Filed under: Cytology / Histology, Medicine Study, Muscular & Skeletal System
Study Guide 1 Year 1 Medicine
Cytology & Histology
and
Study Guide 2
The Musculoskeletal System
Health and Disease
The World Health Organisation definition of Health is:“The state of complete physical, mental and social well-being.”
WHO 1998
It is also:
“Absence of Illness”
WHO 1998
In life, we must consider health from a realistic standpoint, although perhaps we should at least aspire to the ideal. A truly holistic approach to human health must consider:
Physical
Mental
Emotional
Social
Spiritual
Environmental factors. How many of these aspects can one person really affect?
Homeostasis
Cells need relatively stable conditions to function effectively.
This stability is called homeostasis. (homeo = same, stasis = standing still)
Definition:
Homeostasis is a condition in which the body’s internal environment remains within certain physiological limits.
For instance, body fluids must be regulated – kept at correct volume and composition.
Fluid in cells – intracellular (intra = within)
Fluid outside cells – extracellular (extra = outside)
ECF between cells – intercellular (inter = between)
ECF in blood vessels – plasma
Oxygen, nutrients and ions are carried in fluid, moved into and out of cells and around the circulatory systems (blood and lymph). Always a constant amount.
Interstitial fluids surround cells – known as the body’s internal environment. If conditions here are maintained in a consistent way, homeostasis is achieved.
When homeostasis is disturbed, illness may result → death.
Stress (all forms) can have a major impact on homeostatic balance. E.g. poisoning, overexposure to extreme temperatures, severe infection, death of a spouse.
Generally, the body regulates change very well.
Example:
↑ exercise → ↑ O2 use ↑ CO2 production.
nervous element: ↑ circulation
↑ breathing rate
endocrine element: ↑ adrenaline
Feedback systems
An animation about Positive and Negative feedback can be seen here.
Negative feedback
These systems maintain conditions that require frequent monitoring and adjustment within physiological limits e.g. body temperature, blood pressure…
Example 1:
Blood pressure control.
Blood pressure is the force exerted by blood as it presses against walls of the blood vessels. If heart beat ↑, then pressure ↑ or blood volume ↑ → pressure ↑
Hence, somehow the body must bring the pressure back down…
Positive Feedback
In unusual circumstances, where fine-tuning of a situation is less important, the body sometimes needs to amplify controlled conditions. E.g. Labor contractions, initial blood clotting…
Example 2:
Labor contractions
The hormone oxytocin is released from the brain as a muscle contractor of the pregnant uterus.
Labor begins; uterus is stretched → brain responds by releasing ↑ oxytocin. → ↑ contractions and stretching… Until baby is born → feedback is shut off.
Cytology
A cell is a basic, living, structural and functional unit of the body. All cells come into being from pre-existing cells. Virtually all metabolic activities take place within cells.
Definitions:
Prokaryote cell – bacteria (with no nucleus)
Eukaryotes are organisms with complex cells, including nuclei
Living characteristics:
Metabolism
Catabolism – breakdown of large complex things into smaller, useful building blocks. E.g. protein → amino acids.
e.g. O2 and nutrients → cell respiration (chemical energy) → ATP produced.
Anabolism – energy used to build structural and functional body components.
e.g. Protein → muscle and bone.
Responsiveness – ability to detect and respond to changes.
Movement – bodily, tissue (digestive level), intracellular.
Growth with ↑ size and number of cells
Differentiation – unspecialised → specialised.
Specialised cells have structural and functional characteristics that differ from their “ancestors”
E.g. Red bone marrow cells → red and white blood cells with many different functions.
Reproduction – Formation of new cells for growth, repair, replacement or production of a new individual.
Cell Components
Cell Membrane
Cell Nucleus
Cytoplasm : Cytosol
o Ribosomes
o Endoplasmic Reticulum
o Golgi Complex
o Lysosomes
o Mitochondria
o The Cytoskeleton
o Centrosome
Membranes are flexible, shape-shifting barriers between cells, keeping certain things in and out.
The membrane is composed of lipids, steroids and proteins, with chains of carbohydrates attached to the outside. The majority is phospholipids that consist of a polar end (phosphate –hydrophilic) and two fatty acid chains (hydrophobic).
Proteins act as carrier molecules, as entry and exit points, and can control this entry and exit.
Proteins have individual shapes, and hence can act as identity features
They can be enzymes / hormone releases.
Tubules of the cytoskeleton will be anchored to the proteins as well.
Cell shapes are influenced by the contractility of the cell membrane →squamous, cuboidal or columnar.
Surface area / shape can be altered to enable distinctive functions. E.g. formation of microvilli by folding.
Transmembrane transport
Passive (no energy needed)
Diffusion – high concentration to low concentration across a “concentration” gradient. It is consequence of random movement of particles.
Influenced by temperature, surface area, thickness of membrane, concentration gradient and size of molecules.
Osmosis – “diffusion” through a selectively permeable membrane – water can flow through following pressure gradient (high to low) but some of the solute might not pass.
An animation on how Osmosis works can be seen here.
Hypertonic = concentrated solutions
Hypotonic = dilute solutions
Filtration – selectively permeable membrane enables passage from high to low pressure. E.g. creation of glomerular filtrate due to blood pressure; kidney filtration – extraction of plasma and waste from water
Facilitated diffusion – same as diffusion but helped by specific carrier molecules.
Active (energy needed)
ATP (energy) used to pump sodium or calcium out of cells after muscle contraction
Bulk transport – phagocytosis (consider the enveloping style of the amoeba. Also, blood flow is considered “bulk transport”.
Cell organelles and the Nucleus
Spherical or oval. Largest structure in cell
Most cells are uninucleate, although some, like skeletal muscles, are multinucleate
Contains genes – control cellular structure and activities
Genes are arranged in single file along structures called chromosomes.
Tiny granules that contain ribosomal RNA, and are the site of protein synthesis.
Some are free, and produce proteins for that cell’s use. Some are attached to the endoplasmic reticulum, and create proteins for “export”.
Think of these as the “workers” of the cell.
Endoplasmic Reticulum (ER)
A system of membrane-enclosed channels called cisterns.
Continuous with nuclear membrane.
Smooth (agranular) ER – no ribosomes
Rough (granular) ER – studded with ribosomes
Rough ER serves as storage area for proteins.
Smooth ER is site for fatty acid, phospholipids and steroid synthesis. Enzymes produced here can also detoxify chemicals e.g. alcohol, pesticides, carcinogen.
Consider this as the “factory production line” for most things
Golgi Complex
Located near nucleus. Extensive in “secreting” cells. Flattened, saucer-shaped sacs.
It processes, sorts, packages and delivers proteins and lipids to the plasma membrane.
It also forms lysosomes and secretory vesicles.
Consider this as the “postal service” for the cell.
Lysosomes
Formed in Golgi complex, these are membrane-enclosed vesicles containing over 40 kinds of digestive enzyme.
Their job is to break down molecules.
Interior of lysosome is pH 5 (100 times more acidic than pH 7 cytosol)
They digest bacteria etc that enter the cell. The waste products are then released into the cytosol, to be used as building blocks by the cell.
They also digest redundant organelles. (autophagy)
Mitochondria
The “Powerhouse” of the cell.
Main site for generation of ATP
Outer smooth layer
Inner membrane folded to create a large surface area for enzymes to attach to.
These are the source of cellular respiration, providing ATP as the product, to be used by the cell.
They can self-replicate, in response to cellular need for ATP
The cytoskeleton
A complex network of filamentous proteins (microtubules and filaments)
Responsible for movement of organelles and chemicals within the cell. Also supports and shapes cells.
Centrosome
Centre for organizing microtubules, and the formation of “mitotic spindle” in cell division
Cell destiny
A cell has 3 possible destinies:
remain active (e.g. Brain cells)
grow and divide
die
Division and death must be kept balanced.
Some cells have genetically programmed death – Apoptosis – caused by protein produced by the “cell-suicide” gene.
Phagocytes engulf and degrade the cellular remains
Necrosis is a pathological cell death, resulting from tissue injury – cells burst, their contents is dispersed and inflammation results.
Cell Division
Most cells in the body replicate by a process of doubling up their contents, and then splitting in two, dividing the contents out equally. Hence, where once there was one cell, now there are two, identical ones.
BBC Bitesize has a great section that explains Mitosis - visit it here.
The process by which sex cells reproduce. Through a complex series of doubling and dividing, one cell with diploid chromosomes becomes 4 daughter cells with haploid chromosomes (see Tortora pp. 84-6 for details). This makes 4 sperm cells, or 1 ovum (the other 3 dying). Histology
Definition: A tissue is a group of cells that usually have a common embryonic origin, and function together to carry out specialized activities.
The structure and properties of a specific tissue are influenced by such things as the nature of the extracellular material that surrounds the tissue cells, and connections between the cells that compose the tissue.
Types of Tissue
Epithelial – covers body surface, lines hollow organs, body cavities and ducts; forms glands.
Connective – protects, supports and binds the body and organs; stores energy reserves as fat; provides immunity.
Muscle – responsible for movement and generation of force.
Bone – provides framework for body, supports, stores and produces materials and blood cells for the body.
Nervous – initiates and transmits action potentials that help coordinate body activities.
All tissues develop from 3 primary germ layers:
ectoderm
mesoderm
endoderm
Most epithelial tissues replace by mitosis → constant regeneration.
2 types:
covering and lining
glandular
Nomenclature:
Simple epithelium
Single layer of cells found in areas activities such as diffusion, osmosis, filtration, secretion and absorption occur.
Stratified epithelium
2 and layers – protect underlying tissues in area of high wear
Preodostratified epithelium
Looks like it, but it isn’t! Due to varying cell shapes and sizes.
Cell shapes
Squamous
Flat, attached like tiles. Thinness allows rapid movement of substances through them.
Cuboid
Cube / hexagon shaped. Important for secretion and some absorption.
Columnar
Tall and cylindrical – protect underlying tissues. Sometimes secrete and absorb.
Transitional
Can alter shape, often due to movement and stretching of bodily parts / organs e.g. the stomach or bladder.
Types of Epithelial Tissue
Name Description Location Function
Single layer of flat cells Lines heart, lymph vessels, some serous membranes Filtration, Diffusion, Osmosis and some Secretion
Simple Cuboid Epithelium
Single layer of cubed cells Surface of ovary, kidney tubules, capsule of lens of eye Secretion and Absorption
Nonciliated simple columnar epithelium
1 Layer of rectangular cells, often containing goblet cells Lines GI tract from stomach to anus, ducts of glands and gallbladder Secretion and Absorption
Ciliated simple columnar epithelium
As above, but with cilia protruding into cavities Lines parts of upper resp. tract, Fallopian tubes, uterus, canal of spinal cord Moves fluids / particles along passageways
Stratified squamous epithelium
Several layers of cells – some cuboid or columnar cells in deep layers Skin layer; lining of mouth, oesophagus, vagina and tongue. Protection
Stratified cuboidal epithelium
2+ layers of cuboid cells Ducts of sweat glands, male urethra Protection
Stratified columnar epithelium Many polyhedral cell layers – columnar cells in superficial layer Lines part of urethra, excretory ducts of glands, anal mucous membrane Protection and Secretion
Variable appearance – cuboid to squamous… Lines urinary bladder, ureters and urethra Permits distension
Pseudostratified columnar epithelium
All cells attached to membrane, but not all reach surface Upper resp. tract; epididymis; male urethra Secretion and movement of mucus
Glandular Epithelium
The function is to secrete substances into or onto the body surfaces / cavities.
May be one cell or a highly specialised group.
Exocrine Glands: exo – outside kine – to secrete
Flow onto free surfaces – skin (organs) duct surfaces. E.g. sweat glands /salivary glands
E.g. Mucus, sweat, ear wax, digestive enzymes.
Endocrine Glands: endo – within
Secrete information – extracellular fluid and into the bloodstream.
“Hormones” – regulate metabolic and physiological activities to maintain homeostasis. E.g. pituitary, thyroid and adrenal glands.
Most abundant and widely distributed tissue in the body.
Binds, supports and strengthens, protects and isolates internal organs, compartmentalises structures – e.g. skeletal muscle.
Blood is a fluid connective tissue. Adipose (fat) tissue is a major site of stored energy reserves.
General Features
Three basic elements – cells, ground substance and fibres. The latter two form the tissues matrix. Hence, cells are usually kept apart from one another.
Not on surfaces (unlike epithelium), except joint surfaces.
Has a nerve supply, everywhere but in cartilage.
Highly vascular. Exceptions are cartilage which is avascular, and tendons which have reduced vascularisation.
Matrix is secreted by the cells contained therein, and might be fluid, semi fluid, gelatinous, fibrous, or calcified – exception is blood plasma.
Connective tissue functions
These bind structures together
Supports structures → rigidity
Protects – healing, immunity, padding etc.
Subdivides organs
Unites dissimilar tissues
Packing material
Energy store / mineral store
Restraining mechanisms
Deep fascia many aid movement of blood
Cell types (a selection)
-blast = immature cell. Means bud / sprout
-cyte = mature cell
Fibroblasts (fibres), chonrdoblasts (cartilage) and osteoblasts (bone) are capable of mitosis and secrete the matrix element of relevant tissues.
Chondrocytes and osteocytes are mostly involved in maintenance of the matrix.
Macrophages or histiocytes are immune cells, able to engulf bacteria and cellular waste by phagocytosis.
Plasma cells – develop from a certain white blood cell. They secrete antibodies → immune system. Especially found in GI tract and mammary glands (breasts).
Mast cells produce histamine, which dilates blood vessels → abundant alongside blood vessels.
Matrix
Gives specific property of each connective tissue.
Contains protein fibres embedded in ground substance.
Fibres include collagen, elastic fibres and reticular fibres.
Fibres types
The type and arrangements of fibres contributes to the properties the C.T. type. i.e. loose / dense; loose / random.
Collagen
There are over 12 types
It is flexible but with a high tensile strength
Constituent molecules = Tropocollagen. i.e. 3 coiled peptide chains
Produced by fibroblasts
Covalent cross-links between tropocollagen gives a high tensile strength.
Reticular
Much finer, but otherwise similar
Made from reticulin
From fibroblasts
Elastic
Made of elastin
It is very elastic – can stretch up to 1.5 times
From fibroblasts
Ground Substance
Composed of H2O and Proteoglycans. These are a combination of protein and glycosaminoglycan. The purpose of the latter is to trap things within the mix.
The purpose of a ground substance (GS) water content allows diffusion of gasses, ions and molecules.
Viscosity results in it being a mechanical barrier to bacteria.
Lubricates.
Connective Tissue Types
Loose connective tissue
a. Areolar connective tissue – fibres and cells as above, in semifluid ground substance
Found in skin, mucous membranes, blood vessels, nerves and around body organs.
b. Adipose connective tissue – specialised to store fats and oils
Found in skin, around heart and kidney, yellow bone marrow of long bones, around joints
Works to maintain temperature / homeostastic conditions and protection. Serves as an energy reserve..
c. Reticular connective tissue – found in liver, spleen, lymph nodes, red bone narrow
Forms framework (stroma) of organs.
Dense Connective Tissue
d. Regular and irregular
Cartilage
e. Hyaline – found in end of long bones, larynx, trachea, and bronchi.
Provides smooth surface for movement at joints, flexibility and support.
f. Fibrocartilage – found in pubic-symphysis, intervertebral discs and menisci of knee.
Provides support and fusion.
g. Elastic cartilage – in larynx, external ear and eustachian tubes.
Provides support and maintains shape of things.
Cartilage is capable of enduring more stress than most other connective tissues. It has a dense network of collagen fibres and elastic fibres, embedded in a rubbery ground substance.
Cartilage has no blood supply or nerves, except those in the very outside of any structure, within the peri-(outer)-chondrium.
Bone (Osseus) Tissue
Compact/Cortical or Spongy/Cancellous
Skeletal system has many functions.
Blood (Vascular tissue)
· Blood is a connective tissue with a liquid matrix called plasma.
· Plasma is mainly water, with a wide variety of dissolved substances e.g. nutrients, wastes, enzymes, hormones, etc – it is straw coloured.
· Also contains red and white blood cells.
Membranes
Epithelial layer and connective tissue layer = epithelial membrane.
These include:
mucous membranes
serous membranes
cutaneous membranes (skin)
synovial membranes
Mucous Membranes
· These line body cavities that open to the exterior – digestive system, respiratory system, reproductive system and much of urinary system.
· Epithelial layer provides a barrier and secretes mucous and digestive enzymes.
· Function of mucous:
- prevents cavities drying out
- traps particles in respiratory passageways
- lubricates food in GI tract.
· The connective tissue layer binds the epithelium to underlying structures, and holds blood vessel in place. Enables diffusion of O2 and CO2 in correct directions.
Serous Membranes
· Line body cavities that do not open to the exterior, and line organs contained in such cavities
Always two layers:
Parietal (paries = wall)
Visceral (viscus = body)
Includes:
pleura – lungs
pericardium – heart
peritoneum – abdomen and pelvis
Secretes serous fluid to enable slip of layers.
Synovial membranes
· these line the carlines of freely movable joints.
· there is no epithelial surface.
· composed of areolar connective tissue, elastic fibers and fat.
· secrete synovial fluid → lubricates and nourishes cartilage.
· also found in cushioning fatty sacs (burasae) and tendon sheaths.
Body cavities
Cranial:
Brain
Cerebellum
Brain stern
Sensory organs
Arteries/Veins/Cranial nerves/Lymphatics
Thorax:
Oesophagus, Larynx, Bronchial Tree
Lungs
Heart
Diaphragm
Aorta, SVC, IVC
Abdomen – Digestive Viscera:
Stomach
Duodenum
Small Intestine
Large Intestine
Colon
Appendix
Liver / Gallbladder
Pancreas
Spleen
(Kidneys)
Pelvic:
Bladder
Sigmoid colon
Rectum
Ovaries
Uterus
Urethra
Uretas
Body Orientation Vocabulary
Superior - upper
Inferior - lower
Lateral - to side
Medial - in the centre
Proximal - close
Distal
Ipsilateral
Contralateral
Superficial
Deep
Internal
External
Parietal
Visceral
Cephalad
Caudal
Sagittal Plane
Coronal Plane
Transverse Plane
Bones
An animation on bone formation can be seen here.
Types of bone
a. Long – shaft + 2 extremities. E.g. femur, tibia
b. Short – e.g. carpals of wrist
c. Irregular – e.g. vertebrae
d. Flat – e.g. sternum, ribs, skull
e. Sesamoid – e.g. patella
Long Bone structure:
Diaphysis – this is the shaft of the long bone. It has a large open space inside, which contains yellow bone marrow.
2 x Epiphysis – these are the irregular ends of the long bones. They contain red bone marrow
Periosteum – this is the thin membranous layer that envelopes all bone. It is both highly vascular, and has a very good nerve supply. It serves as the attachment layer for muscle/tendon to fix to the bones.
Short bones contain red bone marrow.
Bone structure
Compact (corticol) bone – typically the “solid” outer layer of bone – composed of many “Haversian Systems” that enable a good blood supply throughout the bony structure
Cancellous (spongy) bone – contains a honeycomb framework of bony material called trabeculae. These serve as force distributors throughout the bone, enabling far greater forces to be applied to the skeleton without it breaking. It contains red bone marrow, which produces red and white blood cells.
Terminology:
-blast – gem / bud (osteoblasts from bone)
-clast – to break ( osteoclasts resorb bone – important for repair and maintenance)
-cyte – cell
Bone Functions
Provide framework for body
Provide attachments for muscles and tenders
Permit / control range of movement
Form boundaries, protecting organs
Red bone narrow – produces blood cells
Provide reservoir of minerals – (consider osteoporosis! and homeostasis)
Bone Fracture
Fractures are the same as breaks! They are classified in 3 ways:
- simple
- compound
- pathological
There are many types of fracture. The best way to see these is from X-rays – any good orthopaedic text can provide pictures. The following is a list of some of the major/common fracture types.
Please note that this table is not exhaustive…
Fracture Type Description
Partial The break across the bone is incomplete
Greenstick Partial fracture – one side of bone breaks, and the other side bends. Common in children
Closed (simple) Bone does not come through skin
Open (compound) Broken ends/end protrudes through skin
Comminuted Bone splinters at site of impact, and smaller fragments lie between break ends
Stress Microscopic fractures due to inability to withstand multiple repeated stressful impact
Spiral Bone is twisted apart
Impacted One fragment driven into the other
Colles’ Fracture of distal end of radius, with distal end displaced posteriorly
Pott’s Fracture of distal end of fibula, with serious injury to tibial articulation at ankle
Fracture Healing
Example of a simple break:
Once fractured, blood supply is impaired / broken
ß
Blood pours into the fracture cavity
ß
Blood clots around the site of the fracture
- a fracture haematoma
ß
Swelling, inflammation and start of healing
Fibroblasts arrive on site and capillaries form to provide blood supply
ß
Collagen fibres connect the break ends
ß
A fibrous Callus is formed
Osteoblasts now form and secrete bone, and previous cartilage becomes ossified (turned to bone)
ß
New Trabeculae are formed
ß
Bony callus is formed
Remodelling: dead elements are removed by osteoclasts
ß
Compact bone is formed and medullary canal is reopened.
Muscles
3 kinds of muscles tissue:
Skeletal
Cardiac
Smooth
1. Skeletal muscles tissue:
So named because it is attached primarily to bones, and moves the skeleton.
It is a voluntary muscle tissue, because it can be made to contract and relax by conscious control
2. Cardiac muscles tissue
Forms most of the heart
Involuntary – controlled by automatic effects of nerves and hormones
3. Smooth muscles tissue
In the walls of hollow internal structures e.g. blood vessels, stomach, intestines
Usually involuntary
Function of Muscles
1. Motion – gross and fine
2. Movement of substances within the body
3. Stabilising body positions and regulating organ volume
4. Thermogenesis – by-product of muscle contraction is heat (85% of all body heat) and shivering.
The Neuromuscular Junction
For excitable cells to communicate, specialised regions called synapses exist.
The Sliding Filament Theory.
Muscle Metabolism
ATP – Adenosine Triphosphate
ADP – Adenosine Diphosphate
Initially, creatine photosphate and ATP present in a muscle tissue can supply enough energy to contract maximally for 15 seconds.
After that time, glucose must be catabolised to generate ATP.
The process of catabolism produces a net gain of ATP (after using some in the actual process of creation!).
This process is called Glycolysis , and does not require O2 to occur. Hence, it is an anaerobic reaction.
As well as ATP, pyruvic acid is produced, which, when absorbed by mitochondria and in the presence of O2, produces large amounts of ATP and lactic acid.
¯O2, lactic acid.
As lactic acid builds in the muscles, it prevents maintenance of homeostatic conditions, and muscles begin to fatigue. It takes far longer for this acid to be dispersed than it does to create it.
Point of note – alcohol slows down the rate at which lactic acid is resorbed by the body.
Skeletal Muscles
The following list contains the most commonly mentioned muscles. It is by no means exhaustive. In any health/medical profession, the better your anatomy is, the more you can understand and rationalise things. Hence, it is strongly advised that you try to look at as many as possible, using whatever texts most appeal to your style of learning.
The Neck
Sternocleidomastoid Mastoid process of skull to clavicle and sternum Elevates thorax in deep breathing; flexes head; side-bends and rotates head
Scalene (Ant, Med, Post) Lateral aspects of cervical vertebrae, to ribs 1 and 2 Elevate ribs 1 and 2; flexes spine; side-bends neck, with minor rotation
Trapezius Base of skull, and all cervical and thoracic vertebrae, to scapula and clavicle Elevation and rotation of scapulae; side-bending of neck; retraction of scapulae; neck extension
The Back
Erector Spinae Connects the vertebrae, the skull and the sacrum, in many combinations Spinal extension, side-bending and rotation
Quadratus Lumborum 12th rib to top of pelvis, posteriorly, and vertebrae T12 to L4 Thoracic and lumbar extension; lumbar side-bending; helps breathing
Rhomboid Major T2-T5 to medial border of scapula Retraction and elevation of scapula
Rhomboid Minor C7-T1 to medial border of scapula Retraction and elevation of scapula
Latissimus Dorsi Iliac crest, T7-S5 and lower 4 ribs, to bottom of scapula and internal surface of humerus Extension, medial rotation and adduction of shoulder. Helps breathing
The Abdomen
Rectus Abdominus Pubic area of pelvis to ribs 5-7
External Oblique Ribs 5-12 to anterior pelvic crest and linea alba
Internal Oblique Inguinal ligament and iliac crest to ribs 7-12
Transverse Abdominus Thoracolumbar fascia, ribs 7-12 and anterior pelvic crest to Linea alba
Diaphragm Sternum, lower 6 ribs and cartilage, L1-3 to central tendon in apex of muscular dome Main muscle of breathing; aids in blood flow/pumping
The Pelvis
Coccygeus Ischium of pelvis to sacrum and coccyx Flexion of coccyx; supports pelvic viscera
Levator Ani Inner surface of pelvis to coccyx and fibrous raphe in centre of pelvic bowl Sphincter actions; supports pelvic organs; maintains intra-abdominal pressures
The Shoulder
Coracobrachialis Scapula to medial mid-shaft of humerus Flexion of shoulder; adduction of abducted shoulder
Biceps brachii 2 points on the scapula to proximal end of radius Flex shoulder; flex elbow; supinates forearm and hand
Deltoid Lateral clavicle and scapula to lateral mid humerus Abducts, flexes of extends arm, depending on fibres used
Triceps Attaches to scapula, twice to the humerus, and down to the ulna Extension of Elbow; extension of shoulder
The Rotator Cuff Muscles
Teres Major Lower lateral border of scapula to medial upper humerus Extension and medial rotation of shoulder
Teres Minor Lateral border of scapula to medial upper humerus Lateral rotation of shoulder; part of rotator cuff
Supraspinatus Upper scapula to top of humerus Abduction of arm; part of rotator cuff
Infraspinatus Lower scapula to top of humerus Lateral rotation of arm; part of rotator cuff
Subscapularis Anterior surface of scapula to anterior upper humerus Medial rotation of arm; part of rotator cuff
The Elbow
Brachialis Distal anterior humerus to proximal ulnar Flexion of elbow
Supinator Lateral epicondyle of humerus to tip of ulnar and lateral radius Supinates forearm
Pronator Teres Medial epicondyle of humerus to ulnar and lateral radius Pronates forearm; assists elbow flexion
The Hip
Gluteus (Max, Med, Min) Posterior pelvis, pelvic ligaments and sacrum to proximal femur and ITT Extension of hip; abduction of hip; lateral rotation of hip
Rectus Femoris Anterior aspect of pelvis to patella tendon Flexion of hip; extension of knee
Vastus Lateralis Anterolateral aspect of femur to patella tendon
Vastus Medialis Medial posterior line of femur to patella tendon
Vastus Intermedius Lateral posterior line of femur to patella tendon
Biceps Femoris Base of posterior pelvis and mid femur to head of fibula Hip extension; knee flexion; lat. knee rotation
Sartorius Anterior aspect of pelvis to medial upper tibia Flexion of hip; flexion of knee; lat. hip rotation; medial knee rotation
Psoas major L1-5 and discs L1-5, to internal proximal femur Flexion of hip; flexion of spine; side-bending spine
Adductors Medial lower pelvis (various points) to medial femur Adduction of hip; some of these help with flexion of hip
The Knee
Gastrocnemius Lateral and medial femoral condyles to Achilles tendon Plantar flexion of ankle; Knee flexion
The Ankle
Soleus Superior posterior fibula and across tibia, to Achilles tendon Plantar flexion of ankle;
Tibialis Anterior Superior lateral tibia and interosseous membrane to medial cuneiform and base of 1st metatarsal Dorsiflexion of ankle; inversion of foot
Biomechanics of movement
3 structural classifications of joints:
Ø Fibrous – e.g between the bones of the skull
Ø Cartilaginous – e.g the anterior rib joints
Ø Synovial
Here we focus on the synovial joints.
These are typically also diarthroses. That means they are “freely movable joints”
The distinguishing feature of these is the “Synovial Joint Cavity”. Also the presence of articular cartilage.
Types of Synovial Diarthrosis Joints
Type Description Examples
Gliding Articulating surfaces usually flat Intercarpal/tarsal joints
Hinge Convex into concave surfaces Elbow; ankle; Knee
Pivot Rounded or pointed element fits into ring of bone and cartilage Atlas on Axis; proximal radioulnar joint
Condyloid Oval-shaped condyle fits into elliptical cavity Joint between radius and carpals
Saddle Think of a rider in a saddle. Can tilt forward/back, and side to side Joint between trapezium and metacarpal of thumb
Ball-and-socket Ball fits into cuplike depression Hip; shoulder
Skeletal muscles produce movements by exerting forces on tendons, which in turn pull on bones or other structures, such as skin.
We describe the various motions very specifically, so that communication is facilitated between professionals. The following list is the descriptors for the various bodily motions and positions.
Flexion
Extension
Abduction
Adduction
Circumduction
Inversion/Supination
Eversion/Pronation
Dorsiflexion Plantar flexion
Elevation Depression
Retraction Protraction
