THE LEVATOR SCAPULAE
Its name in Latin describes what it does: it is "a lifter of scapulas." It also assists in bending the neck. It arises as small tendons from the transverse processes of the atlas and axis as well as from the next two vertebrae. It inserts on the top part of the medial border of the scapula.
This muscle is located just below the levator scapulae and the rhomboideus minor muscle. Along with the levator scapulae, it assists in moving the scapula inward or medially, toward the spine, and upward. In the process it assists in moving the arm inward, called adduction. It arises from the spinous processes of the second through the fifth vertebrae —and inserts on the medial border (the one closest to the spine), of the scapula all the way to its tip.
THE RHOMBOIDEUS MINOR MUSCLE
This muscle lies just above the rhomboideus major muscle. Working with the levator scapulae and the rhomboideus
Rhomboideus Major M.
Rhomboideus Minor M.
Rhomboideus Major M.
major muscle, its actions contribute to the actions of the two muscles described above. It arises from the spinous processes of the lowest cervical and the uppermost thoracic vertebrae. It inserts at the base of the spine of the scapula on its medial border, just above the rhomboideus major muscle.
The Latin rhomboides and the Greek rhomboeides mean a parallelogram, a four sided figure with parallel sides but different adjacent angles.
Along with the teres major muscle this muscle assists in drawing the arm backward—medial rotation—as well as in swinging the arm. One of the rotator cuff muscles, it arises on the surface of the scapula somewhat below the spine and under the infraspinatus muscle, courses out over the border of the scapula below the infraspinatus and inserts as a tendon right next to the infraspinatus tendon's insertion on the greater tubercle of the humerus.
This round, smooth muscle, which assists in socket stabilization as well as medial rotation, arises from the bottom of the scapula, courses over the arising fibers of the lower teres minor muscle to insert on the upper shaft of the humerus, just a little below the insertion of the teres minor.
Teres in Latin means round.
THE SUPRASPINATUS MUSCLE
The supraspinatus muscle assists in lifting the arm outward —abduction. Another of the rotator cuff muscles it arises from the top of the scapula, the area above the spine. Its fibers merge into a tendon that crosses the joint to insert on the greater tubercle of the humerus. This tubercle is just behind the head of the humerus.
The infraspinatus muscle along with the supraspinatus muscle assists in rotating the arm backward. Another of the rotator cuff muscles, it arises just under the spine of the scapula, passes over the outside edge of the scapula, and inserts on the greater tubercle right next to, and almost fusing with, the supraspinatus muscle.
This muscle assists in rotating the arm inward and pulling it toward the body—adduction. It is one of the four muscles whose tendinous endings encircle the end of the humerus head to protect the joint, making up part of the rotator cuff. It arises from a major portion of the undersur-face of the scapula and inserts on the lesser tubercle of the humerus. The tubercle is found at the top of the humerus just behind the head of the humerus.
Subscapularis in Latin means "under the scapula."
This thick muscle covers the shoulder protecting the joint. If someone punches you in the shoulder, it helps absorb the blow keeping that inner joint from being damaged. It assists in many movements of the arm, moving it forward, backward, and outward—abduction. It arises from two bones and three places: from the lateral third of the clavicle, from the acromion, and from the spine of the scapula. The fibers cover the shoulder joint to merge as a small tendon which inserts onto the deltoid tuberosity, a small projection on the lateral aspect of the shaft of the humerus, about midway down.
Delta is a Greek letter that corresponds to our D but is shaped like a triangle A.
This large, flat muscle, which looks like a pointed cape over the top half of the back, assists in moving the head backward. It helps in rotating the scapula as well as in drawing it toward the spine. The lower part of the muscle assists in drawing the scapula downward and in drawing the arm inward. It arises from the back of the skull along a part of the superior nuchal line on the occipital bone, from the spinous process of the 7th cervical vertebra, and from the spinous processes of all the thoracic vertebrae. It drapes over the shoulder to insert on the clavicle and along the superior border of the spine of the scapula.
Trapezius comes from the Greek trapezion meaning "four legged bench" and has come to mean a figure with four unequal sides. You will encounter the origin of this word again in the bones of the wrist.
For the most part, the muscles of the upper arm cause the whole arm to move, those of the mid arm allow the lower arm to rotate, and those of the lower arm move the hand and fingers. Working together with the muscles of the upper arm are the muscles that spread across the chest and lower back.
THE BONES OF THE RIGHT ARM AND HAND WITH SHOULDER AND TWO RIBS: ANTERIOR VIEW; THE SAME BONES WITHOUT THE RIBS: POSTERIOR VIEW
You can see the clavicle, the scapula, the humerus, which makes up the whole shoulder joint, the radius, and the ulna, and the elbow that is the joint between the radius and the ulna and the humerus. Below them are the carpal bones, which form the wrist; the metacarpal bones, which form the body of the hand; and the phalanges, which are the fingers. There are many paralles between the arm /hand and the leg/foot. The differences are of interest also. At the knee, the leg can bend in only one direction. The lower leg is always in line with the upper leg. This is not so with the arm. Not only can the arm bend like the leg; the lower arm can also turn back and forth (supination and pronation), with the ulna staying in place and the radius pivoting around.
Ulna is Latin for forearm and radius is the Latin for rod or spoke.
Styloid Process of the Radius
Styloid Process of the Radius
Styloid Process Carpals
Phalanges of the
ANTERIOR VIEW POSTERIOR VIEW
THE HUMERUS, THE CLAVICLE, THE RIB CAGE, THE STERNUM, AND THE SCAPULA: ANTERIOR VIEW
There are some features to be noted when looking at the humerus. At the top you see a rounded portion which fits into the socket called the glenoid cavity of the scapula. There is a small neck and then two protrusions divided by an indentation. The two protrusions are the greater tubercle on the lateral side and the lesser tubercle on the medial side, with each sitting on either side of the intertubercular sulcus. In the middle of the lateral side of the shaft is a slight protrusion called the deltoid tuberosity. As the shaft reaches the bottom it broadens to form the medial condyle on the inside with the medial epicondyle beyond it, and the lateral condyle with its lateral epicondyle beyond it on the outside. The hinge of the elbow, which allows the arm to bend, is made up of the trochlea and the capitulum. Note the xiphoid process at the bottom of the stermun.
A condyle is a rounded end of a bone that fits into a concavity in the adjoining bone so that a joint is formed and the bone can rotate within that joint.
Condyle comes from the Greek hondylos and Latin condylus meaning knuckle or joint. The epi in epicondyle is from the Greek epi- a prefix meaning above or beside. Trochlea is from the Greek trochilia meaning a pulley. Capitulum is from the Latin caput meaning head. Xiphoid is from the Greek word Xiphoeides meaning sword shaped.
This big muscle spreads across the chest area and moves the arm, by rolling the arm inward, or by moving it toward the body if held out. It arises along the middle half of the clavicle, the sternum, and the cartilage of the upper six or seven ribs. It then converges into tendinous endings which are in three parts and insert on the bicipital groove of the humerus; the lower portion attaches above, the middle portion attaches in the middle, and the upper portion attaches below. That middle portion lies beneath the other two portions, with the upper one on top.
This muscle has a wide range of actions. It assists in arm rotation and it pulls the arm backward and inward from an outward position. It also pulls the body up in climbing. It plays a part in breathing as well, it aids in that last puff of expiration just when you think you've finished breathing out. It is also active when playing a wind instrument.
Starting wide and ending up by converging to a point it arises from a sheet of fascia known as an aponeurosis. You saw a tiny aponeurosis in the eye lid. This one is a broad sheet that arises along the vertebral column, from the spinous processes of the lower six thoracic vertebrae and from all of the lumbar vertebrae. It passes over the top of the illi-ac crest of the pelvis, or hip bone, and from there it passes over the tip of the scapula where fibers arise to join the main body of the muscle. All parts of this broad muscle converges to a small tendon that inserts on the humerus, its place of attachment being called the intertubercular groove. The tendon blends with the insertion fibers of the teres major just above it.
When translated from the Latin latissimus dorsi means "the widest back muscle."
THE CORACOBRACHIAL^ MUSCLE
This muscle assists in bringing the arm forward and inward —called adduction. It arises from the coracoid process of the scapula (the supraglenoid tubercle is at the base of this process) and inserts on the shaft of the humerus along the inner border.
Coraco is a medical or anatomical term meaning "connection with or relation to" and brachialis is from Latin brachium meaning the arm from shoulder to elbow.
The brachialis muscle lifts the forearm when you bend the elbow. It arises on the humerus just beneath the insertion of the deltoid muscle, and other fibers of this muscle arise along the bone from just above the elbow joint. It inserts as a thick tendon on the top of the ulna.
The biceps brachii muscle, familiarly known as the biceps, moves the arm forward and assists in turning the hand outward, a movement called supination. The biceps is a long muscle extending the length of the humerus. It arises in two places. It arises in two places; medially, the short head arises from the coracoid process of the scapula and laterally, the long head arises as a slender tendon from the supraglenoid turbercle inside the capsule of the shoulder joint. The tendon passes over the head of the humerus into a goove called the intertubercular sulcus. At this point the muscle has two bellies which fuse and then form a single tendon at the bottom. The tendon inserts on the tuberosity of the radius.
Biceps derives from the Latin hi and caput, meaning two heads.
The triceps brachii muscle extends the forearm, straightens it out from a bent position and assists in pulling the entire arm inward (adduction). It has three heads called long, lateral, and medial. The long head arises from the infraglenoid tuberosity, a slight projection just below the glenoid cavity. The lateral head arises on the upper rear surface of the humerus. The medial head is covered by the bellies of the other two but arises on the rear shaft of the humerus about were the two outer bellies merge. The fibers of this muscle insert into a large tendon which inserts on the olecranon process (at the top rear of the ulna).
Olecranon is from the Greek for "head of the ulna."
TRICEPS BRACHII M.
ELBOW AND FOREARM: PALMER AND DORSAL VIEWS
You can see the radius and the ulna of the lower arm, and the carpals, metacarpals, and phalanges of the wrist and hand.
THE PRONATOR TERES MUSCLE
The pronator quadratus muscle lies right next to the bones, but the pronator teres muscle is in the superficial layer of muscles.
The pronator teres muscle assists in turning the lower arm from the hand facing up to the hand facing in a down position, especially when the arm is raised. It arises on the medial (inside) aspect of the epicondyle of the humerus and the coronoid process of the ulna, wraps around the radius and inserts in the middle of the outside of the shaft of the radius.
Epi condyle comes from the Greek for "upon the knuckle."
Both the teres and the quadratus muscles assist in pronation of the arm and hand—that is in turning the hand and lower arm so the hand faces down when the arm is bent. Found just above the wrist it arises on the inner surface of the ulna, passes along the palmar side of the arm and inserts on the outer surface of the radius.
The supinator muscle turns your lower arm and hand from downward to upward facing positions. It arises from the top rear of the ulna and wraps around the radius to insert on its front surface.
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