Vertebral Column: Overview The vertebral column (spine) is divided into four regions: the and lumbar spines demonstrate lordosis (inward curvature); the thoracic cervical, thoracic, lumbar, and sacral spines. Both the cervical and sacral spines demonstrate kyphosis (outward curvature). Back Fig. 1.1 Vertebral column Left lateral view. ¨ O>KFL@BOSF@>IGRK@QFLK SBOQB?O>B BOSF@>IPMFKB BOSF@LQELO>@F@GRK@QFLK MFKLRP MOL@BPP ELO>@F@PMFKB ELO>@LIRJ?>OGRK@QFLK LPQ>I RJ?>OPMFKB C>@BQP ¨ RJ?LP>@O>IGRK@QFLK SBOQB?O>B OQF@RI>O >@ORJªP>@O>IPMFKB« MOL@BPPBP A Regions of the spine. KQBOSBOQB¦ ?O>ICLO>JFK> Clinical Spinal development ¨ The characteristic curvatures of the adult spine appear over the course SBOQB?O>B of postnatal development, being only partially present in a newborn. The KQBOSBOQB¦ newborn has a “kyphotic” spinal curvature (A); lumbar lordosis develops ?O>IAFPH later and becomes stable at puberty (C). ARIQPMFK>I @LIRJK >@O>I MOLJLKQLOV O>KPFQFLK>I ME>PB >@ORJ VMELQF@ BOSF@>I ª¨ PMFKB ILOALPFP LCQEB SBOQB?O>B« KBT?LOK ELO>@F@ HVMELPFP L@@VU RJ?>O ILOALPFP B Bony vertebral column. >@O>I HVMELPFP ABC 2 Fig. 1.2 Normal anatomical position of the spine & Joints 1 Bones, Ligaments Left lateral view. UQBOK>I BKPLC>UFPª« BKPLC>UFPª« >RAFQLOV@>K>I LKDRB >OVKU MFKLRPMOL@BPPLC SBOQB?O>MOLJFKBKPª « O>@EB> FKBLCDO>SFQV KCIB@QFLKMLFKQP MFK>I@LOA P@BKAFKD >LOQ> BOQB?O>I@>K>I B>OQ PLME>DRP KQBOSBOQB?O>IAFPH F>MEO>DJ MFKLRPMOL@BPP ELIB¦?LAV FSBO @BKQBOLCDO>SFQV QLJ>@E LAVLC LKRPJBARII>OFP ?ALJFK>I >LOQ> A Line of gravity. The line of gravity passes through certain anatomical landmarks, >RA>BNRFK> including the inflection points at the cervi- cothoracic and thoracolumbar junctions. >@O>IMOLJLKQLOV It continues through the center of gravity (anterior to the sacral promontory) before passing through the hip joint, knee, and ankle. I>AABO L@@VU B@QRJ B Midsagittal section through an adult male. 3 Vertebral Column: Elements Fig. 1.3 Bones of the vertebral column Back BKPLC>UFPª« QI>Pª« QI>Pª« UFPª« © SBOQB?O>B Fig. 1.4 Palpable spinous processes as landmarks BOQB?O> Posterior view. The easily palpated spinous MOLJFKBKP processes provide important landmarks dur- ª « ing physical examination. O>KPSBOPB MOL@BPP MFKLRP MOL@BPPBP BOSF@LQELO>@F@ GRK@QFLKª « @>MRI>OPMFKBª« O>KPSBOPB © MOL@BPPBP SBOQB?O>B BOQB?O>I KCBOFLOP@>MRI>O ?LAV >KDIBª « QEOF?ª« KSBOQB?O>I IF>@@OBPQª « AFPH © SBOQB?O>B >@ORJ LPQBOFLO ªCRPBA >@ORJ P>@O>I © CLO>JFK> SBOQB?O>B« KQBOFLO P>@O>I CLO>JFK> L@@VU L@@VU A Anterior view. B Posterior view. 4 Fig. 1.5 Structural elements of a vertebra Fig. 1.6 Typical vertebrae Left posterosuperior view. With the exception of the atlas (C1) and axis Superior view. (C2), all vertebrae consist of the same structural elements. 1 Bones, Ligaments & Joints 1 Bones, Ligaments RMBOFLO >OQF@RI>O BOQB?O>I MFKLRPMOL@BPP BOQB?O>I MOL@BPP CLO>JBK BOQB?O>I>O@E ?LAV >JFK> RMBOFLO>OQF@RI>OC>@BQ BAF@IB O>KPSBOPB BAF@IB BOQB¦ MOL@BPP LPQBOFLOQR?BO@IB ?O>I O>KPSBOPBMOL@BPPTFQE >O@E PRI@RPCLOPMFK>IK O>KPSBOPBCLO>JBK >JFK> MFKLRP MOL@BPP LAV KQBOFLO QR?BO@IB KCBOFLO >OQF@RI>OMOL@BPP A Cervical vertebra (C4). MFKLRPMOL@BPP LPQ>IC>@BQ >JFK> O>KPSBOPBMOL@BPP BAF@IB RMBOFLO>OQF@RI>OC>@BQ KCBOFLO@LPQ>IC>@BQ RMBOFLO@LPQ>IC>@BQ LAV B Thoracic vertebra (T6). BAF>K P>@O>I@OBPQ RMBOFLO RMBOFLO>OQF@RI>OMOL@BPP >@O>I@>K>I >OQF@RI>O MFKLRPMOL@BPP C>@BQ @@BPPLOVMOL@BPP O>KPSBOPBMOL@BPP >QBO>IM>OQ LCP>@ORJ BOQB?O>I>O@E RMBOFLO>OQF@RI>OMOL@BPP BOQB?O>ICLO>JBK RMBOFLOSBOQB?O>I LAV KLQ@E >PBLC OLJLKQLOV FKDLC P>@ORJ P>@ORJ C Lumbar vertebra (L4). D Sacrum. Table 1.1 Structural elements of vertebrae Vertebrae Body Vertebral foramen Transverse processes Articular processes Spinous process Small (may be absent in Superoposteriorly and Cervical vertebrae Small C7); anterior and posterior Short (C3–C5); bifid (C3–C6); Large (triangular) inferoanteriorly; oblique facets: C3*–C7 (kidney-shaped) tubercles enclose long (C7) most nearly horizontal transverse foramen Medium (heart- Large and strong; length Posteriorly (slightly laterally) and Long, sloping postero- Thoracic vertebrae shaped); includes Small (circular) decreases T1–T12; costal anteriorly (slightly medially); inferiorly; tip extends to level T1–T12 costal facets facets (T1–T10) facets in coronal plane of vertebral body below Posteromedially (or medially) and anterolaterally (or laterally); Long and slender; Lumbar vertebrae Large facets nearly in sagittal plane; Medium (triangular) accessory process on Short and broad L1–L5 (kidney-shaped) mammillary process on posterior posterior surface surface of each superior articular process Superoposteriorly (SI) superior Sacral vertebrae (sacrum) Decreases from Fused to rudimentary rib Sacral canal surface of lateral sacrum- Median sacral crest S1–S5 (fused) base to apex (ribs, see pp. 44–47) auricular surface *C1 (atlas) and C2 (axis) are considered atypical (see pp. 6–7). 5 Cervical Vertebrae The seven vertebrae of the cervical spine differ most conspicu- all directions. C1 and C2 are known as the atlas and axis, respectively. ously from the common vertebral morphology. They are special- C7 is called the vertebra prominens for its long, palpable spinous process. Back ized to bear the weight of the head and allow the neck to move in Fig. 1.7 Cervical spine Left lateral view. LPQBOFLO >O@ELC>QI>P KQBOFLO QR?BO@IB ª>QI>P« LPQBOFLO Fig. 1.8 Atlas (C1) QR?BO@IB RMBOFLO OLLSBCLO ª>UFP« >OQF@RI>OC>@BQ SBOQB?O>I> MFKLRP RI@RPCLO MOL@BPP LPQBOFLO KQBOFLO PMFK>IK QR?BO@IB QR?BO@IB BOQB?O>I LPQBOFLO ?LAV VD>ML¦ O>KPSBOPB O>KPSBOPB >O@ELC>QI>P KQBOFLO CLO>JBK MOL@BPP MEVPB>IGLFKQ KCBOFLO QR?BO@IB KCBOFLO>OQF@RI>O >OQF@RI>OC>@BQ LPQBOFLO MOL@BPP QR?BO@IB RMBOFLO>OQF@RI>O A Left lateral view. MOL@BPP RI@RPCLO PMFK>IK Fig. 1.9 Axis (C2) K@FK>QBMOL@BPP MFKLRP MOL@BPP KQBOFLO BKP >OQF@RI>OC>@BQ LPQBOFLO ªSBOQB?O> RMBOFLO >OQF@RI>OC>@BQ MOLJFKBKP« >OQF@RI>OC>@BQ O>KPSBOPB MFKLRP MOL@BPP O>KPSBOPB CLO>JBK MOL@BPP O>KPSBOPBCLO>JBK LAV A Bones of the cervical spine, left lateral view. O>KPSBOPB KCBOFLO BOQB?O>I MOL@BPP >OQF@RI>OC>@BQ >O@E A Left lateral view. Fig. 1.10 Typical cervical vertebra (C4) O>KPSBOPB RMBOFLO CLO>JBK >OQF@RI>OMOL@BPP O>KPSBOPBMOL@BPP RMBOFLO>OQF@RI>OC>@BQ LAV KCBOFLO>OQF@RI>O MOL@BPP RI@RPCLO KCBOFLO MFKLRP PMFK>IK >OQF@RI>OC>@BQ MOL@BPP B Radiograph of the cervical spine, left lateral view. A Left lateral view. 6 Clinical Injuries in the cervical spine & Joints 1 Bones, Ligaments The cervical spine is prone to hyperextension injuries, such as This patient hit the dashboard of his car while not “whiplash,” which can occur when the head extends back much farther wearing a seat belt. The resulting hyperextension than it normally would. The most common injuries of the cervical spine caused the traumatic spondylolisthesis of C2 (axis) are fractures of the dens of the axis, traumatic spondylolisthesis (ventral with fracture of the vertebral arch of C2, as well as slippage of a vertebral body), and atlas fractures. Patient prognosis is tearing of the ligaments between C2 and C3. This largely dependent on the spinal level of the injuries (see p. 600). injury is often referred to as “hangman’s fracture.” RMBOFLO KQBOFLO >OQF@RI>OC>@BQ >O@E LPQBOFLO>O@E LPQBOFLOQR?BO@IB RMBOFLO >OQF@RI>O OLLSBCLO >QBO>I SBOQB?O>I> C>@BQ J>PPBP O>KPSBOPBMOL@BPP O>KPSBOPBCLO>JBK O>KPSBOPB KCBOFLO KQBOFLO O>KPSBOPB >@BQCLOABKP KQBOFLO>O@E CLO>JBK >OQF@RI>O QR?BO@IB MOL@BPP KQBOFLO C>@BQ QR?BO@IB B Anterior view. C Superior view. KQBOFLO MFKLRPMOL@BPP BKP >OQF@RI>OC>@BQ BOQB?O>I BOQB?O>I>O@E CLO>JBK RMBOFLO >OQF@RI>OC>@BQ BKP KCBOFLO >OQF@RI>O O>KPSBOPB O>KPSBOPB MOL@BPP MOL@BPP MOL@BPP KCBOFLO RMBOFLO O>KPSBOPB >OQF@RI>O CLO>JBK LAV >OQF@RI>OC>@BQ C>@BQ KQBOFLO>OQF@RI>OC>@BQ B Anterior view. C Superior view. RMBOFLO K@FK>QB >OQF@RI>O BOQB?O>ICLO>JBK MFKLRPMOL@BPP MOL@BPP MOL@BPP BOQB?O>I>O@E LPQBOFLO >JFK> QR?BO@IB O>KP¦ RMBOFLO RI@RPCLO SBOPB >OQF@RI>OC>@BQ PMFK>IK BAF@IB KQBOFLO MOL@BPP LPQBOFLOQR?BO@IB QR?BO@IB O>KPSBOPB LAV MOL@BPPTFQE O>KPSBOPB KCBOFLO PRI@RPCLO CLO>JBK >OQF@RI>O PMFK>IK LAV MFKLRP C>@BQ KQBOFLO MOL@BPP QR?BO@IB B Anterior view. C Superior view. 7 Thoracic & Lumbar Vertebrae Fig. 1.11 Thoracic spine Fig. 1.12 Typical thoracic vertebra (T6) Left lateral view. Back RMBOFLO RMBOFLO SBOQB?O>IKLQ@E >OQF@RI>OC>@BQ RMBOFLO O>KPSBOPB @LPQ>IC>@BQ MOL@BPP MFKLRPMOL@BPP LPQ>IC>@BQLK PQQELO>@F@ QO>KPSBOPB SBOQB?O>ª« MOL@BPP KCBOFLO>OQF@RI>O LAV MOL@BPP KCBOFLO SBOQB?O>IKLQ@E RMBOFLO>OQF@RI>O KCBOFLO MOL@BPP @LPQ>IC>@BQ KCBOFLO MFKLRP >OQF@RI>OC>@BQ MOL@BPP O>KPSBOPB MOL@BPP A Left lateral view. KCBOFLO LPQ>IC>@BQ @LPQ>IC>@BQ LKQO>KPSBOPB MOL@BPP RMBOFLO O>KPSBOPB RMBOFLO >OQF@RI>OMOL@BPP LAV MOL@BPP @LPQ>IC>@BQ VD>ML¦ MEVPB>IGLFKQ RMBOFLO @LPQ>IC>@BQ BOQB?O>I ?LAV KCBOFLO LPQ>IC>@BQ @LPQ>IC>@BQ LKQO>KPSBOPB MOL@BPP KCBOFLO MFKLRPMOL@BPP >OQF@RI>OC>@BQ KCBOFLO B Anterior view.