Anatomy of the Shoulder The shoulder is the most mobile joint in the entire body. The shoulder joint is a ball and socket joint that allows movement in all three planes of motion. The major bone structure of the shoulder consists of the clavicle (collarbone), the scapula, the humerus (the top bone of the arm), the vertebrae of the spine, and the rib cage. Many muscles act on the shoulder joint. The muscles can be divided into two categories: the major muscles and the rotator cuff muscles. Five major superficial (close to the surface) muscles act on the shoulder joint resulting in the arm and upper back movement (see figure 5.2). The largest of the
muscles are the muscles of the chest and the large muscles of the back. The muscles Of the chest and back are antagonist muscles; they balance each Other during the archery draw. You need to balance the development Of antagonist muscles. An imbalance in strength between antagonist muscles can cause injury. The three remaining major muscles Of the shoulder are the front, the side, and the back deltoids. These muscles must be developed equally to protect the shoulder joint during the repetition Of the archery draw. The rotator cuff muscles are a group of four small muscles deep in the shoulder joint. Even though these muscles are small, they hold and stabilize the arm when it is extended (e.g., during the movement Of the archery draw). These muscles run between the upper arm and the back. The muscles are small and easily injured through overuse secondary to the improper development and error in training. Rotator Cuff Injuries The most common injury to the shoulder joint is shoulder impingement syndrome. Impingement syndrome is a very painful condition caused by the inflammation
Anatomy of the Shoulder The shoulder is the most mobile joint in the entire body. The sho
scapula when the arm or shoulder is moved. If left untreated, chronic bursitis and impingement syndrome can cause debilitating pain. If the archer "works through" the pain, permanent injury can result when the tendons are torn from their bony attachments. Surgery and extensive rehabilitation are required to repair the damage. The initial symptom of impingement syndrome is pain when the arm is held over the head. Untreated impingement syndrome leads to pain when extending the arm forward (e.g„ to shake hands). Pushing motions will also cause pain. Treatment for impingement syndrome starts with rest. A physician should be consulted if the pain persists after an extended (two weeks) period of rest, if the pain has increased, or if the archer has had the pain for more than a rnonth. Pushing movements must be avoided during the healing period. If the damage to the rotator cuff is minor, the physician will prescribe a strength program for the entire shoulder, back, and chest. In addition. exercises specific to rotator cuff development will be added when the muscles have healed. If the damage is severe and involves tearing of the tendons, the only recourse may be surgery. Rotator cuff injury can be prevented by strengthening the rotator cuff muscles, the shoulder, and the chest and back muscles and by following a com- plete flexibility program.
Flexibility Training The final element of a well-balanced fitness program is flexibility. Flexibility exerciæs increase the range Of motion Of the joints, elongate the muscles, provide a warm-up and cool-down Of the body, and decrease the risk Of injury. A stretching program should include a series Of slow stretches Of each body part. Flexibility is especially important for archers. Archery practice usually involves shooting hundreds of arrows over extended periods. Archers spend most Of their training and competi- tion day on their feet, frozen in their archery stance, which causes the muscles to Cool down and shorten. To maintain optimum muscle performance, archers should stretch at least once an hour during competitions and training. A comprehensive stretching program increases the range Of motion Of the joints and is the perfect way to relax the body and mind after a long day of training. A flexible joint has a complete range Of motion (ROM). ROM is defined as the ability Of a joint to move freely in every direction. Joint mobility is limited by the joint structure, the elasticity and strength Of the surrounding muscles, and the connective tissue of the joint. Flexibility training minimizes these factors. Like other aspects of physical conditioning, ROM can be improved with a complete flexibility training program. Warming Up Before performing any stretching activity, warm up the muscles. Your warm- «apula when arm or shoulder is moved. If left untreat«i, and impingement syndrome can cause debilitating pain. If the
In 1932 Klopsteg
"The archery files include correspondence and related materials, published articles, and speech manuscripts. A substantial folder of correspondence with Erle Stanley Gardner concerns their mutual interest in archery. Also of interest are four folders of correspondence with A.J. Costner, a pioneer in the resurgence of archery who also worked with the Pima Indians. Clippings also are included here. Several pertain to "Little Joe," the secret bow-pistol Klopsteg designed during World War II (Box 6, Folder 3; Box 9, Folder 3)."
Earl Hoyt
pope
Erle Stanley Gardner
A.J. Costner
muscles are the muscles of the chest and the large muscles of the back. The muscles Of the chest and back are antagonist muscles; they balance each Other during the archery draw. You need to balance the development Of antagonist muscles. An imbalance in strength between antagonist muscles can cause injury. The three remaining major muscles Of the shoulder are the front, the side, and the back deltoids. These muscles must be developed equally to protect the shoulder joint during the repetition Of the archery draw. The rotator cuff muscles are a group of four small muscles deep in the shoulder joint. Even though these muscles are small, they hold and stabilize the arm when it is extended (e.g., during the movement Of the archery draw). These muscles run between the upper arm and the back. The muscles are small and easily injured through overuse secondary to the improper development and error in training. Rotator Cuff Injuries The most common injury to the shoulder joint is shoulder impingement syndrome. Impingement syndrome is a very painful condition caused by the inflammation
Anatomy of the Shoulder The shoulder is the most mobile joint in the entire body. The sho
scapula when the arm or shoulder is moved. If left untreated, chronic bursitis and impingement syndrome can cause debilitating pain. If the archer "works through" the pain, permanent injury can result when the tendons are torn from their bony attachments. Surgery and extensive rehabilitation are required to repair the damage. The initial symptom of impingement syndrome is pain when the arm is held over the head. Untreated impingement syndrome leads to pain when extending the arm forward (e.g„ to shake hands). Pushing motions will also cause pain. Treatment for impingement syndrome starts with rest. A physician should be consulted if the pain persists after an extended (two weeks) period of rest, if the pain has increased, or if the archer has had the pain for more than a rnonth. Pushing movements must be avoided during the healing period. If the damage to the rotator cuff is minor, the physician will prescribe a strength program for the entire shoulder, back, and chest. In addition. exercises specific to rotator cuff development will be added when the muscles have healed. If the damage is severe and involves tearing of the tendons, the only recourse may be surgery. Rotator cuff injury can be prevented by strengthening the rotator cuff muscles, the shoulder, and the chest and back muscles and by following a com- plete flexibility program.
Flexibility Training The final element of a well-balanced fitness program is flexibility. Flexibility exerciæs increase the range Of motion Of the joints, elongate the muscles, provide a warm-up and cool-down Of the body, and decrease the risk Of injury. A stretching program should include a series Of slow stretches Of each body part. Flexibility is especially important for archers. Archery practice usually involves shooting hundreds of arrows over extended periods. Archers spend most Of their training and competi- tion day on their feet, frozen in their archery stance, which causes the muscles to Cool down and shorten. To maintain optimum muscle performance, archers should stretch at least once an hour during competitions and training. A comprehensive stretching program increases the range Of motion Of the joints and is the perfect way to relax the body and mind after a long day of training. A flexible joint has a complete range Of motion (ROM). ROM is defined as the ability Of a joint to move freely in every direction. Joint mobility is limited by the joint structure, the elasticity and strength Of the surrounding muscles, and the connective tissue of the joint. Flexibility training minimizes these factors. Like other aspects of physical conditioning, ROM can be improved with a complete flexibility training program. Warming Up Before performing any stretching activity, warm up the muscles. Your warm- «apula when arm or shoulder is moved. If left untreat«i, and impingement syndrome can cause debilitating pain. If the
oints of Pectoral Girdle: Anatomy of Shoulder Joint, Acromioclavicular Joint and Sternoclavicular Joint
Pectoral Girdle
Pectoral Girdle or Shoulder Girdle connects the free part of the upper limb with the trunk. It consists ofscapula and clavicle on each side. A series of anatomical organization makes the girdle extremely mobile. The mobility of scapula is essential for free movement of upper limb. The clavicle acts as a strut which holds the scapula laterally allowing the upper limb to swing freely from the side of the trunk.
Pectoral girdle consists of three joints: i) Sternoclavicular joint, ii) Acromioclavicular joint and iii) Glenohumeral joint. The scapula is connected to the clavicle and humerus (bone of the arm) by acromioclavicular and glenohumeral joints respectively. The upper limb and pectoral girdle are connected to the trunk (axial skeleton) only through the sterno-clavicular joint. Scapula does not make any anatomical joint with axial skeleton rather it is connected to the vertebral column and thorax only by the muscles. This connection of scapula with the thorax is sometimes referred as conceptual scapula-thoracic joint orphysiological scapula-thoracic joint. Thus the extremely mobile pectoral girdle is supported and stabilized by the muscles that are attached to the ribs, sternum and vertebrae.
Joints of Pectoral Girdle
Sternoclavicular Joint
Type: Saddle type of synovial joint.
Articulation:
The sternal end of the clavicle articulates with the manubrium sterni and the first costal cartilage.
Capsule: This surrounds the joint and is attached to the margins of the articular surfaces.
Synovial membrane: This lines the inside of capsule and extends to the margins of the cartilage covering the articular surfaces.
Ligaments:
Anterior and Posterior sternoclavicular ligaments reinforce the capsule from the front and behind.
Interclavicular ligament strengthens the capsule superiorly. It extends from sternal end of one clavicle to the sternal end of the other.
Costoclavicular ligament connects the inferior surface of sternal end of clavicle to the 1st rib and its costal cartilage.
Articular disc: It is a fibrocartilaginous disc which divides the interior of the joint into two compartments. The peripheral margin of the disc is attached to the interior of the capsule. It is also strongly attached to the superior margin of the articular surface of the clavicle above and to the first costal cartilage below.
Movements:
It is very mobile to allow movements of the pectoral girdle and upper limb. The movements that occur in SC joint are: forward and backward movements and elevation and depression. During full elevation of upper limb the clavicle is raised to approximately a 600 angle.
Muscles producing the movement:
Forward movement: Serratus anterior
Backward movement: trapezius and rhomboids
Elevation: trapezius, sternocleidomastoid, levator scapulae and rhomboids
Depression: pectoralis minor and subclavius
Nerve supply: The supraclavicular nerve and the nerve to the subclavius muscle.
Blood supply: by internal thoracic and suprascapular arteries.
Acromioclavicular Joint
Type: Plane synovial joint
Articulation: lateral end of clavicle articulates with the acromion of the scapula.
Capsule: Capsuleis relatively loose and is attached to the margin of the articular surfaces. From the capsule an incomplete wedge shaped fibrocartilaginous disc projects into the joint cavity from the above.
Ligaments: Superior and inferior acromioclavicular ligaments reinforces the capsule. The integrity of the joint is maintained by the extrinsic ligament called coracoclavicular ligament. It consists of a pair of strong bands that connect the coracoid process of scapula to the clavicle. The coracoclavicular ligament consists of two parts: conoid and trapezoid part.
The conoid ligament is cone shaped with its apex directed downward and attached to the root of the coracoid process and its base to the conoid tubercle on the undersurface of the clavicle. The trapezoid ligament is extends laterally for its attachment from the superior surface of coracoid process to the trapezoid line on the inferior surface of the clavicle. The coracoclavicluar ligament is also responsible for suspending the scapula and free limb from clavicular strut.
Movement: A gliding movement takes place when the scapula rotates or when the clavicle is elevated or depressed. The thoraco-appendicular muscles that attach to and move the scapula cause the acromion to move on the clavicle.
Nerve supply: Supraclavicular, lateral perctoral and axillary nerves
Blood Supply: Suprascapular and thoracoacromial arteries
Glenohumeral Joint
Glenohumeral joint is also called shoulder joint.
Type: Ball and Socket synovial joint
Articulation: occurs between the large rounded head of the humerus and a shallow glenoid cavity of the scapula. The articular surfaces are lined by the hyaline cartilage. The shallow glenoid cavity is deepened by a fibrocartilaginous tissue called glenoid labrum. The cavity receives more than a third of humeral head which is held in position by the tonus of the musculotendinous rotator cuff muscles.
Capsule:
The fibrous capsule surrounds the joint and is relatively thin and lax allowing the greater range of movement. Superiorly it is strengthened by the fibrous slips from the rotator cuff muscles. Inferiorly it is relatively weaker and is common site for dislocation of the joint.
Attachment of the capsule:
Medially – it is attached to the margin of the glenoid cavity outside the labrum. It also enclosed the origin of long head of biceps brachii.
Laterally – it is attached to anatomical neck of humerus except at two places, a) upper end of bicipital groove to allow the passage of tendon of long head of biceps brachii and b) inferomedially, the line of attachment extends downward for about 1 cm to the surgical neck.
Synovial Membrane: it lines the inside of the capsule and reflects from it onto the glenoid labrum and humerus as far as the articular margin of the head. It forms a tubular sheath around the long tendon of biceps brachii. It passes through the anterior wall of the capsule to form the subscapular bursa beneath the subscapularis muscle.
Ligaments:
Glenohumeral ligament
Coracohumeral ligament
Transverse humeral ligament
Coracoacromial ligament (accessory ligament)
Glenoid labrum
Glenohumeral and coracohumeral ligaments are the thickening of joint capsule that strengthens the anterior and superior aspects of the capsule respectively.
Glenohumeral ligaments are three fibrous bands, evident only on the interior of the joint capsule. The superior, middle and inferior bands of the glenohumeral ligaments are attached medially to the superomedial margin of glenoid cavity and blends with glenoid labrum. Laterally, all three bands radiate and are attached to the upper part of lesser tubercle, lower part of lesser tubercle and lower part of anatomical neck respectively.
The coracohumeral ligament extends from the root of the coracoid process to anatomical neck opposite the greater tubercle of the humerus.
The transverse humeral ligament bridges the gap between the two tubercles and strengthens the capsule.
Coracoacromial ligament is an accessory ligament which along with the inferior aspects of acromion and coroacoid process of scapula forms coracoacromial arch and protects the superior aspect of the joint as it prevents the superior displacement of humeral head. A subacromial bursa intervenes between the arch above and the tendon of supraspinatus and greater tubercle below.
Glenoid labrum:
It is made up of fibrocatilaginous tissue and helps deepening the glenoid cavity. It is attached to the margin of the glenoid cavity except above from where the long head of biceps brachii arises.
Movements at shoulder joint:
The shoulder joint has greater mobility. (Its stability has been compromised at the cost of the mobility as compared to hip joint which has greater stability but has limited range of movements). The freedom of movement is mainly due to the thin and lax capsule and the large size of humeral head compared to the receiving socket provided by the glenoid cavity. The glenohumeral joint produces movements around three axes and permits flexion-extension, adduction-abduction, medial-lateral rotation and circumduction.
Flexion and Extension:
Flexion and extension take place right angle to the plane of the body of scapula around an axis that passes through the humeral head and center of glenoid cavity. Flexion moves the arm forward and medially and is about 900. Extension moves the arm backward and laterally and is about 450.
Adduction-abduction:
Abduction and adduction take place parallel to the plane of the body of scapula around an axis which passes through the head of humerus and is parallel to the glenoid cavity. The abduction carries the arm laterally and adduction medially. During adduction the arm can be swung 450 across the front of the chest.
Mechanism of Abduction:
Abduction of the arm is accomplished by movement at shoulder joint as well as by the rotation of scapula at conceptual scapula-thoracic joint. The abduction is initiated for the first 150 by supraspinatus muscle which also holds the head of the humerus against the glenoid cavity. The later action then allows deltoid to take over and complete the further abduction. The limb can be elevated by 1800 during abduction. Except for the first 30 degree of abduction which occur due to movement at shoulder joint only, in every 150elevation, 100 occurs at shoulder joint and 50 by rotation of scapula at conceptual scapula-thoracic joint in the ration of 2:1. When the arm is abducted to 900, the further elevation is prevented as the articular surface is exhausted and the greater tubercle impinges on the lateral edge of acromion. The further elevation is then accomplished by the lateral rotation of humerus by 1800 which brings the greater tubercle posteriorly thus providing more articular surface to continue elevation. From 1200-1800, the abduction is accomplished by the rotating the scapula.
Medial and lateral rotations:
The plane producing these movements is a vertical axis passing through center of the humeral head to the center of the capitulum. In a semi-flexed elbow, the medial rotation at shoulder joint carries the hand medially and lateral rotation moves the hand laterally.
Circumduction:
It is a combination of above mentioned movements so that the lower end of the humerus defines the base of the core and the humeral head forms apex of the cone.
Muscles producing the movements at shoulder joint:
Flexion: Anterior fibers of Deltoid, Pectoralis Major and Coracobrachialis (weak flexor)
Extension: Posterior fibers of Deltoid, Latissimus Dorsi and Teres Major
Abduction: Supraspinatus (initial 150) and Deltoid
Adduction: Pectoralis Major, Latissimus Dorsi, Teres Major and Subscapularis
Medial Rotation: Subscapularis, Latissimus dorsi, Teres Major, Pectoralis Major, Anterior Fibers of Deltoid
Lateral Rotation: Infraspinatus, Teres Minor and Posterior Fibers of Deltoid
Factors stabilizing the shoulder joint:
As noted earlier, the shoulder joint is relatively weaker joint owing to its thin and lax joint capsule, greater mobility and shallow glenoid fossa to receive larger head of the humerus.
Rotator cuff: The tendons of small muscles namely subscapularis, supraspinatus, Infraspinatus and teres minor on their way to insertion on humerus flatten and blend with each other and with the fibrous capsule of shoulder joint. The tone of these muscles support and strengthen the shoulder joint from the front, above and from the behind.
Glenoid labrum: this fibrocartilaginous tissue deepens the glenoid cavity.
Glenohumeral and Coracohumeral ligaments support the joint from anterior and superior aspects respectively.
The coracoacromial arch prevents the upwards displacement of the joint. Similarly, the tendon of long head of biceps brachii also holds the head of the humerus in position during abduction. Similarly, the downward displacement of humerus during abduction is prevented by the long head of triceps brachii.
Blood Supply:
Anterior circumflex humeral artery, branch of third part of axillary artery
Posterior circumflex humeral artery, branch of third of axillary artery
Branches of suprascapular artery, branch of thyrocervical trunk of subclavian artery or directly from subclavian artery
Nerve Supply:
Axillary nerve and suprascapular nerve
REFERENCES:
Following resources are used while preparing this post (readers are strongly recommended to go through them for more details):
Gray's Anatomy
K. L. Moore's Clinically Oriented Anatomy
R. Snell's Clinical Anatomy
In 1932 Klopsteg
"The archery files include correspondence and related materials, published articles, and speech manuscripts. A substantial folder of correspondence with Erle Stanley Gardner concerns their mutual interest in archery. Also of interest are four folders of correspondence with A.J. Costner, a pioneer in the resurgence of archery who also worked with the Pima Indians. Clippings also are included here. Several pertain to "Little Joe," the secret bow-pistol Klopsteg designed during World War II (Box 6, Folder 3; Box 9, Folder 3)."
Earl Hoyt
pope
Erle Stanley Gardner
A.J. Costner
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