Functional Anatomy

What is the difference between a displaced and non-displaced fracture?
In a displaced fracture, the bone breaks into two or more sections and shifts position so that the two ends are not on a straight line. In a non-displaced fracture, the bone cracks all of the way through or either part but does not move thereby maintaining its proper alignment. Define as related to fracture healing:
Non-Union: This refers to a situation where a broken bone fails to heal.
Mal-Union: This refers to a situation where the fracture heals with the two ends of the bone not lined up correctly.
Delayed Union: This refers to a situation where the fracture takes longer than usual to heal.
What is Open Reduction vs. Closed Reduction treatment of a fracture?
Open reduction entails the exposure of fracture fragments by dissecting the tissues surgically whereas closed reduction refers to the handling of the bone pieces without exposing them.
Explain Wolff’s Law:
Wolff’s law states that a bone in a healthy animal or human being will adapt to the loads under which it is placed. Therefore, if the loading on the bone increases, the bone will become stronger to accommodate the additional load by remodeling itself over time. The inverse is also true.
Define and provide 2 examples for the following articulations:1. Fibrous Articulation-
These are fixed joints in which a layer of white fibrous tissue of varying thickness unites the bones.
Example 1. Sutures between skull bones Example 2. Gomphoses attaching the roots of human teeth to the lower and upper jaw bones
2.

Cartilaginous Articulation-
This refers to a joint in which the cartilage unites the bones thus providing slight flexible movement.
Example 1. Growth plates located between ossification centers in long bones Example 2. The manubriosternal joint between the sternum and manubrium.
3. Synovial Articulation – This refers to a specialized joint that allows more or less free movement, the union of the body elements that are surrounded by an articular capsule that encloses a cavity lined by synovial membrane.
Example 1. Hinge joint located between the humerus and the ulnaExample 2 Wrist or radiocarpal joint
Provide an example for the following “Subtypes” of a Synovial Joint (Clarkson pg. 5 can help)A. Condyloid (bicondylar)- Radiocarpal joint.
B. Pivot/ Rotational – The joint between the first and second cervical vertebrae.
C. Saddle (sellar)- The Carpometacarpal joint of the thumb.
D. Hinge (ginglymus)- Interphalangeal joints between the phalanges of the fingers and toes.
E. Gliding (plane)- Acromioclavicular joint of the shoulder.
F. Ball and Socket (spheroidal)- Glenohumeral joint of the shoulder.

Define Active vs. Passive Insufficiency. Provide examples and use the above image as a reference:
Active insufficiency takes place when the muscle fails to shorten enough and is felt as a cramping sensation since the muscle bunches up like a yarn ball. The biarticular muscle fails to shorten enough to allow the full movement of the joint that it crosses. An example of active insufficiency is where the case of hamstrings that cannot shorten enough to flex the knee when the hip is extended. The flexor digitorum superficialis crosses the wrist, elbow, interphalangeal, and metacarpophalangeal joints and acts to flex the joints. On the other hand, passive insufficiency occurs when the muscle fails to extend far enough to enable both joints to move through their full range. It happens where the movement of both joints stretches the muscles. An example is where the rect femoris cannot stretch far enough to enable the individual to flex the knee on an extended hip.
Define Arthrokinematics:
This refers to the specific movements of joint surfaces. It entails the small amplitude motions of bones at joint surfaces such as roll, glide or slide, and spin.
In your words explain 2 Arthrokinematic Motions1. Roll: This is a rotary movement that involves the rolling of one bone on another.
2. Slide: This refers to a translatory movement where one joint surface glides over another.
What is the concave-convex rule? Provide an example in the body.
The concave-convex rule states that the direction in which sliding occurs depends on whether the moving surface is concave or convex. Glenohumeral articulation is an example of the rule since the concave glenoid fossa articulates with the convex humeral head.
Define what the therapist experiences when assessing an End Feel-
When assessing the end feel on the specific joint, there is some form of motion limitation based on various factors that include the extensibility of tendons, ligaments, and muscles related to the joint and the contact of the articular surface. The factor that is significantly responsible for limiting the motion causes the particular feel thereby allowing the therapist to diagnose the problem. The joint capsule, contact of different joint surfaces, soft tissue approximation, or tight muscle tissue can cause the barrier. The therapist examines the barrier by its exact feel, known as the end feel. This will allow the therapist to differentiate an abnormal end feel from a normal one.
Fill in the table based on Normal End Feels
End Feel Description
Hard The sudden hard stop where bones make contact with each other, such as in elbow extension where the olecranon process makes contact with the olecranon fossa.
Firm A firm or springy feeling stop where soft tissue stretches after a joint is moved.
Soft This is where two soft tissue surfaces make contact with each other to produce a soft compression.
Abnormal End Feels:
End Feel Description/Example
Empty The feeling that nothing should stop the movement besides the great pain felt by the patient that results in the premature stop.
Boggy Abnormal end feel witnessed in acute conditions where soft tissue edema is present, such as after a severely sprained ankle.
Spasm The abrupt stop of movement caused by the spasming of muscles at the end or near the end of the movement. It is accompanied by pain.
Unexpected Hard, Soft or Firm Example: A hard end feel noted with elbow flexion after ORIF may indicate hardware in the joint space.
Hard Normal end feel defined by hard and abrupt end feel limit to passive joint movement.
Soft Normal end feel that occurs after the compression of the muscle bulk.
Firm Normal end feel defined by a firm sensation having a slight give when the joint is taken to the motion’s end range.
Define the following muscle contractions:
Isometric contraction: This is a contraction where the muscle fires or triggers with tension and force in the absence of any joint movement.
Concentric contraction: This is a type of muscle activation that raises the tension on a muscle when it shortens.
Eccentric contraction: This is a type of muscle activation that raises muscle tension as the muscle lengthens.
How can Joint Position affect muscle strength?
Muscle strength is maximum when the joint is in a neutral position or when the muscle is at resting length. The joint angle which enables the muscle to generate maximum force is not the same as the angle at which the moment arm is maximum. Muscles having longer fibers have a longer functional range as compared to muscles with shorter fibers. The muscle’s moment arm determines the amount of change in the muscle length that occurs when the joint rotates. The moment arm is the vertical distance from the axis of joint rotation to the muscle insertion. Therefore, there is a positive correlation between muscle moment arm and the length of the muscle fiber.
Define the following terms:
Agonists
These are muscles that contract when others relax. In the case of bending the elbow, the biceps are the agonists.
Antagonists
These are muscles that relax while others contract. In the case of bending the elbow, the triceps are the antagonists.
Synergists
These are muscles that contract together to achieve the same body movement.
Stabilizers or Fixators
These are muscles that stabilize the body and its extremities during multi-plane movement.
Describe an Open Chain Exercise:
In an open chain exercise, the distal aspect that is the section furthest away from the body is free because it is not fixed to an object. This is usually the foot or the hand in most cases. An example of an open chain exercise is the use of a leg curl machine that allows the lower leg to swing freely.
Describe a Closed Chain Exercise:
In a closed chain exercise, the distal aspect, which is the segment furthest away from the body is stationary or fixed to an object. A squat is an example of a closed chain exercise that involves the pressing of the foot against the floor to raise the body.
In your words describe the Length-Tension Relationship of muscle tissue:
The Length-Tension Relationship of muscle tissue asserts that the isometric force that a muscle exerts is determined by its length when tested. In explaining the relationship, it is proper to consider the interactions between the Passive and Active Length-Tension Relationships since they are the two fundamental mechanisms of the relationship. The active Length-Tension relationship reflects the overlap degree between the myosin and actin filaments. Too little or too much overlap leads to the development of sub-optimal tension. The development of maximal overlap requires the overlap to be “just right.” The Passive Length-Tension Relationship portrays the existence of elastic elements inside a sarcomere. The elements stretch to generate force with an increase in the length. Therefore, the Length-Tension Relationship defines the force that muscles exert. There is a moderate connection between the change in peak-torque angle and the increase in the fascicle length of the muscle.