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I now have thorough content from authoritative textbooks for all four topics. Here are your comprehensive study notes:

Anatomy Basics - Study Notes

1. Anatomical Planes, Position & Terms

(Gray's Anatomy for Students)

The Anatomical Position

The standard reference position: body erect, face looking forward, feet together with toes forward, hands by the sides with palms facing forward.

Anatomical position, planes, and directional terms

The Three Major Planes

Plane	Orientation	Divides Body Into
Coronal (Frontal)	Vertical	Anterior and posterior parts
Sagittal	Vertical, perpendicular to coronal	Right and left parts
Median Sagittal	Sagittal through body midline	Equal right and left halves
Transverse (Horizontal / Axial)	Horizontal	Superior and inferior parts

Directional Terms

Pair 1 - Anterior/Posterior

Anterior (ventral) = toward the front (e.g., nose, sternum)
Posterior (dorsal) = toward the back (e.g., vertebral column)

Pair 2 - Medial/Lateral

Medial = closer to the median sagittal plane (e.g., nose is medial to the eyes)
Lateral = farther from the median plane (e.g., thumb is lateral to the little finger)

Pair 3 - Superior/Inferior

Superior = higher up (e.g., head is superior to shoulders)
Inferior = lower down (e.g., knee is inferior to hip)

Additional Terms

Proximal = closer to a structure's origin or point of attachment (e.g., the shoulder is proximal to the elbow)
Distal = farther from the origin (e.g., the hand is distal to the elbow)
Cranial = toward the head (synonym for superior)
Caudal = toward the tail (synonym for inferior)
Rostral = toward the nose, used especially in the head (e.g., the forebrain is rostral to the hindbrain)
Superficial = external to the outer layer of deep fascia (skin, superficial fascia, mammary glands)
Deep = enclosed by the outer layer of deep fascia (most skeletal muscles, viscera)

2. Bones and Cartilage

(Firestein & Kelley's Textbook of Rheumatology; Imaging Anatomy Atlas Vol. 3)

Bone

Bone is the main rigid structural tissue of the skeleton. Key features:

Provides mechanical support, protection, and locomotion
Serves as a mineral reservoir (especially calcium and phosphate)
Houses bone marrow for hematopoiesis

Ossification centers:

Primary ossification center - forms in the diaphysis (shaft), contains marrow
Secondary ossification center - forms in the epiphysis (ends of long bones)
Growth plate (epiphyseal plate) - cartilaginous zone between ossification centers where longitudinal bone growth occurs in children

Cartilage

Cartilage is an avascular connective tissue with three main types:

Type	Composition	Location	Features
Hyaline	Type II collagen + proteoglycans	Articular surfaces, costal cartilages, tracheal rings, growth plates	Most common; smooth, glassy appearance
Fibrocartilage	Type I + II collagen	Intervertebral discs, pubic symphysis, menisci	High tensile strength
Elastic	Elastic fibres + type II collagen	Ear pinna, epiglottis	Flexible and resilient

3. Joints

(Firestein & Kelley's Textbook of Rheumatology)

Classification by Histology and Mobility

Class	Also Called	Connective Tissue	Mobility	Examples
Fibrous	Synarthroses	Dense connective tissue	Minimal/none	Skull sutures, gomphoses (teeth), syndesmoses (ulna-radius)
Cartilaginous	Amphiarthroses	Hyaline cartilage or fibrocartilage	Slight	Pubic symphysis, intervertebral discs, 1st rib-sternum, growth plates
Synovial	Diarthroses	Synovial cavity + fluid	Freely moveable	Knee, hip, shoulder, elbow, wrist, ankle

The Synovial Joint in Detail

Synovial joints are the most common functional joints in the skeleton and contain:

Synovial cavity filled with synovial fluid (water, plasma filtrate, hyaluronic acid, lubricin, phospholipids)
Articular cartilage covering the opposing bone ends
Fibrous capsule enclosing the joint
Synovial lining (synovium) producing the fluid

Histological section of a synovial joint (juvenile mouse knee stained with safranin O), showing articular cartilage, synovial cavity and fluid, meniscus, and ossification centers

Synovial Joint Sub-types (by Shape)

Shape	Axes of Motion	Example
Ball and socket	Multiaxial	Hip, shoulder
Hinge	Uniaxial	Elbow (humeroulnar)
Saddle	Biaxial	1st carpometacarpal
Plane	Gliding	Patellofemoral
Condyloid/Ellipsoid	Biaxial	Wrist

Movements possible at synovial joints: flexion, extension, abduction, adduction, rotation, circumduction.

4. Muscles - Basics

(Harper's Illustrated Biochemistry, 32nd Ed)

Three Types of Muscle

Type	Appearance	Control	Force Direction
Skeletal	Striated	Voluntary (conscious)	Unidirectional (like a coil spring)
Cardiac	Striated	Involuntary	Unidirectional
Smooth	Non-striated	Involuntary	All directions (like a balloon deflating)

The striated appearance of skeletal and cardiac muscle comes from the parallel alignment of contractile fibrils. Smooth muscle lacks this because its contractile fibrils are more randomly oriented.

Structure of Skeletal Muscle (Hierarchical)

Hierarchical structure from whole muscle down to myofibril and sarcomere, showing H band, Z line, A band, I band

From largest to smallest:

Muscle - the whole organ
Fasciculus (fascicle) - bundle of muscle fibers
Muscle fiber (cell) - a single multinucleated muscle cell; enclosed in the sarcolemma (electrically excitable plasma membrane); may extend the entire length of the muscle
Myofibril - longitudinal bundles of overlapping thick and thin filaments within the fiber, embedded in sarcoplasm
Sarcomere - the repeating functional unit of a myofibril, defined as the region between two Z lines (1500-2300 nm depending on contraction state)

The Sarcomere - Band Pattern

Band/Line	Contents	Appearance
A band	Thick (myosin) + thin (actin) filaments	Dark
I band	Thin filaments only	Light
H band	Thick filaments only (center of A band)	Less dense zone within A band
Z line	Anchors thin filaments; marks sarcomere boundary	Dense, narrow line bisecting I band

Sliding Filament Theory

When muscle contracts, the H zone and I bands shorten while the thick and thin filaments themselves remain the same length - the filaments slide past each other. Tension developed is proportional to the degree of filament overlap.

Sources:

Gray's Anatomy for Students (anatomical planes & terms)
Firestein & Kelley's Textbook of Rheumatology (joints)
Harper's Illustrated Biochemistry, 32nd Ed (muscle basics)
Imaging Anatomy Text and Atlas Vol. 3 (bones, joints, cartilage)

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