1. Chapter 8 Organs/vessels/structures are often named according to adjacent skeletal bones Skeletal anatomy also helps w/ understanding movements of skeletal muscles & provides reference landmarks Divided into 2 regions: axial & appendicular skeleton Axial skeleton forms central axis skull, vertebral column, ribs, sternum, sacrum, coccyx Appendicular skeleton includes limbs & girdles (bones that attach them to axial) 206 bones in typical adult skeleton Varies w/ development of sesamoid bones (bones that form w/in tendons under stress, patella); sutural bones of skull ~270 @ birth, decreases w/ age as bones fuse Surface markings defined in Table 8.2

2. Surface Markings

3. Skull Chapter divided into 4 regions= skull, vertebral column & thorax, upper & lower limbs & girdles Skull= 22 bones + sutures (immovable joints) Fused bones of skull form several cavities (& sinuses): cranial, orbits, nasal, buccal, ear, paranasal sinuses (frontal, spheniod, ethmoid, maxillary) Sinus= air-filled space w/in cranium Foramina= holes allowing passage of nerves/blood vessels (Table 8.3) 8 cranial bones cover meninges of brain: frontal, parietal, temporal, occipital, sphenoid, ethmoid bones Bones lie directly on dura mater of meninges (toughest, thickest, outer layer of 3 layers) 14 facial bones have no direct contact w/ meninges Serve as attachment of facial & mandibular muscles

4. Major Skull Cavities Cranial cavity Orbit contains eyeball & extraocular muscles Ethmoid sinus Nasal cavity Maxillary sinus Buccal cavity

5. Skull (cont.) Spinal cord enters brain through foramen magnum Brainstem can be forced out of f.m. during severe brain swelling 2 parts of cranium= calvaria (skullcap…roof & walls) & base (cranial floor…w/ 3 basins) Basins contour inferior surface for brain= anterior cranial fossa (frontal lobes), middle c.f. (temporal), posterior c.f. (cerebellum) Frontal bone- ‘forehead’ & part of roof; coronal (or frontal) suture, supraorbital margin, supraorbital foramen, glabella, & frontal sinus

6. Parietal & Temporal Bones 2 parietal bones- form cranial roof & part of lateral walls Bordered by 4 sutures= coronal (frontal), sagittal, lambdoid & squamous Marked by temporal lines of temporalis muscle 2 temporal bones- form lateral wall & part of floor of cranial cavity 4 parts of bone= squamous, tympanic, mastoid, petrous parts Squamous= flat vertical portion encircled by squamous suture Zygomatic process, mandibular fossa & TMJ Tympanic= ring of bone around external auditory meatus Styloid process for muscle attachment of tongue, pharynx, hyoid Mastoid= houses air sinuses of mastoid process (mastoiditis) Petrous= separates middle & posterior cranial fossa; houses middle & inner ear cavities Internal acoustic meatus, carotid canal, jugular foramen

7. Parietal & Temporal Bones Petrous part Squamous Tympanic Mastoid Carotid canal Jugular foramen

8. Occipital Bone Occipital bone- rear (occiput) & much of base of skull Foramen magnum= holds spinal cord & attachment area for dura mater Occipital condyles= smooth knobs where skull rests on atlas Hypoglossal canal lies laterally to each condyle External occipital protuberance for nuchal ligament (binds skull to vertebral column) Nuchal lines mark attachment areas for neck & back muscles (external occipital crest runs vertically btw 2 lines) Venous sinuses drain blood from brain before exiting brain via internal jugular veins

9. Sphenoid Bone Sphenoid- body & greater/lesser wings (moth shape), forms ½ middle cranial fossa & houses several foramina Lesser wings form posterior wall of orbit & optic canal Greater wings form part of lateral surface of cranium (anterior to temporal bones) Body houses pituitary gland in sella turcica (deep pit) Foramen rotundum & f. ovale allow for 2 branches of trigeminal nerve (CV) Lesser wing Greater wing Body Medial & lateral pterygoid processes

10. Sphenoid Bone (cont.) Middle & lateral pterygoid plates provide muscle attachment for some jaw muscle Sphenoid sinus w/in body of bone Nasal choanae= internal nasal openings Nasal choanae

11. Ethmoid Bone Ethmoid- btw orbital cavities & forms lateral walls & roof of nasal cavity 7 features to learn: middle & superior nasal conchae, crista galli, cribiform & perpendicular plates, olfactory foramina, ethmoid sinus

12. Ethmoid Bone (cont.) Perpendicular plate= superior part of nasal septum (dividing nasal cavity into left/rgt fossa) Superior & middle nasal conchae= scroll-like extensions that project into fossa Covered w/ mucus membrane & have olfactory receptor cells Ethmoid sinus= honeycomb air spaces on each side p.plate Crista galli= midsagittal crest that meninges attach to Cribiform plate= horizontal bone w/ numerous perforations Olfactory (cribiform) foramina= passage for olfactory receptor cells to brain (CN I) Injury can cause bone fragments to damage meninges/brain tissues; destroy olfactory nerves (anosmia)

13. Facial Bones Support teeth, give shape of face, form part of nasal & orbital cavities, attachment for muscles of mastication & expression 14 facial bones= maxillae, palatine, zygomatic, lacrimal, nasal, inferior nasal conchae, vomer, mandible Maxillae- 2 bones form upper jaw w/ teeth inserted in alveolar sockets…collectively called alveolar margin Forms inferomedial wall of orbit; infraorbital foramen Forms anterior 2/3’s of hard palate Palatine process= horizontal extensions of maxilla to form palate Cleft palate= failure to fuse, cleft lip as well Maxillary sinus

14. Palatine, Zygomatic, & Lacrimal Bones Palatine- 2 bones form posterior part of palate, part of wall of nasal cavity, & part of floor of eye orbit (tiny portion) Zygomatic- 2 bones forming ‘cheeks’ & part of lateral wall of orbit Extends ½ to ‘ear’ as a upside down ‘T’ Zygomatic arch= fusion of temporal process of zygomatic bone + zygomatic process of temperal bone Lacrimal- 2 bones forming part of medial wall of orbit Lacrimal fossa= depression housing lacrimal sac (tears drain into nasal cavity from sac)

15. Nasal Bones Nasal- 2 bones that form bridge of nose & support cartilage Often fractured by blow to the nose Inferior nasal conchae- 2 bones forming part of nasal cavity; largest of 3 conchae (sup & mid part of ethmoid bone) Vomer- 1 bone forming inferior ½ of septum, shaped like a ‘plow blade’ Superior ½ formed by p.p. of ethmoid; septal cartilage of anterior part of septum attaches to both bones Inferior nasal conchae Vomer

16. Mandible Mandible- strongest bone of skull & only bone that moves; supports lower teeth, attachment for muscles of mastication & expression 3 portions of bone= body (horizontal), ramus (vertical, posterior), angle (corner) Ramus ‘Y’ shaped- posterior branch (condyloid process) has an oval knob (mandibular condyle) to articulate w/ mandibular fossa of temporal bone Anterior branch= coronoid process, insertion pt for temporalis muscle (shuts jaw) ‘U’ shape btw branches= mandibular notch Mandibular foramen lies on medial surface of ramus, below notch so nerves/vessels can supply lower teeth Injection area for anesthesia TMJ- temporomandibular joint…hinge of mandible

17. Mandible (cont.) Bone fuses @ midsagittal cartilaginous jnt (mental symphysis) in fetus…ossifies during early childhood Mental protuberance= point of chin Mental foramen= passage for nerves/vessels to chin

18. 7 Bones Associated w/ Skull 3 bones/middle ear= auditory ossicles Malleus (hammer), incus (anvil), & stapes (stirrup) Hyoid bone= slender bone btw chin & larynx suspended from styloid processes by stylohyoid muscles & stylohyoid ligaments muscles of mandible, tongue, larynx evidence of strangulation Skull of children do not completely fuse until ~8-9 yrs Fontanels= unfused spaces btw cranial bones of infants Fibrous membranes join bones & are usually ossified ~1 yr Frontal bone & mandible fuse in early childhood Skull grows more rapidly to allow for brain growth

19. Vertebral Column VC physically supports skull & trunk; allows for movement; protects spinal cord; absorbs stress of walk/run/lifting; provides attachment of limbs, ribs, posture muscles 33 vertebrae & 23 intervertebral discs (fibrocartilage) 7 cervical, 12 thoracic, 5 lumbar, sacrum (5 fused sacral), coccyx (4 fused coccygeal) Variations can occur in # fused in sacrum, coccyx usually has 4, but can have 5 4 bends to VC- cervical, thoracic, lumbar, & pelvic curvatures Newborns C-shaped S-shaped required for bipedalism

20. Abnormal Spinal Curvatures Abnormal curves result from disease, posture, paralysis or congenital defect Scoliosis= abnormal lateral deviation lack of proper development of 1 (or more) vertebrae most common deformity, often of thoracic region Kyphosis= exaggerated thoracic curve, ‘humpback’ osteoporosis, heavy-lifting, sports, diseases Lordosis= exaggerated lumbar, ‘swayback’ weak abdominal muscles

21. Vertebrae Structure General structure= body, spinous & transverse processes, vertebral foramen Body= spongy bone/red marrow, thin layer of compact bone weight-bearing portion of spine rough surfaces for attachment of intervertebral disc Spinous & transverse processes= pts of muscle attachment Series of vertebral foramen form the vertebral canal Superior articular processes project upward to join w/ inferior articular processes projecting down of above vertebra restricts twisting of column Intervertebral discs= gelatinous pad surrounded w/ fibrocartilage ring; bind adjacent vertebae, support body weight, absorb shock expand/bulge laterally to absorb stress…herniated disc

22. Cervical vertebrae Intervertebral foramen= open space for passage of spinal nerves formed by adjacent vertebrae Space created by superior & inferior surfaces of pedicles (& transverse processes) Cervical (C1-C7)- smallest, lightest vertebra; ‘neck region’ Atlas= C1, supports head & articulates w/ occipital condyles No body; superior articular facet art’s w/ occipital, inferior a.f. w/ axis Allows to move head up/down (‘yes’) Axis= C2, allows to move head left/right (‘no’) Body present but differs from other vert’s; dens (odontoid process) a prominent knob unique to C2 for attachment of transverse ligament Spinous process bifid in C2-C6 for nuchal ligament attachment

23. Thoracic Vertebrae C3-C6 similar to typical vertebrae, C7 differs since the spinous process is not bifid & is long…forming bump of lower neck (vertebra prominens) C1-C7 have transverse foramina= passage for vertebral arteries to brain Thoracic (T1-T12)- 12 prs of ribs attach to 12 thoracic vert’s Lack transverse foramina & bifid processes Spinous processes angled down & pointed; body larger than cervical; costal facets Ribs insert btw vertebrae…each vert contributes ½ articulating surface (inferior & superior costal facets) T1, T10-T12 articulate w/ body T11-T12 have no transverse costal facet (2 nd pt of articulation)

24. Lumbar Thoracic Cervical C1 C2

25. Lumbar Vertebrae Lumbar (L1-L5)- thick, stout body w/ blunt, squarish spinous process Superior articular processes face medially (not forward), inferior a.p. face laterally…so lumbar region resists twisting L1 is in transition btw thoracic & lumbar, so s.a.p. faces dorsally & i.a.p. laterally Sacrum- bony plate of dorsal wall of pelvic cavity; S1-S5 in kids fuse ~16 yrs, completed by ~26 Features to know: ala, sacral canal, body, sacral foramina, transverse lines Anterior surface of body is smooth & concave w/ 4 transverse lines leading to sacral foramina Ala= lateral ‘wings’ Sacral canal= runs thru sacrum & houses spinal nerve root endings

26. Sacrum

27. Coccyx/Thoracic Cage Coccyx (Co1-Co4)- small, triangular bone of 4 fused vertebrae (~20-30 yrs) attachment site for muscles of pelvic floor vestige of a tail (mammals) cornua= hornlike projections on Co1 for ligaments attaching coccyx to sacrum fractured by fall or during childbirth Thoracic cage- T1-T12, sternum, ribs; encloses lungs & heart & attachment for pectoral girdle/upper limbs expands for breathing, costal margin (arc of lower ribs) protects spleen, liver, kidneys Sternum- 3 regions= manubrium, body, xiphoid process Manubrium= broad superior bone, suprasternal notch & clavicular notches

28. Sternum/Ribs Sternum (cont.)- Body= longest part, scalloped lateral margins for attachment of costal cartilage of ribs 2-7 Angle= pt where body joins w/ manubrium Xiphoid process= small, pointed bone for attachment of ab muscles Ribs- 12 prs; 1-7 true ribs, 8-12 false ribs, & 11-12 floating ribs attach to vertebra @ proximal end of rib…distal end is attached to sternum by costal cartilage Head (articulates w/ sup/inferior costal facets on vertebra body), neck, tubercle (articulates w/ costal facets on transverse processes), angle, shaft Rib 1 atypical, flat plate that articulates directly w/ T1…then ribs 2-9 articulate btw 2 vertebrae; ribs 10-12 articulate only w/ body of vertebra

29. Pectoral Girdle Pectoral girdle- clavicle & scapula; attaches upper arms Clavicle attaches medially to the sternum (sternoclavicular joint) & laterally to the scapula (acromioclavicular joint) Scapula articulates with the humerus (humeroscapular joint) Shoulders easily dislocated due to loose attachment Clavicle- slight S-shaped bone; inferior surface w/ ridges for muscle attachment sternal end (medial) is rounded & acromial end (lateral) flat Conoid tubercle= roughened area for ligament attachment keeps shoulder back & lateral (pectoral muscles pull forward)

30. Scapula Scapula- triangular plate lying dorsally over ribs 2 to 7 3 sides= superior, medial (vertebral), & lateral (axillary) borders 3 angles= superior, inferior, & lateral angles Acromion process= apex of shoulder, articulates w/ clavicle Coracoid process= muscle attachment Glenoid cavity= socket for head of humerus Subscapular, infraspinous & supraspinous fossa Spine

31. Upper Limb 4 regions of upper limb- brachium, antebrachium, carpus, manus….totals 30 bones per limb Brachium= humerus Antebrachium= radius & ulna Carpus= wrist bones; 8 small bones in 2 rows Manus= hand; 19 bones in 2 groups 5 metacarpals in the palm 14 phalanges in the fingers Humerus- head articulates w/ scapula @ glenoid cavity Greater/lesser tubercles= muscle attachment Intertubercular sulcus (groove)= tendon attachment (bicep) Anatomical/surgical necks= cartilage of head bordered by a.neck; s.neck common fracture…transition to shaft Deltoid tuberosity= rough area for deltoid muscle attachment

32. Arm Bones Humerus (cont.): Capitulum= lateral condyle of distal end articulates w/ radius Trochlea= medial condyle articulates w/ ulna Lateral/medial epicondyles= medial epi is expanded bone to protect ulnar nerve (‘funny bone’) Olecranon fossa= posterior pit, olecranon of ulna fits into when arm extended (back of elbow) Coronoid fossae & radial fossae= anterior pits, c.fossa (medial pit) for coronoid process of ulna when arm flexed; r.fossa (lateral) named for near head of radius Radius- smaller of 2 forearm bones, lies laterally (thumb-side), freely rotates on capitulum Head= distinctive disc articulating w/ capitulum & radial fossa Neck= directly below head, before r.t. Radial tuberosity= medial attachment area for biceps muscle

33. Radius/Ulna Radius (cont.): Styloid process= bony pt @ distal end of bone, proximal to thumb Ulnar notch= articulates w/ medial surface of distal ulna Ulna- lies medially, larger of 2 bones Trochlear notch= wraps around trochlea of humerus Olecranon= bony process of posterior side of elbow Coronoid process= small ‘ridge’ of bone on anterior side of t.n. Radial notch= small notch (medially) for head of radius to fit into Styloid process= small bony pt of distal end (medially) Interosseous membrane/margin= ligament attaching 2 bones, attaches @ i.margin

34. Wrist/Hand Bones Carpals- 8 bones of wrist in 2 rows of 4; small, square- roundish to allow for side/side & up/down movements Pisiform bone- sesamoid bone that develops w/in a tendon Metacarpals- 5 bones of palm (MI-MV)….MI (thumb) Base (proximal), shaft, head (distal end= knuckles) Phalanges- 14 bones forming fingers & thumb (pollex) Bones named as proximal, middle, distal + # of phalange ‘left proximal phalanx II’ or ‘right distal phalanx V’

35. Pelvic Girdle Pelvic girdle= 4 bones, coxae, sacrum, coccyx Coxal bone= 3 bones fused together, ilium, ischium, pubis Join sacrum of axial skeleton @ sacroiliac joint; articulates w/ femur @ acetabulum (hip socket); obturator foramen Ilium- largest portion of coxa; iliac crest, anterior/posterior superior/inferior iliac spines, iliac fossa Spines seen in lean ppl…dimples of back Iliac fossa smooth –vs- posterolateral surface rough for muscle attachment Greater sciatic notch Ischium- thicken bone w/ body & ramus, spine Lesser sciatic notch forms beneath spine Pubis- superior/inferior ramus & triangular body Pubic symphysis= 2 bodies joined

36. Lower Limb Male –vs- female Lower limb- 4 regions, 30 bones; femoral (+ patella), crural, tarsal, pedal regions Femur= thigh bone, spherical head articulates w/ acetabulum Fovea capitis= pit in head where ligament of ace extends into head Neck, greater/lesser trochanters= hip muscles attach to trochanters Linea aspera= posterior ridge of shaft Medial/lateral epicondyles= muscle & ligament attachment

37. Femur/Tibia Femur (cont.)- Medial/lateral condyles= smooth, rounded distal surfaces that articulate w/ tibia…groove btw it (intercondylar fossa) Patellar surface= smooth, medial depression for patella Patella- kneecap, triangular sesamoid bone Forms w/in tendon as child begins to walk Superior edge (base), pointed inferior (apex); articulates w/ femur on posterior surface @ 2 shallow facets Held in place by quadriceps tendon that extends down to tibia as the patellar ligament Tibia- thicker, stronger bone lies medially to fibula Medial/lateral condyles= 2 flat articulating surfaces of proximal end separated by a ridge (intercondylar eminence)

38. Tibia/Fibula Tibia (cont.)- Tibial tuberosity= rough surface for patella ligament attachment Anterior crest= sharp crest along shaft Medial malleolus= bony knob @ distal end (above ankle) Fibula- slender, lateral bone that helps stabilize ankle Broader head than lateral malleolus of distal end Interosseous membrane joins 2 bones Can be removed & used to repair bones Tarsals- 7 ankle bones; arranged in 2 grps for weight-bearing & form part of foot Distal row of carpals: Calcaneous= ‘heel bone’, largest bone, Achilles tendon Talus= 2 nd -largest, articulates w/ tibia Navicular= short, wide bone (upper arch)…3 = proximal row

39. Foot Bones Distal row of carpals- medial, intermediate, & lateral cuneiforms; cuboid 5 metatarsals & 14 phalanges; big toe has 2 bones (hallux) 3 arches to the foot- medial longitudinal arch (heel to hallux) transverse arch (proximal heads of metatarsals) lateral longitudinal arch (heel to little toe)

40. Bipedalism & other Adaptations Humans can stand upright constantly due to: Femur angled medially Feet arched & big toe ‘fixed’ & used to push-off in stride Coxae shortened & bowl-like (supports weight of viscera) Glutes help to balance body weight (front/back) & not laterally Other adaptations include: foramen magnum shifted ventrally & face flatter; spinal column centered above pelvis to shift center of gravity