Overview Of Regional Anatomy Of Thorax And Abdomino-pelvis Wk4 Flashcards
What are features common to the thorax and abdomino-pelvis?
- The 2 largest cavities of the body by volume
– Regions of the body containing the largest number of visceral organs - importance depends on amount of blood they get
– Regions receiving the lion’s share of the cardiac output
– Clinically significant parts of the body
– Their Anatomy forms the basis of specialties in Medicine
what does thorax and abdomen pelvi do?
• Working together, they: – Avail nutrient substance to the body – Excrete large volumes of used fuels • Thorax – Ventilation of tissues of the body – Exhalation of Carbon Dioxide & Water • Abdomino-Pelvis – Absorption of nutrients • Colonised by bacteria – Excretions from GI & Urinary Tracts – Replication of the species
What is the gross anatomy of the thorax and thoracic cavity?
It is constituted from two gross entities of anatomy
– Bony Skeleton
– Skeletal Muscles
• These form an anatomical cavity – The Cavity contains
• VisceralOrgansofThorax – Thoracic Viscera
– Viscera that passes through thorax
What is the bony thorax?
• Architecturally an impressive assembly of bones and cartilages
• Highly dynamic
– Volume changes with the
respiratory cycle
– Movements bring about ventilation
• We need to understand how movements of the thoracic cage are driven
What are components of the articulated bony thorax?
- Manubrium Sterni
- Body of Sternum
- Xiphoid Process
- Coastal cartilages
- Clavicles
- Ribs
- Thoracic Vertebrae
- Joints between the bones
- Joints between bones and cartilages
What bones form the thorax?
– 12 pairs of ribs – 12 Thoracic vertebrae – Sternum (n=1) – Manubrium of the sternum (n=1) – Xiphoid Process (n=1) – Manubrosternal Joint (n=1) - Xiphisternal joins (n=1)
What are the muscles of the chest wall?
• They form the body wall of the thorax
• Collectively known as intercostal muscles between the ribs
• They occur as 3 layers of skeletal muscles
• Complex morphology anteriorly
• The middle layer blends-in bony processes that reinforce it
– These are the ribs
• Continue as the abdominal wall
Allows for vascular structures
What is the architecture of intercostal muscles?
RANDOM ORDER
- Clavicle
- Ribs
- Pectoralis major (dissected)
- Pectoralis minor
- Internal intercostal
- Sternum
- External intercostals
- Serratus anterior
What is pleura?
- Thin membrane lines viscera of thoracic region - 2 membranes very close to each other
- Plural for very thin membranes that line membranes that line internal wall of thoracic wall
Outside In = - Parietal pleura (lines the inner surface of body wall of thorax)
- Pleural space (space between two layers of membrane filled with pleural fluid)
- Visceral pleura (lines surface of all organs of the thorax)
Double folds of pleura are known as ligaments
ISsues with lungs
Air into pleural cavity = vacuum created, lung would collapse - pneumothorax
If no liquid enters, muscles would rub together causing sharp pain known as pleursey
What are soft tissues of the thorax?
Pleura Diaphragm Intercostal muscles Great vessels Nerves Viscera Pleural fluid
What are the boundaries of the thorax?
Superior - thoracic inlet
Inferior - thoracic outlet, diaphragm
Antero-lateral-posterior - Ribs
Posterior - thoracic vertebrae (scapulae (shoulder blades) - reinforcement)
What are the anatomical compartments of the thoracic cavity?
- 2 gross divisions divided by fibrous pericardium Pleural cavities - left pulmonary cavity (outside) - right pulmonary cavity (outside) Mediastinum - “middle of the chest”
what does the abdominal cavity have?
- It is by far, the largest anatomical cavity of the body
- Much of it lies under the cover of • Lower Ribs
- &
- Domes of the Diaphragm
- An appreciable amount of the abdominal cavity projects backwards into the pelvis just in front of the buttocks
- It is continuous with the pelvic cavity, inferiorly
- It is the cavity for:
- The Digestive Tract
- Pregnancy (Primarily in the Pelvis) • Major Excretion
What are boundaries of abdominal cavity?
In gross terms, its boundaries are: • Thoracic Diaphragm (Superior) • Pelvic Brim (Inferior- Imaginary) • Anterolateral Abdomino-pelvic Wall (Ant-Lat) • Posterior Abdominal Wall (Posterior)
What are the points of reference of anterior abdominal wall?
– The Linea Alba
• Xyphoid Process
• Pubic Symphysis – The Umbilicus
What are the 2 horizontal planes of abdominal wall?
- Subcostal plane
- Trans-tubercular plane
What are the tissues contained within the following layers?
- Skin
- Tissue layers of the walls of the abdomen and pelvis
- Anterolateral wall of the abdomen
- Posterior wall of the abdomen
- Walls of the pelvis
- Transversalis Fascia
- Peritoneum
- A lining that forms the deepest tissue envelope housing viscera of the abdomen & pelvis
- Hence known as the ‘epithelium’
What is peritoneum?
• Also known as the pavement epithelium
• It is a one-cell thick tissue membrane
• It lines the:
• Interior surfaces of all of the abdominal wall
• Except Area of the Coronary Ligament
• Surfaces of all viscera of abdomen
• Except Bare Area of the Liver
• It is classified histologically as Simple Squamous
Epithelium
• It shares its characteristics with other epithelia that line inner walls of the body and its organs (in other regions)
• Two variants of peritoneum are recognised
• Parietal peritoneum
• Visceral peritoneum
• Despite having separate names, these variants of epithelium are continuations of the same layer of membrane
• It is given two separate names depending on its relative location & functions
What does the 2 bits of peritoneum line?
• Parietalperitoneum – Lines inner walls of the abdomen, diaphragm and pelvis • Visceralperitoneum – Lines visceral organs of the abdomen
What innervates different parts of the peritoneum?
• Parietal peritoneum
– Innervated by sensory division of the somatic nervous system
• Its pain sensations are sharp & localised • Visceral peritoneum
– Innervated by the sensory division of the autonomic nervous system
• Its pain sensations are not ‘localised ‘but perceived as ‘non-defined’ discomfort
What is the peritoneal cavity?
- The cavity that is created between parietal and visceral peritoneum is known as the peritoneal cavity
- It is one of the spaces derived from the coelomic cavity of the embryo
- Others being the
- Pleural cavities around the lungs
- &
- Pericardial cavity around the heart.
- The pleural cavity is
- The largest fluid-filled cavity in the body
- It secretes approximately 50mL of fluid per day
- Its fluid acts as a lubricant and has anti- inflammatory properties
Double peritoneum layers
- Any double layer of peritoneum can be called different things depending on what is contained within the
- Ligament
- Mesentery • Omentum
- Reflections of peritoneum can also be known as
- Pouches • Recesses • etc
What are the gross anatomical features of viscera of the abdomen and pelvis?
- Taken together, viscera of the abdomen are deployed anatomically in relation to a cavity created by boundaries of the peritoneum
- Structures are said to be either
- Within the compartment created by boundaries of the peritoneum
- Green line forms the boundary
- These are Peritoneal Organs
- Outside the compartment created by boundaries of the peritoneum
- These are Extraperitoneal Organs
What is laparoscopic approach?
Through belly button
What is the abdominal cavity proper divided into?
The Greater Sac
• The rest of the peritoneal cavity apart from the lesser sac
The Lesser Sac
• The space lying posterior to the stomach
• Also known as the Omental Bursa
