Biology 128 Labs covering the Skeleton
and Joints
A list of bones of the body, and other things I said the other night.
Axial Skeleton (skull is included,
but is discussed later on)
Vertebral Column
Cervical
Vertebrae = 7 (But there are 8 cervical nerve pairs)
Thoracic
= 12
(with 12 pairs of ribs attached 24 in all 12 pairs of nerves)
Lumbar = 5
(# does vary fm 4-6 on occasion 5 pairs of spinal nerves)
Sacral = 5 (# varies from 4-7 all are fused, ♂s are elongated usually 5
pairs of spinal nerves)
Coccygeal
= 3 (most variable 3-7 but only 1 pair
of spinal nerves)
Spinal
cord is shorter than spinal columns in Adults
Sternum = 3 bones fused into one point of fusion is later in females
than males
As I said before, the skull, the most complex part of the axial skeleton will be discussed later on
Appendicular Skeleton - the limbs
and bones (girdles) attaching them to the axial skeleton
Upper Limbs Scapula shoulder blade has a ridge that can be felt that leads
out to the shelf over the upper arm
Shelf = Acromion , in front of the shoulder
below the Clavicle (collarbone) Coracoid process can be felt.
Main body of Scapula, the acromion,
and the coracoid all fuse from separate bony elements
to form the adult scapula.
Clavicle (S shaped bone collarbone)
that attaches arm and scapula to sternum = Clavicle and Scapula together form
the Pectoral girdle
Humerus upper arm. forms a weak but mobile joint with scapula
Radius outer bone of forearm that
goes on to form the wrist joint at its far end (distal end) next to the hand.
Carpals group of very strong bones
(wrist bones) that mesh with the hand bones on the far side and with the radius
on the near side.
The carpals and bones of the palm (metacarpals)
move pretty much as a unit.
Metacarpals bones that form the palm
Manual Phalanges bones that form the thumb
and fingers (or digits) there are
5 digits, but 14 phalanges that
make them up.
Lower Limbs Os coxa pelvic bones that together form the pelvic girdle that meshes
with the sacrum of the axial skeleton. The
Os coxae are composed of three bones when we are young which fuse into the os coxae with growth and maturity.
These bones
become important as landmarks and are used in naming areas of the body and
associated structures.
These bones are: the
connecting bar between the ilia.
Ischium
Pubis
Femur (thighbone)
Tibia (shinbone)
Fibula (small long bone on the outside
of the leg malleolus forms the outer Ankle)
Tarsals ankle bones, similar to the carpals, but which bear the weight of the
body. One of these is very
elongated and forms the heal bone (calcaneus bone).
Metatarsals bones forming the Top of
the foot or instep
Pedal
Phalanges your Toes. Like the hand, there are 14 of these that make
up the 5 pedal digits
Biology 128 the skull and a study of joints (arthrology)
Bones of the Skull:
-
Back side and bottom = Occipital
bone,
-
Sides = Parietal Bones
-
In Front over Eyes Frontal
Bone
-
Bones below parietals that include the ear
openings Temporal bones
-
Cheekbones = Zygomatic bones
-
Face bones = mostly the Maxillary
bones
-
Bridge of nose between orbits = Nasal
bones
-
Movable Jaw bone = Mandible
-
In nasal aperture the middle bone = Vomer
-
On sides of nasal aperture = Inferior
nasal conchal bones
-
Back of the orbits = Sphenoid
bone
-
One bone between the eyes forms medial side
of each orbit = Ethmoid bone
-
Bones just behind spur of the maxilla bone
and the Nasal bones with a groove in it are the Lacrimal bones
-
Back part of the roof of the mouth are the
Palatine bones
In the ear are a set of tiny
bones that form a linkage between the eardrum and the auditory sensing organ
of the inner ear.
These bones (only seen embedded
in plastic) are the malleus, incus, and stapes.
All of which brings us to the subject of joints that hold the skeleton together ...
Joints that should not move
very much
-
Suture joints Look at the jagged junctions
between cranial bones (there are 4 subtypes of sutures, some of
which are very strong and rigid.
-
Syndesmoses think of the sacroiliac joint that only moves in late
pregnancy or between the upper part of
the two leg bones the Tibia and Fibula
-
Gomphoses the little plug-in joints between teeth and jaws (a
special form of syndesmoses)
Joints that move a little,
and are supposed to:
-
Synarthroses joined by stiff cartilage like ribs to sternum
they allow you to breathe
-
Symphyses joined by fibrous cartilage like the intervertebral disks
Joints that should move fairly
easily:
-
Synovial Joints usually have slippery cartilage and fluids
in the joints. Most of the time, the
bones would
-
fall apart if it were
not for the ligaments that hold the bones together, but (usually) are outside
the joints.
-
Synovial joints differ
according to how many directions of movement are allowed at that joint.
the more
-
movement, the weaker the joint (usually) and the more muscles
are needed to stabilize the joint.
o
One direction of movement
§
Hinge joints like the elbow, or your fingers
flexion and extension is about all
§
Pivot joints the top two cervical vertebrae
let you turn your head or, the radius and
§
ulna when you rotate your hand from front to
palm facing backward (pronation)
o
Two directions of movement
§
Saddle joints the base of the thumb
o
Ellipsoidal joints try the wrist or the ankle
flexion and extension, abduction and adduction
o
and a movement called circumduction
too (this is also true for the saddle joints)
o
Many directions of movement
§
Planar joints little flat surfaces that let
bones slip over each other in just about any
direction the carpals slip a little against each other, and
so to the facets between vertebrae
§
Ball-and-socket joints humerus
toshoulder or hip to femur.
Can do just about any movement
§
from flexion to extension, abduction and adduction, and,
rotation around the long axis of the leg.