Introduction to Human Anatomy Terminology
Administrative Details and Exam Scope
Lab Schedule Adjustments: Labor Day has been moved to the correct week to align with the fourth week of the semester. Consequently, labs will be held for three consecutive weeks, followed by a skipped week.
There will be no lab during the week of Labor Day on the .
One half of the class has lab on Monday, and the other half meets today.
Exam 1 Content: The first exam will cover the following material:
Chapter 1: The introductory chapter, covering the majority of its content.
Chapter 2: Covering the back.
Chapter 3: Focusing on the upper limb, described as an extensive and significant chapter.
Introduction to Anatomical Study
Course Structure: Chapter 1 serves as an introduction designed to establish a baseline of knowledge. Unlike subsequent chapters, it is not focused on a specific region but provides a "whirlwind tour" of anatomical principles necessary for exploring the human body regionally.
Clinical Example of Physiology: Blushing or flushing is a recorded example of an autonomic nervous response, specifically a sympathetic autonomic nervous response. This relates to the visceral motor system.
Systemic vs. Regional Anatomy:
Systemic Anatomy: This approach organizes the study by systems, such as the nervous, digestive, or cardiovascular systems. There are systems in total. Historically, this is the format used in lower-division undergraduate courses (such as ) and high school anatomy.
Regional Anatomy: This approach examines each region of the body (e.g., thorax, abdomen, pelvis) and discusses all systems discovered within that specific region. This is the standard teaching method at the graduate school level.
Integration: Fluency in both perspectives is required because systems often cross regional boundaries. For example, the urinary system begins with kidneys in the abdomen, transitions to ureters entering the pelvis, and ends with the urethra in the perineum. Similarly, discussing the nails may require understanding the anterior abdominal wall (effluent).
The Language of Anatomy
Etymological Roots: Most complex medical terminology is derived from Greek and Latin roots. Mastering these roots is essential for professional precision and understanding.
Word Structure:
Root: The core meaning (e.g., "cardio" for heart).
Prefix: Added before the root (e.g., "epi" in epigastric means above; "hypo" in hypodermic means below).
Suffix: Added after the root (e.g., "itis" means inflammation; "ology" means the study of; "cyte" means cell).
Specific Examples:
Epigastric: Above (epi) the stomach (gastric).
Hypodermic: Below (hypo) the skin/dermis.
Arthritis: Inflammation (itis) of the joint (arthro).
Adipocyte: A fat (adipo) cell (cyte).
Gastroenterologist: One who studies (ology) the stomach (gastro) and small intestine (entero).
Anatomical Homonyms and Similar Terms: Precision in spelling and usage is vital as many terms sound identical or similar despite referring to different structures:
Zygomaticus vs. Zygomatic: The zygomaticus is a muscle attached to the zygomatic bone.
Ileum vs. Ilium: The ileum is part of the small intestine; the ilium is a bone in the pelvis (though the speaker notes they sound identical/homonyms).
External Oblique: While the most famous external oblique is in the anterior abdominal wall, the body contains several internal and external oblique muscles.
Malleolus vs. Malleus: The malleolus refers to the bony prongs at the ankle; the malleus is a small bone in the middle ear.
Anatomical Position and Reference
Definition: Anatomical position is the universal reference point for all descriptive terms. It is defined as a person standing upright with feet on the floor, arms lateral to the trunk, and palms facing forward.
Standard Assumption: Unless a clinical case or question specifies a different position, always assume the body is in anatomical position.
Sexual Dimorphism: Humans, like most mammals, exhibit sexual dimorphism. This includes differences in reproductive organs and secondary sexual characteristics (e.g., the presence or absence of breasts or a penis), which can affect anatomical observation.
Body Planes and Sections
Sagittal Plane: Divides the body into right and left portions.
Midsagittal (Sagittal): Directly on the midline, creating equal halves.
Parasagittal: Off the midline, creating unequal halves.
Hand and Foot Sagittal Planes: Specific planes used to divide the complex structures of the extremities.
Frontal (Coronal) Plane: Divides the body into front (anterior/ventral) and back (posterior/dorsal) halves. It is named for the coronal suture of the skull.
Transverse Plane: Divides the body into top (superior/upper) and bottom (inferior/lower) halves. This is the most common plane used in MRI and CT scans.
Limb Sections:
Longitudinal Section: Running along the long axis of the limb (often effectively a sagittal or parasagittal section).
Transverse Section: A cross-section through a limb, useful for seeing all internal structures.
Oblique Section: A cut made at an eccentric angle. These are critical for imaging specific structures like the ACL in the knee or the rotator cuff in the shoulder, which run at angles not captured by standard planes.
Directional Terminology
Vertical Axis: Superior (up toward the head/cranial) and Inferior (down toward the tail/caudal).
Depth:
Superficial: External or closer to the skin.
Deep: Internal or further into the body.
Intermediate: Layers situated between superficial and deep.
Limb Proximity:
Proximal: Closer to the point of attachment (e.g., the shoulder is proximal to the elbow).
Distal: Further from the point of attachment (e.g., the wrist is distal to the elbow).
Midline Proximity:
Medial: Closer to the midline (e.g., the sternum is medial to the shoulder).
Lateral: Further from the midline (e.g., the shoulder is lateral to the sternum).
Surfaces:
Palmar: The anterior surface of the hand (the palm).
Plantar: The sole of the foot.
Dorsal: The back of the hand or the top of the foot.
Joint Kinematics and Movement
Shoulder (Ball and Socket Joint):
Flexion: Moving the arm forward and up.
Extension: Moving the arm backward.
Hyperextension: Extending past the normal range.
Abduction: Moving the limb away from the midline.
Adduction: Moving the limb toward the midline ("adding" back to the body).
Internal (Medial) Rotation: Rotating toward the center.
External (Lateral) Rotation: Rotating away from the center.
Elbow and Forearm:
Flexion/Extension: Bending and straightening the arm.
Supination: Rotating the forearm so the palm faces up (like holding a bowl of soup).
Pronation: Rotating the forearm so the palm faces down (like pouring soup out). This motion involves the radius and ulna moving relative to each other at the elbow.
Trunk and Spine:
Flexion: Bending forward at the lumbar spine.
Extension: Straightening or bending backward.
Lateral Bending: Leaning to the side.
Rotation: Turning the torso; most thoracic rotation occurs in the thoracic spine, while the lumbar spine is structured primarily for flexion and extension.
Neck (Cervical Spine): The cervical vertebrae have open joint surfaces that allow for high mobility, including flexion, extension, lateral bending, and rotation.
Foot and Ankle:
Dorsal Flexion (Extension): Pointing toes toward the nose.
Plantar Flexion (Flexion): Pointing toes down or making a fist with the toes.
Inversion: Turning the sole of the foot inward.
Eversion: Turning the sole of the foot outward. These motions occur at the bones lower in the foot, not at the talus-tibia articulation.
Scapula:
Elevation: Raising the shoulder blades up.
Depression: Lowering the shoulder blades.
Medial Translation: Bringing the blades toward the midline.
Protraction: Moving the scapula forward on the back.
Retraction: Moving the scapula backward.
Mandible (Jaw):
Protraction: Sticking the jaw out.
Retraction: Tucking the jaw in. These motions are essential for normal chewing at the Temporomandibular joint (TMJ).
Connective Tissue and Fascia
Fascia: General term for connective tissue. It organizes the body by packing muscles and organs.
Types of Fascia:
Subcutaneous Fat: Located in the hypodermis, superficial to the deep fascia.
Deep (Investing) Fascia: Heavy, white connective tissue encasing structures (e.g., fascia lata in the thigh or crural fascia in the lower leg).
Intramuscular Septa: Fascial sheets that enclose different muscle compartments.
Bursa and Serous Membranes:
Bursa: Sacs filled with synovial fluid that allow tendons to translate without friction. Inflammation is known as bursitis.
Serous Membrane Formation: Can be visualized as an organ (like a fist) pushing into a bag (like a balloon).
Visceral Layer: The layer immediately lining the organ.
Parietal Layer: The outer layer lining the cavity.
Potential Space: The area between these layers (e.g., the pleural cavity around the lungs), which only contains open space if it fills with fluid or if the organ collapses.
The 11 Systems of the Human Body: Overview
Integumentary System (Skin): Serves as the primary barrier to pathogens and mediates communication with the outside world. It prevents dehydration (as humans are water) and regulates temperature. Full-thickness burns often lead to life-threatening infections.
Skeletal System: Consists of approximately bones.
Functions: Support, movement, and storage of minerals (primarily calcium and phosphate, the latter being essential for production).
Bone Density: Bone mass increases until the mid-, then decreases. Women lose bone mineral mass much faster after menopause (approximately per decade), leading to a higher risk of osteoporosis.
Homeopoetic Tissue: Bone marrow produces red and white blood cells. Bone marrow transplants are used to treat leukemia.
Muscular System: Includes over skeletal muscles (approximately will be studied in this course). This system excludes cardiac and smooth muscle.
Lymphatic System: Collects interstitial (extracellular) fluid that leaks from leaky, single-cell-thick capillaries and returns it to the circulatory system.
Lymph Nodes: Critical sites for immune cell activity and cancer monitoring. Cancer staging (e.g., Stage 1 vs. Stage 2) often depends on whether cancer cells are found in regional lymph nodes, such as those in the armpit (axilla) for breast cancer.
Pathology: Peripheral edema (swelling/bruising in lower limbs) occurs when the lymphatic system fails, often seen in cases of Type 2 diabetes.
Respiratory System: Primary organs are the lungs, facilitating gas exchange. A lack of oxygen can cause brain damage within to minutes.
Urinary System: Includes the kidneys, ureters, bladder, and urethra for the processing and excretion of waste.