Anatomical Terminology

Directional Terms

All directional terminology assumes the body is in the standard anatomical position: standing upright with the head and eyes facing forward, upper limbs at the sides, and palms facing anteriorly (supinated). The feet are together or slightly apart, with the toes pointing forward. This reference position ensures consistency Consistency Dermatologic Examination when describing anatomical structures or movements, regardless of the patient’s actual posture or orientation Orientation Awareness of oneself in relation to time, place and person. Psychiatric Assessment.

Directional terms provide healthcare professionals with a standardized vocabulary for describing relative positions of anatomical structures, enabling precise documentation Documentation Systematic organization, storage, retrieval, and dissemination of specialized information, especially of a scientific or technical nature. It often involves authenticating or validating information. Advance Directives of physical examinations, radiological findings, and surgical approaches regardless of patient orientation Orientation Awareness of oneself in relation to time, place and person. Psychiatric Assessment.

• Superior:
  • toward head or upper part of structure
  • synonymous with cranial in humans
• Inferior:
  • away from head or lower part of structure
  • synonymous with caudal in humans
• Anterior:
  • front surface or ahead in position
  • synonymous with ventral in humans
• Posterior:
  • back surface or behind in position
  • synonymous with dorsal in humans
• Medial:
  • toward midline of body or structure
• Lateral:
  • away from midline of body or structure
• Proximal:
  • closer to point of attachment, origin, or trunk of body
• Distal:
  • farther from point of attachment, origin, or trunk of body
• Superficial:
  • toward or at body surface
• Deep:
  • away from body surface, toward interior
• Ipsilateral:
  • on same side of body or structure
• Contralateral:
  • on opposite side of body or structure
• Ventral:
  • toward or at the front
  • anterior in humans
• Dorsal:
  • toward or at the back
  • posterior in humans
• Cranial:
  • toward or at the head
  • superior in humans
• Caudal:
  • toward or at the tail
  • inferior in humans
• Parietal Parietal One of a pair of irregularly shaped quadrilateral bones situated between the frontal bone and occipital bone, which together form the sides of the cranium. Skull: Anatomy:
  • pertaining to walls of a cavity
• Visceral:
  • pertaining to internal organs

Planes and Sections

Anatomical planes and sections serve as essential references in medical imaging, with technologies such as MRI, CT, and ultrasound producing views along these standardized planes to facilitate consistent interpretation and communication Communication The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups. Decision-making Capacity and Legal Competence of findings among healthcare providers.

• Sagittal plane Sagittal plane Anterior Abdominal Wall: Anatomy:
  • vertical plane Vertical Plane Anterior Abdominal Wall: Anatomy dividing body into right and left portions
• Midsagittal plane:
  • median sagittal plane Sagittal plane Anterior Abdominal Wall: Anatomy dividing body into equal right and left halves
• Parasagittal plane:
  • any sagittal plane Sagittal plane Anterior Abdominal Wall: Anatomy not passing through midline
• Coronal Coronal Computed Tomography (CT) plane:
  • vertical plane Vertical Plane Anterior Abdominal Wall: Anatomy dividing body into anterior and posterior portions
  • also called frontal Frontal The bone that forms the frontal aspect of the skull. Its flat part forms the forehead, articulating inferiorly with the nasal bone and the cheek bone on each side of the face. Skull: Anatomy plane
• Transverse plane Transverse plane Anterior Abdominal Wall: Anatomy:
  • horizontal plane dividing body into superior and inferior portions
  • also called axial Axial Computed Tomography (CT) or cross-sectional plane
• Oblique plane:
  • any plane that is not sagittal Sagittal Computed Tomography (CT), coronal Coronal Computed Tomography (CT), or transverse
• Cross section:
  • cut perpendicular to long axis of structure
• Longitudinal section:
  • cut parallel to long axis of structure
• Tangential section:
  • cut across curved surface

Regional Names

Regional anatomical terms allow clinicians to precisely communicate the location of physical findings, pathologies, or procedures, forming the foundation for accurate clinical examinations, medical records, and surgical planning.

• Cephalic region:
  • pertaining to the head 
  • includes cranial and facial areas
• Cervical region Cervical region Spinal Cord: Anatomy:
  • neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess area 
  • contains vital structures connecting head and torso
• Thoracic region Thoracic region Spinal Cord: Anatomy:
  • chest area 
  • houses heart, lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy, and associated structures
• Abdominal region:
  • area between thorax and pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy 
  • contains digestive organs, spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen: Anatomy, kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy
• Pelvic region:
  • lower portion of trunk 
  • contains reproductive organs, rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy, bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess
• Dorsal region:
  • back or posterior aspect of body 
  • includes vertebral column Vertebral column The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy, associated muscles
• Ventral region:
  • front or anterior aspect of body
• Axillary region:
  • armpit area 
  • important neurovascular pathway
• Brachial region:
  • pertaining to the arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy 
  • area between shoulder and elbow
• Antebrachial region:
  • forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy
  • area between elbow and wrist
• Carpal region:
  • wrist area
  • contains eight small bones
• Manual region:
  • hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy
  • includes palm and digits
• Femoral region:
  • thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
  • area between hip and knee
• Patellar region:
  • knee area
  • anterior aspect of knee joint Knee joint The knee joint is made up of the articulations between the femur, tibia, and patella bones, and is one of the largest and most complex joints of the human body. The knee is classified as a synovial hinge joint, which primarily allows for flexion and extension with a more limited degree of translation and rotation. Knee Joint: Anatomy
• Crural region:
  • leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy
  • area between knee and ankle
• Pedal region:
  • foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
  • distal portion of lower limb
• Inguinal region Inguinal region Anterior Abdominal Wall: Anatomy:
  • groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination area
  • junction of lower abdomen and thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
• Umbilical region Umbilical Region Surgical Anatomy of the Abdomen:
  • navel area
  • central abdominal landmark

Abdominal Quadrants

Clinically, the abdomen is often divided into 4 quadrants by 2 perpendicular lines crossing at the umbilicus. This simple division aids in describing symptoms like pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways or masses and in localizing organ pathologies during physical examination and imaging.

• Right Upper Quadrant Right upper quadrant Anterior Abdominal Wall: Anatomy (RUQ): 
  • contains the liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy, gallbladder Gallbladder The gallbladder is a pear-shaped sac, located directly beneath the liver, that sits on top of the superior part of the duodenum. The primary functions of the gallbladder include concentrating and storing up to 50 mL of bile. Gallbladder and Biliary Tract: Anatomy, part of the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy, and sometimes the right kidney
  • clinically important in assessing hepatobiliary conditions, such as hepatitis or cholecystitis Cholecystitis Cholecystitis is the inflammation of the gallbladder (GB) usually caused by the obstruction of the cystic duct (acute cholecystitis). Mechanical irritation by gallstones can also produce chronic GB inflammation. Cholecystitis is one of the most common complications of cholelithiasis but inflammation without gallstones can occur in a minority of patients. Cholecystitis
• Left Upper Quadrant Left upper quadrant Anterior Abdominal Wall: Anatomy (LUQ):
  • contains the stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy, spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen: Anatomy, left kidney, and parts of the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy
  • clinically important in assessing conditions such as splenic injury or gastric ulcers
• Right Lower Quadrant Right lower quadrant Anterior Abdominal Wall: Anatomy (RLQ):
  • contains the appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy, cecum Cecum The blind sac or outpouching area of the large intestine that is below the entrance of the small intestine. It has a worm-like extension, the vermiform appendix. Colon, Cecum, and Appendix: Anatomy, and portions of the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy
  • clinically important in assessing for appendicitis Appendicitis Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. Appendicitis and other inflammatory or reproductive issues in women
• Left Lower Quadrant Left Lower quadrant Anterior Abdominal Wall: Anatomy (LLQ)
  • contains the sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy, left ovary and fallopian tube Fallopian Tube A pair of highly specialized canals extending from the uterus to its corresponding ovary. They provide the means for ovum transport from the ovaries and they are the site of the ovum’s final maturation and fertilization. The fallopian tube consists of an interstitium, an isthmus, an ampulla, an infundibulum, and fimbriae. Its wall consists of three layers: serous, muscular, and an internal mucosal layer lined with both ciliated and secretory cells. Uterus, Cervix, and Fallopian Tubes: Anatomy (in women), and part of the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy
  • clinically important in assessing for diverticulitis Diverticulitis Inflammation of a diverticulum or diverticula. Diverticular Disease, ovarian disorders, or lower GI complaints

Abdominopelvic Regions

For greater precision, the abdominopelvic area can also be divided into 9 regions, which help pinpoint clinical findings more accurately and correlate them with underlying anatomical structures.

• Right Hypochondriac region
  • Located in the upper right area under the costal margin
  • Contains parts of the liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy and gallbladder Gallbladder The gallbladder is a pear-shaped sac, located directly beneath the liver, that sits on top of the superior part of the duodenum. The primary functions of the gallbladder include concentrating and storing up to 50 mL of bile. Gallbladder and Biliary Tract: Anatomy
• Epigastric region Epigastric region Anterior Abdominal Wall: Anatomy
  • Located centrally, below the rib cage Rib cage The bony thoracic enclosure consisting of the vertebral column; the ribs; the sternum; and the costal cartilage. Chest Wall: Anatomy and above the umbilical region Umbilical Region Surgical Anatomy of the Abdomen
  • Contains portions of the stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy, liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy, and pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy
• Left Hypochondriac region
  • Located in the upper left area beneath the left costal margin
  • Contains parts of the stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy and spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen: Anatomy
• Right Lumbar region Lumbar region Spinal Cord: Anatomy
  • Located laterally in the mid-right area
  • Contains segments of the ascending colon Ascending colon The segment of large intestine between the cecum and the transverse colon. It passes cephalad from the cecum to the caudal surface of the right lobe of the liver where it bends sharply to the left, forming the right colic flexure. Colon, Cecum, and Appendix: Anatomy and right kidney
• Umbilical region Umbilical Region Surgical Anatomy of the Abdomen
  • Central portion around the navel
  • Contains segments of the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy
• Left Lumbar region Lumbar region Spinal Cord: Anatomy
  • Located laterally in the mid-left section
  • Contains parts of the descending colon Descending colon The segment of large intestine between transverse colon and the sigmoid colon. Colon, Cecum, and Appendix: Anatomy and left kidney
• Right Iliac (also called Inguinal) region
  • Located in the lower right area
  • Contains the appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy and female reproductive structures
• Hypogastric (also called Pubic) region
  • Lower central region above the pubic bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types
  • Contains the bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess and reproductive organs
• Left Iliac (also called Inguinal) region
  • Located in the lower left section
  • Contains portions of the colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy and female reproductive organs

Body Cavities

Understanding body cavities and their contents is fundamental for clinical practice as it guides physical examination techniques, interpretation of imaging studies, and surgical approaches for accessing specific organs and anatomical structures.

• Dorsal cavity:
  • contains central nervous system Central nervous system The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges. Nervous System: Anatomy, Structure, and Classification
  • divided into cranial and vertebral cavities
• Cranial cavity:
  • houses brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification
  • formed by cranial bones
• Vertebral canal:
  • contains spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy
  • formed by vertebral foramina
• Ventral cavity:
  • larger cavity containing internal organs
  • divided into thoracic and abdominopelvic cavities
• Thoracic cavity:
  • chest cavity
  • contains heart, lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy, esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy; bounded by ribs Ribs A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs. Chest Wall: Anatomy, sternum Sternum A long, narrow, and flat bone commonly known as breastbone occurring in the midsection of the anterior thoracic segment or chest region, which stabilizes the rib cage and serves as the point of origin for several muscles that move the arms, head, and neck. Chest Wall: Anatomy, vertebrae, diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
• Pleural cavities:
  • surround lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy
  • reduce friction during breathing
• Pericardial cavity Pericardial cavity Heart: Anatomy:
  • surrounds heart
  • contains small amount of fluid for frictionless movement
• Mediastinum Mediastinum The mediastinum is the thoracic area between the 2 pleural cavities. The mediastinum contains vital structures of the circulatory, respiratory, digestive, and nervous systems including the heart and esophagus, and major thoracic vessels. Mediastinum and Great Vessels: Anatomy:
  • central compartment of thoracic cavity
  • contains heart, trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy, esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy, thymus Thymus A single, unpaired primary lymphoid organ situated in the mediastinum, extending superiorly into the neck to the lower edge of the thyroid gland and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat. Lymphatic Drainage System: Anatomy
• Abdominopelvic cavity:
  • continuous cavity divided into abdominal and pelvic portions
• Abdominal cavity:
  • contains stomach Stomach The stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy, intestines, liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy, spleen Spleen The spleen is the largest lymphoid organ in the body, located in the LUQ of the abdomen, superior to the left kidney and posterior to the stomach at the level of the 9th-11th ribs just below the diaphragm. The spleen is highly vascular and acts as an important blood filter, cleansing the blood of pathogens and damaged erythrocytes. Spleen: Anatomy, pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy, kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy
• Pelvic cavity:
  • houses bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess, rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy, reproductive organs
• Peritoneal cavity Peritoneal Cavity The space enclosed by the peritoneum. It is divided into two portions, the greater sac and the lesser sac or omental bursa, which lies behind the stomach. The two sacs are connected by the foramen of winslow, or epiploic foramen. Peritoneum: Anatomy:
  • potential space within abdominal cavity
  • lined by peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum: Anatomy
• Retroperitoneal Retroperitoneal Peritoneum: Anatomy space:
  • area behind peritoneum Peritoneum The peritoneum is a serous membrane lining the abdominopelvic cavity. This lining is formed by connective tissue and originates from the mesoderm. The membrane lines both the abdominal walls (as parietal peritoneum) and all of the visceral organs (as visceral peritoneum). Peritoneum: Anatomy
  • contains kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy, adrenal glands Adrenal Glands The adrenal glands are a pair of retroperitoneal endocrine glands located above the kidneys. The outer parenchyma is called the adrenal cortex and has 3 distinct zones, each with its own secretory products. Beneath the cortex lies the adrenal medulla, which secretes catecholamines involved in the fight-or-flight response. Adrenal Glands: Anatomy, pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy, parts of duodenum Duodenum The shortest and widest portion of the small intestine adjacent to the pylorus of the stomach. It is named for having the length equal to about the width of 12 fingers. Small Intestine: Anatomy and colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy

Movements

Movement terminology is crucial in physical therapy Physical Therapy Becker Muscular Dystrophy, orthopedics, and rehabilitation medicine where precise description of motion limitations Limitations Conflict of Interest, exercises, and functional assessments directly impacts diagnosis, treatment planning, and documentation Documentation Systematic organization, storage, retrieval, and dissemination of specialized information, especially of a scientific or technical nature. It often involves authenticating or validating information. Advance Directives of patient progress.

• Flexion Flexion Examination of the Upper Limbs:
  • bending movement decreasing angle between articulating bones
• Extension Extension Examination of the Upper Limbs:
  • straightening movement increasing angle between articulating bones
• Abduction Abduction Examination of the Upper Limbs:
  • movement away from midline of body or part
• Adduction Adduction Examination of the Upper Limbs:
  • movement toward midline of body or part
• Rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays:
  • circular movement around central axis
  • Internal (medial) rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays: turning the anterior surface of a limb segment toward the midline of the body
  • External (lateral) rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays: turning the anterior surface of a limb segment away from the midline of the body
• Circumduction:
  • circular movement combining flexion Flexion Examination of the Upper Limbs, abduction Abduction Examination of the Upper Limbs, extension Extension Examination of the Upper Limbs, adduction Adduction Examination of the Upper Limbs
• Pronation Pronation Applies to movements of the forearm in turning the palm backward or downward. When referring to the foot, a combination of eversion and abduction movements in the tarsal and metatarsal joints (turning the foot up and in toward the midline of the body). Examination of the Upper Limbs:
  • forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays resulting in palm facing posteriorly (anatomical position)
• Supination Supination Applies to movements of the forearm in turning the palm forward or upward. When referring to the foot, a combination of adduction and inversion movements of the foot. Examination of the Upper Limbs:
  • forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays resulting in palm facing anteriorly (anatomical position)
• Inversion:
  • foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy movement turning sole medially
• Eversion Eversion Chronic Apophyseal Injury:
  • foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy movement turning sole laterally
• Protraction:
  • anterior movement in horizontal plane
• Retraction:
  • posterior movement in horizontal plane
• Elevation:
  • superior movement of structure
• Depression:
  • inferior movement of structure
• Dorsiflexion:
  • ankle flexion Flexion Examination of the Upper Limbs bringing top of foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy toward shin Shin Erythema Nodosum
• Plantar flexion Flexion Examination of the Upper Limbs:
  • ankle extension Extension Examination of the Upper Limbs pointing toes downward

Body Systems

The classification of body systems provides a systematic framework for medical education Medical education Conflict of Interest, clinical practice, and research Research Critical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws. Conflict of Interest, allowing healthcare professionals to understand the interconnected nature of organ functions and approach patient care from both specialized and holistic perspectives.

• Integumentary system:
  • skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions, hair, nails, sweat glands Sweat glands Sweat-producing structures that are embedded in the dermis. Each gland consists of a single tube, a coiled body, and a superficial duct. Soft Tissue Abscess
  • forms external body covering; protection, temperature regulation, sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology reception
• Skeletal system:
  • bones, cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology, ligaments
  • structural support, protection, movement, blood cell production, mineral storage
• Muscular system:
  • skeletal, cardiac, smooth muscles Smooth muscles Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. Muscle Tissue: Histology
  • movement, posture, heat production Heat Production Fever
• Nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification:
  • brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification, spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy, nerves, ganglia
  • control center for body functions, communication Communication The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups. Decision-making Capacity and Legal Competence network
• Endocrine system:
  • hormone-producing glands
  • regulation of metabolism, growth, development, reproduction
• Cardiovascular system:
  • heart, blood vessels, blood
  • transport of nutrients, gases, waste products, hormones Hormones Hormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types
• Lymphatic system Lymphatic system A system of organs and tissues that process and transport immune cells and lymph. Primary Lymphatic Organs:
  • lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs vessels, lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy, lymphoid organs Lymphoid organs A system of organs and tissues that process and transport immune cells and lymph. Primary Lymphatic Organs
  • fluid balance, immune defense
• Respiratory system:
  • airways, lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy
  • gas exchange Gas exchange Human cells are primarily reliant on aerobic metabolism. The respiratory system is involved in pulmonary ventilation and external respiration, while the circulatory system is responsible for transport and internal respiration. Pulmonary ventilation (breathing) represents movement of air into and out of the lungs. External respiration, or gas exchange, is represented by the O2 and CO2 exchange between the lungs and the blood. Gas Exchange, acid-base balance
• Digestive system:
  • alimentary canal and accessory organs
  • food processing, nutrient absorption Absorption Absorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation. Digestion and Absorption
• Urinary system:
  • kidneys Kidneys The kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine. Kidneys: Anatomy, ureters Ureters One of a pair of thick-walled tubes that transports urine from the kidney pelvis to the urinary bladder. Urinary Tract: Anatomy, bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess, urethra Urethra A tube that transports urine from the urinary bladder to the outside of the body in both the sexes. It also has a reproductive function in the male by providing a passage for sperm. Urinary Tract: Anatomy
  • waste elimination Elimination The initial damage and destruction of tumor cells by innate and adaptive immunity. Completion of the phase means no cancer growth. Cancer Immunotherapy, water balance, acid-base balance
• Reproductive system:
  • gonads Gonads The gamete-producing glands, ovary or testis. Hormones: Overview and Types, accessory organs
  • production of offspring, hormone production

Histological Terminology

Histological terminology forms the foundation of pathology and laboratory medicine, enabling accurate diagnosis of diseases through microscopic examination of tissues and providing a common language for describing cellular changes in conditions ranging from inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation to cancer.

• Tissue:
  • group of similar cells performing specialized function
  • four basic types
• Epithelial tissue:
  • covering and lining tissue
  • classified by cell shape and arrangement
• Connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology:
  • most abundant tissue type
  • support, connection, protection
• Muscular tissue:
  • contractile tissue
  • movement, posture
• Nervous tissue:
  • specialized for impulse conduction
  • information processing
• Parenchyma:
  • functional parts of organ or tissue
• Stroma:
  • supporting framework of organ or tissue
• Extracellular matrix Extracellular matrix A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere. Hypertrophic and Keloid Scars:
  • non-cellular component providing structural support
• Basement membrane Basement membrane A darkly stained mat-like extracellular matrix (ecm) that separates cell layers, such as epithelium from endothelium or a layer of connective tissue. The ecm layer that supports an overlying epithelium or endothelium is called basal lamina. Basement membrane (bm) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. Bm, composed mainly of type IV collagen; glycoprotein laminin; and proteoglycan, provides barriers as well as channels between interacting cell layers. Thin Basement Membrane Nephropathy (TBMN):
  • specialized layer supporting epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium: Histology