Intro to Anatomy and Embryology Flashcards
Midline
Line between left and right
Also called sagittal plane
Parasagittal plane
Line between mid-line and edge of body
Horizontal plane
Divided top and bottom half of body
Coronal plane
Divides front and back portions of the body
Superior
Towards the head
Inferior
Towards feet
Medial
Closer to the midline
Lateral
Further from the midline
Anterior
Front of body
Posterior
Back of body
Proximal
Used when describing limbs, closer to hand or foot
Distal
Used when describing limbs, closer to hand or foot
Superficial
Closer to surface of body e.g. skin
Deep
Closer to bones
Functions of the skeleton
Provides support for soft tissues
Protects our internal organs
Aids body movement
Joint
When a bone meets another bone, they form an articulation
Main types of joints
Bony
Fibrous
Cartilginous
Synovial
Bony joints
Bones are connected by bones e.g 3 bones of the pelvis
Fibrous
Bones connected by fibres e.g bones of the skull
Cartilganous
Bones connected by cartilage
Foramen
A hole in a bone
Fossa
Shallow depression or crater
Spine
Sharp, raised region
Tuberosity, tubercle, trochanter
Raised bump for an attachment of muscles or ligaments
Two groups of veins
Deep
Superficial
Deep veins
Generally follows course of arteries and have same name - run in ipp. directions
Superficial veins
Much more variable than deep veins
Blood in the veins MUST drain into deep veins before returning to the heart
Neurovascular bundle
When a nerve, artery and vein all supply the same structure and therefore travel together
Latin terminology
Longus - long muscle Rectus - straight muscle Cep - muscle belly/ head e.g. triceps, bicep Brevis -short Magnus - large
Muscle compartments in the lower limb
Anterior thigh Medial thigh Anterior leg Lateral leg Inferior Gluteal Superior gluteal Posterior thigh Posterior leg - superficial Posterior leg - deep
How are muscles separated into groups
By fascia
Along w/ their blood and nerve supply
Common muscle actions of the anterior thigh
Flexion of hip
Extension of knee
Muscle actions of the sartorius
Flexion of the knee
Lateral rotation of hip
Muscle actions of vastus medalis
Medial deviation of the kneecap
Muscle actions of the medial thigh
Adduction of hip
Nerve supply of the medial thigh
Obturator nerve
Muscle actions of anterior leg
Extension of ankle
Extension of toes
Nerve supplies of the anterior leg
Deep peroneal nerve
Muscle actions of the superior gluteal compartment
Abduction of hip
Nerve supplies of the superior gluteal compartment
Superior gluteal nerve
Muscle actions of inferior gluteal nerve
Extension of hip
Nerve supplies of inferior gluteal nerve
Inferior gluteal nerve
Muscle actions of lateral leg
Eversion of ankle
Nerve supplies of lateral leg
Superficial peroneal nerve
Muscle actions of posterior thigh
Extension of hip
Flexion of knee
Nerve supplies of posterior thigh
Tibial nerve
Muscle actions of posterior leg (superficial)
Flexion of ankle
Muscle actions of posterior leg (deep)
Flexion of toes
Flexion of ankle
Nerve supplies of posterior leg (superficial)
Tibial nerve
Nerve supplies of posterior leg (deep)
Tibial nerve
Week 1 of early development
Fertilisation to implantation
Week 2 of early development
Bilaminar Germ disc
Amniotic cavity
Primary yolk sac
Week 3 of early development
Gastrulation
Gastrulation
Trilaminar Germ Disc Primitive Streak Notochord Neural tube Body Axes/ Growth of embryonic disc Determination of mesodermal elements
Weeks 3-8 of early development
Neurulation Development of: Somites --> skeleton Intraembryononic coelom Primitive cardiovascular system All major organs
Neurulation
Development of the nervous system
Intraembryonic coelom
Body cavities
Weeks 8 - birth of early development
Foetal period
Maturation tissues and organs as they aren’t all fully functional
Rapid growth of the foetal body
Induction
One group of cells and tissues (inducer) cause another group of cells and tissues to change their fate (responder) e.g epithelium - mesenchymal interaction
Cell signalling involved in early development
Signal transduction
Paraxrine interactions
Juxtacrine
Signal transduction
Signal molecules (ligand) and a receptor
Paracrine interactions
Protein diffusion between cells, paracrine factors or growth and differentiation factors and neurotransmitters
Juxtacrine
Non-diffucible factors
Cell’s surface ligands or direct cell-to-cell communication
Where do the spermatozoon and ovum make contact
In the ampulla (12-24 hrs after ovulation)
Fertilisation to implantation
Two-cell zygote cleaves —> morula
Ingress of fluid inside forces cells to migrate to poles –> blastocyst cavity, embeds itself into wall
Blastocyst forms
Uterine secretory phase
Blastocyst
2 cell layers formed from cells that migrated and implanatation
Inner cell mass - embrypblast
Outer cell mass - trophoblast
Bilaminar disc
Two cell layers in the inner cell mass
Epiblast - high columnar cell
Hypoblast - cuboidal cell
Processes in week 2 of early development
Bilaminar disc
Formation of primary yolk sac and amniotic cavity
Cyotrophoblast and synciotrophoblast form
Chorionic activity and plate form
Deblopmnet of uterplacental circulations
Connecting stalk - primitive umbilical cord
Formation of secondary yolk sac
Uteroplacental circulation
By 3rd week diffusion can no longer supply needs of the developing embryo Formation of primitive blood vessels
Where does the trilaminar disc originate from
Epiblast as well as notochord
Invagination of some epiblast mesenchyme cells
Formation of endoderm from hypoblast @ day 14/15
Mesoderm formed in between @ day 16
Epiblast cells remaining on surface - ectoderm
Mesodermal elements
Paraxial mesoderm
Intermediate mesoderm
Lateral mesoderm (somatic and splanchnic)
Neural crest cells migrate to
Contribute to tissues and organs incl craniofacial skeleton
What do neural crest cells form
Dorsal root ganglia and ganglia of autonomic nervous system
Meninges (surroundings of our brain)
Several skeletal and muscular components of the head
Dorsal yolk sac
Construction between embryo and yolk sac after longitudinal and transverse folding converts the flat trilaminar embryonic disc into a C-shaped, cylindrical embryo
Development of somites
Mesoderm form bilateral longitudinal columns that divide into paired somites in a craniocaudal sequence (38 pairs)
Early somites
Paired bead-like elevations along the dorsolateral surface of the embryo
What do mesenchyme cells from the smite give rise to
Axial skeleton and associated muscles
Dermis
Ectoderm folding
Dorsal folding to form the neural tube - neurulation
Endoderm folding
Forms ventral surface of embryo and roof of yolk sac, ventral folding ro form the inner lining of the gut tube
Transverse folding (weeks 4-8)
Expansion of the amniotic cavity into extraembryonic (chorionic) cavity
Formation of the intraembryonic coelom (primitive body cavity)
Formation of embryonic gut tube
Formation of intra-embryonic coelom
Lateral plate splitting into 2 layers, visceral and splanchnic
Visceral (splanchnic) layer
Continuous w/ extraembryonic mesoderm covering the yolk sac
Forms wall of primitive gut
Parietal (somatic) layer
Continuous w/ extra embryonic mesoderm covering amnion
Forms body wall
What happens to somites after they’re formed
Their ventral and medial walls divide into 2 masses of cells, sclerotome and dermomyotome
Sclerotome
Ventromedial, vertebral column and ribs
Dermomyotome
Forms in the dorsolateral wall of the somite
Further differentiates into 2 regions, myotome region (muscles) and dermomyotome region (dermis of skin)
Somite differentiation
Paraxial mesoderm
Somites - occipital region caudally
Somitomeres - head
Somite differentiation - muscle development
Involves myotomes cell masses
Cell of myotome leave myotome to become elongated and spindle shaped - myoblasts
Myoblasts differentiate and fuse w/ other myoblasts - myotubes
Fusion of myotubes will form muscle fibres
Myoblasts
Embryonic muscle cells
Where do myotomes develop from
Small dorsal division of somite - epaxial
Large ventral decision of somite - hypaxial
What does each division of a myotome form
A spp group of muscles w/ elongation on these groups split into flexor and extensor components
Where does each myotome receive innervation from
Spinal nerves from the same somite segment as the muscle cell
What do epimeres form
Epaxial division
Extensors of the back and vertebral column
Extensors of the lumbar
What do hypomeres form
Hypaxial division
Lateral and ventral flexor musculature of the trunk
Branchiomeres
Myoblasts from the branchial arches –> develops into face
How does bone start as
Condenstation of mesenchymal cells
Bones formed by intrammebranous bone formation
Most flat bones
Bones formed by endochondral bone formation
Most limb bones
Chondrofication centres
Mesenchyme cells differentiate into chondroblasts
Collagenous/ elastic fibres are deposited in matrix and a cartilaginous (hyaline) bine model forms
Chondroblasts function
Secrete collagen and ground (substance) matrix
Where are primary chondrification centres formed
In the diaphysis
Sites of secondary ossification centres
Epiphysis
What does the sternum develop from
Lateral plate (parietal) mesoderm Costal cartilage from paraxial mesoderm
How many separate bony elements make up the face
45
What is the skull divided into
Neurocranium
Viscerocranium
Neurocranium
Protects the brain
Membranous part and cartilaginous part (base of skull)
Viscerocranium
Facial skeleton
Formed mainly by the first 2 pharyngeal arches
Intramembranous ossification of the skull
Mesenchyme condense and osteoblasts form a matrix, later calcium phosphate deposits
Bone spicules radiate from the primary ossification centres within membranous sheaths
Enlarge by apposition of new layers on the outer surface and osteoclastic resorption inside
What are flat bones separated by
Sutures (connective tissue)
Fontanelles
Membrane connecting >2 parts of a baby’s skull
Types of fontanelles
Anterior
Posterior
Sphenoidal
Mastoid
Anterior fontanelle closure
~ 1-3 yrs post birth
Posterior fontanelle closure
~ 2 months post birth
Sphenoidal fontanelle closure
~ 2 months post birth
Mastoid fontanelle closure
~ 6-18 months post birth
What do limb buds consist of initially
Mesenchymal core from the parietal (somatic) layer of the lateral plate mesoderm covered by an outer layer off ectoderm
Apical Ectodermal Ridge (AER)
Ectoderm at the distal border of the limb thickens to form AER
AER exerts an inductive influence of the adjacent mesenchyme causing it to remain undifferentiated, rapidly proliferating cells – Progression Zone
Cells further from the AER differentiate into cartilage and muscles
Digit formation
In the distal end of the limb bud a flat hand or foot plate forms
Cell death in the AER creates 5 separate AER regions for finger growth; cell death in the interdigital spaces separates the fingers
Limb development
Onset of development of arm bud ~ 27 days Well-developed arm bud ~ 28-30 days Elongation of arm bud ~ 34-36 days Formation of hand paddle ~ 34-38 days Onset of finger separation ~ 38-40 days Full separation of fingers ~ 50-52 days
Limb organisation in development
Upper limbs - 90 degrees rotation laterally - flexors anterior/ extensors posterior
Lower limbs - 90 degrees rotation medially - flexors posterior/ extensors anterior
Hyaline cartilage
Glassy, smooth form of cartilage that helps to reduce friction between the bones
Joint capsules
Surround joints
Usually contain supportive ligaments
Lined by synovial membrane
Major type of joints
Hinge joint Ball and socket Saddle joint Pivot joint Plane/ gliding Ellipsoid
Muscle biomechanics principles
To have an action at a joint, a muscle needs to attach on either side of the joint. A muscle will have an action at every joint it crosses. We need at least one muscle for every possible movement at a joint. How a muscle crosses a joint will determine which action it has at the joint
Bone spicules
Small cells laid down in formation of new bone matrix
Inferomedial
Nearer the feet and closer the median plane
Superolateral
Nearer the head and further from the median plane
Bilateral
Paired structures having left and right e.g. kidneys
Unilateral
Structures occurring on one side only e.g. spleen
Ipsilateral
Occurring on the same side of the body e.g. right thumb and right big toe
Contralateral
Occurring in the opposite side of the body e.g. right hand and left hand
Palmar vs Dorsal surfaces
Anterior hand (palm) Posterior hand (dorsum)
Spp to hands and feet
Plantar vs Dorsal surfaces
Inferior foot surface (sole)
Superior foot surface (dorsum)
Spp for hands and feet
Flexion
Usually brings distal part of joint to anterior part of body e.g. at shoulder, wrist, hip
Exception is at knee and ankle joints, where distal part is brought to the posterior part of the body
Extension
Opposite to flexion, muscles straighten out and pull back
Extension of hand at wrist
Dorsal surface brought up
Flexion of hand at wrist
Palmar surface brought down
Flexion and extension of vertebral column at interverbral joints
Bending forward and backwards
Abduction
Takes limb away from body and midline
Adduction
Adds limb back to body
Medial rotation
Brings structures close to midline
Medial rotation at hip
Would bring feet inwards
Medial rotation at shoulder
Brings wrist to abdomen
Lateral rotation
Twists structures out and away from midline
Lateral rotation at hip
Feet facing outwards
Lateral rotation at shoulder
Brings wrists outwards
Supination
Hands out with palms facing up
Only occurs at elbows (radio-ulnar joints)
Pronation
Hands out with palms facing down
Only occurs at elbows (radio-ulnar joints)
Inversion
Turning soles of feet inwards
Ankle eversion
Turning soles of the feet outwards
Circumduction
Circular movement of lower limb at hip joint
Elevation and depression
Lifting shoulders up and down
Protrusion and retrusion
Moving mandible forward and backwards
Opposition and reposition
Bringing thumb to little finger and back again
Sesamoid bone
Develop in certain tendons
Protect tendons from excessive wear and change angle of tendons as they pass to their attachments
Condyle
Rounded articulate area
Epicondyle
Eminence superior to condyles
Malleolus
Rounded prominence
Major regions of lower limbs
Gluteal region Femoral region Knee region Leg region Ankle/ talocrural region Foot region
Innervation of anterior thigh
Femoral nerve
