Practical Exam 2

Microscopic Anatomy of Compact Bone

osteon/haversian system- cylindrical structures of multiple concentric lamellae around a central canal

central canal- passageway for nerves/vessels to supply osteon cells

lamellae- thin rings of bone tissue, collagen fibers run in opposite direction of adjacent rings

lacunae- hold osteocytes

canaliculi- tiny canals running from central canal to lacunae

circumferential lamellae- encircle all osteons

interstitial lamellae- fill in gaps between osteons

perforating canal- connect central canals, allow nerves/blood to enter the bone

periosteum- cover outside of bone

endosteum- lines medullary cavity

Microscopic Anatomy of Spongy Bone

trabeculae- mesh network of bone tissue

endosteum- thin, vascularized CT covering internal surfaces of bone

red marrow- fills the space between trabeculae

Projections that are Sites of Muscle and Ligament Attachment

• crest

• epicondyle

• line

• spine

• trochanter

• tubercle

• tuberosity

Crest

ridge

Epicondyle

raised area on or above a condyle

muscle/ligament attachment site

Line

slight, elongated ridge

Spine

sharp process

Trochanter

large, irregularly shaped process

Tubercle

small, rounded process

Tuberosity

rough surface

Projections that Fit into Joints

• condyle

• head

• facet

Condyle

rounded surface

Head

prominent rounded surface

Facet

flat surface

Depressions and Openings Allowing Passage for Blood Vessels and Nerves

• foramen

• fossa

• groove

Foramen

hole through bone

Fossa

elongated basin

Groove

furrow, narrow trench

Long Bone Examples

humerus, radius, ulna, metacarpals, phalanges, femur, tibia, fibula, metatarsals

Short Bone Examples

tarsals, carpals

Flat Bone Examples

skull bones, ribs, sternum, scapulae

Irregular Bone Examples

vertebrae, facial bones

Sesamoid Bone Example

patella

Structure of Long Bone

epiphysis- head of bone

metaphysis- between epiphysis and diaphysis

diaphysis- shaft of bone

articular cartilage- caps the tops of bones

periosteum- outer lining

medullary cavity- hollow inside of shaft, yellow marrow

endosteum- inner lining

yellow bone marrow- in medullary cavity

compact bone- shell, makes up diaphysis and shell of epiphysis

spongy bone- inside of epiphysis

red bone marrow- inside of spongy bone

Parts of Axial Skeleton

1. skull

2. vertebral column

3. thoracic cage

Functions of Axial Skeleton

1. forms the longitudinal axis of the body

2. supports the head, neck, and trunk

3. protects the brain, spinal cord, and organs within the thorax

Cranial Bones

frontal bone → forehead, separated from parietal by coronal suture

parietal bones → upper lateral sides of skull, separated by sagittal suture

temporal bones → lower lateral sides of skull, separated from sagittal by squamous suture

occipital bone → back of skull, separated from parietal by lambdoid suture

sphenoid bone → forms base of skull, looks like a bat, seen in back of eye cavity

ethmoid bone → single, midline bone that forms walls of upper nasal cavity and medial wall of the orbit

Sutures

coronal suture- joins frontal bones to parietal bones

sagittal suture- joins left and right parietal bones

lambdoid suture- joins occipital bone to parietal/temporal bones, upside-down V

squamous suture- joins parietal bones to temporal bones

Facial Bones

nasal bones (left and right) → form bony bridge of nose

maxilla (left and right) → upper jaw, hard palate, lateral base of nose

zygomatic bones (left and right) → cheekbone

mandible → lower jaw

lacrimal bones (left and right) → small bone that forms the anterior medial wall of orbit- part of orbit closest to the nasal bones

palatine bones (left and right) → lateral walls of nasal cavity- back portion of roof of mouth

vomer → lower portion of nasal septum

Temporal Bone Markings

external acoustic meatus → large opening on lateral side of skull, associated with ear

mandibular fossa → deep, oval shaped depression on external base of skull where mandible joins to

Occipital Bone Markings

foramen magnum → opening where spinal cord enters/exits brain

occipital condyles → sit on either side of foramen magnum, form joints w/ first vertebrae and support skull

Sphenoid Bone Markings

sella turcica → looks like a saddle, behind the nose in front of foramen magnum, holds the pituitary gland

Maxillae Bone Markings

alveoli → forms upper jaw + contains the upper teeth

palatine process → roof of upper mouth

Mandible Bone Markings

alveoli → forms lower jaw + holds lower teeth

mandibular ramus → extends upwards to ear

5 Divisions of Vertebral Column

TOP

• cervical (7)

• thoracic (12)

• lumbar (5)

• sacrococcygeal (fused, 9 total)

BOTTOM

Primary Curvature

thoracic

sacrococcygeal

primary because they existed in their curved state in a newborn

Secondary Curvature

cervical

lumbar

secondary because they adapted as the newborn began walking + holding head up

Scoliosis

abnormal lateral bending of the vertebral column

Kyphosis

exaggerated thoracic curve resulting in a hunchback appearancev

Lordosis

exaggerated lumbar curve resulting in a protruding stomach

Features of Vertebra

body- anterior portion that supports weight

transverse process- project laterally

spinous process- singular, projects straight back

vertebral foramen- opening where spinal cord runs through

First Vertebra

name- C1 or atlas

shape- flat with a large hold, 2 smaller holes on side

Second Vertebra

name- C2 or axis

shape- has a bone that protrudes up into atlas

Cervical Vertebra Characteristics

body: small

vertebral foramen: large and triangular

spinous process: short, point posteriorly

transverse foramen: yes

Lumbar Vertebra Characteristics

body: intermediate

vertebral foramen: small, circular

spinous process: long, slender, point down

transverse foramen: no

Thoracic Vertebra Characteristics

body: large and thick

vertebral foramen: intermediate, triangular

spinous process: short, thick, points back

transverse foramen: no

Sternum Regions

TOP

• Manubrium → heart shaped top, connects to clavicles

• Body → rectangular portion of tie

• Xiphoid process → tip of the sword

True Ribs

their costal cartilage directly attaches to the sternum

RIBS 1-7

False Ribs

their costal cartilage is either not directly attached to sternum (shared) or not attached at all

RIBS 8-12

Floating Ribs

not attached to the sternum at all

RIBS 11+12

Appendicular Skeleton

bones of upper and lower extremities

bones of the pectoral girdle (clavicles and scapulas)

bones of the pelvic girdle (hip bones)

Clavicle

sternal end is flatter, attached to sternum

acromial end is rounded and slightly curved, attached to shoulder

Scapula

glenoid cavity/fossa → articulates with head of humerus

spine → long prominent ridge on back portion

acromion → articulates with clavicle, end of spine that extends out

coracoid process → attachment site for biceps brachii

Humerus

head → top, articulates w/ shoulder

deltoid tuberosity → attachment site for deltoid

medial epicondyle → bottom projection of bone on inside (in anatomical), w/ ulna

lateral epicondyle → bottom projection of bone on outside, w/ radius

trochlea → articulates w/ ulna

capitulum → articulates w/ radius

olecranon fossa → groove on back where ulna comes up into

Ulna

lines up with pinkie finger

general shape- near elbow sticks out and up, gets narrower, bottom near wrist skinny

olecranon → sticks up from top of bone, grips humerus

trochlear notch → part of olecranon

coronoid process → sticks up from bone under olecranon, grips humerus

head → attaches to wrist

styloid process → tiny projection off head near wrist

Radius

lines up with thumb

general shape- head near elbow looks like screw, slight curve in shaft, bottom gets wider near wrist

head → attaches w/ capitulum of humerus

radial tuberosity → attachment site for biceps brachii, protrudes into ulna

shaft- long portion of bone

styloid process- tiny point at bottom near wrist

Hand Bones

carpals → 8 small bones in wrist

metacarpals → 5 bones that connect carpals to phalanges of each finger → palm

phalanges → 2 in thumb, 3 in other fingers, make up digits

Pelvic Girdle

ilium → superior portion of hip bone

• iliac crest- curved superior portion

• greater sciatic notch- allows sciatic nerve to enter thigh, U-shaped indent

ischium → inferior posterior part of hip bone

• ischial spine- bony projection separating the greater and lesser sciatic notches

• ischial tuberosity- bears weight when sitting, site of ligament/tendon attachment

pubis → inferior, anterior part of hip bone

general bone markings

• acetabulum- articulates w/ head of femur

• obturator foramen- blood vessel and nerve passage, lower smaller holes of butterfly

Femur

head → articulates w/ acetabulum of pelvic girdle

neck → bend in bone leading towards head

gluteal tuberosity → gluteus maximus attachment, on upper outside under neck

medial condyle → articulates with tibia on inside

lateral condyle → articulates with tibia on outside

medial epicondyle → roughened area of femur on medial side of medial condyle

lateral epicondyle → roughened area of femur on lateral side of lateral condyle

Patella

triangular sesamoid bone that sits in front of bottom femur

Tibia

innermost thicker bone of lower leg, thick head and thinner bottom with point

medial condyle → inner articulation to femur

lateral condyle → outer articulation to femur

tibial tuberosity → attachment site of patellar tendon on front of bone

medial malleolus → medial bulge of ankle, articulates with talus

Fibula

outermost thinner bone of lower leg, thin head and shaft, pointed body to outside

head → top portion of bone near knee

lateral malleolus → lateral bulge of ankle, articulates with talus

Foot Bones

calcaneus and talus bear most of the weight

metatarsals connect tarsals to phalanges

phalanges are visible digits/toes

Basic Function of Joints

hold bones together

give flexibility + allow movement (not in synarthrosis joints)

Functional Classification of Joints

synarthrosis- no movement, immovable

amphiarthrosis- slightly movable

diarthrosis- freely movable, large range of motion

Structural Classification of Joints

1. fibrous joints

2. cartilaginous joints

3. synovial joints

Fibrous Joint Characteristics

bones are joined by fibrous CT

no joint cavity is present, no separation between bones without CT

amount of movement varies, but most are synarthrotic

Types of Fibrous Joints

1. suture

2. gomphosis

3. syndesmosis

Suture

united by very short CT fibers

ex: most skull joints

Gomphosis

tooth secured into bony socket by ligament

Syndesmosis

bones connected by short ligaments

amphiarthrotic

ex: distal articulation of tibia and fibula

Cartilaginous Joint Characteristics

articulating bones are connected by plate or pad

no joint cavity is present

most are amphiarthrotic

Types of Cartilaginous Joints

1. synchondrosis

2. symphysis

Synchondrosis

bones joined together by hyaline cartilage

ex: ribs to sternum via costal cartilage

Symphysis

bones connected by fibrocartilage disc

ex: intervertebral discs, pubic symphysis

Synovial Joint Characteristics

articulating bones separated by joint cavity containing synovial fluid

ALL ARE DIARTHROTIC

joint surfaces are enclosed by a two-layered joint

General Structure of Synovial Joints

joint cavity contains synovial fluid

articular cartilage caps bones

articular capsule

• inner layer of synovial membrane, secretes fluid

• outer layer of fibrous membrane

Movements at Synovial Joint

gliding

angular

rotational

special

Gliding Movements

two flat surfaces sliding relative to one another

Angular Movements

flexion

extension

hyperextension

abduction

adduction

circumduction

Flexion

decreasing of the joint angle

ex: when you do bicep curls, your arm angle goes from 180 to 45

Extension

increasing of the joint angle

ex: when you go down from a bicep curl, your arm angle goes from 45 to 180

Hyperextension

increasing joint angle beyond resting/anatomical position

ex: arm going backwards

Abduction

movement of a limb away from the midline

ex: moving arm away from body

Adduction

movement of a limb towards the midline

ex: moving arm back towards torso

Circumduction

simultaneous combination of flexion, extension, abduction, and adduction

ex: circling arm

Rotational Movements

internal/medial rotation

external/lateral rotation

Internal/Medial Rotation

rotation towards the midline

ex: turning head from facing right to facing forward

External/Lateral Rotation

rotation away from midline

ex: turning head from forward to facing the side

Special Movements

pronation

supination

dorsi flexion

plantar flexion

inversion

eversion

Pronation

turning palm to face backwards

Supination

turning palm to face forwards

Dorsi Flexion

pointing toe towards ceiling, resting weight on heels

Plantar Flexion

pointing toe towards ground, resting weight on toes

Inversion

turning the bottom of your foot in to face other leg

Eversion

turning the bottom of your foot out to face laterally

Types of Synovial Joints

1. plane

2. hinge

3. pivot

4. condyloid

5. saddle

6. ball and socket

Plane Synovial Joint

description: flat articular surfaces

movement: gliding

example: sternoclavicular, acromioclavicular, intercarpal, intertarsal, patellofemoral, proximal tibiofibular joint, tarsometatarsal joint, sacroiliac joint

Hinge Synovial Joint

description: 1 bone is convex; 2nd bone is concave

movement: flexion and extension

example: elbow, knee, interphalangeal, ankle

Pivot Synovial Joint

description: 1 bone has projection; 2nd bone has ring-like structure

movement: rotation

example: C1 and C2 vertebra, proximal and distal radioulnar joints