Anamtomy And physiclogy Labs 1,3,and 4

EXPERIMENT 7: ARTICULATIONS Articulations, or joints, are formed when two bones come together. The joints of the body are crucial to keep the body intact and facilitate movement. Joints can be classified by structure or type of mobility. As mentioned earlier, the three structural classifications are fibrous, cartilaginous, and synovial joints. The three mobility-based classifications are synarthroses (immobile), amphiarthroses (slightly mobile), and diarthroses (mobile). Though both classifications are useful, we will focus on structural classifications in this exercise.

PROCEDURE

Fibrous Joints 1. Fibrous joints are held together with fibrous tissue and do not possess a joint cavity. There are few amphiarthrotic fibrous

joints; rather most are synarthrotic. The two main types of fibrous joints are sutures and syndesmoses.

2. Sutures are composed of tight-fitting bones with little or no connective tissue. They are found only within the skull.

3. In syndesmoses, the bones are joined together by a small amount of dense, fibrous connective tissue. Though there can be slight movement with the joints, they’re typically considered synarthrotic.

4. Use Table 28 to locate the four prominent sutures between the cranial bones of the skull on the virtual model.

5. Locate the articulation between the distal ends of the tibia and fibula on the model skeleton. Additionally, look at the articulation between the radius and ulna. These are both examples of syndesmoses.

Experiment 7 Articulations Materials Virtual Model

Experiment Inventory

Table 28: Skull Suture Locations

Skull Sutures Location

Coronal Suture Articulation between the posterior portion of the frontal bone and anterior por-tion of the parietal bones.

Lambdoid Suture Articulation between the anterior portion of the occipital bone and the posteri-or portion of the two parietal bones.

Sagittal Suture Articulation between the two parietal bones.

Squamous Suture Articulation between the inferior portion of the parietal bone and the superior portion of the temporal bone.

Cartilaginous Joints 1. In cartilaginous joints, bones are connected with either a hyaline cartilage plate or a fibrocartilage disc. These joints, similar

to fibrous joints, do not have a joint cavity, although most of them are amphiarthrotic.

2. There are two types of cartilaginous joints: symphyses and synchondroses. In symphyses joints, the bones are connected with a disc of fibrocartilage. In synchondroses joints, the bones are connected with a plate of hyaline cartilage.

3. Locate the pubic symphysis on the virtual model. As the name suggests, this is a symphysis joint. Examine the vertebral column. Each vertebra is connected via an intervertebral disc composed of fibrocartilage.

4. Locate the articulation between the first rib and the sternum on the virtual model. This is an example of a synchondroses joint.

Synovial Joints 1. Synovial joints are the most common articulation within the body. Between the two articulating bones lies a joint cavity filled

with synovial fluid, allowing all synovial joints to be diarthrotic. It is important to note, however, that the type of mobility (side- to-side, multiple directions, etc.) varies.

2. Six subcategories have been created based on type of movement, due to the many synovial joints in the body. Use Table 29 to learn examples of the six synovial joint subcategories

3. Using Table 30, perform the listed movements on the model skeleton. Then, perform the same movements using your own body. Pay attention to the type of synovial joint that is involved with each movement.

Subcategory of Synovial Joints Movement Examples

Gliding Flat articulating surfaces allow for sliding movement side-to-side and back-and-forth.

• Intercarpal Joints (wrist) • Intertarsal Joints (foot) • Sacroiliac Joints

Hinge

Articulating surfaces between a con- vex bone and concave bone allow for uniaxial (one plane) movement. Typically, this movement is flexion or extension.

• Elbow Joint • Knee Joint • Ankle Joint

Pivot

Uniaxial rotation (one plane) occurs from the conical surface of one bone articulating with a shallow depression of another bone.

• Atlantoaxial Joint (atlas and axis) • Radioulnar Joint (arm)

Condyloid (Ellipsoidal)

An oval condyle of one bone fits with an elliptical cavity of another allowing biaxial (two plane) movement.

• Radiocarpal Joint (wrist) • Metacarpophalangeal Joints (knuckles)

Saddle

Both bones involved in the articula- tion possess both a concave and con- vex surface, called a saddle, which allows for biaxial (two plane) move- ment.

• Metacarpal (thumb) • Trapezium (wrist)

Ball and Socket Ball-like head articulates with a cup- like depression allowing for multiaxial (all directions) movement.

• Shoulder Joint • Hip Joint

Table 29: Synovial Joint Information

Table 30: Types of Joint Movement Type of Movement Definition Example

Flexion Bending motion that decreases the angle between the two bones. In anatomical position, bring the palm of the hand toward the shoulder, bending the elbow.

Extension Straightening motion that increas- es the angle between the two bones (opposite of flexion).

With the elbow bent and the palm of the hand touch- ing the shoulder, straighten the arm, bringing the palm down to the original starting position.

Abduction Moving a body part away from the midline of the body. Move the left thigh laterally away from the midline of the body.

Adduction Moving a body part toward the midline of the body (opposite of abduction).

With the thigh positioned laterally away from the body, bring it back toward the midline until it reaches the original starting position.

Circumduction Movement combining flexion, extension, abduction, and adduc- tion.

In anatomical position, bend the wrist anatomically to produce flexion, then move the wrist laterally to produce abduction, then move the wrist posteriorly to produce extension, and then move the wrist medially to produce adduction. Continue these motions, in- creasing the speed to produce a single motion.

Rotation Movement around the longitudi-nal axis of the bone. With the head beginning in anatomical position, look left and then look right as if shaking your head “no.”

Pronation Rotating movement of the palm and forearm from an anterior po- sition to a posterior position.

In anatomical position with the palm facing up, rotate the palm medially until it is facing down.

Supination Rotating movement of the palm and forearm from a posterior po- sition to an anterior position.

With the palm facing down (posterior), rotate the palm laterally until it is facing up.

Inversion Moving sole of foot medially. In anatomical position, move the sole of the foot me-dially.

Eversion Moving sole of foot laterally (op-posite of inversion). In anatomical position, move the sole of the laterally.

Dorsiflexion Bending movement of the ankle where the foot is flexed upward. In anatomical position, lift the toes upward, as if standing on the heels.

Plantar flexion Bending movement of the ankle where the foot is flexed down- ward.

In anatomical position, point the toes toward the ground, as if standing on the toes.