LABORATORY EXERCISE

SCAPULAOBJECTIVES

1. Identify scapular bony landmarks 2. Identify the scapular rotator muscles and their actions 3. Determine the scapular muscular action of simple arm movement.

Materials

a. Crutches b. Two different colors of yarn, scissors , cardboard c. Comfortable clothing d. Anatomical models of muscles of the scapula

Methods

1. Palpation and visual observation of scapular landmarks /movements on human subject 2. Creation of working visual paper / cardboard model of scapular rotation

3. Discussion of pathological implications THEORY

The scapula forms the basis for attachment of the upper limb to the trunk via the clavicle and functions by gliding across the post rib cage. Without coordinated movement of the muscles that control the scapula, the arm is severely limited in its ability to flex or abduct at the shoulder. One of the important landmarks of the scapula is acromion process. Is the hardest spot to locate in the small depression at the tip of the shoulder (especially shoulder abducted). The inferior angle is another important landmark that can often be seen easily, as most people have weak serratus anteriors and rhomboids leading to the condition of winged scapula (upward tilt). Placing the back of the hand in the small of the back will facilitate placing the scapula in upward tilt and thus observation /palpation of inferior angle of scapula. The inferior angle is an

excellent landmark to track the motion upward rotation, which occurs in fontal plane .Since the

ribs curve at the sides the frontal plane movement is not pure and the novice have difficulty

visualizing upward and downward rotation. Three muscles work together to perform upward

rotation of scapula (trapezius2&4, serratus anterior) and three muscles work together to perform downward rotation of the scapula (rhomboids, levator scapulae, pectoralis minor). This coordinated movement of muscles is critical at the scapula. Teaching people how to use the scapula muscles in a balanced manner with other upper limb muscles (scapulohumeral rhythm) is an important goal for kinesiologist. Feedback meaningful information give to a performer is one of the most important tools to reach the learning goals.

Activites for objective (bony landmarks) It is important to be able to find bony landmarks through human tissue .Identify the following landmarks on the skeleton and then use the hints in TABLE 1.1 to palapate the landmark on partner ( try to feel the bony part underneath the skin , muscle anf the tissues )

SHOULDER

Bony landmark to palpate Hints for palpating

Three angles of the scapula InferiorSuperiorlateral

Easiest , put hand in lower backUp by neck and spinal columnMay be under too much tissue to palpate

Three borders of the scapula VertebralLateralSuperior

Edge near spinal columnEdge under the arm pit

Usually not possible

Scapular spine Ridge across back

Root of scapular spine Near vertebral border

Acromion process Abduct arm ,hard spot in depression

Spinous process of C7 Ist big bump on back of neck

Spinous process of T12 Focus of trunk movement in spine

Sternoclavicular joint Shruf shoulder feel near neck

Acromioclavicluar joint Shrug shoulder feel near shoulder

Coaracoid process Soft spot on front of chest under clavicle

OBJECTIVES

1. Identify the movement and primary concentric muscle actions of the shoulder joint in six different activities

2. Locate and name the rotator cuff muscles 3. Identify the bony landmarks of the shoulder

Theory

The rotator cuff is composed of four muscles that insert neatly around the top of humerus . The subscapularis is the ant member of the grp , supraspinatus is the superior member while infraspinatus and teres mionr blend nicely to attach from behind .They all help to Stabiles the humerus by pulling medially as well as downwardly in a balance manner with other shoulder muscles . These are small muscles positioned precariously making them at risk of injury .It is important to strengthen these in concert with larger muscles .The movements of the shoulder are dependent on the position o f scapula .The shoulder is critically link in the chain of transferring speed to the hand such as in throwing or batting ball. The shoulder should move through all the plane of movement and can bring the entire arm upto move in the horizontal plane .The infraspinatus contributes to optimal placement of the humerus . An underactive infraspinatus is sometimes part of the problem in a painful impingement of the humerus against the acromion process because deltoid has nothing to counteract its upward rotation .

MOVMENETS

Activity 1

Moment analysis of shoulder forces in Fig - 1

ACTIVITY 2

Write down the names of rotator cuff muscles in the box next to fig 2 . Perform Inward and outward rotation of the humerus and attempt to palpate each of these cuff muscles

Activity 3

Identify from the Picture the muscle action in throwing ball during each Phase

Identify from the figure the muscle action.

Describe e the joint actions and concentric muscle actions for one shoulder joint activity

Describe how the location of muscle is related to muscle action

Explain when and why the anterior deltoid fibers are active during arm extension