Chapter 7 The Skeleton PDF

The Skull ● ● ● ● ● Cranium – protects the brain and is the site of attachment for head and neck muscles Facial bones Supply the framework of the face, the sense organs, and the teeth Provide openings for the passage of air and food Anchor the facial muscles of expression Copyright © 2006 Pearso...

The Skull ● ● ● ● ● Cranium – protects the brain and is the site of attachment for head and neck muscles Facial bones Supply the framework of the face, the sense organs, and the teeth Provide openings for the passage of air and food Anchor the facial muscles of expression Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy of the Cranium ● ● ● ● ● ● ● Eight cranial bones: 2 Temporal 2 Parietal Occipital Sphenoid Frontal Ethmoid (Telling People Odd Stories Frightens Everyone) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sutures ● 1. 2. 3. 4. Four sutures mark the articulations of parietal bones with frontal, occipital, and temporal bones: Same as plane lines Coronal suture—between parietal bones and frontal bone Sagittal suture—between right and left parietal bones Lambdoid suture—between parietal bones and occipital bone Squamous (squamosal) sutures—between parietal and temporal bones on each side of skull Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Wormian Bones ● Tiny irregularly shaped bones that appear within sutures (sutural bones) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Facial Bones ● ● Mandible Maxillary bones (maxillae) (2) ● Zygomatic bones (2) ● Nasal bones (2) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings ● Lacrimal bones (2) ● Palatine bones (2) ● Vomer ● Inferior nasal conchae (2) Mandible and Its Markings ● The mandible (lower jawbone) is the largest, strongest bone of the face. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Other Facial Bones ● ● ● Nasal bones – thin medially fused bones that form the bridge of the nose Lacrimal bones – contribute to the medial walls of the orbit and contain a deep groove called the lacrimal fossa that houses the lacrimal sac Palatine bones – two bone plates that form portions of the hard palate Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Other Facial Bones ● ● ● Vomer – plow-shaped bone that forms part of the nasal septum Inferior nasal conchae – paired, curved bones in the nasal cavity Zygomatic bones - cheekbones Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Paranasal Sinuses ● ● ● ● ● ● Mucosa-lined, air-filled sacs found in five skull bones: Frontal Sphenoid Ethmoid Maxillary bones (paired) Lighten the skull and enhance the resonance of the voice Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hyoid Bone ● Not a bone of the skull ● Does not articulate directly with another bone ● ● Site of attachment for muscles of swallowing and speech Located at the C3-C4 vertebral level Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Vertebral Column ● ● ● ● ● ● Memorize Formed from 26 irregular bones (vertebrae) connected in such a way that a flexible curved structure results Cervical vertebrae – 7 bones of the neck Thoracic vertebrae – 12 bones of the torso Lumbar vertebrae – 5 bones of the lower back Sacrum – bone inferior to the lumbar vertebrae that articulates with the hip bones Coccyx—terminus of vertebral column Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Vertebral Column: Curvatures ● Increase the resilience and flexibility of the spine ● Normal Curvatures: ● ● ● ● ● ● ● ● Two posteriorly concave curvatures (lordotic) Cervical and lumbar Two posteriorly convex curvatures (kyphotic) Thoracic and sacral Abnormal spine curvatures: Scoliosis (abnormal lateral curve) Hyperkyphosis of the thoracics (hunchback) Hyperlordosis of the lumbars (swayback) anterior pelvic not use this word Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings rotation Vertebral Column: Curvatures ● ● ● ● ● ● ● Abnormal cervical curvatures: Ima Hypolordotic cervical curve Decrease in cervical lordosis Kyphotic cervical curve Reversal of the cervical curve “Military” Neck A straight cervical curve Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Intervertebral Discs Cushionlike pad composed of two parts Nucleus pulposus Inner gelatinous nucleus that gives the disc its elasticity and compressibility Anulus fibrosus Outer collar composed of collagen and fibrocartilage Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings General Structure of Vertebrae ● ● ● ● ● ● ● ● Body or centrum Anterior weight-bearing region Vertebral arch Composed of pedicles and laminae that, along with centrum, enclose vertebral foramen Vertebral foramina Together make up vertebral canal for spinal cord Intervertebral foramina Lateral openings between adjacent vertebrae for spinal nerves Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings General Structure of Vertebrae ● ● ● ● ● Seven processes per vertebra: Spinous process—projects posteriorly Transverse processes (2)—project laterally Superior articular processes (2)—protrude superiorly inferiorly Inferior articular processes (2)—protrude inferiorly Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cervical Vertebrae ● C1 to C7: smallest, lightest vertebrae ● C2 to C7 characteristics: ● ● ● Oval body (except C2) Spinous processes are bifid (except C7) Transverse foramen in each transverse process s cervical in found Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cervical Vertebrae: The Atlas (C1) ● ● ● The atlas has no body and no spinous process It consists of anterior and posterior arches, and two lateral masses The superior surfaces of lateral masses articulate with the occipital condyles Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cervical Vertebrae: The Axis (C2) ● ● ● ● The axis has a body, spine, and vertebral arches as do other cervical vertebrae Unique to the axis is the dens (odontoid process), which projects superiorly from the body and is cradled in the anterior arch of the atlas The dens is a pivot for the rotation of the atlas 80% of cervical rotation happens between atlas and axis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Thoracic Vertebrae ● ● ● There are twelve vertebrae (T1-T12) all of which articulate with ribs Major markings include: heart-shaped body, the circular vertebral foramen, long transverse processes, and a long inferiorly angled spinous process The location of the articulate facets prevents flexion and extension, but allows rotation of this area of the spine Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lumbar Vertebrae ● L1 to L5 ● Short, thick pedicles and laminae ● Flat hatchet-shaped spinous processes ● Orientation of articular facets locks lumbar vertebrae together so as to prevent rotation (provides stability) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Sacrum and Coccyx ● ● ● ● Sacrum 5 fused vertebrae (S1–S5) Forms posterior wall of pelvis Articulates with L5 superiorly, and with auricular surfaces of the hip bones laterally Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings ● ● ● ● Coccyx Tailbone 3–5 fused vertebrae Articulates superiorly with sacrum Sternum (Breastbone) ● ● ● ● ● ● ● ● Three fused bones Manubrium Articulates with clavicles and ribs 1 and 2 Body Articulates with costal cartilages of ribs 2 through 7 Xiphoid process Site of muscle attachment Not ossified until ~ age 40 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Ribs ● ● ● ● ● There are twelve pair of ribs forming the flaring sides of the thoracic cage All ribs attach posteriorly to the thoracic vertebrae The superior 7 pair (true, or vertebrosternal ribs) attach directly to the sternum via costal cartilages Ribs 8-10 (false, or vertebrocondral ribs) attach indirectly to the sternum via costal cartilage Ribs 11-12 (floating, or vertebral ribs) have no anterior attachment attached to Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings sternum w cartilage Appendicular Skeleton ● ● ● The appendicular skeleton is made up of the bones of the limbs and their girdles Pectoral girdles attach the upper limbs to the body trunk Pelvic girdle secures the lower limbs Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Pectoral Girdle (Shoulder Girdle) ● ● ● Clavicles and the scapulae Attach the upper limbs to the axial skeleton Provide attachment sites for muscles that move the upper limbs Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Clavicles (Collarbones) ● ● ● Flattened acromial (lateral) end articulates with the scapula (at the acromion process) Cone-shaped sternal (medial) end articulates with the sternum Act as braces to hold the scapulae and arms out laterally Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Scapulae (Shoulder Blades) ● ● Situated on the dorsal surface of rib cage, between ribs 2 and 7 Flat and triangular, with three borders and three angles Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Upper Limb ● ● ● ● ● ● ● ● ● 30 bones form the skeletal framework of each upper limb Arm Humerus Forearm Radius and ulna Hand 8 carpal bones in the wrist 5 metacarpal bones in the palm 14 phalanges in the fingers Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Humerus ● ● ● ● ● Largest, longest bone of upper limb Sole bone of the arm Articulates superiorly with glenoid cavity of scapula Articulates inferiorly with radius and ulna The surgical neck is where the tubular shaft begins and is a common area of fracture Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bones of the Forearm ● ● ● ● ● ● ● Ulna Medial bone in forearm Forms the major portion of the elbow joint with the humerus Radius Lateral bone in forearm Head articulates with capitulum of humerus and with radial notch of ulna Interosseous membrane connects the radius and ulna along their entire length Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hand: Carpus ● ● ● ● ● ● Eight bones in two rows Proximal row Scaphoid, lunate, triquetrum, and pisiform proximally Distal row Trapezium, trapezoid, capitate, and hamate distally Only scaphoid and lunate articulate with radius to form wrist joint Some Lover Take Positions That They Cannot Handle scaphoid cant lunate see is most commonly fractured pisiform from most often Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings posterior dislocated Hand: Metacarpus and Phalanges ● ● ● ● ● ● Metacarpals Five metacarpal bones (#1 to #5) form the palm Phalanges Each finger (digit), except the thumb, has three phalanges—distal, middle, and proximal Fingers are numbered 1–5, beginning with the thumb (pollex) Thumb has no middle phalanx Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Pelvic (Hip) Girdle ● ● ● Two hip bones (each also called coxal bone or os coxae) Each hip bone consists of three fused bones: ilium, ischium, and pubis Together with the sacrum and the coccyx, these bones form the bony pelvis Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hip Bone ● ● ● ● ● ● Three regions 1) Ilium Superior region of the coxal bone Auricular surface articulates with the sacrum (sacroiliac joint) 2) Ischium Posteroinferior part of hip bone 3) Pubis Anterior portion of hip bone Midline pubic symphysis joint Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Comparison of Male and Female Pelves ● ● ● ● Female pelvis Adapted for childbearing True pelvis (inferior to pelvic brim) defines birth canal Cavity of the true pelvis is broad, shallow, and has greater capacity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Comparison of Male and Female Pelves ● ● ● ● Male pelvis Tilted less forward Adapted for support of male’s heavier build and stronger muscles Cavity of true pelvis is narrow and deep Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Lower Limb ● Carries the weight of the body ● Subjected to exceptional forces ● Three segments of the lower limb ● ● ● Thigh: femur medial Leg: tibia and fibulalateral Foot: 7 tarsal bones in the ankle, 5 metatarsal bones in the metatarsus, and 14 phalanges in the toes Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Femur ● ● The sole bone of the thigh is the femur, the largest and strongest bone in the body It articulates proximally with the hip and distally with the tibia and fibula Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bones of the Leg ● ● ● ● ● ● ● ● Tibia inside Medial leg bone Receives the weight of the body from the femur and transmits it to the foot Fibula Not weight bearing; no articulation with femur Site of muscle attachment Connected to tibia by interosseous membrane Articulates with tibia via proximal and distal tibiofibular joints Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Foot: Tarsals ● ● ● Seven tarsal bones form the posterior half of the foot Talus transfers most of the weight from the tibia to the calcaneus Other tarsal bones: cuboid, navicular, and the medial, intermediate, and lateral cuneiforms Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Foot: Metatarsals and Phalanges ● ● ● ● ● ● ● Metatarsals: Five metatarsal bones (#1 to #5) Enlarged head of metatarsal 1 forms the “ball of the foot” Phalanges: The 14 bones of the toes Each digit (except the hallux) has three phalanges Hallux has no middle phalanx Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Calcaneus ● Forms the heel of the foot ● Carries the talus on its superior surface ● Point of attachment for the calcaneal (Achilles) tendon of the calf muscles Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Developmental Aspects: Spinal Curvature ● ● ● ● Only thoracic and sacral curvatures are present at birth The primary curvatures are convex posteriorly, causing the infant spine to arch like a four-legged animal Secondary curvatures – cervical and lumbar – are convex anteriorly. They appear as child develops (e.g., lifts head, learns to walk) Failure of proper development of the vertebral arches leads to spina bifida Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Developmental Aspects: Old Age ● ● ● ● ● Intervertebral discs become thin, less hydrated, and less elastic Risk of disc herniation increases Loss of stature by several centimeters is common after age 55 lose height Costal cartilages ossify causing the thorax to become rigid All bones lose mass Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings