Not to be confused with naphtha or naphthene.
|Preferred IUPAC name|
|Systematic IUPAC name|
|Other names |
white tar, camphor tar, tar camphor, naphthalin, naphthaline, antimite, albocarbon, hexalene, mothballs, moth flakes
3D model (JSmol)
|Molar mass||128.17 g·mol−1|
|Appearance||White solid crystals/ flakes|
|Odor||Strong odor of coal tar|
|Density||1.145 g/cm3 (15.5 °C)|
1.0253 g/cm3 (20 °C)
0.9625 g/cm3 (100 °C)
|Melting point||78.2 °C (172.8 °F; 351.3 K)|
80.26 °C (176.47 °F; 353.41 K)
at 760 mmHg
|Boiling point||217.97 °C (424.35 °F; 491.12 K)|
at 760 mmHg
Solubility in water
|19 mg/L (10 °C)|
31.6 mg/L (25 °C)
43.9 mg/L (34.5 °C)
80.9 mg/L (50 °C)
238.1 mg/L (73.4 °C)
|Solubility||Soluble in alcohols, liquid ammonia, carboxylic acids, C6H6, SO2,CCl4, CS2, toluene, aniline|
|Solubility in ethanol||5 g/100 g (0 °C)|
11.3 g/100 g (25 °C)
19.5 g/100 g (40 °C)
179 g/100 g (70 °C)
|Solubility in acetic acid||6.8 g/100 g (6.75 °C)|
13.1 g/100 g (21.5 °C)
31.1 g/100 g (42.5 °C)
111 g/100 g (60 °C)
|Solubility in chloroform||19.5 g/100 g (0 °C)|
35.5 g/100 g (25 °C)
49.5 g/100 g (40 °C)
87.2 g/100 g (70 °C)
|Solubility in hexane||5.5 g/100 g (0 °C)|
17.5 g/100 g (25 °C)
30.8 g/100 g (40 °C)
78.8 g/100 g (70 °C)
|Solubility in butyric acid||13.6 g/100 g (6.75 °C)|
22.1 g/100 g (21.5 °C)
131.6 g/100 g (60 °C)
|Vapor pressure||8.64 Pa (20 °C)|
23.6 Pa (30 °C)
0.93 kPa (80 °C)
2.5 kPa (100 °C)
Magnetic susceptibility (χ)
|Thermal conductivity||98 kPa:|
0.1219 W/m·K (372.22 K)
0.1174 W/m·K (400.22 K)
0.1152 W/m·K (418.37 K)
0.1052 W/m·K (479.72 K)
Refractive index (nD)
|Viscosity||0.964 cP (80 °C)|
0.761 cP (100 °C)
0.217 cP (150 °C)
a = 8.235 Å, b = 6.003 Å, c = 8.658 Å
α = 90°, β = 122.92°, γ = 90°
Std enthalpy of
Gibbs free energy (ΔfG˚)
Std enthalpy of
|Main hazards||Flammable, sensitizer, possible carcinogen. Dust can form explosive mixtures with air|
|GHS signal word||Danger|
GHS hazard statements
|H228, H302, H351, H410|
GHS precautionary statements
|P210, P273, P281, P501|
|Flash point||80 °C (176 °F; 353 K)|
|525 °C (977 °F; 798 K)|
Threshold limit value
|10 ppm (TWA), 15 ppm (STEL)|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|1800 mg/kg (rat, oral)|
490 mg/kg (rat, oral)
1200 mg/kg (guinea pig, oral)
533 mg/kg (mouse, oral)
|US health exposure limits (NIOSH):|
|TWA 10 ppm (50 mg/m3)|
|TWA 10 ppm (50 mg/m3) ST 15 ppm (75 mg/m3)|
IDLH (Immediate danger)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|N verify (what is YN ?)|
Naphthalene is an organic compound with formulaC
8. It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatichydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is best known as the main ingredient of traditional mothballs.
In the early 1820s, two separate reports described a white solid with a pungent odor derived from the distillation of coal tar. In 1821, John Kidd cited these two disclosures and then described many of this substance's properties and the means of its production. He proposed the name naphthaline, as it had been derived from a kind of naphtha (a broad term encompassing any volatile, flammable liquid hydrocarbon mixture, including coal tar). Naphthalene's chemical formula was determined by Michael Faraday in 1826. The structure of two fused benzene rings was proposed by Emil Erlenmeyer in 1866, and confirmed by Carl Gräbe three years later.
Structure and reactivity
A naphthalene molecule can be viewed as the fusion of a pair of benzene rings. (In organic chemistry, rings are fused if they share two or more atoms.) As such, naphthalene is classified as a benzenoid polycyclic aromatic hydrocarbon (PAH). There are two sets of equivalent hydrogen atoms: the alpha positions are numbered 1, 4, 5, and 8 (per diagram in right margin), and the beta positions, 2, 3, 6, and 7.
Unlike benzene, the carbon–carbon bonds in naphthalene are not of the same length. The bonds C1−C2, C3−C4, C5−C6 and C7−C8 are about 1.37 Å (137 pm) in length, whereas the other carbon–carbon bonds are about 1.42 Å (142 pm) long. This difference, established by X-ray diffraction, is consistent with the valence bond model in naphthalene and in particular, with the theorem of cross-conjugation. This theorem would describe naphthalene as an aromatic benzene unit bonded to a diene but not extensively conjugated to it (at least in the ground state). As such, naphthalene possesses several resonance structures.
Two isomers are possible for mono-substituted naphthalenes, corresponding to substitution at an alpha or beta position. Bicyclo[6.2.0]decapentaene is a structural isomer with a fused 4–8 ring system.
Reactions with electrophiles
In electrophilic aromatic substitution reactions, naphthalene reacts more readily than benzene. For example, chlorination and bromination of naphthalene proceeds without a catalyst to give 1-chloronaphthalene and 1-bromonaphthalene, respectively. Likewise, whereas both benzene and naphthalene can be alkylated using Friedel–Crafts reactions, naphthalene can also be easily alkylated by reaction with alkenes or alcohols, using sulfuric or phosphoric acid catalysts.
In terms of regiochemistry, electrophiles attack occurs at the alpha position. The selectivity for alpha over beta substitution can be rationalized in terms of the resonance structures of the intermediate: for the alpha substitution intermediate, seven resonance structures can be drawn, of which four preserve an aromatic ring. For beta substitution, the intermediate has only six resonance structures, and only two of these are aromatic. Sulfonation, however, gives a mixture of the "alpha" product 1-naphthalenesulfonic acid and the "beta" product 2-naphthalenesulfonic acid, with the ratio dependent on reaction conditions. The 1-isomer forms predominantly at 25 °C, and the 2-isomer at 160 °C. Sulfonation to give the 1- and 2-sulfonic acid occurs readily:
4 + C
8 → C
3H + H
Further sulfonation occurs to give di-, tri-, and tetrasulfonic acids.
Analogous to the synthesis of phenyllithium is the conversion of 1-bromonaphthalene to 1-lithionaphthalene, a lithium-halogen exchange:
- C10H7Br + BuLi → C10H7Li + BuBr
The resulting lithionaphthalene undergoes a second lithiation, in contrast to the behavior of phenyllithium. These 1,8-dilithio derivatives are precursors to a host of peri-naphthalene derivatives.
Reduction and oxidation
With alkali metals, naphthalene forms the dark blue-green radical anion salts such as sodium naphthalenide, Na+C10H−
8. The naphthalenide salts are strong reducing agents.
Naphthalene can be hydrogenated under high pressure in the presence of metal catalysts to give 1,2,3,4-tetrahydronaphthalene(C
12), also known as tetralin. Further hydrogenation yields decahydronaphthalene or decalin (C
Oxidation with O
2 in the presence of a vanadiumcatalyst gives phthalic anhydride:
- C10H8 + 4.5 O2 → C6H4(CO)2O + 2 CO2 + 2 H2O
This reaction is the basis of the main use of naphthalene. Oxidation can also be effected using conventional stoichiometric chromate or permanganate reagents.
Most naphthalene is derived from coal tar. From the 1960s until the 1990s, significant amounts of naphthalene were also produced from heavy petroleum fractions during petroleum refining, but today petroleum-derived naphthalene represents only a minor component of naphthalene production.
Naphthalene is the most abundant single component of coal tar. Although the composition of coal tar varies with the coal from which it is produced, typical coal tar is about 10% naphthalene by weight. In industrial practice, distillation of coal tar yields an oil containing about 50% naphthalene, along with twelve other aromatic compounds. This oil, after being washed with aqueous sodium hydroxide to remove acidic components (chiefly various phenols), and with sulfuric acid to remove basic components, undergoes fractional distillation to isolate naphthalene. The crude naphthalene resulting from this process is about 95% naphthalene by weight. The chief impurities are the sulfur-containing aromatic compound benzothiophene (< 2%), indane (0.2%), indene (< 2%), and methylnaphthalene (< 2%). Petroleum-derived naphthalene is usually purer than that derived from coal tar. Where required, crude naphthalene can be further purified by recrystallization from any of a variety of solvents, resulting in 99% naphthalene by weight, referred to as 80 °C (melting point). Approximately 1.3M tons are produced annually.
In North America, the coal tar producers are Koppers Inc., Ruetgers Canada Inc. and Recochem Inc., and the primary petroleum producer is Monument Chemical Inc. In Western Europe the well-known producers are Koppers, Ruetgers, and Deza. In Eastern Europe, naphthalene is produced by a variety of integrated metallurgy complexes (Severstal, Evraz, Mechel, MMK) in Russia, dedicated naphthalene and phenol makers INKOR and Yenakievsky Metallurgy plant in Ukraine, and ArcelorMittal Temirtau in Kazakhstan.
Other sources and occurrences
Aside from coal tar, trace amounts of naphthalene are produced by magnolias and certain species of deer, as well as the Formosan subterranean termite, possibly produced by the termite as a repellant against "ants, poisonous fungi and nematode worms." Some strains of the endophytic fungus Muscodor albus produce naphthalene among a range of volatile organic compounds, while Muscodor vitigenus produces naphthalene almost exclusively.
Naphthalene in the interstellar medium
Naphthalene has been tentatively detected in the interstellar medium in the direction of the star Cernis 52 in the constellation Perseus. More than 20% of the carbon in the universe may be associated with polyaromatic hydrocarbons, including naphthalene.
Protonatedcations of naphthalene (C
9) are the source of part of the spectrum of the Unidentified Infrared Emissions (UIRs). Protonated naphthalene differs from neutral naphthalene (e.g. that used in mothballs) in that it has an additional hydrogen atom. The UIRs from "naphthalene cation" (C
9) have been observed by astronomers. This research has been publicized as "mothballs in space."
Naphthalene is used mainly as a precursor to other chemicals. The single largest use of naphthalene is the industrial production of phthalic anhydride, although more phthalic anhydride is made from o-xylene. Many azo dyes are produced from naphthalene, and so is the insecticide1-naphthyl-N-methylcarbamate (carbaryl). Other useful agrichemicals include naphthoxyacetic acids.
Naphthalenesulfonic acids and sulfonates
Many naphthalenesulfonic acids and sulfonates are useful. Alkyl naphthalene sulfonate are surfactants, The aminonaphthalenesulfonic acids, naphthalenes substituted with amines and sulfonic acids, are intermediates in the preparation of many synthetic dyes. The hydrogenated naphthalenes tetrahydronaphthalene (tetralin) and decahydronaphthalene (decalin) are used as low-volatility solvents. Naphthalene sulfonic acids are also used in the synthesis of 1-naphthol and 2-naphthol, precursors for various dyestuffs, pigments, rubber processing chemicals and other chemicals and pharmaceuticals.
Naphthalene sulfonic acids are used in the manufacture of naphthalene sulfonate polymer plasticizers (dispersants), which are used to produce concrete and plasterboard (wallboard or drywall). They are also used as dispersants in synthetic and natural rubbers, and as tanning agents (syntans) in leather industries, agricultural formulations (dispersants for pesticides), dyes and as a dispersant in lead–acid battery plates.
Naphthalene sulfonate polymers are produced by treating naphthalenesulfonic acid with formaldehyde, followed by neutralization with sodium hydroxide or calcium hydroxide. These products are commercially sold in solution (water) or dry powder form.
Molten naphthalene provides an excellent solubilizing medium for poorly soluble aromatic compounds. In many cases it is more efficient than other high-boiling solvents, such as dichlorobenzene, benzonitrile, nitrobenzene and durene. The reaction of C60 with anthracene is conveniently conducted in refluxing naphthalene to give the 1:1 Diels–Alder adduct. The aromatization of hydroporphyrins has been achieved using a solution of DDQ in naphthalene.
Wetting agent and surfactant
Alkyl naphthalene sulfonates (ANS) are used in many industrial applications as nondetergent wetting agents that effectively disperse colloidal systems in aqueous media. The major commercial applications are in the agricultural chemical industry, which uses ANS for wettable powder and wettable granular (dry-flowable) formulations, and the textile and fabric industry, which utilizes the wetting and defoaming properties of ANS for bleaching and dyeing operations.
As a fumigant
Naphthalene has been used as a household fumigant. It was once the primary ingredient in mothballs, although its use has largely been replaced in favor of alternatives such as 1,4-dichlorobenzene. In a sealed container containing naphthalene pellets, naphthalene vapors build up to levels toxic to both the adult and larval forms of many moths that attack textiles. Other fumigant uses of naphthalene include use in soil as a fumigant pesticide, in attic spaces to repel animals and insects, and in museum storage-drawers and cupboards to protect the contents from attack by insect pests.
Naphthalene is a repellent to opossums.
It is used in pyrotechnic special effects such as the generation of black smoke and simulated explosions. It is used to create artificial pores in the manufacture of high-porosity grinding wheels. In the past, naphthalene was administered orally to kill parasitic worms in livestock. Naphthalene and its alkyl homologs are the major constituents of creosote. Naphthalene is used in engineering to study heat transfer using mass sublimation.
Exposure to large amounts of naphthalene may damage or destroy red blood cells, most commonly in people with the inherited condition known as glucose-6-phosphate dehydrogenase (G6PD) deficiency, which over 400 million people suffer from. Humans, in particular children, have developed the condition known as hemolytic anemia, after ingesting mothballs or deodorant blocks containing naphthalene. Symptoms include fatigue, lack of appetite, restlessness, and pale skin. Exposure to large amounts of naphthalene may cause confusion, nausea, vomiting, diarrhea, blood in the urine, and jaundice (yellow coloration of the skin due to dysfunction of the liver).
When the US National Toxicology Program (NTP) exposed male and female rats and mice to naphthalene vapors on weekdays for two years, male and female rats exhibited evidence of carcinogenesis with increased incidences of adenoma and neuroblastoma of the nose, female mice exhibited some evidence of carcinogenesis based on increased incidences of alveolar and bronchiolaradenomas of the lung, and male mice exhibited no evidence of carcinogenesis.
The International Agency for Research on Cancer (IARC) classifies naphthalene as possibly carcinogenic to humans and animals (Group 2B). The IARC also points out that acute exposure causes cataracts in humans, rats, rabbits, and mice; and that hemolytic anemia (described above) can occur in children and infants after oral or inhalation exposure or after maternal exposure during pregnancy. Under California's Proposition 65, naphthalene is listed as "known to the State to cause cancer". A probable mechanism for the carcinogenic effects of mothballs and some types of air fresheners containing naphthalene has been identified.
US government agencies have set occupational exposure limits to naphthalene exposure. The Occupational Safety and Health Administration has set a permissible exposure limit at 10 ppm (50 mg/m3) over an eight-hour time-weighted average. The National Institute for Occupational Safety and Health has set a recommended exposure limit at 10 ppm (50 mg/m3) over an eight-hour time-weighted average, as well as a short-term exposure limit at 15 ppm (75 mg/m3).
Mothballs and other products containing naphthalene have been banned within the EU since 2008.
In China, the use of naphthalene in mothballs is forbidden. Danger to human health and the common use of natural camphor are cited as reasons for the ban.
The partial list of naphthalene derivatives includes the following compounds:
|Name||Chemical formula||Molar mass [g/mol]||Melting point [°C]||Boiling point [°C]||Density [g/cm3]||Refractive index|
|1-Naphthoyl chloride||C11H7ClO||190.63||16–19||190 (35 Torr)||1.265||1.6552|
|1-Naphthaldehyde||C11H8O||156,18||1–2||160 (15 Torr)|
- ^Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 13, 35, 204, 207, 221–222, 302, 457, 461, 469, 601, 650. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
- ^ abc"Ambient Water Quality Criteria for Naphthalene"(PDF). United States Environmental Protection Agency. Retrieved 2014-06-21.
- ^ abcdefghijklmnLide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0.
- ^ abcAnatolievich, Kiper Ruslan. "naphthalene". chemister.ru. Retrieved 2014-06-21.
- ^ abcdefSeidell, Atherton; Linke, William F. (1919). Solubility of Inorganic and Organic Compounds (2nd ed.). New York: D. Van Nostrand Company. pp. 443–446.
- ^ abNaphthalene in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD), http://webbook.nist.gov (retrieved 2014-05-24)
- ^"Thermal Conductivity of Naphthalene". DDBST GmbH. DDBST GmbH. Retrieved 2014-06-21.
- ^"Dynamic Viscosity of Naphthalene". DDBST GmbH. DDBST GmbH. Retrieved 2014-06-21.
- ^ abcdDouglas, Bodie E.; Ho, Shih-Ming (2007). Structure and Chemistry of Crystalline Solids. New York: Springer Science+Business Media, Inc. p. 288. ISBN 0-387-26147-8.
- ^ abcdefSigma-Aldrich Co., Naphthalene. Retrieved on 2014-06-21.
- ^ abc"NIOSH Pocket Guide to Chemical Hazards #0439". National Institute for Occupational Safety and Health (NIOSH).
- ^"Naphthalene". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
- ^Amoore JE, Hautala E (1983). "Odor as an aid to chemical safety: Odor thresholds compared with threshold limit values and volatiles for 214 industrial chemicals in air and water dilution". J Appl Toxicology. 3 (6): 272–290. doi:10.1002/jat.2550030603.
- ^John Kidd (1821). "Observations on Naphthalene, a peculiar substance resembling a concrete essential oil, which is produced during the decomposition of coal tar, by exposure to a red heat". Philosophical Transactions. 111
Transcript of Assignment 1: Structure and Function of the Skeletal System
Principles of Anatomy and Physiology:
1.1 Structure of the Skeletal System
P1: To describe the structure and function of the skeletal system
To know all three classifications of joint and the movement available at each
P2: To describe the different classifications of joints
P1: Structure of the skeletal system
The skeletal system is made up of:
The function of the skeletal system is to provide:
Joints are also important, giving you the freedom to flex or rotate parts of your body. However this gets harder with age, as your bones lose their strength and density.
The human body is made up of 206 bones, which are divided into two groups: 80 form your axial skelton; the other 126 form your appendicular skelton.
P1: Bones of the Human Skeleton
Label the bones of the human skeleton.
P1: Axial Skeleton
The axial skeleton forms the main axis or core of your skeletal system, it is made up of 80 bones and consists of the:
Skull (cranium andd facial bones)
Thorax (sternum and ribs)
Task: colour in the axial section of the skeleton
Task: Label the axial skeleton
P1: Appendicular Skeleton
The appendicular skeleton consists of the shoulder and the pelvic girdle
The shoulder girdle consists of four bones which connect the limbs of the upper body to the thorax
The upper limbs consist of 60 bones. Each upper limb is made up of:
P1: Appendicular Skeleton
The pelvic girdles main function is to provide a solid base through which to transmit the weight of the upper body and protect the digestive and reproductive organs. The pelvic girdle consists of three bones:
The lower limbs consist of 60 bones. Each lower limb is made up of:
The principle function of the pelvic girdle is to provide a solid base through which to transmit the weight of the upper body. It also provides attachment for muscles of the lower back and legs, and protects the digestive and reproductive organs.
P1: Appendicular Skeleton
P1: Types of major bone
Task: Watch the following video and answer the questions
P1: Types of major bone
Bones vary in shape and size according to their location and function. They are classified as follows:
• Long bones
• Short bones
• Flat bones
• Sesamoid bones
• Irregular bones
are found in the limbs such as the femur, tibia, and fibula. They have a shaft known as the diaphysis and two expanded ends known as the epiphysis.
are small, light, strong, cubed shaped bones. The carpals and tarsals are of the wrists and ankles are examples of short bones.
P1: Types of major bone
have a specialised function. They are usually found within a tendon such as the patella in the knee.
have complex shapes that for none of the above categories. The bones of the spine are a good example.
are thin, flattened and slightly curved, and have a large surface area, examples include the scapula, sternum, and cranium.
Write the following term into your workbooks:
Anterior: To the front or in front
Posterior: To the rear of behind
Medial: Towards the midline
Lateral: Away from the midline
Proximal: Near to the root or orgian
Distal: Away from the root or orgian
P1: Vertebral Column
The vertebrae column has many functions. It protects the spinal cord and supports the ribcage. The larger vertebrae of the lumbar region support a large amount of body weight. The flatter thoracic vertebrae offer attachment for the large muscles of the back and the curves of the spine – four in all. These, along with the intevertebral discs, receive and distribute impact associated with the dynamic functioning of the body in action, reducing shock.
The vertebrae can be classified as:
Cervical vertebrae (in the neck)
Thoracic vertebrae (in the chest region)
Lumbar vertebrae (in the small of the back)
Sacral vertebrae (fused vertebrae that form the sacrum)
Coccygeal vertebrae (fuses vertebrae that form the coccyx)
Label the vertebrae column:
Using the image in your books label the anatomical positions.
Principles of Anatomy and Physiology:
1.2 Function of the skeletal system
To know the function of the skeletal system
Support: Your bones give your body shape and provide a frame work for the soft tissues of your body.
Protection: Your skeleton protects vital tissues and organs in your body e.g. cranium (brain),rib cage (lungs), vertebrae (spinal column) .
Movement: Parts of your skeleton provide a surface for your skeletal muscles to attach to, allowing you to move. Muscles pulling on bones act as leavers and movement occurs at joints so you can walk, run, jump etc.
Blood cell production: Blood vessels feed the centre of your bones and stored within them is bone marrow. Blood cell production in prevalent in long bones e.g. femur, fibula and tibula.
Store minerals: None is a reservoir for minerals such as calcium and phosphorus, essential for bone growth and the maintenance of bone health.
P2: Joint Classification
A joint is formed where two or more bones meet. The function of a joint is to hold bones together and allow movement.
There are three classifications of joints:
Fixed / immovable (fibrous)
Slightly movable (cartilaginous)
Freely moveable (synovial)
Are also known as fibrous or immovable joints, they do not move. They interlock and overlap and are held together by bands of tough fibrous tissue e.g. the plates in your cranium.
These joints allow slight movement. The ends of the bone are covered in articular or hyaline cartilage that reduces friction. Slight movement at these articulating surfaces is made possible because the pads of cartilage compress e.g. between most vertebrae.
P2: Joint Classification
P1: Vertebrae Column
Cervical: the vertebrae of the neck. The first two are known as atlas (C1) and axis (C2). They form a pivot that allows the head and neck to move freely. There are 7 vertebrae in this area (C1-C7)
Thoracic: the vertebrae of the mid spine, which articulate with the ribs. The thoracic section has12 vertebrae (T1-T12).
Lumbar: the largest of the moveable vertebrae, situated in the lower back. They support more weight than other vertebrae and provide attachment for many of the muscle in the lower back. The lumber has 5 vertebrae (L1-L5).
Sacrum: Five sacral vertebrae are fused to form the sacrum, a triangular bone located below the lumber vertebrae. It forms the back wall of the pelvic girdle, sitting between tow hip bones.
Coccyx: at the bottom of the vertebral column there are four coccygeal vertebrae, which are fused to form the coccyx or tail bone.
Synovial joints / freely moveable
joints offer the highest level of mobility at a joint. These joints make up most of the joints of your limbs. They are surrounded by a
, lined with a
When movement occurs the synovial membrane secretes a fluid known as
into the joint cavity to lubricate and nourish the joint. The synovial fluid acts like a buffer between articulating bones to prevent injury. The
is held together by though bands of connective tissue known as
. This provides the strength to avoid dislocation, while being flexible enough to allow movement.
The characteristics of a synovial joint are:
An outer sleeve or joint capsule to help to hold the bones in place and protect the joint
A synovial membrane, secreting synovial fluid to lubricate the joint
A joint cavity - the cap between the articulating bones
Articular cartilage on the ends of the bones to provide a smooth and slippery covering to stop the bones knocking or grinding together
Ligaments to hold the bones together
P2: Types of Synovial Joints
Hinge - Allows movement in one direction e.g. flexion/extension at the knee/elbow joint - kicking a football.
Ball and socket - The round end of one bone fits into a cup shaped socket in the other bone, allowing movement in all directions e.g. Flexion/Extension/Adduction/Abduction/Internal & External Rotation at the hip and shoulder joint - front crawl
Condyloid/Ellipsoid - Movement is backwards and forwards and from side to side e.g. Flexion/Extension/Adduction/ Abduction/Circumduction at the wrist joint (intercarple) - dribbling in basketball
P2: Types of Synovial Joints
Gliding - These joints allow movement over a flat surface in all directions, but this is restricted by ligaments e.g. carpels and tarsals - dribbling the ball in hockey by moving the hockey stick over and back.
Pivot - A ring of one bone fits over a peg of another, allowing controlled rotational movement, such as the joint of the atlas and axis in the neck e.g bilateral breathing in swimming
Saddle - Movement occurs backwards and forwards and from side to side, like that at the base of the thumb e.g. flexion/Extension/Adduction/Abduction/Circumduction e.g. holding a tennis racket or golf club.
P2: Types of movement
reducing the angle at the joint e.g. bicep curl
increasing the angle at a join e.g. straightening your arm to return to your starting position of the bicep curl
movement away from the midline of the body e.g. side step in gymnastics
: movement towards the midline of the body e.g. pulling the oars whilst rowing
circular movement of the limb e.g. occurs at the shoulder joint during a serve in tennis
an inward rotation of the forearms so the palm of the wrist is facing backwards and downwards e.g. table tennis forehand top spin
an outward rotation of the forearm so that the palm of the hand is facing forwards and upwards e.g. table tennis backhand top spin
points the toes downwards by straightening the ankle e.g. jumping in gymnastics
an upward movement, as in moving the foot to pull the toes towards the knee when walking
involves movement beyond the normal anatomical position in a direction opposite to flexion. This occurs at the spine when a cricketer arches their back when approaching the crease to bowl.
when we start to exercise the movements of our joints means that synovial fluid starts to secrete within the joints. The fluid becomes less viscous and therefore the range of movement within the joint increases. An example of this in sport is the need for a warm up for a butterfly swimmer. So they can get the full range of movement at the shoulder joint that area must be warmed up prior to the race.
To know the structure and function of the skeletal system
To describe the axial and appendicular skeleton
To learn the location and names of all major bones
To know all three classifications of joints and the movement available at each
Label the bones of the human skeleton.
Task: colour in the appendicular section of this skeleton
Q: Name the five types of bones and provide two examples for each
P2: Joint Classification