How many degrees of freedom does the scapula have?
The scapula also has three degrees of freedom for rotatory motion; it can move in three planes around three axes: Scapular WINGING occurs around a vertical axis that passes through the AC joint. Scapular TIPPING occurs around a lateral axis that passes through the AC joint.
What are scapulothoracic movements?
Scapulothoracic movements (movements of the scapula on the thorax) The scapula has five degrees of freedom for movement on the thorax: It can move in two "straight-line" directions or "translations." It can move in three planes, around three different axes. The scapula's two degrees of freedom for translatory motion permit:
What are the degrees of freedom in joints?
A fixed joint secures the relative positions of two bodies and completely restricts their movement with no degree of freedom. Six degrees of freedom of the knee joint, which include 3 rotational and 3 translational motions.
What is the importance of scapulothoracic joint in kinesiology?
Movements of scapulothoracic joint are a very important element of shoulder kinesiology. The wide range of motion available to the shoulder joint is due to the large movement available at ST joint. Observation and measurement of individual SC and AC joint motions are more difficult than observing or measuring motions of scapula on the thorax.
What is the scapula acromioclavicular junction?
How long does it take to read a scapulothoracic joint?
What is the scapula junction?
What is the innervation of the scapulothoracic junction?
What are the three degrees of freedom of the scapulothoracic junction?
How is the scapulothoracic junction stabilized?
Which nerve is used for the levator scapulae and rhomboids?
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Scapulothoracic Disorders | OrthoPaedia
Figure 1: A) The 4 basic straight motions of the scapula: elevation (purple) depression (red) protraction (yellow) and retraction (green). B) Medial rotation of the scapula (right scapula rotates clockwise as seen from the rear, medial side up).
What is the primary motion of the scapula during active elevation of the arm?
Retraction of the scapula is often performed in the context of pulling an object towards the body. Upward rotation of the scapula on the thorax is the primary motion of the scapula observed during active elevation of the arm and plays a significant role in increasing the range of elevation of the arm overhead.
What is the magnitude of upward rotation at rest?
If the vertebral or medial border of the scapula is used as the reference axis, the magnitude of upward rotation at rest is usually described as 2° to 3° from vertical. Although these “normal” values for the resting scapula are cited, substantial individual variability exists in scapular rest position, even among healthy subjects.
How many rotations of the scapula are there?
The motions of the scapula from the resting or reference position includes three rotations that occur at the AC joint. These are:
What is SC protraction?
SC protraction increases the extent of forward reach. As SC protraction occurs as a summation of both SC and AC joint, a decrease in motion at one joint can be atleast partially compensated by an increase at the other.
Where is the scapula located?
Normally, the scapula rests at a position on the posterior thorax approximately 2 inches from the midline, between the second through seventh ribs (scapula extends from the level of T2 spinous process to T7 orT9 spinous process, depending on the size of the scapula) and the medial border is about 6 cms lateral to the spine.
What is the movement of the scapulothoracic joint?
Movements of scapulothoracic joint are a very important element of shoulder kinesiology. The wide range of motion available to the shoulder joint is due to the large movement available at ST joint.
Does the scapula have translatory motions?
The scapula also has available translatory motions of scapular elevation/depression and protraction/retraction. The linkage of the scapula to the AC and SC joints prevents scapular motions both from occurring in isolation and from occurring as true translatory motions. Instead, scapular motions on the thorax must occur in combinations, such as the simultaneous upward rotation, external rotation, and posterior tipping that occur when the arm is abducted.
How many straight lines can a spherical object move in?
It can move in two "straight-line" directions or "translations."
Where does scapular swinging occur?
Scapular WINGING occurs around a vertical axis that passes through the AC joint.
Does the scapula move on the thorax?
Although a third degree of freedom is theoretically possible, the scapula does not move anteriorly or posteriorly on the thorax. Notice that we don't identify axes for these motions. These motions are are "translations;" they don't occur around axes! The scapula also has three degrees of freedom for rotatory motion;
What is the AC joint?
The AC joint is the articulation between the acromial end of clavicle and the clavicular facet of the acromion of scapula. The clavicular articular surface is oval and slightly convex while the acromial surface is accordingly concave. Both articular surfaces are covered with fibrocartilage.
What is the acromioclavicular joint?
Acromioclavicular joint (Articulatio acromioclavicularis) The acromioclavicular (AC) joint is the articulation between the two bones of pectoral girdle; the clavicle and scapula. It is a plane synovial joint, with flat articular surfaces which are approximately the same in size. Since there are no muscles that act directly on this joint, ...
Where does retraction occur?
Protraction and retraction of the acromion occur around a vertical axis that goes through the lateral end of clavicle, between the AC joint and coracoclavicular ligament. Protraction is limited by the posterior part of the joint capsule and conoid part of acromioclavicular ligament.
Which ligament connects the superior surfaces of the acromion and acromial end of?
The superior acromioclavicular ligament connects the superior surfaces of the acromion and acromial end of clavicle. A part of the trapezius muscle fibers fuse with this ligament, supporting the joint capsule from its superior side. Similarly, the inferior acromioclavicular ligament connects the inferior surfaces of the acromion and ...
How long does it take for a clavicle to heal?
Most grade I injuries do not require operative treatment. Instead, rest, pain killers, anti-inflammatory drugs combined with physical therapy leads to healing in two to three months. Higher grade injuries require reconstructive surgical methods, after which the joint usually heals in 2-3 months.
What is the function of the AC joint?
The function of this joint is to enable the pectoral girdle to follow the movements of the shoulder joint, particularly after the sternoclavicular joint has reached its maximal range of motion. In addition, the AC joint also allows for transmission of forces from the upper limb to the clavicle.
Where is the articular disc located?
Very rarely, a complete articular disc is found within the joint, attaching to the superior and inferior acromioclavicular ligaments. Besides its fully congruent arrangement, the stability of the AC joint is enhanced by a joint capsule and two sets of strong ligaments.
What is the scapula acromioclavicular junction?
The scapulothoracic junction enables the mobility of the scapula around the fulcrum of the acromioclavicular joint. Scapular mobility is important for the proper positioning of the shoulder joint in space. The scapula moves by gliding against the chest wall in three degrees of freedom;
How long does it take to read a scapulothoracic joint?
Reading time: 6 minutes. Scapulothoracic joint (Junctio scapulothoracica) The scapulothoracic joint is not a true anatomical joint but is rather considered as a unit that gathers the sternoclavicular and acromioclavicular (AC) joints and the junction between the anterior surface of the scapula and the thoracic cage (scapulothoracic junction).
What is the scapula junction?
The scapulothoracic junction is a connection between the anterior surface of scapula and the superolateral surface of the thoracic wall. The former is slightly concave anteriorly, while the latter is accordingly convex. The surfaces don’t adhere directly to each other.
What is the innervation of the scapulothoracic junction?
The innervation of the scapulothoracic junction refers to the nerves that supply the main muscles of the scapulothoracic motion;
What are the three degrees of freedom of the scapulothoracic junction?
The movements within the scapulothoracic junction are described into three degrees of freedom; elevation-depression, protraction-retraction, external rotation-internal rotation. Key facts about the scapulothoracic joint. Type. Not a true joint; comprised of acromioclavicular, sternoclavicular and scapulothoracic junction.
How is the scapulothoracic junction stabilized?
Since it has no ligaments, the scapulothoracic junction is stabilized by the synchronized actions and passive tensions of the three functional muscle units;
Which nerve is used for the levator scapulae and rhomboids?
Dorsal scapular nerve for the levator scapulae and rhomboids.