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Post-Cranial Skeleton  Axial skeleton = vertebrae, sternum, & ribs; endochondral bone.  Appendicular Skeleton Pectoral skeleton supports pectoral appendages.

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Presentation on theme: "Post-Cranial Skeleton  Axial skeleton = vertebrae, sternum, & ribs; endochondral bone.  Appendicular Skeleton Pectoral skeleton supports pectoral appendages."— Presentation transcript:

1 Post-Cranial Skeleton  Axial skeleton = vertebrae, sternum, & ribs; endochondral bone.  Appendicular Skeleton Pectoral skeleton supports pectoral appendages (arms); dermal and endochondral bone. Pelvic skeleton supports pelvic appendages (legs); endochondral bone.

2 Human Vertebra body (centrum) spinous process (neural spine) superior articular process inferior articular process transverse process neural arch facet for head of rib facet for tubercle of rib

3  Intervertebral discs between (annulus and nucleus)  Cervical Vertebrae – 7; #1 = atlas, #2 = axis; forked neural spine on #2-#7  Thoracic Vertebrae – 12 (ribs articulate)  Lumbar Vertebrae – 5 (no ribs)  Sacral Vertebrae – 5; fusion begins at and usually completed at 25  Coccygeal Vertebrae – 3-5; may become fused (= caudal vertebrae) Human Vertebrae

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5 Intervertebral Disc Problems

6 Atlas, Axis, & Other Cervical Vertebrae transverse foramen (vertebral artery)

7 Thoracic Vert. Articulate w/ Ribs costal cartilage

8  Ribs – 12; on thoracic vertebrae  True Ribs – 7; contact sternum directly  False Ribs – 5; don’t contact sternum directly “False” / Vertebrochondral Ribs – 3; fuse to a single costal cartilage element Floating Ribs – 2; don’t contact sternum  Sternum – segments fuse to form 3 bones; manubrium, body, xiphoid process (x.p. doesn’t articulate with ribs) Human Ribs & Sternum

9 Human Ribs

10 Human Sacral/Coccygeal Vert. sacrum coccyx

11 Vertebral Development  Sclerotome = forms vertebral elements  Myotome = forms muscle Both separated into segments when the somites form.  Vertical myosepta exist between segments of myotome (derived from the somite).  The myotome is also divided by a horizontal septum.  Neural & hemal arches are centered on the vertical myosepta.

12 Vertebral Development

13 Vertebrate Neurula (section) notochord somite inter- mediate meso- derm lateral plate mesoderm gut

14 Vertebrate Embryo (section) neural crest cells dermatome sclerotome myotome splanchnic mesoderm somatic mesoderm gut inter- mediate meso- derm lateral plate mesoderm

15 Vertebrate Embryo (section) gut inter- mediate meso- derm lateral plate mesoderm neural crest cells dermatome sclerotome myotome splanchnic mesoderm somatic mesoderm

16 Vertebrate Embryo (section) gut coelom pigment cell precursors (neural crest) ganglionic neuron precursors (neural crest) dermatome sclerotome myotome dorsal & ventral mesenteries (splanchnic mesoderm) lateral plate mesoderm

17 Vertebrate Embryo (section) gut dermatome vertebra myotome horizontal septum dorsal & ventral mesenteries (splanchnic mesoderm) coelom lateral plate mesoderm

18 Vertebrate Embryo (section) gut dermatome vertebra myotome horizontal septum dorsal mesentery (splanchnic mesoderm) coelom lateral plate mesoderm

19 Fish Section

20 Comparative Vertebra Structure  Hagfishes lack vertebral structures.  Neural arches dorsal to notochord surrounds dorsal nerve cord.  Neural spines project above neural arch  Hemal arches ventral to notochord around blood vessels in “tail”  Hemal spines project below hemal arch notochord

21 Vertebral Centra  Centrum = solid bone or cartilage vertebral “segment;” “replaces” part of notochord  Intervertebral pads = separate centra; derived, in part, from the notochord  Centra evolved at least three times in vertebrates (Chondrichthys, Tetrapoda, & Amia + Teleosts)

22 Non-tetrapod vertebrates  Trunk (Thoracic, Abdominal) vertebrae = anterior; often bear ribs, lack hemal arches  Caudal vertebrae = posterior; rarely bear ribs, have hemal arches Tetrapods  Have Ant. & Post. Articulatory Processes  Cervical vertebrae = neck vertebrae  Thoracic vertebrae = have ribs  (Lumbar vertebrae = lack ribs)  Sacral vertebrae = attached to pelvic girdle Vertebral Regionalization

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24  Synsacral vertebrae = vertebrae attached to pelvic girdle (homologs of sacral, lumbar, some thoracic and some caudal vertebrae) Bird Vertebral Regionalization

25  Atlas = first cervical vertebra in tetrapods; reduced centrum, large neural canal  Axis = second cervical vertebra in amniotes (Lissamphibians have only 1 cervical vertebra, an atlas.); odontoid process (dens) for rotation of atlas, large neural canal  Atlas/Occipital Condyle joint = tilting  Atlas/Axis joint = rotation Cervical: Atlas & Axis

26 Vertebral Regionalization GroupTrunk Vertebrae “fish”: hagfishes, lampreys, chondrichthyans, lungfish, actinopterygiians, many trunk (number greatly variable) amphibians 1 cervical, few to many trunk, 1 sacral mammals 7 cervical, trunk (9-20 thoracic & 4-7 lumbar), 3-5 sacral, turtles, lizards & snakes, & crocodilians 7-9 cervical, few to many trunk (especially many in snakes), 2 sacral (0 in snakes) birds cervical, 3-10 trunk, synsacral  Caudal (“Tail”) Vertebrae vary greatly in number, even within groups.

27 Subphylum Vertebrata hagfishes lampreys Chondrichthys Actinopterygii coelacanths lungfishes amphibians Mammalia Reptilia centra R S G AT centra axis, >1 sacral vertebrae (Amniota) centra; atlas; sacral vertebrae; articulatory processes

28 Ribs  Form within myosepta from cartilage.  Dorsal ribs form where the myoseptum intersects the horizontal septum  Ventral ribs form where the myoseptum intersects the coelom somatic mesoderm. HOMOLOGY CONTROVERSY

29 Vertebrate Embryo (section) gut dermatome vertebra myotome horizontal septum dorsal mesentery (splanchnic mesoderm) coelom lateral plate mesoderm

30 Ribs dorsal rib ventral rib

31 Tetrapod Ribs dorsal rib? or ventral rib? capitulum tuberculum

32 Sternum  Sternum (midventral endochondral element) where ribs often articulate  Evolved independently in most groups.  Mammalian sternum composed of multiple ossified elements (stern - ebrae); manubrium = 1st; xiphisternum/xiphoid process = last

33 Subphylum Vertebrata hagfishes lampreys Chondrichthys Actinopterygii coelacanths lungfishes amphibians Mammalia Reptilia Ribs (of some kind) (Gnathostomata) 2 headed dorsal ribs, ventral ribs lost (Tetrapoda) *** * segmental sternum ** solid sternum

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35 Human Pectoral Skeleton

36 clavicle supra- sternal notch acromion  Clavicle – (collar bone) large, connects acromion process of scapula and superior sternum; dermal  Scapula – (shoulder blade; endochondral Acromion process – contacts clavicle Coracoid process Glenoid fossa Scapular blade Scapular spine Human Pectoral Girdle

37 coracoid process Human Scapula acromion coracoid process glenoid fossa coracoid process scapular blade scapular spine

38 Human Arm Bones

39 olecranon process of ulna styloid process of ulna lateral epicondyle of humerus Human Arm External

40 Human Hand (Manus) I III II IV V pisiform

41 Human Hand (Manus) Bones

42 Human Hand External

43 Human Pelvic Skeleton

44  Innominate Bone – pelvis; 3 pairs bones; connects to sacral vertebrae; endochondral  Ilium – fused to sacrum  Ischium – posterior & inferior  Pubis – anterior & inferior  Obturator foramen – btw. pubis & ischium  Acetabulum – femur articulates Human Pevic Girdle

45 Human Pelvic Girdle ilium sacrum coccyx ischium obturator foramen acetabulum pubis

46 iliac crest (iliac spine) Human Pelvis External iliac crest (iliac spine)

47 Human Leg Bones

48 Human Leg External patella tibial tuberosity lateral epicondyle of femur medial epicondyle of femur tibial shaft (“shin”) head of fibula

49 Human Pes

50 Human Foot (Pes) Bones

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52  Pectoral girdle =cartilaginous scapulocoracoid  Pelvic girdle = cartilaginous puboischiac bar  Radials = support keratinous “fin rays” --Only Gnathostomes Have-- Chondrichthyan Pectoral & Pelvic scapulocoracoid puboischiac bar radials

53  Scapulocoracoid (or scapula & coracoid) = endochondral; articulate(s) with radials (also endochondral)  Extensive, dermal pectoral girdle Posttemporal, supracleithrum, cleithrum, clavicle, and interclavicle (median & unpaired)  Fin rays = dermal bony rods (support most of fin); modified lamellar bone “scales” Osteichthyan Pectoral Girdles

54 Radials Scapulo- coracoid Osteichthyan Pectoral Girdle Lepido- trichia Cleithrum Supracleithrum Posttemporal Clavicle Interclavicle

55  Actinopterygiians - loss of ventral dermal bones (Teleosts & Amia lack clavicles & interclavicles. Gars lack interclavicles, but have clavicles.)  Tetrapods - loss of dorsal dermal bones (lack posttemporal, supracleithrum, & cleithrum)  Humerus = single radial articulates with “scapulocoracoid” in sarcopterygiians. (Glenoid fossa = articulation point) In Tetrapods - Humerus  Radius & Ulna  Carpals  Metacarpals  Phalanges Osteichthyan Pectoral Girdles

56 Tetrapod Pectoral Appendages Coracoid Scapula Clavicle Interclavicle Humerus Radius Ulna Carpals Metacarpals Phalanges Glenoid fossa

57  Clavicles & interclavicle in turtle ventral shell.  furcula = fused clavicles & interclavicle in birds.  postcoracoid = endochondral ossification unique to mammals; fuses to scapula in therians (= coracoid process of scapula)  Therian mammals lack interclavicle and coracoid. Amniote Pectoral Girdles

58 Echidna Skeleton

59 Dermal Pectoral Girdle Group inter- clavicle claviclecleithrumsupra- cleithrum post- temporal reedfishes and sturgeons present garsabsentpresent teleosts & Amiaabsent present lungfishespresent absent amphibianspresent absent monotremespresent absent Theriaabsentpresentabsent turtles, birds, & lizards/snakes present absent crocodilianspresentabsent

60 Endochondral Pectoral Girdle Group scapulacoracoid postcoracoid Chondrichthys present, fused to → present, fused to ← absent reedfishespresent absent sturgeons & paddlefish, gars, & Amia present, fused to → present, fused to ← absent teleostspresent absent lungfishes present, fused to → present, fused to ← absent amphibianspresent sometimes fused to → present sometimes fused to ← absent monotremespresent Theriapresentabsentpresent, fused to scapula (= coracoid process) Reptiliapresent sometimes fused to → present sometimes fused to ← absent

61 Subphylum Vertebrata hagfishes lampreys Chondrichthys Actinopterygii coelacanths lungfishes amphibians Mammalia Reptilia loss of cleithrum, supracleithrum, & posttemporal (have “neck”) (Tetrapoda) R S G AT * ** **loss of interclavicle *loss of clavicles pectoral & pelvic appendages (Gnathostomata) dermal pec. girdle (Osteichthys)

62 Subphylum Vertebrata hagfishes lampreys Chondrichthys Actinopterygii coelacanths lungfishes amphibians Mammalia Reptilia radius, ulna, metacarpals, (tibia, femur, metatarsals), phalanges (Tetrapoda) humerus, (femur) (Sarcopterygii)

63 Amniota montremes marsupials eutherians turtles lizards & snakes crocodylians birds furcula clavicles & interclavicle in ventral shell posterior coracoid loss of interclavicle & anterior coracoid loss of clavicles

64  ALL Endochondral  Not in actinopts. = radials.  3 “bones” in tetrapods.  Ilium = contacts sacral vert.  Pubis = Anterioventral  Ischium = Posterioventral  Femur = single radial articulates with plvic girdle in sarcopterygiians. (Acetabulum = articulation point) Osteichthyan Pelvic Girdles anterior turtle is il pu

65 Tetrapod Pelvic Appendages Ilium Ischium Pubis Acetabulum Femur Fibula Tibia Tarsals Metatarsals anterior

66  In Archosaurs the acetabulum is “perforated.”  In birds the 3 pelvic bones fuse (innominate bone); form a synsacrum.  In mammals the 3 pelvic bones often fuse (innominate bone). Amniote Pelvic Girdles anterior bird is il pu

67 Subphylum Vertebrata hagfishes lampreys Chondrichthys Actinopterygii coelacanths lungfishes amphibians Mammalia Reptilia ilium, ischium, & pubis (Tetrapoda) pelvic girdle lost; fused basal radials pelvic girdle

68 Amniota montremes marsupials eutherians turtles Lizards & snakes crocodilians birds synsacrum; tibiotarsus; tarsometatarsus perforated acetabulum (Archosauria)

69  Manus = “hand”  Pes = “foot”  Digits numbered anterior to posterior. Ancestrally 5 digits per limb in amniotes.  Pollux = “thumb;” digit I of manus  Hallux = “big toe;” digit I of pes  Phalangeal formula = number of phalanges in each digit starting with digit I. (e.g., ) Tetrapod Digit Terminology

70 Ancestral Tetrapod Manus phalanges meta- carpals radius ulna ulnare radiale inter- medium distal carpals I II III IV V centrales

71 Ancestral Tetrapod Pes phalanges meta- tarsals tibia fibula fibulare tibiale inter- medium distal tarsals I II III IV V centrales

72 Human Manus

73  Birds: much fusion of elements Only 2 free carpals Carpometacarpus = distal carpals + metacarpals of digits III & IV Tibiotarsus = tibia + proximal tarsals Tarsometatarsus = distal tarsals + metatarsals Bird Manus & Pes

74  Talus = tibiale + intermedium (called Astragalus in non-mammals)  Mammals - Maximum of only 1 free centrale (humans = 0 in manus, 1 in pes) Pisiform = sesamoid ossification on manus  Calcaneus = fibulare with posterior process; forms heel Amniote Manus & Pes

75 Genetralized Amniote Pes phalanges meta- tarsals tibia fibula Calcaneus (fibulare) Astragalus (tibiale + intermedium) distal tarsals I II III IV V centrales

76 Amniota monotremes marsupials eutherians turtles lizards & snakes crocodilians birds carpometacarpus; tibiotarsus; tarsometatarsus calcaneus (= “heel” on fibulare) ; tibia-tarsal joint (not an intratarsal joint) astragalus / talus (= tibiale + intermedium)


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