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#2 Lecture name: The Axial skeleton Written By: Batool Ajaleen , Mariam Ababneh & Marwa Abozoor Edited By: Buthaina Almasaeed & Bushra Slaeem Sphenoid Bone Sphenoid bone articulates with 12 bones from cranial and facial bones(occipital , vomer , ethmoid , frontal bone ,temporal , parietal , zygomatic , palatine ) - it’s a single bone . - it’s the base of cranial bone * structure : body , greater wing , lesser wing , pterygoid process 1- the body : lies at the center of the sphenoid bone and is almost completely cubical in shape . It contains sphenoid sinuse( )جيوبwhich are separated by a septum meaning that the body is essentialy hollow. - body articulates with athmoid bone anteriorely . *sella turcica : saddle shape depression .( )تشبه السرج. Which is a superior surface of the sphenoid body bony landmark . - the parts of the sella turcica : 1- tuberculum sellae : anterior wall of the sella turcica 2- hypophyseal fossa : (the deepest part) 3-dorsum sallae : posterior wall of the sella turcica 2- greater wing : extends from the sphenoid body in lateral superior and posterior direction (curved lateral upward) *the curved shape of the sphenoid bone is the reason why we can see a small part of sphenoid when looking from right or left side . Copyright 2009, John Wiley & Sons, Inc. Great wing contributes to the facial skeleton like : 1- The floor of middle cranial fossa . 2- posterior wall of the orbit . * Greater wing formina : ovale / spinosum / rotundom which has a large bundle of nerve that branched into 3 smaller nerves : ( maxillary nerve / mandibular nerve /middle meningeal vessels) *optic canal can be viewed from the anterior aspect and is in the posterior of the eye orbit just middle to the superior orbital fissure and also can be viewed from the posterior aspect *the optic nerve extend from the posterior of the eye passes through the optic canal to the brain . 3-lesser wings : arise from the anterior aspect of the sphenoid body and it’s the superior part of the sphenoid bone , it separates the anterior cranial fossa from the middle cranial fossa . fissure : is the elongated opening fossa . 4-pterygoid process : descends inferiorly from the points of junction on between sphenoid body of the greater wing it has two parts : 1) medial pterygoid plate which supports the posterior opening of the nasal cavity 2) lateral pterygoid plate is the John Wiley & Sons, Inc. muscles. site of origin of the medialCopyright and 2009, lateral pterygoid Sphenoid Bone Ethmoid bone Ethmoid bone : it takes its name from the sieve (غربال/)منخلon its surface. Its shape is like L shape but inverted , located in the midline of the anterior cranium it has two parts , the horizontal part (superior part) & the vertical part (when I look from the front ) it is located at the roof of the nasal cavity & between the two orbital cavities . it contributes to medial wall of the orbit and forms part of the anterior cranial fossa where it separates the nasal cavity into left & right side . the ethmoid one has three parts : 1) cribriform plate : roof of the nasal cavity and received into the ethmodial notch of the frontal bone , it supports the olfactory bulb and is perforated by foramina for the passage of the all factory nerve . 2) perpendicular plate : superior two-thirds of the nasal septum . 3) the ethmoid labyrinths : (lateral masses of the ethmoid bone and it’s irregular in shape) medial sheets : upper lateral wall of the nasal cavity from which the superior & middle conchae extends into the nasal cavity . Copyright 2009, John Wiley & Sons, Inc. These lateral masses have an important role in the inhaled air which warms it before it arrives the lungs. inferior conchae is separated from the ethmoid bone and consider from the facial bone superior and medial concha are parts of ethmoid bone Copyright 2009, John Wiley & Sons, Inc. Occipital Bones Occipital bone : at the base of the skull in the occipital bone there is a large oval opening called the foramen magnum which allows the passage of spinal cord . It’s a flat bone External occipital protuberance is sharpened area ()منطقة مدببة and has two lines superior nuchal line and inferior nuchal line. * the occipital bone located at the back and lower part of the cranium is a trapezoid ( )شبه منحرفin shape and curved on it self . It is pierced( )مثقوبby a large oval called the foramen magnum through which the cranial cavity communicates with the vertebral canal. Copyright 2009, John Wiley & Sons, Inc. The occipital bone is composed of four parts : 1- squamous part :is the curved expanded plate located behind the foramen magnum . (external/internal surfaces ) 2- basilar part 3- jugular part . 4-lateral part. * external surface features : superior nuchal line ,inferior nuchal line , median nuchal line . * jugular process excavated in front by jugular notch , forming posterior part of jugular foramen . Copyright 2009, John Wiley & Sons, Inc. Skull Skull Skull Copyright 2009, John Wiley & Sons, Inc. Skull Skull Skull Skull Skull Skull Skull (Facial Bones) Nasal Bones Form the bridge of the nose Maxillae Form the upper jawbone Form most of the hard palate Zygomatic Bones Form a part of the medial wall of each orbit Palatine Bones commonly called cheekbones, form the prominences of the cheeks Lacrimal Bones Separates the nasal cavity from the oral cavity Form the posterior portion of the hard palate Inferior Nasal Conchae Form a part of the inferior lateral wall of the nasal cavity Skull (Facial Bones) Vomer Mandible Divides the interior of the nasal cavity into right and left sides “Broken nose,” in most cases, refers to septal damage rather than the nasal bones themselves Orbits Lower jawbone The largest, strongest facial bone The only movable skull bone Nasal Septum Forms the inferior portion of the nasal septum Eye socket Foramina Openings for blood vessels , nerves , or ligaments of the skull Skull Unique Features of the Skull Sutures an immovable joint that holds most skull bones together Paranasal Sinuses Sutures, Paranasal sinuses, Fontanels Cavities within cranial and facial bones near the nasal cavity Secretions produced by the mucous membranes which line the sinuses, drain into the nasal cavity Serve as resonating chambers that intensify and prolong sounds Fontanels Areas of unossified tissue At birth, unossified tissue spaces, commonly called “soft spots” link the cranial bones Eventually, they are replaced with bone to become sutures Provide flexibility to the fetal skull, allowing the skull to change shape as it passes through the birth canal #mandible : single bone .. It’s the only movable bone in the skull. It consists of : curved horizontal portion called the body and vertical part called Ramus The mandible bone composed of two halfs Joined at the midline at vertical symphysis * there is a mandible notch(incomplete opening) * it also articulates to the neurocranium via the temporal bone forming the temporomanndibular joint (TMJ) *from the internal side we can see the mandibular foramina * the mandibular foramina nerve branched into smaller nerves * في اشي بيسأل الدكتور عنه في الالب بالـmandible bone Copyright 2009, John Wiley & Sons, Inc. - Hard palate consists of horizontal plate of palatine bone and palatine process of maxilla. The hard palate separate the oral cavity from the nasal cavity #nasal bone ()مكان ما بنحط النظارة *orbital cavity is made of 7 bones ; 3 cranial and 4 facial . (frontal , sphenoid , lacrimal , maxilla , palatine , zygomatic ) **في نقطة عن عظم األطفال أول ما ينولد و كيف لما يكبر بلتحم **في نقطة عن بنية العظم و انها فاضية من جوا عشان هيك ال خفيفskull Copyright 2009, John Wiley & Sons, Inc. Skull Skull Hyoid Bone (U shape ) Does not articulate with any other bone(the ONLY) Supports the tongue, providing attachment sites for some tongue muscles and for muscles of the neck and pharynx The hyoid bone also helps to keep the larynx (voice box) open at all times Vertebral Column Also called the spine, backbone, or spinal column Functions to: irregular bone Protect the spinal cord Support the head Serve as a point of attachment for the ribs, pelvic girdle, and muscles The vertebral column is curved to varying degrees in different locations Curves increase the column strength Help maintain balance in the upright position Absorb shocks during walking, and help protect the vertebrae from fracture Vertebral Column • • • • 7 cervical vertebrae 12 thoracic vertebrae 5 lumbar vertebrae 5 fused sacral vertebrae • 4 fused coccygeal vertebrae Vertebral Column Various conditions may exaggerate the normal curves of the vertebral column Kyphosis Lordosis Scoliosis Composed of a series of bones called vertebrae (Adult=26) 7 cervical are in the neck region 12 thoracic are posterior to the thoracic cavity 5 lumbar support the lower back 1 sacrum consists of five fused sacral vertebrae 1 coccyx consists of four fused coccygeal vertebrae Vertebral Column kyphosis scoliosis (vertebral column takes a side position ) (over exaggerated areas ) lordosis للداخلlumbar • انحناء بمنطقة الـ . Kyphosis ولكن غير مبالغ مثل • بسبب وجود ثقل يشد العمود لألمام مثل Pregnancy / obesity or anything else … Vertebral Column (Intervertebral Discs) Found between the bodies of adjacent vertebrae Functions to: Form strong joints Permit various movements of the vertebral column Absorb vertical shock Vertebrae typically consist of: A Body (weight bearing) A vertebral arch (surrounds the spinal cord) Several processes (points of attachment for muscles) (7 processes) Vertebral Column The vertebral arch encloses a very important structure(spinal cord) to protect it from any damage. The vertebral arch has an anterior & posterior part. The anterior portion is majorly by the body & the posterior portion is the two lamina. * there is two horizontal transverse processes and they lie approximately between pedicle and lamina . تكونlamina posteriorly مع الـpedicle anteriorly نقطة التقاء الـ .transverse process الـ single spinous process يعطيناtwo lamina التقاء الـ ””لربط األجزاء مع بعضها و هي فكرة واردة كسؤال Copyright 2009, John Wiley & Sons, Inc. - The function of the two transverse processes and the spinous process is to hold the muscles of the back. we have Superior articular process and an inferior one. -The superior one articulates with the superior articular process of adjacent vertebrae. - Inferior articular process articulates the vertebrae with the inferior one . ) (حتى يركبوا على بعض So we have seven processes project from each typical vertebra : 2 transverse 1 spinous 2 articular 2inferior Copyright 2009, John Wiley & Sons, Inc. Vertebral Column (Regions) Cervical Region Thoracic Region Lumbar vertebrae (L1–L5) Provide for the attachment of the large back muscles Sacrum Thoracic vertebrae (T1–T12) Articulate with the ribs Lumbar Region Cervical vertebrae (C1–C7) The atlas (C1) is the first cervical vertebra The axis (C2) is the second cervical vertebra The sacrum is a triangular bone formed by the union of five sacral vertebrae (S1–S5) Serves as a strong foundation for the pelvic girdle Coccyx The coccyx, like the sacrum, is triangular in shape It is formed by the fusion of usually four coccygeal vertebrae Vertebral Column How to distinguish between cervical/thoracic /lumbar : 1-cervical : - it articulates with the skull ( occipital bone ). - The smallest but its foramen is the largest (heart or triangular shaped ). - the vertebral arteries that supply the brain passes through the cervical foramina . - spinous process is often bifid . - two transverse foramen appear ONLY in cervical vertebrae . Copyright 2009, John Wiley & Sons, Inc. 2-thoracic : - It articulates with the superior and inferior vertebrae so do the cervical and the lumbar BUT it is the ONLY kind that articulates with ribs this special articulation happens in two areas , on the body and on the transverse process. - the rib articulates with the vertebrae in two areas one with the body and one with the transverse process through a smooth area called a facet. - The spinous process is inclined downward * و هذا مفيد في المختبر حيث عند وضعها على سطح مست ٍو فإنها لن تستقر لالسفل كونها غير مستوية - It is bigger than cervical and smaller than lumbar Copyright 2009, John Wiley & Sons, Inc. 3-lumbar : -The largest. -No transverse foramina and no facets because it does not articulates with the ribs. - )مستوية من األسفل (تستقر عند وضعها على سطح مست ٍو - The spinous process is very thick and vertical. Copyright 2009, John Wiley & Sons, Inc. Atypical vertebrae o o o The first vertebrae in cervical (C1) is called Atlas : it lacks the body, it takes the shape of a ring (extra information: it lacks the spinous process) . The second one (C2) is called Axis : it has a special projection called Dens (odontoid process ) . "projecting from its superior surface " The vertebra prominens (C7) has the longest spinous process of all cervical vertebrae. It is also non-bifid. These features give rise to its name. Copyright 2009, John Wiley & Sons, Inc. Vertebral Column Vertebral Column Vertebral Column Vertebral Column 4-The sacrum : - There is lines of fusion shown between the fused bones. lateral sacral line لزقوا مع بعض و عملواtransverse process فيmedian sacral line لما لزقوا مع بعض عملواspinous process و ال ) (**الدكتورة كررت فكرة ربط األجزاء -There is a notch in the body of vertebrae from upside and downside constitute a foramen that a spinal nerve coming from the spinal cord passes through it . 5-Coccyx : - 3-5 vertebrae attached to each other. Copyright 2009, John Wiley & Sons, Inc. Thorax Thoracic cage is formed by the: Sternum Ribs Costal cartilages Thoracic vertebrae Functions to: Enclose and protect the organs in the thoracic and abdominal cavities Provide support for the bones of the upper limbs Play a role in breathing Thorax Sternum Ribs “Breastbone” located in the center of the thoracic wall Consists of the manubrium, body, xiphoid process Twelve pairs of ribs give structural support to the sides of the thoracic cavity Costal cartilages Costal cartilages contribute to the elasticity of the thoracic cage The sternum : 1- thin flat bone at the midline of the thoracic cage consists of three parts ( originally it consists of three bones but when we grow it fuses to make one bone "sternum”. 2- The ribs don’t attach directly on the sternum. They attach to the sternum through the cartilage. If it was bone-bone attachment (fixed) the thorax won’t be able to expand during breathing. Copyright 2009, John Wiley & Sons, Inc. Vertebral Column Typical ribs : 1- contain a head that articulates the ribs with the thoracic vertebrae, there is a constricted area under the head called "neck". ""every head projection has a neck constriction .. near the neck there is another projection called tubercle”. 2- The ribs articulate with the thoracic vertebrae in two areas, the head with the body of vertebrae and the tubercle with the transverse process. 3-When we look at the rib from inside we can see a line called costal groove. (Costal means rib in latin) through the groove there is a veine ... artery .. Nerve that pass VAN Copyright 2009, John Wiley & Sons, Inc. Vertebral Column Classifications of ribs : 1 – T / F / floating : (1,2,3,4,5,6,7 ) true : the rib articulates to sternum with its own cartilage. (8,9,10) false : the rib articulates the sternum indirectly by joining the 7th cartilage . (11,12) Floating : no articulation. 2- Typical / Atypical : The declination of the ribs as its own surface (anterior & posterior ). - typical : the rib articulates with the corresponding and the above vertebrae . Contains the basic features of a rib like head , neck … - atypical : have features that are not common to all the ribs. - R 1 atypical : the shortest .. the thickest and the surface is superior &inferior flatly - R 2 atypical : the surface is superior& inferior not anterior & posterior - R 3 4 5 6 7 8 9 typical articulation & surface. - R10 atypical : articulates with 10 only - R11 / 12 a typical .. don’t articulate with sternum .. No angle .. No articulation with the upper . Copyright 2009, John Wiley & Sons, Inc. In other words : Rib 1 is shorter and wider than the other ribs. It only has one facet on its head for articulation with its corresponding vertebrae (there isn’t a thoracic vertebrae above it). Rib 2 is thinner and longer than rib 1, and has two articular facets on the head as normal. Rib 10 only has one facet – for articulation with its numerically corresponding vertebrae. Ribs 11 and 12 have no neck, and only contain one facet, which is for articulation with their corresponding vertebrae. ا ُ الصفرإذا شئت وأنت الّلمتناهي أنت Copyright 2009, John Wiley & Sons, Inc. We have 12 ribs 1-7 8-10 11,12 3-9 1,2,11 ,12 Copyright 2009, John Wiley & Sons, Inc. THANK YOU