chapter 7 and 8 skeletal system Flashcards
human skeleton
206 bones
longitudinal axis
80 bones
appendicular skeleton limbs
126 bones
axial skeleton functions
- support and protect organs in dorsal and ventral body cavities.
- provide surface area for muscle attachment:
A. adjust position of head, neck and trunk
B. Perform respiratory movements
C. stabilize appendicular skeleton
skull bones interconnect at immovable joints called sutures (dense fibrous CT). Four major sutures:
- Lambdoid
- Coronal
- Sagittal
4 Squamous
skull
22 bones
Lambdoid
separates occipital bone from parietal bones
coronal
separates frontal bone from parietal bones
sagittal
separates pareital bones
squamous
separates temporal bone from parietal bone
sinuses
air filled chambers inside flat bones
Function of sinuses
- reduce weight of bone
- house mucus membranes that moisten and clean incoming air
Found in: sphendoid, Ethmoid Frontal, palatine and maxillary bones
Skull development
-intramembranous ossification from many centers of ossification
-during development brain grows more rapidly than cranial bones
-growing skull bones held together by bands of fibrous CT to provide flexibility (expansion of brain, compression for birth)
-large intersections of CT between bones=fontanels (soft spots), persist until age 5
-around age 5 brain stops growing in size solid sutures form between cranial bones
craniostenosis
premature closure of fontanels w/o surgery brain is crushed
microcephaly
brain fails to enlarge cranium remains small
Vertebral column (26 bones)
7 cervical vertebrae (c1-c7)
12 thoracic vertebrae (t1-t12)
5 lumbar vertebrae (L1-L5)
1 sacrum ( 5 fused)
1 coccyx (3-5 fused)
-vertebral column not straight: 4 curves bring weight of body in line with central axis
Primary curves
-thoracic and sacral
-present at birth
-accomodate organs
secondary curves
-lumbar and cervical
-appear in first year
-necessary for bipedalism
-cervical= hold head up
-lumbar= standing
kyphosis
exaggerated thoracic curvature
lordosis
exaggerated lumbar curvature
scoliosis
abnormal lateral curvature
construction of column
-vertebral body: stacking
-intervertebral disc: spacing between bodies (not c1 and c2) annulus fibrosus: fibrocartilage, outside nucleus pulposus: gel inside (cushion) (loss of water from discs= shrinking height)
elastic ligaments
link bodies for alignment
intervertebral foramen
holes formed by spacing from discs allow spinal nerves to exit column
vertebral arch
bone attached to vertebral body, with body forms vertebral foramen
vertebral foramen
hole for spinal cord
vertebral canal
bony canal for spinal cord formed by stacking of vertebral foramen
spina bifida
vertebral arch fails to develop correctly at 3 weeks 9fetus) and spinal cord is unprotected or even exposed. 4/1000 births show some degree (due to lack of folic acid)
Thoracic cage (25 bones)
1 sternum
24 ribs:
7 pair true ribs: separate costal cartilage to attach to sternum
3 pair false ribs: common shared costal cartilage to attach to sternum
2 pair floating ribs: no cartilage no attachment to sternum
Appendicular skeleton
126 bones
-consists of limbs and limb girdles to provide movement
1. pectoral girdle: 4 bones
2. upper limbs: 60 bones
carpal tunnel syndrome
-carpals arranged in two rows of four bones
-creates a U shape enclosed by the flexor retinaculum (ligament)
-all tendons, vessels and nerves of hand must pass through channel between bones and ligament ( no extra space)
-any inflammation= pressure on nerves leading to pain
Pelvic girdle
2 bones 2 os coxae
note: “pelvis ( not anatomical) = pelvic girdle (2 os coxae) + sacrum + coccyx
lower limbs
60 bones
*individual bones and bone markings will be examined in detail in lab
