Anatomy 2201 Exam 2 MIZZOU - Hill

Functions of Skeletal System

Support, protection, movement, mineral storage (Ca²⁺/phosphate), blood cell production (hematopoiesis)

Appendicular Skeleton vs Axial Skeleton

Appendicular: limbs, girdles; Axial: skull, vertebral column, ribs, sternum

Axial Skeleton

Skull, vertebral column, thoracic cage, hyoid bone

Appendicular Skeleton

Pectoral girdle, pelvic girdle, upper and lower limbs

Three types of cartilage

Hyaline (joints, nose), Elastic (ear, epiglottis), Fibrocartilage (discs, pubic symphysis)

Hyaline Cartilage

Smooth matrix with invisible fibers; found in nose, trachea, articular surfaces

Elastic Cartilage

Flexible with visible elastic fibers; ear, epiglottis

Fibrocartilage

Thick collagen bundles; intervertebral discs, pubic symphysis

Bone cells

Osteoblasts (build), Osteocytes (maintain), Osteoclasts (break down)

Osteoblasts

Build bone matrix

Osteocytes

Maintain bone tissue

Osteoclasts

Break down (resorb) bone

Spongy bone vs Compact bone

Spongy: trabeculae, light; Compact: dense, strong

Spongy Bone

Porous, trabecular bone at ends of long bones

Compact Bone

Dense cortical bone forming outer surface

Examples of bone types

Long (femur), Short (carpals), Irregular (vertebrae), Flat (skull)

Parts of a long bone

Epiphysis, diaphysis, metaphysis, periosteum, medullary cavity

Ossification types

Endochondral (cartilage → bone, most bones), Intramembranous (flat bones, clavicle)

Endochondral Ossification

Bone replaces cartilage model (most bones)

Intramembranous Ossification

Bone forms from mesenchyme (flat skull bones, clavicle)

Epiphyseal plate

Cartilage growth zone for bone elongation

Cranial vs facial bones

Cranial protect brain; Facial form face and openings

Cranial bones

Frontal, parietal, temporal, occipital, sphenoid, ethmoid

Facial bones

Zygomatic, maxilla, mandible, nasal, vomer, palatine, lacrimal, inferior nasal concha

Sutures

Coronal, sagittal, lambdoid, squamous

Important skull features

Foramen magnum, occipital condyles, sella turcica, crista galli, alveolar process, palate

Orbit bones

Frontal, sphenoid, zygomatic, maxilla, palatine, lacrimal, ethmoid

Thoracic cage function

Protect organs, aid breathing

Vertebrae

7 cervical, 12 thoracic, 5 lumbar, sacrum, coccyx

Cervical vs Thoracic vs Lumbar

Cervical: transverse foramina; Thoracic: costal facets; Lumbar: large body

Cervical Vertebrae Features

Transverse foramina, small bodies, bifid spinous processes

Thoracic Vertebrae Features

Costal facets, long downward spinous process

Lumbar Vertebrae Features

Large kidney-shaped body, blunt spinous process

C1 Atlas

Supports skull, no body

C2 Axis

Dens allows head rotation

Atlas and Axis

C1 supports skull, C2 dens allows rotation

Rib articulations

Head with vertebral body, tubercle with transverse process

True vs False vs Floating ribs

True (1-7, direct), False (8-10, indirect), Floating (11-12, none)

True Ribs (1-7)

Attach directly to sternum by costal cartilage

False Ribs (8-10)

Attach indirectly via rib 7's cartilage

Floating Ribs (11-12)

No anterior attachment to sternum

Sternum landmarks

Manubrium, body, xiphoid process

Pectoral girdle

Clavicle and scapula

Scapula features

Spine, acromion, coracoid process, glenoid cavity

Upper limb bones

Humerus, radius, ulna, carpals, metacarpals, phalanges

Humerus parts

Head, deltoid tuberosity, epicondyles, olecranon fossa

Hand bones

14 phalanges, 8 carpals

Pelvis bones

Ilium, ischium, pubis; articulate at acetabulum

Femur features

Head, neck, greater/lesser trochanters, condyles

Tibia vs Fibula

Tibia = medial, weight-bearing; Fibula = lateral, slender

Foot bones

7 tarsals, 14 phalanges

TMJ Bones

Mandibular condyle + mandibular fossa of temporal bone

Types of joints

Fibrous (sutures), Cartilaginous (symphysis), Synovial (shoulder)

Synchondrosis vs Symphysis

Synchondrosis: hyaline cartilage; Symphysis: fibrocartilage

Synovial joint types

Plane (glide), Hinge (flex/extend), Pivot (rotate), Condylar (biaxial), Ball-and-socket (multiaxial)

Common joint movements

Flexion/extension, abduction/adduction, pronation/supination, inversion/eversion, rotation, dorsiflexion/plantarflexion

Knee joint

Femur, tibia, patella; ACL, PCL, MCL, LCL, meniscus

Elbow joint

Humerus, radius, ulna; collateral and annular ligaments

Hip joint

Coxal (acetabulum) and femur

Glenohumeral joint

Scapula and humerus (shoulder)

Three Types of Muscle Tissue

Skeletal (voluntary, striated), Cardiac (involuntary, striated, intercalated discs), Smooth (involuntary, non-striated)

Skeletal Muscle Functions

Movement, posture, support, guards openings, heat production

Skeletal muscle properties

Excitability, contractility, extensibility, elasticity

Synergist vs Antagonist

Synergist: assists movement; Antagonist: opposes it

Connective layers in muscle

Epimysium (whole), Perimysium (fascicle), Endomysium (fiber)

Epimysium

Surrounds entire muscle

Perimysium

Surrounds fascicles

Endomysium

Surrounds individual fibers

Sarcomere

Contractile unit of myofibril

Muscle shapes

Circular (orbicularis), Convergent (pectoralis major), Parallel (sartorius), Pennate (deltoid)

Circular Muscle Example

Orbicularis oculi

Parallel Muscle Example

Sartorius

Convergent Muscle Example

Pectoralis major

Pennate Muscle Example

Deltoid

Trapezius

Elevates, depresses, retracts & rotates scapula

originates- vertebrae C1-T12

inserts- scapular spine, clavicle

rhomboid major & minor

elevates and retracts scapula

originates- vertebrae

inserts- scapula

Serratus anterior

Protracts & rotates scapula, holds scapula against body wall

originates- scapula

inserts - ribs

pectoralis major

medially rotates, adducts, flexes arm

originates- sternum, clavicle, ribs

inserts- humerus

Latissimus dorsi

Extends, adducts, medially rotates arm

originates lower back

inserts- humerus

teres major

extends, adducts, medially rotates arm

originates- scapula

inserts humerus

deltoid

abducts, flexes, extends, rotates arm

originates- scapular spine, clavicle

inserts- humerus

Supraspinatus

Abducts arm (0-15°)

originates- scapula, supraspinous fossa

inserts- humeral tuberosities

infraspinatus

laterally rotates arm

originates- scapula infraspinous fossa

inserts- humeral tuberosities

Teres minor

Laterally rotates arm

originates- scapular infraspinous fossa

inserts- humeral tuberosities

subscapularis

medially rotates arm

originates- scapula subscapular fossa

inserts- humeral tuberosities

Coracobrachialis

Flexes shoulder

originates- scapula

inserts- humerus

brachialis

flexes forearm

originates- humerus

inserts- ulna

biceps brachii

flexes arm, flexes & supunates forearm

originates- scapula

inserts- radial tuberosity

Triceps brachii long head

Extends arm and forearm

originates- scapula

inserts- ulna-olecranon

triceps brachii medial and lateral head

extends forearm

originates- humerus

inserts- ulna-olecranon

forearm flexors

flex wrist and digits

originates- humerus medial epicondyle & forearm

inserts- wrist & digits

forearm extensors

extends wrist & digits

originates- humerus lateral epicondyle & forearm

inserts-wrist and digits

thenar group

move thumb, opposes to digits

originates- wrist

inserts- pollex

hypothenar group

move 5th finger (pinky), opposes to thumb

originates- wrist

inserts- 5th digit

Interossei

Abduct & adduct digits

originates- metacarpals 2-5

inserts- phalanges 2-5

Iliopsoas

Flexes trunk and hip

originates- illium & lumbar vertebrae

inserts- femus

gluteus maximus

extends & laterally rotates thigh

originates- illium & sacrum

inserts- femur

gluteus medius and minimus

abducts thigh

originates- illium

inserts- femur

tenor fascia lata

flexes & abducts thigh

originates- illium

inserts- femur

Rectus femoris

Flexes hip, extends knee

originates- illium

inserts- tibia via patella