Skeletal system pt 2 Flashcards
chapter 8
Vertebral column
transmits weight of trunk to lower limbs
- surrounds + protects spinal cord
- flexible curved structure containing 26 irregular bones (vertebrae) in 5 major regions
1. cervical vertebrae (7): vertebrae of neck
2. Thoracic vertebrae (12): vertebrae of thoracic cage
3. Lumbar vertebrae (5): vertebrae of lower back
4. sacrum: bone inferior to lumbar vertebrae
5. coccyx: terminus of vertebral column
Curvatures
increase resilience + flexibility of spine
- cervical + lumbar curvatures: concave posteriorly
- thoracic + sacral curvatures: convex posteriorly
abnormal spine curvatures
- scoliosis: abnormal lateral curve
- kyphosis (hunchback): exaggerated thoracic curvature
- lordosis (swayback): accentuated lumbar curvature
Ligaments
Anterior + posterior longitudinal ligaments (on body)
- from neck - sacrum
- anterior: stronger prevents hyperextension
- posterior: narrow + weak, prevents extreme forward flexion
- ligamentum flavum: connects adjacent vertebrae
- short ligaments: connect each vertebra to those above + below
Intervertebral discs
Cushionlike pad composed of 2 parts
1. nucleus pulposus: inner gelatinous nucleus, gives discs its elasticity + compressibility
- anulus fibrosus: outer collar composed of collagen + fibrocartilage, limits expansion of nucleus pulposus
General structure of vertebrae (4)
- Body/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 bw adj vertebrae for spinal nerves
Vertebrae (3)
- Cervical (C1-C7)
- short spinous process (bifid)
- transverse foramen in ransverse processes
- C1 atlas, C2 axis - Thoracic (T1-T12)
- long, downward pointing spinous processes
- articulate with ribs in posterior - Lumbar (L1-L5)
- short, hatchet shaped spinous processes
- very large bodies
Cervical vertebrae
- C1 atlas, C2 axis have unique features
- Atlas C1
- no body/spinous process
- consists of anterior and posterior arches
- articulate with occipital condyles
- movement for yes
- carries skull - Axis C2
- Dens projects superiorly into anterior arch of atlas (missing body of atlas)
- dens is a pivot for rotation of atlas
- movement for no
- no intervertebral discs bw atlas + axis
Thoracic vertebrae
T1 - T12
- all articulate with ribs at facets and demifacets
- long, spinous process that points inferiorly
- circular vertebral foramen
- location of articular facets allows rotation of this area of spine
Lumbar vertebrae
L1 - L5
- recieves most stress
- short, thick pedicles, and laminae
- flat hatchet shaped spinous processes point posteriorly
- vertebral foramen triangular
- orientation of articular facets locks lumbar vertebrae together to prevent rotation
Sacrum
5 fused vertebrae (S1-S5)
- forms posterior wall of pelvis, completes the ring
- articulates with L5 superiorly, and with auricular surfaces of hip bones, forming sacroiliac joints
Coccyx
tailbone
- 3-5 fused vertebrae
- articulates superiorly w/ sacrum
Ribs + attachments
- all attach posteriorly to bodies + transverse processes of thoracic vertebrae
1. Pairs 1 - 7 - True ribs: attach directly to sternum via costal cartilage
2. Pairs 8-12 - false ribs
- pairs 8-10: attach indirectly by joining cartilage of rib above
- pairs 11-12: floating ribs that have no attachment to sternum
Appendicular skeleton
- Pectoral (shoulder) girdle: clavicle, scapula
- upper limb: arm, forearm, hand
- pelvic (hip) girdle: ilium, ischium, pubis
- lower limb: thigh, leg, foot
Upper limb
30 bones from skeletal framework of each upper limb
- arm: humerus
- forearm: radius + ulna
- hand: 8 carpal bones in wrist, 5 metacarpal bones in palm, 14 phalanges in fingers
Humerus
- articulates superiorly with glenoid cavity of scapula
- articulates inferiorly with radius + ulna
Bones of forearm (2)
- Ulna
- medial bone in forearm
- forms major portion of elbow jt with humerus - radius
- lateral bone in forearm
- forms major portion of wrist jt
- head articulates with capitulum of humerus and radial notch of ulna
- interosseous membrane connects radius + ulna along their entire length
Hand + 3 parts
- Carpus (wrist)
- 8 bones in 2 rows
- proximal row: lateral-medial, scaphoid, lunate, triquetrum, pisiform
- distal row: lateral-medial, trapezium, trapezoid, capitate, hamate - matacarpus (palm)
- phalanges (fingers)
Pelvic (hip) girdle
2 hip bones (coxal bones) and sacrum
- attach lower limbs to axial skeleton
- support pelvic organs
- less mobility but more stable than shoulder joint
- 3 fused bones form coxal (ilium, ischium, pubis)
- bony pelvis formed by coxal bones, sacrum, coccyx, pelvic ring
Male vs Female pelves
Female
- adapted for childbearing
- true pelvis (inferior to pelvic rim) defines birth canal
- cavity of true pelvis is broad, shallow, and has greater capacity
Male
- tilted less far forward
- adapted for support of male’s heavier build + stronger muscles
- cavity of true pelvis is narrow + deep
