Basic Concepts of Anatomy Flashcards
Horizontal plane (transverse or cross-section)
Plane parallel to the floor with the body in the anatomical position
Structures on the right side of the body will be on the left side of the sectional image
Sagittal plane
Perpendicular to the horizontal plane, to the left or the right
Mid-sagittal plane splits the body into equal right and left halves
Coronal plane
Right angles to the sagittal plane.
Exposes the body from right to left side of the body
Oblique plane
Any plane that’s not coronal, transverse, or sagittal
Medial/lateral
Relative to the mid-sagittal plane
Medial is towards the body, lateral is away from body
Superior/inferior
Position along the vertical axis
Superior: towards the head
Inferior: towards the feet/tail
Cranial/caudal
Same as superior/inferior
Used in embryology
Ventral/dorsal
Same as anterior/posterior
Anterior/posterior
Anterior: front of body
Posterior: back of the body
Proximal/distal
Relative to the origin of a structure
Proximal: closet
Distal: furtherest
Flexion
Decreasing the angle between two body parts.
Ex: bringing arm up towards upper body, bended st elbow
Extensión
Increasing the angle between two body parts or an angel at a joint
Ex: extending arms from up and bended at elbow, straight down towards anatomical position
Abduction
Moving a body part away from the midline of the body
Adduction
Moving body part towards the midline of the body or defined midline of an extremity
Rotation
Movement around an axis
Medial rotation is towards the body
Lateral rotation is away from body
Movements of trunk and head
Flexión: upper body bends anteriorly (like bending down to touch one’s toes)
Extension: bending the trunk backwards (like you’re about to do a backbend
Lateral flexion: bending trunk away from the midline of body (like you’re using your left hand to touch your left ankle while standing up straight)
Movements of pictorial girdle
scapula and clavicle always move in coordinated fashion
Retraction: moving medial border of scapula away from the vertebra (bringing bended elbow towards back
protraction: moving the medial border of the scapula away from the vertebra (extending arm arm outwards away from back, body)
Elevation: moving the superior border of the scapula superiorly (towards the head)
Depression: moving the superior border of the scapula inferiorly
Movements of the arm
Flexion-Extension
abduction-adduction
medial-lateral rotation
circumduction: imagine moving arm in big circle to the side of your body, doing abduction, flexion, extension, and adduction in one movement
Movements of the forearm
flexion-extension
pronation-supination: complex movement occurring at the elbow and at the distal end of the radius and ulna
Pronation: palm down
suprination: palm up ( think eating soup)
Movements of hand
Flexion- extension
abduction- adduction
Movements of the fingers
flexion-extension
abduction: spreading fingers apart
adduction: bringing the fingers together
Movements of thumb
extension-flexion
abduction: swinging thumb out of the plane of the palm
adduction: swinging thumb into the plane of the palm
opposition: swinging the thumb from anatomical position across the palm touching the palm of the fingers
Movements at the hip joint
ball and socket joint like shoulder so movements are similar, but more stable.
flexion: swings the thigh anteriorly
extension: swings the thigh posteriorly
abduction:swings the thigh laterally away from the body
(when foot is planted, abduction pulls the pelvic bone down on that side and up on the opposite side. Motion maintains a straight erect truck posture during gait or when balancing on one foot.)
adduction: returns thigh back into anatomical position
Movements of the hip joint
Rotation around the long axis of the femur
internal rotation = medial rotation
external rotation = lateral rotation
Movements at the knee
knee is a simple hinge joint
flexion: moves leg posteriorly in relation to the thigh
extension: moves the leg anteriorly
Medial and lateral rotation
Movement at the ankle
ankle is the hinge joint between the distal tibia and the talus.
plantarflexion: is true flexion, occurs when the ankle is pointed down from the anatomical position
dorsiflexion: is true extension, occurs when the foot is pointed up from the anatomical position
Movements within the foot
inversion: bottom of foot angles toward the midline of the body
eversion: bottom of the foot angles away from the body
supination: a combined plantar flexion, inversion, and adduction
pronation: a combined dorsiflexion, eversion, and abduction
Movements of the toes
flexion (curing toes under) and extension
Abduction and adduction
The skeleton- Axial skeleton
vertebral column: the midline support of the body
thoracic cage: protection of the heart and lungs and forms a study chamber for respiration
skull: solid protection of the brain and sensory organs and moveable jaw for mastication and phonation
The skeleton- appendicular skeleton
pectoral and pelvic girdles connecting the limbs to the axial skeleton
long bones of limbs for locomotion
Bone structure
layers of typical bone (outer to inner):
1) periosteum: fibrous connective tissue covering that is highly innervated
2) compact bone: dense, strong outer layer
3) spongy bone: internal part with lots of spaces to lighten the bone
4) medullary (marrow) cavity: site of blood cell formation
composition:
60-70% mineral (calcium phosphate)
30-40% collagen, an elastic protein
synovial joints
synovial joints: have a set of structural elements that allow smooth movement between the bones
4 structures:
1) articular cartilage
2) fibrous capsule
3) fluid-filled joint cavity
4) synovial membrane
solid joints: simple connective tissue that allow little movement
fibrous capsule
fibrous capsule: completely envelopes the joint, is strengthened by thickenings called capsular ligaments. innervation of the capsule is important in controlling movement
articular cartilage
cartilage placed on the end of the bones in moveable joints. ends of bones are capped with hyaline cartilage (makes up articular cartilage)
Articular cartilages are devoid of perichondrium and the outer layer is acellular
Joint cavity
potential space enclosed by the articular capsule
cavity is filled with synovial fluid which lubricates the joint
provides microenvironment that supplies nutrients to the articular cartilage
synovial membrane
membrane lines the fibrous capsule and is reflected over the bones and ligaments but not onto the articular cartilage.
secretes the synovial fluid that acts as a lubricant (think oil for door hinge)
ligaments
bands of strong connective tissue, connecting bone to bone. limit joint movement and prevent dislocation
intrinsic: thickenings of the joint capsule
extrinsic: lie outside or inside the joint capsule
meniscus, labrum, and articular disc
fibrocartilage additions that provide a modified bearing surface for the bones
bursae and synovial sheaths
sacs of synovial membrane providing a lubicated surface between tenons, ligaments and bones
hinge joints
flexion and extension ex: elbow, knee joints, fingers
plane joint
two flat surfaces sliding against each other
ex: shoulder/clavicle
saddle joint
movement in to plans. same kinds of movements of condyloid joints
pivot joint
allows spinning around longitudinal axis. rotational movements
ball and socket joint
rotation, flex, extend, abduct and adduct
condyloid joint
allows movement in two planes. flex/extension, abduction and adduction
Suture
(fibrous joint) only found in skull. connects different bones skull together.
interosseous membrane
(fibrous joint) found in the forearm and in the leg.
membrane acts in force distribution between parallel long bones
cartilagenous joints
primary cartilagenous joint: cartilage between the bones is simply a part of the cartilaginous bone model that does not ossify
secondary cartilagenous joint: skeletal elements are covered by a layer of hyaline cartilage with fibrocartilage between them
Degenerated hernia disk in vertebrae is an example of this joint
muscle
skeletal muscle: striated muscle which moves bones and other structures. under voluntary control
smooth muscle: non striated mulled contracting the walls of blood vessels and hollow organs. under involuntary control by the autonomic nervous system
cardiac muscle: muscle of the heart, controlled by the autonomic nervous system
muscle structure:
muscle fibers are grouped into fascicles, which are surrounded by a perimysium layer of connective tissue. whole muscle is wrapped in an epimysium layer
tendons: connect tp the periosteum or to deeper bone by specialized fibers. transfer muscle energy to the skeleton but also can act as energy storing springs
central nervous system
brain and spine cord; central processing unit
peripheral nervous system
input/output connections from the CNS to the rest of the body
how to tell difference in arteries and veins
arteries deal with high blood pressure - thick walled
veins deal with low pressure - thin walled but carry same volume as arteries. veins are numerous and and of larger diameter
venous valves assist one-way valves that allow blood flow toward the heart
lymphatics
drain excess fluid from intercellular space
very important in spread of infection and cancer
types of bones
Long bones: long shaft with articulations at each end
ex: humerus and femur
Irregular bones: complex shapes that do not fit another category
ex: vertebrae and some skull bones
flat bones: dominated by large thin flat areas
ex: skull bones, scapula, and ribs
short bones: small with irregular shape and articular surfaces
ex: carpals and tarsals
sesamoid bones: develop within tendons
ex: patella
day 10-11
- lacunae anastomose with maternal capillaries to form blood-filled sinusoids
- extraembryonic reticulum forms between Heuser’s membrane and the cytotrophoblast (acellular ECM)
- Heuser’s membrane becomes the primary yolk sac and the blastocoel changes its name to yolk sac cavity
formation of the chorion
- extraembryonic mesoderm is formed from the hypoblast layer and migrates to fill the extra embryonic reticulum
- chorionic cavity develops in the extraembryonic mesoderm
- fetal placenta forms from the chorion
- yolk sac is now a two layered structure: extraembryonic mesoderm and the original lining cells of heuser’s membrane
formation of the secondary yolk sac
-additional cells from the hypoblast migrate and dispose the primary yolk sac, forming the secondary (definitive) yolk sac (site of the initial hematopoiesis and primordial germ cell development
gastrulation
- bilaminar disk defines the dorsal and ventral sides of the embryo only.
- create body consisting of a gastrointestinal tube surrounded by a body wall tube with a space between these two tubes
- create body that has a distinct head and tail as well as front and back and left and right
gastrulation
1) converts the bilaminar disk to a trilaminar disk with three distinct layers: endoderm, mesoderm, and ectoderm
2) establishes the crainocaudal - defines head and tail
3) establishes bilateral symmetry and a left-right directionality which shows up later as specific left-right asymmetries
4) builds populations of cells in specific locations so they can interact by induction
formation of the promotive streak
- epiblast form the primitive streak
- parts of the primitive streak:
1) primitive node
2) primitive groove
3) primitive pit
-formation of the primitive streak = establishment of dorsal-ventral, cranial-caudal, and right-left axes of the body
mesenchyme
- undifferentiated embryonic connective tissue
- usually mesodermal cell but can also be ectomesenchyme
- migrates before differentiating
- epiblast transforms into mesenchyme
mesenchyme
-undifferentiated embryonic connective tissue
-
resulting cell types from gastrulation
epiblast leads to:
1) primordial germ cells -> yolk sac
2) hematopoietic stem cells -> yolk sac
3) extraembryonic mesoderm -> chorion, amnion, and yolk sac
What comes from the germ layers?
ectoderm: nervous system and outer covering of the body
mesoderm: musculoskeletal, vascular, and some organ systems
endoderm: lining of gut tube and all derivatives
paths of gastrulating cells
1) early streak stage: gut endoderm forms from the cranial end of the primitive streak. the earliest mesoderm, from the primitive node region forms the prechordal plate
2) mid streak stage: cardiogenic mesoderm migrates to the head. extraembryonic mesoderm exits the embryo proper
3) late streak stage: mesodermal fields for notochord, paraxial mesoderm, intermediate mesoderm and lateral plate are defined
formation of the prechordal plate and notochord
- mesoderm grows down and cranial from the primitive pit
- prechordal plate is behind buccopharyngeal membrane and is very important in organizing head development
- notochordal process develops behind the prechordal plate- this is a hollow tube, as the streak moves caudally, the notochord lengthens
functions of the notochord
- important inducer of the spinal cord, spinal nerve, and vertebral column
- most notochord later regresses, but a part remains in the nucleus pulpous of the intervertebral disk
fate of the laterally migrating mesoderm
paraxial mesoderm -> somites -> axial Skelton, musculature
intermediate mesoderm -> urinary and reproductive systems; adrenal gland
lateral plate mesoderm -> connective tissues; layers of gut wall and body cavity, limbs
fate of ectoderm
1) surface ectoderm -> skin
placodal ectoderm is a specialized surface ectoderm -> cranial nerve sensory neurons, inner ear and lens
2) ectoderm over the prechordal plate and notochord thickens to become the neural plate -> neural tube -> CNS
3) the edge of the neural plate becomes the neural crest -> PNS
