INTRODUCTION TO

HUMAN ANATOMY

By
Odaro Anne Edith
MCM: Accidents and Emergency Medicine
 OBJECTIVES
By the end of the session, the learner should be able to:
To understand the basics of human anatomy
To describe and use various anatomical terms
OVERVIEW
 INTRODUCTION
Anatomy is a field in biological sciences
concerned with the identification and description
of the body structures of living things.
• Gross anatomy involves the study of major body
structures by dissection and observation.
• Microscopic anatomy (micro; small) is a branch of
anatomy that relies on the use of microscopes to
examine the smallest structures of the body; tissues,
cells, and molecules.
Branches of human anatomy
 THE ANATOMICAL POSITION
Anatomical terms used to describe location are based on
a body positioned in what is called the standard
anatomical position.
This position is one in which a person is standing,
feet apace, with palms forward and thumbs facing
outwards.
Using the standard anatomical position reduces
confusion. It means that regardless of the position of a
body, the position of structures within it can be
described without ambiguity.
The anatomical position
 ANATOMICAL REGIONS
In terms of anatomy, the body is divided into regions.
• In the front, the trunk is referred to as the "thorax" and "abdomen".
• The back as a general area is the dorsum or dorsal area, and the lower back is
the lumbus or lumbar region.
• The shoulder blades are the scapular area and the breastbone is the sternal
region.
• The abdominal area is the region between the chest and the pelvis.
• The breast is also called the mammary region
• the armpit as the axilla and axillary, and
• the navel as the umbilicus and umbilical.
• The pelvis is the lower torso, between the abdomen and the thighs.
• The groin, where the thigh joins the trunk, are the inguen and inguinal area.
• The entire arm is referred to as the brachium and brachial
• The front of the elbow as the antecubitis and antecubital, the
back of the elbow as the olecranon or olecranal,
• The forearm as the antebrachium and antebrachial,
• The wrist as the carpus and carpal area,
• The hand as the manus and manual,
• The palm as the palma and palmar,
• The thumb as the pollex, and
• The fingers as the digits, phalanges, and phalangeal.
• The buttocks are the gluteus or gluteal region and
• The pubic area is the pubis.
ANATOMICAL TERMS OF DIRECTION
• Anterior and posterior, which describe structures at the front
(anterior) and back (posterior) of the body. For example, the toes are
anterior to the heel, and the popliteus is posterior to the patella.
• Superior and inferior, which describe a position above (superior) or
below (inferior) another part of the body. For example, the orbits are
superior to the oris, and the pelvis is inferior to the abdomen.
• Proximal and distal, which describe a position that is closer to
(proximal) or farther from (distal) the trunk of the body. For example,
the shoulder is proximal to the arm, and the foot is distal to the knee.
• Superficial and deep, which describe structures that are closer to
(superficial) or farther from (deep) the surface of the body. For
example, the skin is superficial to the bones, and the brain is deep to
the skull. Sometimes profound is used synonymously with deep.
• Medial and lateral, which describe a position that is closer to
(medial) or farther from (lateral) the midline of the body. For
example, the shoulders are lateral to the heart, and the
umbilicus is medial to the hips. The medial side of the left knee
is the side toward the opposite knee.
• Radial and ulnar, which describe only structures at or distal to
the elbow and may be used interchangeably with medial and
lateral in that particular area because they are less confusing.
Examples: The thumb is on the radial side of the hand (the
same as saying the lateral side); the ulnar side of the wrist is the
side toward the little finger (medial side).
• Ventral and dorsal, which describe structures derived from the
front (ventral) and back (dorsal) of the embryo, before limb
rotation.
• Rostral and caudal, which describe structures close
to (rostral) or farther from (caudal) the nose. For
example, the eyes are rostral to the back of the skull,
and the tailbone is caudal to the chest.
• Cranial and caudal, which describe structures close
to the top of the skull (cranial), and towards the
bottom of the body (caudal).
• Occasionally, sinister for left, and dexter for right
are used.
• Paired, referring to a structure that is present on both
sides of the body. For example, the hands are paired
structures.
 ANATOMICAL PLANES
Anatomy is often described in planes, referring to two-
dimensional sections of the body.
A section is a two-dimensional surface of a three-
dimensional structure that has been cut.
A plane is an imaginary two-dimensional surface that
passes through the body. Three planes are commonly
referred to in anatomy and medicine:
a) Sagittal
b) Coronal and
c) Transverse
• The sagittal plane is the plane that divides the body or an
organ vertically into right and left sides. If this vertical plane
runs directly down the middle of the body, it is called the
midsagittal or median plane. If it divides the body into unequal
right and left sides, it is called a parasagittal plane, or less
commonly a longitudinal section.
• The frontal plane is the plane that divides the body or an organ
into an anterior (front) portion and a posterior (rear) portion.
The frontal plane is often referred to as a coronal plane,
following Latin corona, which means "crown".
• The transverse plane is the plane that divides the body or
organ horizontally into upper and lower portions. Transverse
planes produce images referred to as cross sections.
 ANATOMICAL TERMS OF MOTION
Joints, especially synovial joints allow the body a
tremendous range of movements. Each movement
at a synovial joint results from the contraction or
relaxation of the muscles that are attached to the
bones on either side of the articulation. The type
of movement that can be produced at a synovial
joint is determined by its structural type.
 General motion
• Flexion and extension, which refer to a movement that decreases
(flexion) or increases (extension) the angle between body parts. For
example, when standing up, the knees are extended.
• Abduction and adduction refers to a motion that pulls a structure
away from (abduction) or towards (adduction) the midline of the body
or limb. For example, a star jump requires the legs to be abducted.
• Internal rotation (or medial rotation) and external rotation (or
lateral rotation) refers to rotation towards (internal) or away from
(external) the center of the body. For example, the lotus position
posture in yoga requires the legs to be externally rotated.
• Elevation and depression refer to movement in a superior (elevation)
or inferior (depression) direction. Primarily refers to movements
involving the scapula and mandible.
 Special motions of the hands and feet
• Dorsiflexion and plantarflexion refers to flexion (dorsiflexion) or extension
(plantarflexion) of the foot at the ankle. For example, plantarflexion occurs
when pressing the brake pedal of a car.
• Palmarflexion and dorsiflexion refer to movement of the flexion
(palmarflexion) or extension (dorsiflexion) of the hand at the wrist. For
example, prayer is often conducted with the hands dorsiflexed.
• Pronation and supination refer to rotation of the forearm or foot so that in the
anatomical position the palm or sole is facing anteriorly (supination) or
posteriorly (pronation). For example, if a person is holding a bowl of soup in
one hand, the hand is "supinated" and the thumb will point away from the body
midline and the palm will be superior; if the hands are typing on a computer
keyboard, they will be "pronated" with the thumbs toward the body midline
and the palms inferior.
• Eversion and inversion refer to movements that tilt the sole of the foot away
from (eversion) or towards (inversion) the midline of the body.
 MUSCLE ACTIONS
Muscle action that moves the axial skeleton work over
a joint with an origin and insertion of the muscle on
respective side. The insertion is on the bone deemed to
move towards the origin during muscle contraction.
Muscles are often present that engage in several
actions of the joint; able to perform for example both
flexion and extension of the forearm as in the biceps
and triceps respectively. This is not only to be able to
revert actions of muscles, but also brings on stability
of the actions though muscle coactivation.
Agonist and antagonist muscles
The muscle performing an action is the agonist, while
the muscle which contraction brings about an opposite
action is the antagonist. For example, an extension of
the lower arm is performed by the triceps as the
agonist and the biceps as the antagonist (which
contraction will perform flexion over the same joint).
Muscles that work together to perform the same action
are called synergists. In the above example synergists
to the biceps can be the brachioradialis and the
brachialis muscle.
 OTHER
• Body cavities: The body maintains its internal
organization by means of membranes, sheaths, and other
structures that separate compartments, called body
cavities. The ventral cavity includes the thoracic and
abdominopelvic cavities and their subdivisions. The
dorsal cavity includes the cranial and spinal cavities.
• Membranes: A serous membrane (also referred to as a
serosa) is a thin membrane that covers the walls of organs
in the thoracic and abdominal cavities. The serous
membranes have two layers; parietal and visceral,
surrounding a fluid filled space.
THANK YOU
QUESTIONS?