Human Anatomy & Physiology Basics

Flashcards covering human anatomy basics including directional terms, planes and axes of motion, osteokinematic actions, body cavities, and anatomical regions.

Anatomical Position

The standard universal reference position used by clinicians to describe body parts and positions, with the body standing erect, facing forward, arms at sides, and palms facing forward.

Anterior/Ventral

Pertaining to the front surface or towards the front of the body; also referred to as ventral.

Posterior/Dorsal

Pertaining to the back surface or towards the back of the body; also referred to as dorsal.

Proximal

Located closer to the trunk of the body or point of origin/attachment.

Distal

Located farther from the trunk of the body or point of origin/attachment.

Median Plane

The single vertical plane dividing the body centrally into equal right and left halves.

Medial

Positioned closer to the median plane or midline of the body.

Lateral

Positioned farther away from the median plane or midline of the body.

Superior

Positioned higher or towards the head end of the body.

Inferior

Positioned lower or towards the feet end of the body.

External/Superficial

Located on or near the outer surface of the body

Internal/Deep

Located farther inside or away from the body surface

Frontal Bone

The anterior cranial bone that forms the forehead and upper rims of the orbits.

Occipital Bone

The posterior cranial bone forming the back and lower base of the skull.

Body Planes

Imaginary flat 2D surfaces that section or cut through the human body in anatomical position.

Sagittal Plane

A vertical plane dividing the body into right and left sections.

Coronal Plane

A vertical plane dividing the body into anterior (front) and posterior (back) sections.

Transverse Plane

A horizontal plane dividing the body into superior (upper) and inferior (lower) sections.

Anatomical Axes

Perpendicular imaginary lines passing through the body around which joint rotation occurs.

Horizontal Axis (X-axis)

medial to lateral.

Vertical Axis (Y-axis)

superior to inferior.

Sagittal Axis (Z-axis)

anterior to posterior.

Osteokinematic Actions

Gross movements of bones relative to one another at joints.

Flexion

A joint movement that decreases the angle between two articulating bones (e.g., angle $< 90^\times$ or $< 90^\text{o}$).

Extension

A joint movement that increases the angle between two articulating bones (e.g., angle $> 90^\text{o}$).

Lateral Flexion

A sideways bending movement of the trunk or spine away from the midline.

Abduction

Movement of a limb or body structure away from the midline of the body.

Adduction

Movement of a limb or body structure towards the midline of the body.

External Rotation

Rotational movement of a limb region around its axis away from the midline (lateral rotation).

Internal Rotation

Rotational movement of a limb region around its axis towards the midline (medial rotation).

Protraction

Anterior or forward movement of a body structure across a plane, such as pushing shoulders forward.

Retraction

Posterior or backward movement of a body structure across a plane, such as pulling scapulae together.

Elevation

Movement of a body part in a superior (upward) direction.

Depression

Movement of a body part in an inferior (downward) direction.

Circumduction

A circular movement combining flexion, extension, abduction, and adduction at ball-and-socket or condyloid joints.

Supination

Forearm movement that rotates the palm anteriorly or upward.

Pronation

Forearm movement that rotates the palm posteriorly or downward.

Ulnar Deviation

Wrist movement bending the hand medially toward the ulna.

Radial Deviation

Wrist movement bending the hand laterally toward the radius.

Opposition

Movement bringing the pad of the thumb across the palm to contact other digits, enabling grip.

Reposition

Movement returning the thumb from opposition back to its anatomical stance.

Plantarflexion

Ankle movement pointing the foot or toes downward toward the ground.

Dorsiflexion

Ankle movement lifting the foot or toes upward toward the shin.

Inversion

Movement turning the plantar surface (sole) of the foot inward toward the midline.

Eversion

Movement turning the plantar surface (sole) of the foot outward away from the midline.

Agonist

The prime mover muscle primarily responsible for producing a specific motion (e.g., Biceps brachii in elbow flexion).

Antagonist

The muscle that opposes the action of an agonist muscle (e.g., Triceps brachii in elbow flexion).

Simple Joints

Uniaxial hinge joints that accommodate basic flexion and extension (e.g., elbows, knees, interphalangeal joints).

Compound Joints

Complex joint combinations involved in movement, such as the intervertebral joints of the neck and spine.

Body Cavities

Fluid-filled internal spaces that function to protect organs, compartmentalize systems, and limit the spread of infection.

Dorsal Body Cavity

The posterior fluid-filled cavity consisting of the cranial cavity and the vertebral canal.

Ventral Body Cavity

The anterior body space encompassing the thoracic, abdominal, and pelvic cavities.

Cranial Cavity

The cavity inside the skull that encloses and protects the brain.

Neurocranium

The protective bony braincase consisting of 8 bones: 1 ethmoid, 1 sphenoid, 1 frontal, 2 parietal, 2 temporal, and 1 occipital.

Ethmoid Bone

A single cranial bone forming part of the nasal cavity walls, neurocranium, and superior border of the anterior cranial fossa.

Sphenoid Bone

An unpaired wedge-shaped bone at the base of the skull forming central neurocranial structures.

Parietal Bones

A pair of bones forming the curved roof and superior side walls of the skull.

Temporal Bones

A pair of bones forming the lower sides and base of the skull.

Calvaria

The roof of the skull (skullcap) composed of the frontal bone, parietal bones, and occipital bone.

Foramen Magnum

The large opening in the base of the occipital bone allowing the spinal cord to exit the cranial cavity.

Anterior Cranial Fossa (Fossa cranii anterior)

The shallowest cranial fossa bounded by the orbital plate of the frontal bone, superior ethmoid bone, and lesser wings of the sphenoid bone.

Middle Cranial Fossa (Fossa cranii media)

The middle cranial depression formed by the sphenoid bone, temporal bones, and parietal bones.

Posterior Cranial Fossa (Fossa cranii posterior)

The deepest cranial fossa bounded by the temporal bones, parietal bones, and occipital bone.

Cerebrum

The major superior brain structure housed inside the cranial cavity.

Cerebellum

The posterior brain structure situated in the posterior cranial fossa controlling motor coordination.

Brainstem

The central trunk structure of the brain housed within the cranial cavity connecting the cerebrum to the spinal cord.

Vertebral Canal (Canalis vertebralis)

The bony canal extending through the vertebral column that houses the spinal cord and spinal nerves.

Spinal Cord

The primary cylindrical nerve trunk contained within the vertebral canal.

Spinal Nerves

Paired nerve roots issuing laterally from the spinal cord through intervertebral spaces.

Cauda Equina

The collection of lumbar and sacral nerve roots extending downward beyond the end of the spinal cord within the vertebral canal.

Thoracic Cavity

The upper division of the ventral cavity bounded by the ribcage, sternum, spine, and respiratory diaphragm.

Superior Border of Thoracic Cavity

Anatomical border formed by the body of T1 vertebra, the first pair of ribs, and the manubrium of the sternum.

Inferior Border of Thoracic Cavity

The anatomical floor of the thoracic cavity formed by the respiratory diaphragm.

Contents of Thoracic Cavity

Key internal organs consisting of the trachea, bronchi, lungs, oesophagus, heart, and great vessels.

Pleural Cavity

The serous space enclosing each lung lined by pleural membranes.

Parietal Pleura

The outer fibrous membrane lining the internal surface of the thoracic cavity wall.

Visceral Pleura

The inner delicate membrane adhering tightly to the surface of the lung.

Intrapleural Pressure

The pressure inside the pleural cavity, which must remain lower than intrapulmonary pressure to prevent lung collapse.

Pericardial Cavity (Cavitas pericardiaca)

The fluid-filled serous space surrounding the heart situated in the inferior mediastinum.

Fibrous Pericardium

The tough external fibrous connective sac enclosing the heart and pericardial cavity.

Parietal Pericardium

The outer serous layer lining the interior aspect of the fibrous pericardium.

Visceral Pericardium

The inner serous layer that directly covers the epicardial surface of the heart.

Pericardial Fluid

Serous fluid contained in the pericardial space that reduces friction during heart contractions.

Abdominal Cavity

The ventral body cavity region situated between the diaphragm and pelvis housing digestive and metabolic organs.

Greater Omentum

A large apron-like fold of visceral peritoneum extending downward from the stomach over the abdominal viscera.

Mesentery

A double-layered fold of peritoneum attaching the intestines to the posterior abdominal wall.

Pelvic Cavity

The lowermost division of the ventral body cavity situated within the bony pelvis.

Female Pelvic Cavity Contents

Encloses the sigmoid colon, rectum, ureters, urinary bladder, vagina, uterus, and Fallopian tubes.

Male Pelvic Cavity Contents

Encloses the rectum, distal end of the sigmoid colon, bladder, seminal vessels, and prostate.

Right Upper Quadrant (RUQ)

The superior-right division of the abdominal wall in a 4-quadrant anatomical layout.

Subcostal Plane

The upper horizontal grid line passing beneath the costal margins in the 9-region abdominal breakdown.

Intertubercular Plane

The lower horizontal grid line intersecting the iliac tubercles in the 9-region abdominal breakdown.

Epigastric Region

The upper central abdominal region located superior to the umbilical region and between hypochondriac regions.