Chapter 7 Flashcards
(47 cards)
The appendicular skeleton
- Pectoral (shoulder) girdle
* clavicle
* scapula - Upper limb: arm, forearm & hand
- Pelvic (hip) girdle
* ilium
* ischium
* pubis
-Lower limb: thigh, leg, foot
Glenoid
shallow socket to allow mobility
The upper limb
- 30 bones form skeletal framework
- Arm
- Humerus (funny bone)
- Forearm
- Radius and ulna
- Hand
- 8 carpal bones in the wrist
- 5 metacarpal bones in the palm
- 14 phalanges in the fingers
Humerus
- Articulates superiorly with glenoid cavity of scapula
- Articulates inferiorly with radius and ulna
- have greater and lesser tubercle
Bones of the forearm
- Ulna:
- Medial bone in forearm
- forms major portion of elbow joint with the humerus
- so much bigger
- Radius:
- Lateral bone in forearm
- Forms major portion of wrist joint
- Head articulates with capitulum of humerus and radial notch of ulna
- Interosseous membrane connects radius and ulna along their entire length
- small but as you get lower down, radius gets larger
Hand: carpus, metacarpus, and phalanges
-Carpus (wrist)
*8 bones in 2 rows
*Proximal row-lateral to
medial
**scaphoid, lunate,
triquetrum, and
pisiform
* Distal row-lateral to medial
* trapezium, trapezoid, capitate, an dhamate
- metacarpus (palm)
- phalanges (fingers)
Pelvic (Hip) Girdle
- Two hip bones (coxal bones) and sacrum
- Attach lower limbs to axial skeleton
- Support pelvic organs
-Less mobility but more stable than shoulder joint
- Three fused bones form coxal bone:
- Ilium, ischium, and pubis
Bony pelvis formed by coxal bones, sacrum, and coccyx, pelvic ring
Comparison of Male and Female Pelves
Female Pelvis
- Adapted for childbearing
- true pelvis (inferior to pelvic brim) defines birth canal
- cavity of true pelvis is broad, shallow, and has greater capacity
Male pelvis
- tilted less far forward
- higher up, right under ribs
- adapted for support of males heavier build and stronger muscles
- cavity of true pelvis is narrow and deep
The lower limb
Carries entire weight of erect body
Subjected to exceptional forces if jump or run
Three segments of lower limb
- Thigh
- Leg
- Foot
Bones of the thigh
Femur
- Largest and strongest bone in the body
- Length~ 1/4 of persons height
- articulates proximally with acetabulum of hip and distally with tibia and patella
- comparison to humerous
Patella
-Sesamoid bone in quadriceps tendon
Bones of the leg
Tibia
- medial leg bone
- receives weight of body from femur; transmits to foot
Fibula
- Not weight bearing; no articulation with femur
- Several muscles originate from fibula
- Articulates proximally and distally with tibia
-Tibia and fibula connected by interosseous membrane
Foot: Tarsus, metatarsus, phalanges
Tarsus
- Seven tarsal bones
- Body weight carried primarily by talus and calcaneus
- Other tarsal bones: cuboid, navicular, and medial, intermediate, and lateral cuneiform bones
- Several joints in ankle and foot to accommodate uneven ground surfaces
Metatarsals (foot)
*Metatarsal head
Phalanges (toes)
Arches of the foot
- Maintained by interlocking foot bones, ligaments, and tendons
- Allow foot to bear weight
- Three arches
- Lateral longitudinal
- Medial longitudinal
* Transverse
Developmental Aspects: Fetal Skull
- Infant skull has more bones than adult skull
- Skull bones such as mandible and frontal bones are unfused
=Unossified remnants of fibrous membranes
=Ease birth and allow brain growth
=Four fontanelles (soft spots)
-Anterior, posterior,
mastoid, and
sphenoidal
Development of Spinal curves
At birth, only thoracic & sacral (primary) curves are present (convex posteriorly)
Cervical & lumbar (secondary) curvatures develop in childhood (convex anteriorly)
- cervical curve: when baby starts lifting head
- lumbar curve: baby begins to walk (12th mo.)
Developmental Aspects: old age
Intervertebral discs thin, less hydrated, and less elastic
*Risk of disc herniation increases
Several centimeter height loss common by 55
Costal cartilages ossify
*Rigid thorax causes shallow breathing and less efficient gas exchange
All bones lose mass, so fracture risk increases, spontaneous fractures
Skeletal System
Composed of bones, cartilages, joints, ligaments
Two major parts:
1. Axial:
-Skull
*Cranium and facial
bones
-Vertebral column
*Cervical, thoracic,
lumbar, sacrum, coccyx
- Thoracic cage
2. Appendicular
8 cranial bones
P (arietal) 2
E (thmoid)
S (phenoid)
T (emporal) 2
O (ccipital)
F (rontal)
6
Frontal bone (forehead)
Anterior portion of cranium
Most of anterior cranial fossa
Superior wall of orbits
Contains air-filled frontal sinus
Articulates with parietal bones by coronal suture
Parietal bones and major associated sutures (walls)
Superior and lateral aspects of cranial vault
Four sutures mark articulations:
- 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
Occipital Bone
Most of skull’s posterior wall and posterior cranial fossa
Articulates with 1st vertebra
Sites of attachment for ligamentum nuchae and many neck and back muscles
Temporal bones
Inferolateral aspects of skull and parts of cranial floor (complicated shape)
Four major regions:
Squamous - zygomatic
Tympanic –outer ear
Mastoid – anchor for neck MM
Petrous – inner/middle ear
Sphenoid bone
Complex, bat-shaped bone
Embedded in skull
Keystone bone:
Articulates with all other cranial bones
Three pairs of processes:
- Greater wings
- Lesser wings
- Pterygoid processes
Ethmoid bone (delicate bone)
Deepest skull bone
Superior part of nasal septum, roof of nasal cavities
Contributes to medial wall of orbits
Crista galli for dural attachment, secures brain in cranial cavity
