SCAPULAR ABDUCTION AND UPWARD ROTATION: SERRATUS ANTERIOR
Prof. Dr: Amr. A. Abo-Gazia SERRATUS ANTERIOR
Range of Motion Serratus anterior
• 1) Origin: • Outer surfaces and superior borders of upper eight or nine ribs. • 2) Insertion: • Costal surface of medial border of scapula. • 3) Nerve Supply: • Long thoracic nerve C5, C6, C7, C8. Action: • - With the origin fixed, it abducts the scapula, rotates it so the glenoid cavity faces cranially and holds the medial border of the scapula firmly against the thorax. • - In addition the lower fibers may depress the scapula and the upper fibers may elevate it slightly. • - Starting from a position with the humerus fixed in flexion and the hands against a wall, the serratus acts to displace the thorax posteriorly as the effort is made to push the body away from the wall. NOTE A strong element of this type of action in which the serratus moves the thorax in relation to the fixed scapula comes into play in a properly executed push up. • Also with fixed insertion by the Rhomboids, the serratus may act in forced inspiration. • Range of Motion:
• In general the abduction displacement of the scapula is approximately equivalent to the space of 3 to 4 fingers. • This range of motion may be limited by: • - Tension of trapezoid ligament (limits forward rotation of scapula upon clavicle). • - Tension of trapezius and Rhomboids major and minor. SCAPULAR ABDUCTION AND UPWARD ROTATION
Grade "3" Fair Strength
Grade "4, 5" Good and Normal Strength
Grade "2" Poor Strength
Grade "1, 0" Trace and Zero Strength
SCAPULAR ELEVATION
Range of Motion
• Trapezius (upper fibers) . * Levator scapulae Trapezius (upper fibers)
• 1) Origin: • - External occipital protuberance • - Medial 1/3 of superior nuchal line • - Ligamentum nuchae • - Spinous process of seventh cervical vertebra • 2) Insertion: • - Lateral 1/3 of clavicle • - Acromion process of scapula • 3) Nerve Supply: • Accessory and ventral ramus: C2, C3, C4. • Action:
• - The trapezius upper fibers elevate the scapula.
• - With the insertion fixed and acting: unilaterally, the upper fibers extend laterally flex and rotate the head and joints of the cervical vertebrae so that the face turn toward the opposite side.
• - With the insertions fixed and acting: bilaterally the upper trapezium extends the head and neck. • Levator Scapulae:
• 1) Origin: • Transverse processes of first four cervical vertebrae. • 2) Insertion: • Medial border of scapula between superior angle and root of spine. • 3) Nerve Supply: Dorsal Scapular Nerve: C3 C4 C5 • Action: • - With the origin fixed, elevates the scapula and assists in rotation, so that the glenoid cavity faces caudally. • - With the insertion fixed and acting unilaterally, it rotates and flexed the cervical vertebrae to the same side • - Acting bilaterally, the levator scapulae may assist in extension of the cervical spine. Accessory Muscles:
• Rhomboids major and minor Range of motion:
• With full range of motion the shoulder is brought upper with a distance of approximately 3 fingers separating it with the ear inferior lobe.
• This range of motion may be limited by the following factors:
• - Tension of costoclavicular ligament
• - Tension of muscles depressing the scapula and clavicle: Pectoralis minor, subclavius and trapezius (lower fibers). SCAPULAR ELEVATION
Grade "3" Fair Strength
Grade "4, 5" Good and Normal Strength
Grade "2" Poor Strength
Grade "1, 0" Trace and Zero Strength
SCAPULAR ADDUCTION Trapezius (middle fibers)
Trapezius (middle fibers) Trapezius (middle fibers)
• 1) Origin: • Spinous processes of first through fifth thoracic vertebrae. • 2) Insertion: • Superior lip of spine of scapula. • 3) Nerve Supply: • Accessory ventral ramus: C2, C3, C4. • Action: • - The trapezius middle fibers are mainly responsible for the scapula adduction. • - They also maintain a stabilization role during the scapula downward rotation. • Accessory Muscles: • a. Trapezius upper and lower fibers. • b. Rhomboid major and minor. • Range of Motion:
• From the abduction position to the adduction position, the scapula travels a distance equivalent to the space formed by 3 to 4 fingers.
• This range of motion may be limited by the following factors:
• Tension of the coronoid ligament (limits backward rotation of scapula upon clavicle).
• Tension of Pectoralis major and minor and serratus anterior muscles.
. Contact of vertebral border of scapula with spinal musculature. SCAPULAR ADDUCTION
Grade "3" Fair Strength
Grade "4, 5" Good and Normal Strength
Grade "2" Poor Strength
Grade "1, 0" Trace and Zero Strength
Note
SCAPULAR DEPRESSION AND ADDUCTION: TRAPEZIUS (LOWER FIBERS) SCAPULAR DEPRESSION AND ADDUCTION: TRAPEZIUS (LOWER FIBERS) Trapezius (lower fibers)
• 1) Origin: • Spinous processes of sixth through twelfth thoracic vertebrae. • 2) Insertion: • Apex of spine of scapula • 3) Nerve supply: • Accessory and ventral ramus: C2, C3, C4. • 4) Action: • - The trapezius lower fibres mainly depress the scapula. • - They also provide stabilization when the upper and middle fibers are working. • Accessory Muscle • Trapezius middle fibers Range of Motion
• The distance covered by the depressed scapula is similar to the adduction motion as both motion are closely related together. It can also be compare to elevation motion as it is the opposite motion. • This range may be limited by the following factors: • - Tension of interclavicular ligament and articular disc of sternoclavicular joint. • - Tension of trapezius (upper fibers) levator scapulae and sternocleidomastoid (clavicular head) muscles. SCAPULAR DEPRESSION AND ADDUCTION
Grade "3 + 2" Fair and Poor Strength
Grade "4, 5" Good and Normal Strength
Grade "4, 5" "Alternate" If deltoideus are weak
Grade "1, 0" Trace and Zero Strength
SCAPULAR ADDUCTION AND DOWNWARD ROTATION: RHOMBOIDS
1. Rhomboid major 2. Rhomboid minor • Rhomboids Major and Minor • 1) Origin: • * Major: • - Spinous processes of second through fifth thoracic vertebrae. • * Minor: • - Ligamentum nuchae. • - Spinous processes of seventh cervical and first thoracic vertebrae. • 2) Insertion: • - Major: By fibrous attachment to medial border of scapula between the spine and inferior angle. • - Minor: Medial border at root of spine of scapula. • • 3) Nerve supply: • Dorsal scapular nerve: C4, C5. • 4) Action: • Adduct and elevate the scapula, and rotate it so that the glenoid cavity faces caudally. • • Accessory Muscle • Trapezius (adductor) Range of Motion
• The range of motion is similar in distance as for the adduction of scapula. • This range may be limited by the same factors as for the motion of scapular adduction. • SCAPULAR ADDUCTION AND DOWNWARD ROTATION
Grade "3" Fair Strength
Grade "4, 5" Good and Normal Strength
Grade "2" Poor Strength
Grade "1, 0" Trace and Zero Strength
Effect of weakness of the scapula adductor depressor and downward rotator muscles:
• - Weakness of these muscles will cause the scapula to abduct and the inferior angle to rotate outward.
• - The strength of adduction and extension of the humerus is diminished by the loss of the Rhomboids fixation of the scapula.
• - Ordinary function of the arm is affected less by loss of Rhomboids than by loss of either Trapezius or Serratus Anterior Muscles. Effect of Contracture of these Muscles
• The scapula is drawn into a position of adduction and elevation. • Contracture tends to accompany paralysis or weakness of Serratus Anterior Muscle because the Rhomboids are direct opponents of the Serratus •Thank You