The Appendicular SkeletonTHE SKELETAL SYSTEM The Appendicular SkeletonPectoral Girdle (Shoulder Girdle)Scapulae: triangular, paired, but don’t connect in back (adds thoracic flexibility)ScapulaUpper extremityArmRight humerus, anterior viewRight humerus, posterior viewForearmPowerPoint PresentationSlide 12Slide 13Slide 14HandSlide 16Slide 17Pelvic Girdle (Hip Girdle)Hip bone (os coxae): 3 separate bones in childhood which fuseIliumIschiumPubisSlide 23Pelvis and childbearingLower limbThighRight femur, anterior viewRight femur, posterior viewLegRight lower leg, anterior viewSlide 31FootRight foot, superior (dorsal) view and inferior (plantar) viewSlide 34The Appendicular SkeletonTHE SKELETAL SYSTEMThe Appendicular Skeleton2 pairs of limbs and 2 girdlesPectoral (shoulder) girdle attaches upper limbsPelvic (hip) girdle secures lower limbs3-Segmented limbsUpper = armArmForearmHandLower = legThighLegFootPectoral Girdle(Shoulder Girdle)Clavicle – anterior: collar boneSternal end attaches to the manubrium mediallyAcromial end articulates with the scapula laterallyScapula – posterior: shoulder bladeScapulae: triangular, paired, but don’t connect in back (adds thoracic flexibility)ScapulaGlenoid cavity articulates with the humerusAcromium articulates with clavicleCoracoid process projects anteriorlyUpper extremityArm or Brachium = upper armBetween shoulder and elbow (humerus)Forearm or AntebrachiumRadius & ulnaHand includes: Wrist (carpus)Palm (metacarpus)Fingers (phalanges)ArmHumerus is the only boneHead of humerus fits into glenoid cavity of scapulaDistal & medially, trochlea articulates with the ulnaDistal & laterally capitulum articulates with the radiusMedial & lateral epicondylesRight humerus, anterior viewRight humerus, posterior viewForearm2 bones: articulate with each other proximally and distallyInterosseous membrane between themUlnaOlecranon hinges with the humerus forming elbowStyloid process distally RadiusContributes to wrist jointStyloid process anchors a ligament to wrist (thumb side)Radius is thinner proximally, like a spool of thread, and wide distally; ulna is slightly longer and looks like a monkey wrench (supposedly!)Right forearm bones, anterior viewRight forearm bones, posterior viewIn the anatomical position, the radius is lateral (thumb side); with pronation the palm faces posteriorly and the bones crossLeft forearmProne: body lying face downSuppine: body lying face up (you can remember prone if you think about how you would fall forward onto your face if you passed out) Anatomical positionpronepronation moves the forearm into the prone position and supination moves it back to the anatomical positionproximal ulnaProximal and distal joints of the forearmHandProximal is “wrist” – 8 carpal bonesPalm of hand - 5 metacarpalsFingers (or digits) consist of miniature long bones called phalanges: thumb (“pollex”) has 2; fingers have 3: proximal, middle, distalRight hand, 2 views:Pelvic Girdle (Hip Girdle)Strongly attached to axial skeleton (sacrum)Deep socketsMore stable than pectoral (shoulder) girdleLess freedom of movementMade up of the paired hip bones“Bony pelvis” is basin-like structure: hip bones plus the axial sacrum and coccyxHip bone (os coxae): 3 separate bones in childhood which fuseIliumIschiumPubisIliumIliac crestAnterior superior iliac spineGreater sciatic notchForms part of “acetabulum” (hip socket) which receives ball-shaped head of femuriliumiliumIschiumBodyRamusIschial spineIschial tuberosityPart of socketischiumischiumPubisJoins medially in pubic symphysisForms “obturator foramen” (large hole) with ischiumPart of socketpubispubisHip bones with labelsPelvis and childbearingMale/female differencesLarge & heavy vs light & delicateHeart shaped pelvic inlet vs ovalNarrow deep true pelvis vs wide & shallowNarrow outlet vs wideLess than 90 degree pubic arch vs more than 90 degreeBirth canal changes shape as baby descends: head turns ¼Lower limbThigh: femurLeg (lower leg)TibiaFibulaFootThighFemur is largest, longest and strongest bone in the bodyHead fits in socket (acetabulum) of pelvisNeck is weakestGreater trochanterDistal: lateral & medial condyles and epicondylesPatella: sesmoid boneRight femur, anterior viewRight femur, posterior viewLegTibia: shin boneMedial and lateral condylesTibial tuberosityDistal medial malleolus (medial ankle)FibulaDistal lateral malleolus (lateral ankle)Interosseous membraneRight lower leg, anterior viewFootTarsus: 7 tarsal bonesTalus: articulates with tibia and fibula anteriorly and calcaneus posteriorlyCalcaneus: heel boneSmaller cuboid, navicular, and 3 cunieforms (medial, intermediate and lateral)5 metatarsals14 phalangesGreat toe is halluxRight foot, superior (dorsal) view and inferior (plantar) viewRight foot, lateral and medial