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Locomotion and Movement, , , , , , The study of bone structure and treatment of bone disorders is, called osteology, The specialized branch of medicine that deals, with preservation and restoration of skeletal system, joints is called, orthopedics. Bones are made up of a protein called ossein and, cartilage are made of a protein called chondrin, Hence study of, bones is called osteology and study of cartilage is called, chondrology. Body of animals (vertebrates) is supported by, ‘skeleton., , , , Skeleton, , She letone a, , ‘The hardened tissues of the body together form the skeleton, (sclero = hard). Skeleton of invertebrates is most often secreted on, the surface, forming a lifeless or dead exoskeleton. Whereas, skeleton of vertebrates develops most often underneath the surface, forming a living or growing endoskeleton. Three types of skeletons, develop in vertebrates, , (1) EpidermaV/Horny exoskeleton : These include hard, and homy keratinized derivatives of epidermal layer of skin, such, as claws, most reptilian’s scales, bird feathers and mammalian, hairs, homs, nails and hoofs, ete. All living amphibians lack an, exoskeleton., , (2) DermalBony skeleton : Dermal bony skeleton is, derived from the dermis of skin. It includes bony scales and plates, or scutes (osteoderms}, finrays and antlers of fishes, some reptiles, (crocodiles, turtles and tortoises) and mammals. In fishes, dermal, scales become exposed due to wearing out of epidermis, and form, exoskeleton., , (3) Endoskeleton : Greater part of vertebrate skeleton lies, more deeply, forming the endoskeleton, It develops from, mesenchyme. Endoskeleton is formed by bones in vertebrates. Skeleton, in diferent animals are as follows ~, , Invertebrate —, , (i) Protozoa —No skeleton., , (i) Porifera ~ Caleareous spicules + slicious spicules + spongin, fibre in mesenchyme., Spicules in porifera represent endoskeleton., {ii) Coelenterata ~ Calcareous (corals) and chitinous (perisarc)., (iv) Helminth — No skeleton, cuticle? present., (v) Annelida - No skeleton, cuticle present., , In earthworm and ascaris hydrostatic skeleton is found that is,, fluid is filled in coelom and form turgid skeleton., , (vi) Arthropoda — Dead chitinous exoskeleton, shed at, intervals, called ecdysis or moulting. Cuticle made up of non, chitinous outer epicuticle and chitinous, inner endocuticle., , , , (vil) Mollusca - Caleareous shell, may be extemal or internal, or absent,, , (ili) Echinodermata - Dermal calcareous plates are present., , (ix) Hemichordates - Endoskeleton in form of proboscis, skeleton, pygochord., , In vertebrates exoskeleton may be epidermal or dermal., , Vertebrates : In vertebrates dermal skeleton is formed by, bones. Bone is the connective tissue with intercellular spaces filled, with ossein matrix composed of 25% water, 25% protein fibers,, 150% mineral salts. The inner most region is full of bone marrow, having various types of cells. In mammals the bone is full of, haversian canals. The bones are of following types ~, , (i) Cartilage bones : The bones which are formed by the, ossification of preexisting carlilage are called cartilage bones or, replacing bones. e.g,, vertebra, Girdles, limb bones, basioccipital,, supraoctipital, sphenoid, Incus, malleus, stapes., , (i) Membrane or dermal bones ; The bones which are, formed by independent ossification in connective tissue are called, dermal, membrane or investing bones. e.g., Ribs, sternum, clavicle, Nasal, vomer, palatine, maxilla., , i) Sesamoid bones : Ossification takes place on ligament, e.g, cotyloid bone of Rabbit and tendons e.g., Patella, Pisiform.

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Locomotion and Movement 915, , , , , , (iv) Pneumatic bones : Bones with hollow spaces, containing air e.g, bones of bird, frontal, sphenoid, ethmoid,, ‘maxilla of human., , (v) regular bones : Vertebrae are irreqular bone., , Flat bones : Cranial bone, scapula, Ribs,, , (vii) Short bones : Carpals and tarsals., , Functions of endoskeleton : Chief function of vertebrate, endoskeleton can be enumerated as follows, , {i) To provide physical support to body by forming a firm and, rigid internal framework,, , (ii) To give definite body shape and form,, , (itl) To protect delicate intemal organs like brain, heart, lungs etc., , , , , , iv} To permit growth of huge body size (whale, elephant,, extinct dinosaurs), since itis living and growing,, , (¥) To provide surface for attachment of muscles,, , (vi) To serve as levers on which muscles can act., , (vii) To manufacture blood corpuscles in bone marrow., , (viii) To help in breathing (tracheal rings, ribs), , Endoskeleton of vertebrates, , (1) Axial endoskeleton : (Skull + Vertebral column +, ‘Sternum + Ribs), , (2) Appendicular endoskeleton : (Girdle + Limb bones), , SKELETON, , Axial skeleton, , , , , , , Sey, , ‘Appendicular skeleton, , , , ‘Skull Vertebral column ‘Sternum and Ribs Girdles Limb bones, 1. Cranten 1. Corea rein 1. Pectoral |, 2. Facial region 2. Thoracic region 2. Pelvic, Opi cops 3. Lintin gos Bones of forelimb Bones of hind limb, 4; Auditor capsule A Bacal ean 1. Upper arm 1. Thigh bone, 5, Olfactory capsule 5. Caudal region (2. Fore arm 2, Shank bone, 6, Visceral part 3. Wrist bones 3. Ankle bone, 4, Palm bones 4. Foot bones:, 5. Phalanges 5, Phalanges, Sleull and tall if present, sternum and ribs in the thorax. It form the, \gje)) Sita postion upright axis of body and includes 80 (87 in children) bones as, Rei#!— Facial portion f, y Pectoral (Shoulder) Girdle ‘Hows in man, Glaviele Cranium -8 Hyoid—1, Thorax Face - 14 Vertebrae — 26, Sern 28 Shull sfikdien 83), * Upper limb (Extremity) ene, Vertebral column, Humerus: Ear ossicle~6 Stemum ~1, Pele (Hi) ge A\_uine kee, f IN Basra Skull (General structure) : It is the anterior most axial, , , , Lower limb (Extremity), Femur, , Phalanges, Fig: 5.5-1 Divisions of skeletal system, , Axial skeleton (Human), It occupies the body's main longitudinal axis. It includes four, structure ; skull in the head, vertebral column in the neck, trunk, , , , skeleton. Itis divisible into two main parts —, , {i) Chondrocranium (i) Splanchnocranium, , (i) Chondrocranium : Chondrocranium is formed by (a), brain box or cranium proper and (b) two sense capsules ~ Orbit or, optic capsule (eye) and auditory or otic capsule (ea)., , (2) Cranium proper : Itis a strong and firm bony box with a, helmetilike covering over the brain, called vault of skull, and a, relatively thicker and stronger floor of base upon which the brain, rests. Its cavity is called cranial cavity, Ske of cranial cavity, averages 1475 cubic centimetres (em?) in adult men. At about the, middle of the floor of cranium, there is a large opening of cranial, cavity called foramen magnum. The brain is connected to. spinal, cord at this foramen, Cranium proper of mammal has following, , inct zones ~

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916 Locomotion and Movement, , , , , , Occipital zone : Occipital zone has one supra-occipital, ‘bone on dorsal side, one basioccipital on ventral side and two, exoccipital on both lateral side of foramen magnum. Foramen, ‘magnum is present in ventral side of skull, which fits on Ist alas, vertebra. Two occipital condyles forming dicondylic skull at the, junction of supra and exo-occipital, , Parietal zone : In the dorsal side of cranium parietal, zone has three bone, that is two parietal, one inter parietal and, ‘ventral side of cranium has 3 bone ie. one basisphenoid with pituitary, foramen and two alisphenaid bone., , Frontal : Frontal part of cranium has two frontal bone in, dorsal side, each frontal bone has one process called supra orbital, process of frontal. Two orbitosphencid, one presphenoid bone in, ventral side., , CQ Ethmoidal : Ethmoidal part has one circular plate called, cribriformplate. That plate is having two perforation for exit of |, cranial nerve., , (b) Sense capsule : Chondrocranium contains two sense, capsule, , 1 Optic or orbital capsule, , Otic or auditory capsule, , Optic capsule : One pair of optic or orbital capsule is, present in frontal zone of chondrocranium. It is made up of 7 pairs, cof bones which are ~, , I~ Pre frontal Il - Post frontal Ill — Anterior orbital, , IV — Posterior orbital V ~ Infra orbital VI - Supra orbital, , Vil - Lacrimal, , In frog optic capsules are absent but in place of optic capsule, eye-orbit are present in same position, In between two eye capsule,, a separating bone is present in mammals only, This separating, bone is called inter-orbital septum. This septum is absent in frog, between two eve orbits, , Auditory or Otic capsule : Auditory capsule is located, between occipital and parietal zone, It has two parts ~ Tympanic, bulla and Extemal auditory meatus. Auditory capsule in vertebrates is, formed by 5 pairs of atc bones., , (I) Prectic (If) Epiotic (Ill) Opisthotic (IV) Sphaenotic, , (V) Prerotic, , Out of these 5 pairs only I pair Le. preotic participate in, formation of auditory capsule of frog ie. amphibian. In mammals, eg, rabbit |, Il & Il pair fuse to form a fusion bone called periotic,, which forms the auditory capsule. In reptiles and birds (aves) all 5, pairs bone together constitute auditory capsule. Membranous, labyrinth is enclosed in the preotic and tympanic bulla. Auditory, capsule has two distinct part - Outer spongy part called petrous, part and inner bony part called mastoid part., , (i) Splanchnoeranium : It is also known as facial. It, includes following parts —, , , , (2 Visceral skeleton : Visceral skeleton is formed by pairs, of visceral arches which are —, , Mandibular arch (I pair of visceral arch) : Its made of, two arches one is upper forming upper jaw and second is lower, called lower jaw. In tadpole stage upper jaw ie. upper part of, mandibular arch is formed by the fusion of three cartilage called, , palatine, pterygoid and quadrate. These all fused to form palatopterygoquadrate., , Lower jaw or Il part of mandibular arch is cartilagenous, initially and is called Meckel's cartilage which soon changes into, bony structure., , The mandibular arch, Palato-pteryge-quadrate Meckels cartilage, ‘oar forming, , (forming lower jaw), , Suspensorium Upper jaw, , Quadrate, (Autostylic suspensorium, in amphibia, reptiles and, , birds), , ywarnosal, (Craniostylic, suspensorium, in mammals), , Premaxilla Maxilla Palatine Pterygoid Jugal, , ‘Angular Articular Dentary —Splenial Supra angular Coronary, , (a) Upper jaw : The upper jaw is made of 14 bones i.e. 7, pairs of bones which are - Premaxilla, Maxilla, Jugal, Squamosal,, Prerygoid, Palatine, Quadrate, , Out of these 7 pairs of bones only quadrate are not visible, because they constitute Il ear ossicle i.e. ~ incus. In man the nasal, cavity is separated from the buccal cavity by bone called palatine, complex. Palate of birds is identical in animal kingdom, which is, used for birds classification., , Process of upper jaw, , Premaxilla : Nasal process on dorsal side which are covered, by Nasal; Palatine process of premaxilla., , Maxilla : Nasal process of maxilla; Palatine process of, maxilla; Zygomatic process of maxilla., , Squamosal : Only zygomatic process of squamosal., , (b) Lower jaw : It is composed of 6 pairs of bone ie. 12, bones maximum, These are articular, angular, splenial, dentary,, coronoid and supra angular., , In frog out of 6 pairs only 4 pairs of bones are present. Only 3, pairs form lower jaw and one pair forms I ear ossicle ie, collumella, auris. Remaining 3 pairs ie. Angular, splenial and dentary combine, to form lower jaw of frog. In mammals only one pair of bones are, present of which only one pair Le. dentary forms lower jaw., , Upper jaw in vertebrates is completely ossified with sleull but, lower jaw is always free from chondrocranium and hangs, downwardly. A bone hangs lower jaw from upper jaw. This bone is, called suspensorium. A skull in which suspensorium is formed by, quadrate is called autostylic skull e.g., frog skull, A skull in which, suspensorium is formed by squamosal is called craniostylic skull, g,, rabbit skull (all mammal),, , Hyold arch (If pair of visceral arch) : It is also one pair, which is called Hyoid proper and Hyomandibular.

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r cc, , (a) Hyoid proper : It is a, hhorse-shoe shaped bone in our, neck between lower jaw and, sound box or larynx. It is not, articulate to any bone but is, simply suspended from temporal, bones by means of ligament. It, consists of an elliptical main part, or body and two processes on, each side of body, called greater, and lesser comua. It supports our tongue and provides insertion to, some tongue muscles, In colloboration with branchial arches forms, hhyoid apparatus in terrestial vertebrates, It is absent in fishes, because branchial arches form gill rackers which support ails., , (b) Hyomandibular ; It is second part of hyoid arch which, constitutes ear ossicles in vertebrate. In frog hyomandibular forms, stapidial plate which is Hear ossicle which is dot or lid like bone. In, rabbit hyomandibular forms stapes which is Ill ear ossicle. That Is, , , , Fig. 5.5-2 : Human hyoid bone, viewed from above, , , , , , , , , , , , , , stirrup like bone,, Table : 5.5-1 Ear ossicles, 1 ut, Malleus Tneus Stapes, Articular Quadrate Hyomandibular, Hammer | Anvil Stirrup, , , , , , Branchial arches (III to VII pair of Visceral arches) :, ‘These are five pairs, which constitute Ill to VII pair of visceral, arches. These constitute gill racker in fishes but terrestrial animals, then form hyold apparatus in collaboration with hyoid proper. Five, airs of branchial arches are as follows, , (a) Il pair ceratohyle. (b) IV pair ie. is epihyal,, , {c) V pair ie. is stylohyal. (d) VI pair i.e. tympanohyal,, , (e) VII pair ie. thyrohyal., , Slaull of man, , In man however the skull remain erect at top of vertebral, column because of perfectly erect posture of body it is divisible into, the large and hollow cranium and the facial region together, protects and support some useful organ for vision, taste, smell,, hearing and equilibrium., , (1) Cranium (Brain case) : Cranium stabilize the position of, brain, In skull of man all eight bones are articulated with each other, to form the cranium as follows —, , Vault of skull, , , , , , , , ‘Malae (zygomatic), ‘Coronoid, , Condvie, Fig: 5.5.3 Human skull viewed from right side, , Locomotion and Movement 917, , , , , , Table : 5.5-2 Bones of cranium, , , , Name, , Ne., , Description, , , , Forms the forehead anterior or fiont, part of the top of cranium) and some, Upper parts (roofs) of eye orbits or, sockets and nasal cavities. A newbom, Infant displays a faint suture in midline, of frontal, indicating that adult frontal is, ‘actually formed of two completely fused, frontal. Frontal suture between two, frontal disappear by age 6 years. If, persists throughout life refered as, metopic sutures, , , , Ariiculated to and situated just behind, frontal. Form the main parts of bulging, top and sides of cranium., , , , Articulated to and situated just behind, Parietals. Forms posterior (back) and, lower (base) parts of cranium, Foramen, ‘magnum is a large perforation in this, bone, On each side of the foramen, the, occipital bears a prominent elevation, called occipital condyle. The condyles, articulate the skull with first vertebra, (atlas). Thus, human skull is dicondylic, , , , Temporals, , Form lower parts of right and left sides, of cranium, as well as, the floor of, ‘cranial cavity, These house structures of, internal and middle ears and form a, part of extemal auditory meatus. The, middle ear of each side encloses the, three small ear ossicles ~ malleus, incus, ‘and stapes. The mastoid process with, ‘mastoid air cells in adult., , , , Sphenoid, , A typically butterfly.shaped bone that, forms the middle and anterior parts of, base of cranium in front of eceipltal in, the middle and temporals on the sides., Ht articulates with all skull bones,, keeping these firmly together. It also, forms parts of lateral walls and floors of, eve orbits. Sphenoid with sella tureiea, depression for pituitary body., , , , , , Ethmoid, , , , , , ‘A small, imegular bone in front of, sphenoid and behind nasal bones, It, fashions the front (ante, ‘and loser of cranial cavity, contributes to the architecture of eye, orbits and proximal paris of nasal, chambers,, , , , 1) extremity, , 1 also

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918 Locomotion and Movement, , , , (2) The facial region : This is the front or anterior part of, ‘our skull comprising of 14 bones as follows :, , Table : 5.5-3 Facial bones, , Vertebral column, , It is our backbone which extends in the mid axis of the back, (posterior) part of our trunk from head to the lower (inferior), , , , , , , , , , , , , , , , , , , , , , , , , , , , Name | No. Description, ‘Small, along bones in middle of upper part, Nas 2 | of face, forming proximal part ofthe bridge, ‘of our nose. The remaining, lower part of, our nose is formed of cartilage, Two highly coiled, scrolike processes of, ethmoid bone, called conchae project into, each nasal cavity from lateral wall of the, Inferior nasal proximal bony part of concerned nasal, rch 2 | chamber. One ethmoidal concha is superior, {Turbinates) (uppermost). The other one is called middle, concha, because it is followed by a thin,, separaie scrolllike bone which Is named, inferior nasal concha or turbinate, ‘A thin, elongated, platelike bone, forming a, Vorer 1 | part of the septum which separates the two, nasal cavities,, Small and thin, finger shaped bones, each, located in front part of the medial (inner), Lacrimals 2. | side of comesponding eye orbit these form, fa part of the passages of comesponding tear, ucts,, ee ‘Cheelcbones, form the prominences of our, ae 2 | checks and parts of the floor and side walls, of eye orbits,, Lhaped bones that form the back, de | (Posterior) part of our hard palate (roof of, et mouth), Also contribute tothe framework of, nagal cavities and floor of eye orbits., Large, upper jaw bones that form the major, part of our face and upper jaw. Comprise, entire front (anterior) part of our hard, Mesiles 2 | palate Also contribute tothe architecture of, eye orbits and nose. Bear the teeth of upper, jaw., Largest bone of our face, and strongest of, all bones of the body. Forms entire lower, Mandible 1 | jaw and bears all lower jaw teeth., Articulated with temporal bones of skull., ‘Only skull bone that moves., Frontal bone, Parietal bone q, Sphenoid bone _| ‘Temporal bone, Ethmoid bons" ’ an, Lacrimal bone | Zygemaic bone, Manilla “79°, Perpendicular plate >." ae, Inferior nasal, concha Veer \ Manlibte, , , , Fig : 5.5-4 Human sleull viewed from the front, , extremity of trunk. Vertebral column of vertebrates is a, modification of notochord. Together with the stemum and rib, it, forms the supporting frame work of our trunk. It supports and, rotate the head, suspends the viscera, protect vital organs, provides, attachment to limb girdles, facilitates some movement of the trunk, and houses the spinal cord. Vertebral column make two-fifth of, total weight of body. The lenath of human vertebral column is 71, cm, (28 Inc.) in adult male and about. 61 cm (24 inches) in an, average adult female., , Curvatures of vertebral column : In a foetus, there is only, a single anteriorly concave curve, in adult there are 4 curves like,, cervical, thoracic, lumbar, and sacral. Cervical and lumbar are, anteriorly convex, while thoracic and sacral are anteriorly concave., ‘At approximately 3% month after birth, when an infant begins to, hold its head erect, cervical curves develops. Later, when the child, sits up, stands, and walks, the lumbar curves develops. The, thoracic and sacral curves retains anterior concavity of foetus thus, are called ‘Primary curves’ . The cervical and lumbar curves are, modification of the original foetal curves, and are called as, “Secondary curves”., , , , Posterior Anterior, , , , ~ Conical curve (formed, bby 7 cervical vertebrae), , Thoracic curve (formed by, 12 thoracie vertebrae), , Intervertebral dise, , sai, , Lumbar curve (formed, , Scum 44, ¢ Sacral curve (formed, Coccyx ‘by sacrum), , Fig : 5.5-5 Right lateral view showing four normal curves, The curves of vertebral column are important because they, increases its strength, help to maintain balance in upright position, absorb shock during walking and running and help to protect the, column from fracture. Certain abnormalities of curvature are, , (i) Kyphosis : Exaggeration of thoracic curve, resulting in, “round-shouldered” appearance, also called hunch back., , {ii) Lordosis : An exaggeration of lumbar curve, also called, sway back., , (iii) Scoliosis : An abnormal lateral curvature in any region, of spine., , The vestigeal notochord called nucleus pulposus is found in, intervertebral disc, Inter-vertebral disc is fibro cartilagenous disc, present between centrum of vertebrae., , Structure of Typical vertebrae, , (1) Neural arch : It arises from the dorsal side of the centrum, and encloses a neural canal for the spinal cord. The arch may be, produced into a dorsal process, the neural spine, which may be, elongated pointed or flattened and directed upwards or backwards