I. Anatomic Terminology

Directional Terms

Directional terms are used to describe the locations of structures in relation to other structures or locations in the body.

• Anterior (ventral): toward the front

• Posterior (dorsal): toward the back

• Superior (above): toward the head

• Inferior (below): toward the feet

• Lateral: away from the midline

• Medial: toward the midline

• Proximal: closer to the point of attachment

• Distal: farther from the point of attachment

• Superficial: toward the body surface

• Deep: away from the body surface

Body Planes

Body planes are imaginary lines used to divide the body into sections for anatomical study.

• Sagittal: divides the body into left and right halves

• Frontal (coronal): divides the body into anterior and posterior parts

• Transverse: divides the body into superior and inferior parts

II. Axial Skeleton

Skull Structures

The skull is composed of several bones that protect the brain and form the structure of the face.

• Ethmoid: forms part of nasal cavity and eye orbit

• Frontal: forms forehead and superior eye orbit

• Lacrimal: forms part of medial wall of orbit; contains tear duct

• Mandible: lower jawbone; only movable skull bone

• Maxilla: upper jawbone

• Nasal: bridge of nose

• Occipital: posterior skull; contains foramen magnum

• Palatine: posterior part of hard palate

• Parietal: forms top and sides of skull

• Sphenoid: bat-shaped bone at skull base; contains sella turcica

• Temporal: sides of skull; contains external auditory meatus and carotid canal

• Vomer: forms inferior nasal septum

• Zygomatic: cheekbone

Vertebral Column Regions

• Cervical (7): smallest vertebrae; have transverse foramina

• Thoracic (12): articulate with ribs; have long downward spinous processes

• Lumbar (5): largest vertebrae; short, thick spinous processes

• Sacrum (5 fused): forms posterior pelvis

• Coccyx (4 fused): tailbone

Vertebral Structures

• Vertebral Body: weight-bearing part

• Vertebral Foramen: opening for spinal cord

• Spinous Process: posterior projection

• Transverse Process: lateral projection

• Articular Process: projections for articulation with other vertebrae

III. Appendicular Skeleton

Scapula Structures

• Acromion: highest point; connects to clavicle

• Coracoid Process: anterior projection for muscle attachment

• Glenoid Cavity: socket for humerus head

• Inferior Angle: bottom tip of scapula

• Spine: prominent ridge on posterior side

• Superior Angle: top point of scapula

• Suprascapular Notch: notch for nerve passage

Upper Limb Structures

• Humerus: head articulates with glenoid cavity

• Capitulum: articulates with radius

• Trochlea: articulates with ulna

• Lateral/Medial Epicondyle: distal articulating surfaces

• Lateral/Medial Condyle: muscle attachment sites

• Radius: lateral forearm bone; rotates around ulna

• Ulna: medial forearm bone; forms elbow joint with humerus

Pelvic Girdle Structures

• Ilium: superior portion; iliac crest is upper ridge

• Pubis: anterior portion; joined by pubic symphysis

• Ischium: inferior portion; bears body weight when sitting

• Obturator Foramen: large opening for nerves/vessels

• Acetabulum: socket for femur head

Lower Limb Structures

• Femur: head articulates with acetabulum

  • Greater/Lesser Trochanter: muscle attachment

  • Lateral/Medial Condyle & Epicondyle: articulate with tibia

• Patella: kneecap; protects knee joint

• Tibia: medial lower leg bone; medial malleolus forms inner ankle

• Fibula: lateral lower leg bone; lateral malleolus forms outer ankle

Upper & Lower Limb Articulation

• Shoulder joint: humerus head + glenoid cavity

• Elbow joint: trochlea (humerus) + trochlear notch (ulna)

• Hip joint: femur head + acetabulum

• Knee joint: femur condyles + tibia condyles

• Ankle joint: tibia/fibula malleoli + talus

IV. Muscle Anatomy

Naming Categories

• Action: flexor, extensor, abductor, adductor

• Location: carpi (wrist), pollicis (thumb), digitorum (fingers)

• Other descriptors: shape, size, direction of fibers, number of origins

Muscles of Head and Neck

• Buccinator: compresses cheek

• Corrugator Supercilii: wrinkles forehead

• Epicranius: raises eyebrows

• Levator Scapulae: elevates scapula

• Masseter: elevates mandible (chewing)

• Mentalis: protrudes lower lip

• Orbicularis Oculi: closes eye

• Orbicularis Oris: closes lips

• Sternocleidomastoid: flexes neck, rotates head

• Temporalis: elevates mandible

• Trapezius: elevates and retracts scapula

Muscles of Body Trunk

• External/Internal Abdominal Obliques: compress abdomen, flex trunk

• External/Internal Intercostals: elevate/depress ribs for breathing

• Latissimus Dorsi: extends and adducts arm

• Rhomboid Major/Minor: retract scapula

• Serratus Anterior: pulls scapula forward

• Serratus Posterior: assists in respiration

• Teres Major/Minor: rotate and adduct arm

Muscles of Upper Limbs

• Biceps Brachii: flexes forearm, supinates

• Brachialis: flexes elbow

• Brachioradialis: flexes forearm

• Deltoid: abducts arm

• Extensor Carpi Radialis: extends wrist

• Extensor Digitorum: extends fingers

• Flexor Carpi Radialis: flexes wrist

• Supinator: supinates forearm

• Triceps Brachii: extends elbow (lateral, medial, long heads)

Muscles of Lower Limb

• Adductor Longus/Magnus: adduct thigh

• Biceps Femoris: flex leg, extend thigh

• Flexor Digitorum Longus: flexes toes

• Gastrocnemius: plantar flexion (lateral/medial heads)

• Gluteus Maximus: extends thigh

• Gluteus Medius: abducts thigh

• Plantaris: assists plantar flexion

• Popliteus: unlocks knee

• Soleus: plantar flexion

• Tibialis Anterior: dorsiflexion

• Vastus Intermedius/Lateralis/Medialis: extend leg

V. Muscle Physiology

Key Terms

• Sarcomere: basic contractile unit of muscle

• Actin: thin filament

• Myosin: thick filament

• Motor Neuron: nerve cell that stimulates muscle fiber

• Neuromuscular Junction: site where motor neuron meets muscle fiber

• Voltage-Gated Ion Channels: control electrical signal flow

• Sarcoplasmic Reticulum: stores and releases calcium ions

Mechanisms of Contraction

• Sliding Filament Model: actin and myosin slide past each other, causing muscle shortening

• Action Potential: electrical signal triggers calcium release, leading to contraction

Isotonic vs. Isometric

• Isotonic: muscle changes length (movement occurs)

• Isometric: muscle tension increases without length change

Muscle Fatigue

• Decline in ability to contract due to ATP depletion or ion imbalance

Muscles in Common Exercises

• Trunk: rectus abdominis, obliques

• Shoulders: deltoid, trapezius

• Arms: biceps, triceps

• Wrists: flexors, extensors

• Abdominals: rectus abdominis, obliques

• Hips: gluteus maximus/medius

• Legs: quadriceps, hamstrings

• Ankles: gastrocnemius, soleus, tibialis anterior

VI. Clinical Correlates & Injuries

• Elbow tears: tears of biceps tendon

• Rotator cuff: supraspinatus, infraspinatus, teres minor, subscapularis

• Ankle sprain: ligaments of tibia/fibula

• Clavicle fracture: clavicle

• Dislocation: humerus (shoulder joint)

• Plantar fasciitis: foot arch inflammation

• Shin splints: tibialis anterior inflammation

• AC joint injury: clavicle-scapula connection

• TMJ: jaw joint strain (masseter, temporalis)

• Stress fractures: repetitive bone strain

• Sciatica: compression of sciatic nerve

• Trauma: fractures or dislocations from accidents/falls