Lecture #3.  Axial skeleton – skull, vertebral column, ribs,...

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Transcript of Lecture #3.  Axial skeleton – skull, vertebral column, ribs,...

Skeletal system

Skeletal systemLecture #3Skeletal organizationAxial skeleton skull, vertebral column, ribs, sternumAppendicular skeleton pectoral girdle, pelvic girdle, limbs

Axial Skull bonesCranial flat bones enclose and protect brainFrontal bone: forehead and upper ridges of eye socketsParietal bones: upper left and right sides of skullTemporal bones: lower left and right (ears)Skull bones contdSphenoid bone: back of the eye socketsEthmoid bone: contributes to eye sockets and helps to support the noseOccipital bone: curves underneath to form the back & base of the skullForamen magnum (L. great opening): where vertebrae connects to skull

But wait, theres moreSkull bones!Facial bones - frontMaxilla forms part of eye sockets and sockets to anchor upper row of teethPalatine bones hard palate (roof of mouth)Vomer bone behind palatine & part of nasal septum

But wait, theres moreSkull bones!Zygomatic bones: cheek bones & outer portion of eye socketNasal bones: underlie the upper bridge of nose (space between maxilla & nasal bones is the nasal cavity)Lacrimal bones: inner eye sockets with tear duct (drains to nasal cavity)All skull bones joined tightly except for mandible (speak & chew)Mandible: lower jaw w/ sockets for teethSinuses are air spaces which make the skull lighter and give the human voice its tone and resonanceEach sinus is lined with tissue that secretes mucus & connects to nasal cavity by small passageways

Blocked sinuses = painRespiratory infections cause sinus tissue to become inflamed and block the passages to the nasal cavitySinusitis = sinus inflammationFluid gets trapped causing sinus pressure headache


Hyoid Bone structure & functionU-shaped, superior to larynx in the neckThe only bone that isnt articulated with another boneSuspended from styloid processes of temporal boneAnchors the tongue & serves as attachment for swallowing muscles

Vertebral ColumnSkull to pelvis - rib attachment, pelvic girdle attachmentProtects spinal cord as it passes through vertebral canal 33 vertebrae7 neck / cervical12 chest / thoracic5 lumbar / lower back5 sacral 3-5 tailbone / coccygeal 4 curvaturesCervical & lumbar = convexThoracic & sacral = concave

Figure 5.7

Thoracic (Rib) Cage12 thoracic vertebrae = 12 ribs connect to vertebrae posteriorlyUpper 7 connect directly to sternum via cartilage = true ribsLower 5 = false ribs upper 3 attach to sternum with common cartilage & bottom 2 are not attached to sternum (floating)Figure 5.9