FT 131 Muscle Origins and Insertions PART #1

17 terms by Aust9622 

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Sternocleidomastoid

Origin: The manubrium of the sternum and the anterior superior surface of the medial clavicle.
Insertion: Mastoid process.
Action: Extension of the head at the alantooccipital joint, flexion of the cervical spine.
Right side: rotation to the left and lateral flexion to the right.
Left side: rotation to the right and lateral flexion to the left.

Serratus Anterior

Origin: Surface of the upper nine ribs at the side of the chest.
Insertion: Anterior aspect of the whole length of the medial border of the scapula.
Action: Abduction(protraction), Upward rotation.

Pectoralis Minor

Origin: Anterior surfaces of the third to fifth ribs.
Insertion: Coracoid Process of the scapula.
Action: Abduction(protraction), downward rotation, depression.

Levator Scapulae

Origin: Transverse processes of the upper four cervical vertebrae(C1-C4)
Insertion: Upper medial border of the scapula
Action: Elevates scapula, weak downward rotation, weak adduction.

Rhomboids

Origin: Spinous process of the 7th cervical and upper 5 thoracic vertebrae(C7-T5)
Insertion: Medial border of the scapula below the spine.
Action: Adduction(retraction) of scapula, downward rotation, elevation.

Trapezius

Origin: Base of skull(occipital bone) Spinous processes of C7 through T12.
Insertion: Lateral third of clavicle, acromion process, spine of scapula.
Action:
Upper fibers: elevation of scapula, upward rotation, extension and rotation of head at neck.
Middle fibers: elevation, upward rotation, and adduction(retraction) of scapula.
Lower Fibers: depression, adduction(retraction), and upward rotation of the scapula.

Latissimus dorsi

Origin: Posterior crest of the illium, back of the sacrum, and spinous processes of the lumbar and lower six thoracic vertebrae, lower 3-4 ribs.
Insertion: Medial lip of the intertubercular groove of the humerus, just below shoulder joint.
Action: Adduction, extension, Internal rotation, and horizontal abduction of the glenohumeral joint.

Deltoid

Origin: Clavicle, acromion process, and spine of the scapula.
Insertion: Deltoid tuberosity on the lateral humerus.
Action:
Anterior fibers: abduction, flexion, horizontal adduction and internal rotation of the glenohumeral joint.
Middle fibers: abduction of the glenohumeral joint.
Posterior fibers: abduction, extension, horizontal abduction, and external rotation of the glenohumeral joint.

Pectoralis Major

Origin: Clavicular head--medial half of the anterior surface of the clavicle.
Sternal head: anterior surface of the costal cartilages of the first six ribs and adjacent portion of the sternum.
Insertion: Upper shaft of humerus.
Action: Clavicular head(upper fibers) --internal rotation, horizontal adduction, flexion(to about 60 degrees) abduction(once the arm is abducted 90 degrees the upper fibers assist), adduction(with arm below 90 degrees) of the glenohumeral joint.
Sternal head(lower fibers): Internal rotation, horizontal adduction, and adduction and extension of the glenohumeral joint from a flexed position to the anatomical position.

Biceps Brachii

Origin: Long head--supraglenoid tubercle of scapula(area just above socket of shoulder joint)
Short head: Tip of corocoid process of scapula.
Insertion: Radial tuberosity (on medial aspect of upper part of radius. Bicipital aponeurosis.(Deep fascia on the medial aspect of the forearm.
Action Flexes the elbow joint, supination of the forearm, weak flexion of the shoulder, weak abduction of the shoulder joint during external rotation of shoulder joint.

Triceps Brachii

Origin: Long head--infraglenoid tubercle of the scapula(just below socket of shoulder joint,
Lateral head: upper half of the posterior surface of the humerus.
Medial head: distal two-thirds of the posterir surface of the humerus.
Insertion: Olecrannon process of the ulna.
Action: All heads- extension of the elbow
Long head: extesion, adduction and horizontal abduction of the shoulder joint.

Brachioradialis

Origin: Distal two-thirds of the lateral condyloid(supracondylar) ridge of the humerus.
Insertion: Lateral surface of the distal end of the radius at the styloid process/
Action: Flexion of the elbow, pronatioin of the forearm from supinated position to neutral, supination of the forearm from pronated position to neutral.

Brachialis

Origin: Distal half of the anterior shaft of the humerus.
Insertion: Coroncoid process of the ulna.
Action: Flexes elbow joint.

Rectus Abdominis

Origin: Crest of the pubis.
Insertion: Cartilage of fifth,sixth, and seventh ribs and the xiphoid process.
Action: Both sides--lumbar flexion, posterior pelvic rotation.
Right side: weak lateral flexion to the right.
Left side: weak lateral flexion to the left.

Internal oblique

Origin: Upper half of the inguinal ligament, anterior two-thirds of teh crest of the ilium and lumbar fascia.
Insertion: Costal cartilages of the eighth ninth and tenth ribs and the linea alba.
Action: Both sides-lumbar flexion, posterior pelvic rotation.
Right side: Lumbar lateral flexion to the right, rotation to the right, lateral pelvic rotation to the left.
Left side: Lumbar lateral flexion to the left and rotation to the left, lateral pelvic roation to the right.

Exterior Oblique

Origin: Anterior surface of lower eight ribs.
Insertion: Illiac crest and linea alba.
Action: Both sides--lumbar flexion, posterior pelvic rotation.
Right side: lumbar lateral flexion to the right and rotation to the left, lateral pelvic rotation to left.
Left side: lumbar lateral flexion to the left and rotation to the right, lateral pelvic rotation to the right.

Transversus Abdominus

Origin: Lateral third of the inguinal ligament, anterior two thirds of iliac crest, costal cartilages of lower six ribs, thoracolumbar fascia.
Insertion: Crest of the pubis and iliopectineal line, abdominal aponeruosis of the linea alba.
Action: Forced expiration by pulling the abdominal wall inward.

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