Exam 2 Flashcards
When does the most significant growth if the skull occur
Age 5
The brain is 90-95% developed by nos
Appendicular skeleton
Bones of the upper and lower limbs
2) Bones that hold the limbs to the trunk of the body (pectoral girdle and pelvic
girdle)
Epicondyle
Projection adjacent to a Condyle
epiphyseal growth plate” is located in growing children and teenagers
(a) This growth plate is composed of hyaline cartilage and has intense mitotic activity
that helps bones increase in length.
(b) This mitotic activity is controlled by human growth hormone produced by the
pituitary gland located at the base of the brain.
(c) Fracture of a long bone in a growing child is especially serious if it results in
displacement of an epiphyseal growth plate. Such fractures can lead to a failure of the
damaged bone to elongate properly and a permanent shortening of the injured limb!
(d) In an adult when bone growth is completed the epiphyseal growth plate ceases its
activity and ossification occurs between the epiphysis and the diaphysis. The only
remnant is a defined area of compact bone called the “epiphyseal line”.
Outer ring of Fibrocartilage of intervertebral discs
Anulus fibrosus
TMJ movements
1) Depression and elevation of the lower jaw as a hinge joint.
2) Protraction and retraction of the lower jaw as a gliding joint.
3) Side-to-side lateral movements to grind food between the teeth as a gliding joint.
Compound (open)
Broken ends of bone protrude through the skin
Inversion
the movement of the sole (plantar surface) of the foot inward or
medially.
4 spinal curves
Cervical curve
Thoracic curve
Lumbar curve
Sacral curvature
Supination
occurs when the forearm rotates laterally so that the palm faces anteriorly or superiorly. In the anatomic position, the forearm is supinated and the radius and ulna are parallel
Crest
Narrow, prominent, ridge like projection
Lateral flexion
(d) “Lateral flexion” occurs when the trunk of the body moves in a coronal plane away
from the body.
- This type of movement occurs primarily between the vertebrae in the cervical
and lumbar regions of the vertebral column.
Condyloid joints
are biaxial joints with an oval, convex surface on one bone that articulates with a concave articular surface on the second bone of the joint.
(a) A good example are the metacarpophalangeal joints (commonly referred to as
“knuckles”) where fingers #2-#5 attach to the palm.
- Examine the metacarpophalangeal joint at the base of your finger #2 as an
example. You will note that it can flex and extend (one axis of movement) and
move side-to-side (second axis of movement).
(b) Another example is the radiocarpal joint were the distal end of the radius articulates
with the carpals.
3 types of fibrous joints
Gomphoses
Sutures
Syndesmoses
Alveolus
Deep pit or socket in the maxillae or mandible
Protraction
is the movement of a body part anteriorly in a horizontal plane.
- Examples are a jaw thrust, hunching the shoulders anteriorly, or moving the pectoral girdle forward (pelvic thrust).
Sutures
immoveable fibrous joints (synarthroses) that are
found only between certain bones of the skull.
1) Sutures form at about 15-24 months of age and replace the flexible fontanels of an
infant’s skull.
Rotational motion
pivoting motion in which a bone turns on its own
longitudinal axis (See Fig. at bottom of page 263).
(a) An example is turning the head from side to side (a “no” motion”) by rotation at the
atlantoaxial joint
Saddle joints
are biaxial joints that have a concave surface in one direction and
a convex surface in another. One is shaped like a saddle and the other is shaped like a rider sitting in the saddle.
(a) This arrangement allows a greater range of movement than either a condyloid or
hinge joint.
(b) The articulation of one of the carpal bones of the wrist (trapezium) with metacarpal
bone #1 in the meaty portion of the thumb forms the first carpometacarpal joint, which is a saddle joint.
- This joint permits the thumb to move toward the other fingers (opposable thumb)
so we can grasp objects.
- Having such opposable thumbs is most useful for grasping objects.
Step to bone healing
1) A “fracture hematoma” forms when blood vessels inside the bone and in the
periosteum are torn.
2) The traumatized area is cleaned up by phagocytic blood cells and by osteoclasts
that resorb the bone fragments. A soft “fibrocartilage callus” forms to bridge the
gap of the injured bones.
3) Osteoblasts begin ossifying the cartilage and soon a hard “bony callus” forms in
the injured area.
4) The final step is remodeling of the injured area. The excess callus is broken down,
a new vascular system is established, and compact bone develops around the periphery of the fracture.
Depressions, grooves, and tunnels
Blood vessels and nerves
Spongy (cancellous) bone
- This type of bone appears more porous, like a sponge.
- In a long bone, spongy bone is found primarily within epiphyses (See Fig. on
page 151). - In many of the flat bones of the skull there is spongy bone sandwiched between
two layers of compact bone. The spongy bone in this arrangement is referred to as “diploe” (See Fig. 6.7 on page 154). A blow to the head may fracture the outer compact layer of bone without harming the inner compact layer and the underlying brain. The central layer of spongy (cancellous) bone helps to distribute stresses and forces.
3 arches of the foot
(a) Medial longitudinal arch
(b) Lateral longitudinal arch
(c) Transverse arch
Sternoclavicular joint
a. The “sternoclavicular joint” is considered by your authors to be a saddle joint.
1) Some references agree that it is a saddle joint and some say it is a gliding joint.
b. The sternoclavicular joint is the articulation between the clavicle (collar bone) and the manubrium of the sternum.
c. An articular disc partitions the sternoclavicular joint into two parts and creates two separate synovial joint cavities.
d. A wide range of movements is possible: elevation, depression, and circumduction.
e. Support and stability are provided by the fibers of the articular capsule and by
reinforcing ligaments.
f. While dislocation of this joint is possible, typically when a person falls on an
outstretched hand the clavicle fractures before the joint dislocates.
Tempomandibular joint
The “temporomandibular joint” is the articulation formed at the point where the mandibular condyle of the lower jaw articulates with the mandibular fossa of the temporal bone.
1) This small, complex articulation located just anterior to the opening of the ear is
the only movable joint between skull bones.
Sulcus
Narrow groove
Third division nerve block
The mandibular teeth and gums can be desensitized by an injection of anesthetic near the mandibular foramen
Endochondral ossification
1) This is how the majority of the skeleton (the bones of the upper and lower limbs, the pelvis, the vertebrae, and the ends of the clavicles) develops.
Avulsion
Bone or bone fragments accompany soft tissues as it is pulled from its origin or insertion
Abduction
which means to “move away”, is a lateral movement of the body part away from the body midline.
- Examples are moving the leg or arm away from the midline of the torso or
spreading the fingers away from the midline of the hand.
Fibrous joints
Immoveable or slightly moveable
Lack a joint cavity
Purpose of skeletal system
form an internal framework to support soft tissues, protect vital organs, bear the weight of the body, and help us move
Planar (gliding) joints
are the simplest synovial articulations and are the least moveable type of diarthroses.
(a) They are uniaxial because they only allow side-to-side movements and the articular
surfaces are flat (planar). (b) Examples are:
- Intercarpal joints
- Intertarsal joints
- Joints between the articulating processes of adjacent vertebrae. Note that the
spine employs cartilaginous symphyses and synovial gliding joints!
Axial skeleton
The axial skeleton, which is composed of bones along the central axis of the body (See Fig. on page 174).
1) Skull and bones associated with the skull (auditory ossicles and hyoid bone) 2) Vertebral column
3) Rib cage (thoracic cage)
When does the squamoussal suture
By 60’s and might not ever ossify
2 types of ossification
Intramembranous
Endochondral
Trochanter
Massive, rough projection found only on the femur
Syndesmoses
Amphiarthroses
Between the shafts of the ulna and radius and between the tibia and fibula
Joined together by inter osseous membrane
Oblique
Diagonal fracture at an angle between linear and transverse
Arthrology
The study of joints
Pronation
the medial rotation of the forearm so that the palm of the hand is directed posteriorly or inferiorly. The radius and ulna are crossed to form an “x”
Common diarthotic synovial joints
shoulder (glenohumeral), jaw (temporomandibular), elbow, and knee (tibiofemoral).
Compact bone
- As its name implies, compact bone is solid and relatively dense.
- In a long bone, compact bone forms the solid external walls of the bone.
- In many of the flat bones of the skull compact bone forms both an inner and outer
layer
Line
Low ridge
Extension
which is the opposite of flexion, is movement in an anterior-posterior
plane that increases the angle between the bones.
- Examples are straightening the elbow, straightening of the knee, straightening the
fingers, or extending the neck so it is straight up.
- Extension typically returns a body part to the anatomical position.
Bones the develop by intramembranous ossification
flat bones of the skull, some of the facial bones (zygomatic bone, maxilla, and mandible), the central part of the clavicle (collarbone), and sesamoid bones (i.e.-kneecap)
Hollow paranasal sinuses
1) Sphenoidal 2) Maxillary 3) Frontal
4) Ethmoidal
Where does the glenohumeral joint get its strength
Rotator cuff
Head
Prominent, rounded epiphysis
Epiphyseal
Epiphysis is separated from the diaphysis at the Epiphyseal plate
Effects of hormones
a. Several hormones either directly, or indirectly, influence bone growth. A few will be discussed here.
1) “Growth hormone” (somatotropin) is produced by the anterior portion of the
pituitary gland and stimulates the activity of the epiphyseal growth plates.
2) Sex hormones (estrogen and testosterone), which begin to be secreted in great
amounts at puberty, dramatically accelerate bone growth at the epiphyseal growth
plates.
Depressed
Broken part of the bone forms a concavity (as in skull fracture)
Radiocarpal
a. The “radiocarpal articulation” is also called the “carpus”.
1) Three proximal carpal bones interface with the distal articular surface of the
radius to form the raiocarpal articulation.
2) A fibrocartilaginous articular disc separates the ulna from the radiocarpal joint,
which is why the ulna is not considered part of this joint.
Crepitus
Fracture of the maxillary sinus, a cracking sound caused by escaping air under the skin
Anatomic features of the TMJ
1) A loose “articular capsule” surrounds the joint and promotes an extensive range of motion.
(a) Consequently, the TMJ is poorly stabilized and thus a forceful anterior or lateral blow to the mandible can result in partial or complete dislocation of the lower jaw.
2) The TMJ contains an “articular disc”, which is a thick pad of fibrocartilage separating the articulating bones and extending horizontally to divide the synovial cavity into two separate chambers.
(a) As a result, the TMJ is really two synovial joints: one between the temporal bone and
the articular disc and a second between the articular disc and the mandible.
Impacted
One fragment of bone is firmly driven into the other
Synovial joints
Diarthotic, very mobile
Joints are separated by joint capsule
Classification of joints
Structure and function
Osteoblasts
secrete the initial semisolid form of bone matrix, called “osteoid”. This osteoid later calcifies and becomes bone. Once osteoblasts become entrapped in the matrix they produce and secrete, they differentiate into osteocytes