Download MTC8: Introduction to Anatomy 28/09/07

MTC8: INTRODUCTION TO ANATOMY
28/09/07
LEARNING OUTCOMES
Use basic anatomical terms to describe planes, surfaces and movements
Planes
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The anatomical position is the standard position for studying the anatomy of a body, which must be
stood upright with arms by the sides and palms facing out, a neutral facial expression, eyes open and
facing forward focussing on something distant, and feet facing forwards
The median plane is the vertical plane that bisects the body parallel to the direction it is facing from
front to back, head to toe
Sagittal planes are parallel to the median plane
The coronal planes are the vertical planes that cut across the body perpendicular to the direction it is
facing, i.e. from the left thumb to the right thumb, and are perpendicular to the sagittal planes
The transverse / horizontal / axial planes are the horizontal planes that cut through the body as if to
slice it and are at right angles to both the coronal and sagittal planes
Terms of Location and Orientation
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Superior is up towards the top of the head; inferior is down towards the soles of the feet
Anterior is out along the coronal plane in the back to front direction; posterior is the opposite
Lateral is away from the median plane; medial is towards the median plane
Proximal describes something as being closer to the structure’s origin; distal is the opposite
Superficial describes something as being closer to the surface of the body; deep is the opposite
Ipsilateral describes things that are on or affect the same side of the body; contralateral is the
opposite
Parietal describes something in relation to the walls of a body cavity; visceral instead considers the
contents
Describe the anatomy of the respiratory system
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The thorax is formed by the ribcage and is described as an irregularly shaped cylinder with two
apertures: the superior thoracic aperture is small and open joining to the neck, whilst the inferior
thoracic aperture is larger and enclosed by the diaphragm.
The thoracic wall or thoracic skeleton consists of twelve posterior vertebrae numbered incrementally
in the superior to inferior direction (i.e. T1 to T12) as well as twelve pairs of ribs which primarily
provide lateral cover as well as partial posterior and anterior protection.
Ribs themselves articulate with the thoracic vertebrae posteriorly whereas costal cartilage joins ribs I
to X to the sternum (directly for ribs I to VII, via superior costal cartilages for ribs VIII to X); ribs XI and
XII are floating ribs.
Intercostal muscles span the intercostal spaces between adjacent ribs and provide further support.
The sternum is composed of the manubrium, body and the xiphisternum (or xiphoid process).
The thoracic cavity is divided into three parts: left and right pleural cavities and the mediastinum.
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The mediastinum is a protective partition oriented along the median plane and contains the heart,
oesophagus and trachea, among others.
The pleural cavities lie laterally on either side of the mediastinum and so are completely separated
from one another, covering the inside of the ribs (reaching above rib I) and containing the lungs.
The lungs do not entirely fill either pleural cavity leaving recesses including the costodiaphragmatic
recess which is found inferiorly between the thoracic wall and the diaphragm.
Each pleural cavity is lined by a mesothelial membrane called the pleura which has both parietal and
visceral layers relative to the thoracic wall.
The trachea begins at the lower margin of the larynx and runs centrally through the mediastinum
before dividing at T4 into two main bronchi which supply the left and right lungs.
The lungs are divided into lobes which are separated by fissures: the left lung has a superior and
inferior lobe, whilst the right lung has a superior, inferior and middle lobe.
The right lung is usually bigger than the left since the middle mediastinum containing the heart bulges
to the left.
The medial surfaces of the lungs contain the roots which are short tubular collections of structures
that link the lungs to other structures on the mediastinum; these are surrounded by a sleeve of
mediastinal pleura called the hilum.