notes

Intro

Anatomy – study of structure
Physiology – study of function
Anatomy before physiology à need to know structure before function

Regions of the Body
Cranium – surrounds brain, face, skull
Cervical – neck; attaches cranium to body
Thorax – dome-shaped compartment, floor à diaphragm, closed compartment
Abdomen & pelvis
Continuous
Abdomen – region above hip
Pelvis – region below hip
Extremities

Extremities
Upper
Arm (brachium) – shoulder to elbow
Forearm – elbow to wrist
Wrist & hand
Wrist – 2 rows of 4 bones
Lower
Thigh (femoral) – hip to knee
Leg – knee to ankle
Ankle & foot

Relative Terms
*anatomical position: upright, extremities to the side, palms forward
Superior vs. inferior – closer to the top of the head vs. farther away
Medial vs. lateral – midline
Anterior vs. posterior – front vs. back of body
Superficial vs. deep – surface
Proximal vs. distal – source

Anatomical Planes
Sagittal – divides object into left & right halves; infinite number
Midsagittal – divides body into equal left & right halves
Coronal (frontal) – anterior & posterior
Horizontal – superior & inferior


The Skeletal System: Overview & the Skull

The Skeletal System
Includes:
Bones (206)
Cartilages
Ligaments

Functions of the Skeletal System
Support & protection
Storage of calcium
Blood cell production
Movement
Bone is a Living Organ
o Osteocyte – bone cell
o Osteon
o Basic functional unit of bone, a cylindrical canal consisting of blood vessels, nerves, and osteocytes
o Formed in concentric ring around vain, artery, nerve
o Shaft of bone made of osteons

Osteoporosis
o Major pathology of bone
o Decrease in bone density
o Results in bone fractures mainly in wrist (Colles fracture), hip, and vertebrae
o 2 types
o Estrogen-dependent – caused by decrease in estrogen
o Age-related

Organization of Skeleton
Axial – bones associated with skull, thorax, and vertebral column…80 bones
Appendicular – bones associated with extremities and shoulder and hip joints…126 bones
Total: 206 bones in human skeleton

Axial Skeleton
Consists of:
Skull – 22
Auditory ossicles – 6
Hyoid – 1
Thoracic cage – 25
Vertebral column – 26
Total: 80 bones

The Skull (22)
Cranial (8) – those in direct contact with the brain
Facial (14) – not in direct contact
Sutures – immovable joints shared between skull bones
Mandible only moveable bone in skull

Terms
Articulate – to make a joint with
Articulated – in place & forming joints
Disarticulated – isolated
Squamous – flat
Process – bony projection
Stylous – pointed
Fossa – bony depression
Foramen – hole
Condyle – smooth articulating surface
Ramus – bone at right angle

Temporal Bone
Squamousal suture forms boundary
Squamous portion largest, thinnest part
External auditory meatus – opening to ear
Zygomatic process – articulates w/ zygomatic bone
Mandibular fossa – articulates w/ mandible

Sphenoid Bone
Spans entire width of skull
Most centrally located bone of skull
Shaped like four-winged, two legged flying creature
Articulates with:

Does not articulate with:

Sella turcica
Center of sphenoid bone à center of skull
Sits within pituitary gland
Pterygoid process – located just posterior to the last upper molar teeth

Ethmoid Bone
95% found in nasal cavity
Forms roof of nasal cavity
Forms upper half of nasal septum
Forms lateral wall of both nasal cavities
Crista galli
Separates 2 cribiform plates and continues down into nasal cavity as perpendicular place
Comes in direct contact with the brain, superior to ethmoid bone
Cribiform plates (2)
Perforated bones leading to the nasal cavity
On either side of crista galli
Forms medial & lateral walls of nasal cavity
Superior & middle conchae form lateral mass of ethmoid bone

Nasal Septum
Divides right & left nasal cavities
Upper half is perpendicular plate of ethmoid bone
Lower half is vomer bone
Forms medial wall of both cavities
Normally straight, but can be crooked (deviated), leading to sinus problems

--occipital bone most posterior bone of skull

The Orbit
Bony structure of skull that supports & protects eye
Comprised of 6 bones

--lacrimal bone forms medial wall of orbit
--nasolacrimal canal – provides passage of tears from surface of eye to nasal cavity
--palatine bone – 4 bones form hard palate
--vomer – forms lower half of nasal septum
--temporalmandibular joint (TMJ) – joint between temporal bone & mandible; only moveable joint
--mandibular condyle of mandible articulates w/ mandibular fossa of temporal bone
--coronoid process serves as attachment for a muscle that elevates mandible

Fetal Skull
Major sutures are not formed
Head can change shape slightly during labor
Fontanels – open areas w/o bone
Anterior fontanel takes 12-15 months to close
Posterior – 3-6 months

--auditory ossicles – 3 microscopic bones in middle ear: malleus, incus, stapes (L-M)

Hyoid Bone
U-shaped bone
Just inferior to mandible
Only bone in body that doesn’t articulate w/ another bone
Serves as attachment for muscles involved in swallowing


Vertebral Column

Purpose: provide support & protection
Consists of bones called vertebrae (26)

4 curvatures:
Cervical – anterior curve; 7 vertebrae (C1-C7)
Thoracic – posterior curve; 12 vertebrae (T1-T12)
Lumbar – anterior curve; 5 vertebrae (L1-L5)
Sacral – posterior curve; 2 vertebrae (sacrum, coccyx)

Normal spine curved to create upright posture

Abnormal curvatures of column
Kyphosis – “hunchback” or exaggerated posterior thoracic curvature; can be lethal à pressure on lungs
Lordosis – “swayback” or exaggerated anterior lumbar curvature
Scoliosis – lateral curvature mostly in the thoracic region; most common curvature

Typical vertebrae
Spinous process – points posterially
Lamina à roof
Pedicle à wall
Body largest part of every vertebrae & weight-bearing part of each vertebrae
Intervertebral foramen – formed by 2 vertebrae; spinal nerves
Intervertebral disk – prevents bone to bone contact

Vertebrae
7 cervical
12 thoracic
5 lumbar
1 sacrum & 1 coccyx
Typical vertebrae: C3-C7, T1-T12, L1-L5
Total: 22
First 2 and last 2 not typical

Atypical vertebrae
C1 – atlas
C2 – axis
Sacrum
Coccyx

C1 – atlas
No body
No spinous process
Articular facets (facet – smooth area)
In contact w/ occipital condyles (articular facets)

Occipital condyles – provides “yes” motion of skull
C2 – axis – odontoid process (dens)

Atlas & axis
Atlas rotates around odontoin process of axis
Rotation provides “no” motion of skull
Shaking baby syndrome

Unique to cervical vertebrae: all possess transverse foramen within their transverce processes
Transverse foramen – transmit vertebral arteries as the course the brain

Sacrum & coccyx
Sacrum – fusion of 5 vertebrae
Coccyx – fusion of 4 vertebrae
Fusions completed 25-30 yrs.


Thoracic Cage

Consists of 12 pairs of ribs & sternum
All 12 pairs of ribs articulate with vertebral column

True ribs
Articulate posterially w/ all 12 thoracic vertebrae
Articulate anteriorly directly w/ sternum via costal cartilages
Ribs 1-7

False ribs
Articulate posteriorly w/ all 12 thoracic vertebrae
Do not articulate with sternum directly
Articulate w/ costal cartilage just superior to it
Ribs 8-12
Ribs 11 & 12 “floating ribs” à no anterior articulation

Sternum
3 bones ultimately fused around 40 yrs.
manubrium – articulates with clavicle, rib#1, & rib #2
body – articulates with ribs 2-7
xiphoid process

sternal angle – articulation of manubrium & body of sternum; where rib #2 shares articulation with both bones

Ribs
Head – articulates with 2 adjacent vertebrae (same # and one above)
Neck
Tubercle – serves articulation with transverse process of vertebra of same #
Angle – most common site of rib fracture
Costal groove – found on deep inferior portion of rib; VAN
Body


Appendicular Skeleton: Overview & Upper Extremity

Appendicular Skeleton
Consists of:
Bones of upper extremity (60)
Bones of lower extremity (60)
Bones of pectoral girdles (joint that attaches upper extremities to torso (4)
Bones of pelvic girdles (joint that attaches lower extremities to torso (2)
Total: 126 bones

Pectoral Girdle
Left and right
Each consists of
Clavicle
Scapula
Purpose: provide attachments for muscles & ligaments that hold upper extremities to torso

Clavicle
S-shaped bone
Articulates with manubrium and sternum (medially) & acromion of scapula (laterally)
Joint with manubrium attaches upper extremity to body
Most frequently fractured bone in human body
Posterior fracture most dangerous

Scapula
Broad, flat, triangle-shaped bone
Each consists of
3 borders
2 angles
1 spine
2 processes
4 fossae
1 anterior
2 posterior
1 lateral
Glenoid fossa (cavity) articulates with head of humerus

Upper Extremity
Each consists of
Arm – 1
Forearm – 2
Wrist – 8 (carpal bones)
Palm – 5 (metacarpals)
Fingers – 14 (phalanges)

Arm: Humerus
Anatomical neck – muscles & tendons attach
Greater tubercle – lateral surface
Lesser tubercle – anterior surface
Surgical neck – most frequently fractured part of humerus; requires surgery

Forearm
2 parallel bones
Radius
Ulna

Radius & Ulna
Articulate with each other at proximal and distal ends
Head of radius – proximal
Diameter of a dime
Articulates in radial notch of ulna
Head of ulna – distal
Most common fracture site of upper extremity

Colles Fracture
Fracture of distal radius
Usually incurred when a person extends their hand while trying to break a fall

Carpal Bones
Wrist bones
8 à 2 rows of 4
Mneumonic:
Some scaphoid
Lovers lunate
Try triquetrum
Positions pisiform
That trapezium
They trapezoid
Can’t capitate
Handle hamate
**scaphoid – pisiform: proximal
**trapezium – hamate: distal

o Metacarpal bones – bones of the palm
o Phalanges – bones of the fingers
o Proximal, middle, distal
o Thumb only has 2


Appendicular Skeleton: The Lower Extremity

Pelvic Girdle
Left & right
Each consists of single bone called os coxae, or hip bone
Each os coxae result of fusion of 3 separate bones
Ilium
Ischium
Pubis
Fusion usually completed by end of second decade of life

--ilium – iliac crest most common site of bone marrow sampling
--ischium – V-shaped bone; most inferior part of pelvis
--pubis: pubic bone protects urinary bladder; pubic symphysis – slightly moveable joint
--acetabulum – accommodates head of femur; all 3 bones contribute & meet to form

Male vs. Female Pelvis
Pelvic inlet wider in females
Sacrum projects anteriorly into male pelvic inlet
Ilium laterally flaired in female
Pubic angle greater in female

--femur – only bone in thigh; longest, heaviest, strongest bone of the body
--patella – articulates with patellar surface of femur
--bones of knee joint: femur, patella, tibia
*--bones of elbow joint: humerus, radius, ulna
--bones of leg – tibia (medial), fibula (lateral)

Bones of Ankle & Foot
Tarsal bones – 7 – form ankle & proximal foot
Metatarsals – 5 – sole of foot
Phalanges – 14 – bones of toes (big toe only has 2)
Talus
Major weight-bearing bone of foot
Articulates with tibia
Congenital clubfoot – can be caused by malformation of talus
Calcaneus – heel bone


Articulations

Types of Joints
Synarthrotic – immovable; ex: suture
Amphiarthrotic – slightly moveable; ex: intervertebral disk & pubic symphysis
Diarthrotic – highly moveable; most common; ex: shoulder, elbow, hip, wrist, finger

Diarthrotic
All possess the same 4 characteristics:
Articular cartilages
Cover articulating surfaces of opposing bones
Reduces friction during movement
Prevent bone to bone contact
Articular capsule
Synovial membrane
Joint cavity w/ synovial fluid