle (collar bone). The
scapula forms the posterior (back) located part of the shoulder girdle.
In humans, it is a flat bone, roughly triangular in shape. Because of
its sturdy structure and protected location, scapular fractures are
uncommon; when they do occur, they are an indication that severe
chest trauma has occurred.

Clavicle: In human anatomy, the clavicle or collar bone is a flat bone of short
length that serves as a strut between the scapula and the sternum. It
is the only long bone in body that lies horizontally. The clavicle is a
doubly curved short bone that connects the arm (upper limb) to the body
(trunk), located directly above the first rib. It acts as a strut to keep
the scapula in position so the arm can hang freely.

Humerus: The humerus is a long bone in the arm or forelimb that runs from the
shoulder to the elbow. Anatomically, it connects the scapula and the
lower arm (consisting of the radius and ulna), and consists of three
sections; the upper extremity, the body and the lower extremity.

Ulna: The ulna is one of the two long bones in the forearm, the other
being the radius. It is prismatic in form and runs parallel to the radius,
which is shorter and smaller. In anatomical position (when the palms
of the hands face forward) the ulna is located at the side of the forearm
closest to the body (the medial side), the side of the little finger.

Radius: The radius is one of the two large bones of the forearm, the other
being the ulna. It extends from the elbow to the thumb side of the
wrist and runs parallel to the ulna, which exceeds it in length and size.
It is a long bone, prism-shaped and slightly curved longitudinally. The
radius articulates with the humerus and the head of the ulna. The radius
has a body and two extremities.

Carpus: The carpus is the sole cluster of bones in the wrist between the radius
and ulna and the metacarpus. The bones of the carpus do not belong to
individual fingers (or toes in quadrupeds), whereas those of the metacarpus
do. In human anatomy, the main role of the carpus is to facilitate effective
positioning of the hand and powerful use of the extensors and flexors of the
forearm, but the mobility of individual carpal bones increase the freedom of
movements at the wrist.

Metacarpus: In human anatomy, the metacarpus is the intermediate part of the hand
skeleton that is located between the phalanges (bones of the fingers) distally
and the carpus which forms the connection to the forearm. The metacarpus
consists of metacarpal bones. Each metacarpal bone consists of a body and
two extremities.

Phalanges: In anatomy, phalanx bones (plural phalanges) are those that form the
fingers and toes. In primates such as humans and monkeys, the thumb
and big toe have two phalanges, while the other fingers and toes consist
of three. Phalanges are classified as long bones. The phalanges do not really
have individual names. They are named for the digit they represent, their
distance from the body and, in the case of the intermediate phalange, their
location relative to each other. The phalanges of the hand are commonly
known as the finger bones. There are fourteen in number, three for each finger,
and two for the thumb. Each consists of a body and two extremities.

-------------------------------------------------------------------------------------------------------------------------------------

-------------------------------------------------------------------------------------------------------------------------------------

Leg

Femur: The femur or thigh bone is the longest and strongest bone in the skeleton. It is almost perfectly
cylindrical in the greater part of its extent. The femur, like other long bones, is divisible into a body and
two extremities. The lower end joins the tibia to form the knee joint. The upper end is rounded into a
ball that fits into a socket in the pelvis to form the hip joint. The neck of the femur gives the hip joint a
wide range of movement, but it is a point of weakness and a common site of fracture.

Patella: The patella is the technical name for the kneecap, the triangular-shaped bone at the front of
the knee joint. The patella is held in place by muscles, the lower end of which surrounds the patella
and is then attached to the upper part of the tibia (shin) by patellar tendons. The patella protects the
knee joint. The primary functional role of the patella is knee extension. The patella increases the
leverage that the tendon can exert on the femur by increasing the angle at which it acts.

Tibia: The tibia is the inner and thicker of the two long bones in the lower leg. It is also called
the shin bone. he tibia is the supporting bone of the lower leg and runs parallel to the other, smaller
bone (the fibula) to which it is attached by ligaments. The upper end joins the femur to form the knee
joint, and the lower end forms part of the ankle joint.

Fibula: The fibula is the outer and thinner of the two long bones of the lower leg. It is much
narrower than the other bone (the shin), to which it runs parallel and to which it is attached at both
ends by ligaments. The upper end of the fibula does not reach the knee, but the lower end descends
below the shin and forms part of the ankle. Its main function is to provide attachment for muscles. It
doesn't give much support or strength to the leg, which explains why the bone can safely be used for
grafting onto other bones in the body.

Tarsus: The tarsus is a cluster of seven articulating bones in each foot situated between the
lower end of tibia and fibula of the lower leg and the metatarsus. In humans the largest bone in the
tarsus is the calcaneus, which is the weight-bearing bone within the heel of the foot.

Metatarsus: The metatarsal bones are five long, cylindrical bones in the foot. The bones make
up the central skeleton of the foot and are held in an arch formation by surrounding ligaments. The
metatarsus or metatarsal bones are a group of five long bones in the foot located between the tarsal
bones of the hind- and mid-foot and the phalanges of the toes.

Phalanges (toes): The phalanges of the foot are the bones in the toes. They correspond, in
number and general arrangement, with those of the hand; there are two in the big toe, and three in
each of the other toes. The toes, especially the big toe are essential for the "push-off" phase of the
walking cycle. Without an efficient push off, walking would require more energy due to the need for
muscle action rather than a perfect balance of muscle action and forces like momentum.

-------------------------------------------------------------------------------------------------------------------------------------

Basic anatomy manual [Tarkuul]

Who is online