Revive Massage and Wellness


Basics of Motion

The muscle must cross over a joint to act on it.

Muscle tissue will pull its attachment points closer to each other.

Types of Joints

  • Ball and Socket (shoulder)
  • Ellipsoid (radiocarpal joint in the wrist)
  • Gliding (carpal joints in the wrist)
  • Saddle (thumb)
  • Hinge (elbow)

What are synovial joints?

Synovial joints join bones with a fibrous joint capsule. The joint capsule is filled with synovial, the end of the bones will be covered with cartilage.

Synovial Joint Structure

  • Articular Capsule: A continuation of periosteum (the connective tissue covering of the bones) that surrounds the synovial joint.
  • Synovial Membrane: Membrane that contains the synovial fluid.
  • Synovial Fluid: This fluid provides shock absorption and nutrients to the cartilage. It also lubricates and protects the joint.
  • Articular Cartilage: Cartilage pads on the articular surfaces of the bones. These are on surfaces that could come in direct contact.
  • Ligaments: Fibrous connective tissue that frames that joint capsule, strengthening and stabilizing the joint.

Deltoid is divided into 3 fiber groups; anterior, middle, and posterior

Origin: Lateral 1/3 of the clavicle, acromion, and spine of the scapula.

Insertion: Deltoid tuberosity on the humerus

Action:

  • All fibers: abduct the shoulder.
  • Anterior fibers: flex the shoulder, medially rotate the shoulder, and horizontally adduct the shoulder
  • Posterior fibers: extend the shoulder, laterally rotate the shoulder, horizontally abduct the shoulder

Trapezius is also divided into 3 fiber groups; upper, middle, and lower. This muscle can work either bilaterally or unilaterally.

Origin: external occipital protuberance, medial portion of the superior nuchal line of the occiput and spinous processes for C-7 through T-12

Insertion: lateral 1/3 of the clavicle, acromion, and spine of the scapula.

Action:

  • Upper fibers: Bilaterally; extend the head and neck. Unilaterally; laterally flex the head, elevate the scapula, upwardly rotate the scapula
  • Middle fibers: adduct and stabilize the scapula
  • Lower fibers: depress the scapula, upwardly rotate the scapula

Latissimus Dorsi (Lats) is a large, superficial muscle that acts on the glenohumeral joint of the shoulder.

Action: Extend the shoulder, adduct the shoulder, medially rotate the shoulder.

Origin: Last 6 thoracic vertebrae, last 4 ribs, thoracolumbar aponeurosis, and posterior iliac crest

Insertion: Crest of the lesser tubercle of the humerus.


Thoracolumbar Aponeurosis: This is a connective tissue sheet on either side of the lumbar spine and iliac crest. Many muscles attach to it. This is similar to the IT band in the upper leg.


Teres Major works to assist the lats.

Action: Extend the shoulder, adduct the shoulder, medially rotate the shoulder.

Origin: Lateral side of the inferior angle of the scapula and the lower half of the lateral border of the scapula.

Insertion: Lesser tubercle of the humerus


Latissimus Dorsi and Teres Major work together to bring your arms behind you.