---

Comprehensive Anatomy Guide

---

1. Anatomical Terms and the Anatomical Position

The Anatomical Position

---

Anatomical Planes

---

Terms to Describe Location

• Anterior (ventral) = toward the front; Posterior (dorsal) = toward the back
• Example: the nose is anterior to the ears; the vertebral column is posterior to the sternum

• Medial = toward the median sagittal plane; Lateral = toward the sides
• Example: the thumb is lateral to the little finger; the nose is medial to the eyes

• Superior = toward the head; Inferior = toward the feet
• Example: the head is superior to the shoulders; the knee is inferior to the hip

• Proximal = closer to origin/root of limb; Distal = farther from origin
• Example: the hand is distal to the elbow; the glenohumeral joint is proximal to the elbow

• Cranial = toward the head; Caudal = toward the tail
• Rostral = toward the front of the brain (used in neuroanatomy)

• Superficial = toward the surface; Deep = toward the core
• Example: skin is superficial to muscle; bone is deep to muscle

• Ipsilateral = on the same side; Contralateral = on the opposite side

---

Terms of Movement (Range of Motion)

• Flexion = decreasing the angle at a joint (e.g., bending elbow)
• Extension = increasing the angle (straightening); hyperextension = extension beyond anatomical position

• Abduction = moving away from the median plane
• Adduction = moving toward the median plane

• Rotation of a limb about its long axis toward or away from the midline

• Circular movement combining flexion, extension, abduction, adduction (e.g., shoulder)

• Supination = palm faces anteriorly (as in anatomical position)
• Pronation = palm faces posteriorly (rotating radius over ulna)

• Eversion = sole faces laterally; Inversion = sole faces medially

• Dorsiflexion = dorsum of foot moves toward shin (toes up)
• Plantarflexion = foot points downward

• Moving thumb pad to meet fingertips - unique to the thumb and little finger

• Elevation = superior movement (e.g., shrugging shoulders)
• Depression = inferior movement (e.g., pulling shoulders down)

• Protraction = anterior movement (e.g., pushing mandible forward)
• Retraction = posterior movement

---

2. Bones in General

The Skeletal System

• Axial skeleton: skull (cranium), vertebral column, ribs, and sternum
• Appendicular skeleton: bones of the upper and lower limbs

Cartilage

Bone - Structure and Function

1. Structural support for the body
2. Protection of vital organs (e.g., skull protects brain, ribs protect lungs)
3. Reservoir of calcium and phosphorus
4. Levers on which muscles act to produce movement
5. Container for blood-producing cells (red bone marrow)

• Compact (cortical) bone: dense, forms the outer shell of all bones; surrounds spongy bone
• Spongy (trabecular/cancellous) bone: spicules enclosing cavities containing blood-forming marrow

Classification of Bones by Shape

Vascular Supply and Periosteum

• Each bone is supplied by a nutrient artery that enters the internal cavity and supplies the marrow, spongy bone, and inner compact bone layers
• All bones (except articular surfaces) are covered by periosteum - a fibrous connective tissue membrane capable of forming new bone; it is richly innervated with sensory fibers and very sensitive to injury
• Bone deprived of its periosteum will not survive

Ossification (Bone Development)

• Intramembranous ossification: mesenchymal models undergo direct ossification (e.g., flat bones of skull)
• Endochondral ossification: cartilaginous models form from mesenchyme and then ossify (e.g., long bones)

---

3. Bones of the Upper Limb

Shoulder Girdle

• Clavicle (collarbone): connects upper limb to axial skeleton via the sternoclavicular joint
• Scapula (shoulder blade): flat, triangular bone on the posterior thoracic wall; provides the glenoid cavity for the glenohumeral (shoulder) joint

Arm (Brachium)

• Has a head articulating with glenoid cavity (ball-and-socket glenohumeral joint)
• Surgical neck - common fracture site
• Greater and lesser tubercles - muscle attachments
• Shaft marked by the radial groove (carries radial nerve and profunda brachii artery)
• Distal end has: condyle (with capitulum + trochlea), medial and lateral epicondyles, and three fossae (coronoid, radial, olecranon)
• Capitulum articulates with radius; trochlea articulates with ulna

Forearm (Antebrachium)

• Head proximally articulates with capitulum of humerus and radial notch of ulna
• Distal end is wider and articulates with carpal bones at the wrist
• Styloid process at the distal lateral end

• Olecranon process (the "point of the elbow") = proximal end
• Trochlear notch articulates with trochlea of humerus (hinge joint)
• Coronoid process below the trochlear notch
• Head at the distal end; styloid process distally

Hand

• 8 Carpal bones (wrist) - arranged in two rows:
  • Proximal row: Scaphoid, Lunate, Triquetrum, Pisiform
  • Distal row: Trapezium, Trapezoid, Capitate, Hamate
  • Mnemonic: "Some Lovers Try Positions That They Can't Handle"
• 5 Metacarpals (palm) - numbered I-V from thumb
• 14 Phalanges (fingers): thumb has 2 (proximal + distal); fingers 2-5 have 3 each (proximal, middle, distal)

---

4. Bones of the Lower Limb

Pelvic Girdle

• Ilium (superior, wing-shaped): forms the iliac crest, anterior superior iliac spine (ASIS), anterior inferior iliac spine (AIIS); articulates with sacrum at sacroiliac joint
• Ischium (posteroinferior): forms the ischial tuberosity (weight-bearing when seated) and ischial spine
• Pubis (anterior): forms the pubic symphysis anteriorly; pubic tubercle is a key landmark

Thigh

• Head articulates with acetabulum (ball-and-socket hip joint)
• Neck - connects head to shaft; angle of inclination ~126°; common fracture site in elderly
• Greater and lesser trochanters - muscle attachments (hip abductors and iliopsoas)
• Shaft bowed forward, oblique course - brings knee close to midline under body's center of gravity
• Linea aspera - broad roughened crest on posterior shaft for muscle attachment
• Distal end: medial and lateral condyles articulate with tibia; intercondylar fossa separates condyles posteriorly; adductor tubercle on medial condyle
• Patella - sesamoid bone in the quadriceps tendon; articulates with patellar surface of femur

Leg (Crus)

• Medial and lateral condyles proximally articulate with femoral condyles
• Tibial plateau - flat articular surface superiorly
• Tibial tuberosity anteriorly - attachment of patellar ligament (quadriceps insertion)
• Medial malleolus at distal end (forms medial part of ankle mortise)

• Head proximally (just below lateral tibial condyle)
• Lateral malleolus distally (forms lateral part of ankle mortise)
• Non-weight-bearing; mainly for muscle attachment and ankle stability

Foot

• 7 Tarsal bones: Calcaneus (heel), Talus (articulates with tibia/fibula), Navicular, Cuboid, and three Cuneiforms (medial, intermediate, lateral)
• 5 Metatarsals - numbered I-V from medial to lateral
• 14 Phalanges: great toe has 2; toes 2-5 have 3 each

---

5. Joints

Classification of Joints

Solid Joints

Synovial Joints - Key Features

1. Articular cartilage (hyaline) covers the articulating bone surfaces - bones do not contact each other directly
2. Joint capsule with two layers:
   • Inner synovial membrane: highly vascular, produces synovial fluid for lubrication
   • Outer fibrous membrane: dense connective tissue; thickened regions form ligaments
3. Articular cavity filled with synovial fluid
4. Additional structures may include:
   • Articular discs (fibrocartilage): absorb compression, adjust to contour changes, increase range of motion (e.g., menisci of knee, disc of TMJ)
   • Fat pads: between synovial membrane and capsule
   • Bursae: closed synovial sacs reducing friction between tendons, bones, and skin
   • Tendon sheaths: surround tendons, reduce friction

Types of Synovial Joints by Shape and Movement

---

6. Vertebral Column

Overview

Typical Vertebra Structure

• Vertebral body (anterior): major weight-bearing component; increases in size from CII to LV; separated from adjacent bodies by intervertebral discs
• Vertebral arch (posterior): attached to body by two pedicles (lateral pillars); roof formed by right and left laminae fusing at midline

• Spinous process: projects posteriorly/inferiorly from junction of laminae
• Transverse processes: extend laterally from lamina-pedicle junction (bilateral)
• Superior and inferior articular processes: articulate with processes of adjacent vertebrae (form zygapophyseal/facet joints)

Regional Characteristics

• Small bodies; bifid spinous processes; foramen transversarium in each transverse process (transmits vertebral artery and veins)
• CI (Atlas): No body or spinous process; ring-shaped; articulates with occipital condyles (atlanto-occipital joint - nodding "yes")
• CII (Axis): Has the dens (odontoid process) - a tooth-like projection that fits into atlas (pivot joint - rotation "no")
• CVII: Vertebra prominens - most prominent spinous process, used as palpation landmark

• Have costal facets on bodies and transverse processes for rib articulation
• Long spinous processes angled downward
• Relatively limited mobility (ribs restrict movement)

• Massive vertebral bodies (progressively larger LI to LV)
• Short, stocky pedicles; long slender transverse processes; large stubby spinous processes
• Articular processes oriented medially/laterally - promotes flexion and extension

• Formed by fusion of 5 sacral vertebrae; wedge-shaped (broad superiorly, narrow inferiorly)
• Concave anterior surface with anterior sacral foramina (for anterior rami)
• Convex posterior surface with posterior sacral foramina (for posterior rami)
• Articulates with ilia at sacroiliac joints

Spinal Curvatures

• Cervical: secondary curve (concave posteriorly = lordosis) - develops when infant begins to hold head up
• Thoracic: primary curve (concave anteriorly = kyphosis) - retained from fetal position
• Lumbar: secondary curve (concave posteriorly = lordosis) - develops when child begins to walk
• Sacral/Coccygeal: primary curve (concave anteriorly = kyphosis)

---

7. Skull

Overview

Division of the Cranium

• Covers the cranial cavity (containing brain)
• Formed mainly by: paired temporal and parietal bones + parts of unpaired frontal, sphenoid, and occipital bones

• Formed by: parts of sphenoid, temporal, and occipital bones

• Paired bones: nasal, palatine, lacrimal, zygomatic, maxillae, inferior nasal conchae
• Unpaired: vomer

• Only truly mobile bone of the skull (via temporomandibular joints)
• Not part of the cranium or facial skeleton

Bones of the Skull - Individual Bones

Sutures

• Coronal suture: between frontal and parietal bones
• Sagittal suture: between right and left parietal bones
• Lambdoid suture: between parietal bones and occipital bone
• Squamous suture: between parietal and temporal bones

Fontanelles

• Head deformation during birth passage
• Postnatal brain growth
• Anterior fontanelle (largest): between frontal and parietal bones; closes at ~18 months
• Posterior fontanelle: between parietal and occipital bones; closes at ~3 months
• Most fontanelles close during the first year of life
• Full ossification of sutures begins in the late twenties and is normally complete by the fifth decade

Synovial Joints of the Skull

1. Temporomandibular joints (TMJ) - between mandible condyle and temporal bone (largest)
2. Incudomalleolar joint - between malleus and incus (middle ear ossicles)
3. Incudostapedial joint - between incus and stapes (middle ear ossicles)

Key Foramina of the Skull

---

Quick Reference Summary Table

---