acromioclavicular joint

Examples of acromioclavicular joint in the following topics:

• Types of Synovial Joints

  • Examples include the carpals of the wrist and the acromioclavicular joint.
  • The atlanto-axial joint, proximal radioulnar joint, and distal radioulnar joint are examples of pivot joints.
  • Examples include the wrist joint (radiocarpal joint) and the temporomandibular joint.
  • The knee joint is an example of a compound joint/modified hinge joint where different types of joints combine.
  • The left shoulder and acromioclavicular joints, and the proper ligaments of the scapula.

• Clavicle

  • Medially the clavicle is quadrangular in shape and articulates with the manubrium of the sternum forming the sternoclavicular joint. 
  • Laterally, the clavicle is flattened and attaches to the acromion process of the scapula forming the acromioclavicular joint.

• Scapula

  • The scapula articulates with the clavicle through the acromion process, a large projection located superiorly on the scapula forming the acromioclavicular joint.
  • The scapula also articulates with the humerus of the upper arm to form the shoulder joint, or glenohumeral joint, at the glenoid cavity.

• Clavicle Fracture

  • The medial end connects with the manubrium of the sternum and gives attachments to the fibrous capsule of the sternoclavicular joint, articular disc, and interclavicular ligament.
  • The lateral end connects at the acromion of the scapula which is referred to as the acromioclavicular joint.

• Impingement Syndrome

  • This can be caused by bony structures such as subacromial spurs (bony projections from the acromion), osteoarthritic spurs on the acromioclavicular joint, and variations in the shape of the acromion.
  • Plain x-rays of the shoulder can be used to detect some joint pathology and variations in the bones, including acromioclavicular arthritis, variations in the acromion, and calcification.
  • The impinging structures may be removed in surgery, and the subacromial space may be widened by resection of the distal clavicle and excision of osteophytes on the under-surface of the acromioclavicular joint.

• Rib Fracture, Dislocation, and Separation

  • A joint dislocation occurs when bones in a joint become displaced or misaligned.
  • It is important that the joint be reduced as soon as possible as, in the state of dislocation, the blood supply to the joint (or distal anatomy) may be compromised.
  • Some joints are more at risk of becoming dislocated again after an initial injury.
  • After a dislocation, injured joints are usually held in place by a splint (for straight joints like fingers and toes) or a bandage (for complex joints like shoulders).
  • When ligaments that hold the AC (acromioclavicular) joint together are partially or completely torn, the outer end of the clavicle may slip out of place, preventing it from properly meeting the scapula.

• Rotator Cuff Injury and Dislocated and Separated Shoulder

  • However, this flexibility comes at a cost which is that the shoulder joint is at greater risk of injury than other, less flexible joints.
  • The main functions of the cuff are to stabilize the glenohumeral joint and rotate the humerus outward.
  • The shoulder joint is the most frequently dislocated major joint of the body .
  • Doctors treat a dislocation by putting the head of the humerus back into the joint socket (glenoid fossa) of the scapula.
  • When ligaments that hold the AC (acromioclavicular) joint together are partially or completely torn, the outer end of the clavicle may slip out of place, preventing it from properly meeting the scapula.

• Muscles of the Shoulder

  • Muscles of the shoulder include those that attach to the bones of the shoulder to move and stabilize the joint.
  • The shoulder or glenohumeral joint is a ball and socket joint formed between the humerus and scapula.
  • Due to the shallowness of the socket and relatively loose connections, the shoulder joint allows for a wide range of motion; however, this wide range makes the joint unstable and thus more prone to dislocation and injury than other joints.
  • Two other joints make up the shoulder; the acromioclavicular joint of the clavicle and scapula, which allows the arm to be raised above the head, and the sternoclavicular joint of the clavicle and sternum, which plays an important role in facilitating movement of the upper arm and connecting it to the rest of the skeleton.
  • Highlighted in orange, the deltoids cover the rounding of the shoulder joint.

• Functional Classification of Joints

  • This category includes fibrous joints such as suture joints (found in the cranium) and gomphosis joints (found between teeth and sockets of the maxilla and mandible).
  • Most joints in this category include cartilaginous joints such as those found between vertebrae and the pubic symphysis.
  • An example is the elbow joint.
  • Multiaxial – Includes the ball and socket joints.
  • An example is the hip joint.

• Joint Venture