ch 10 shoulder joint

how many degrees of freedom does the shoulder joint have?

3

motions that occur in the frontal plane around the sagittal axis?

Abduction and adduction

prime movers of muscles p.158 Flexion Extension Hyperextension

Anterior deltoid, pectoralis Posterior deltoid, latissimus dorsi, Teres major, pectoralis major Posterior deltoid, latissimus dorsi

arthrokinematic motion of glenohumeral joint flexes and abduction extension and adduction medial rotation lateral rotation

At the glenohumeral joint, the convex humeral head moves within the concave glenoid fossa. As stated by the convex-concave rule, this convex joint surface (humeral head) glides in a direction opposite to the movement of the distal end of the moving bone (the humerus). Therefore, when the shoulder joint flexes (Fig. 10-3) or abducts, the humeral head glides posteriorly or inferiorly, respectively. This keeps the head of the humerus articulating with the glenoid fossa. In extension and adduction, the humeral head glides anteriorly or superiorly, respectively. With medial rotation, the humeral head glides posteriorly. With lateral rotation, the opposite motions occur. The head rolls glides anteriorly.

innervation of teres minor

Axillary nerve (C5, C6)

muscles that span the shoulder joint

Deltoid Pectoralis major Latissimus dorsi Teres major Supraspinatus Infraspinatus Teres minor Subscapularis Coracobrachialis Biceps brachii Triceps brachii, long head

abduction adduction prime movers

Deltoid, supraspinatus Pectoralis major, teres major, latissimus dorsi

what motion occurs in the sagittal plane around the frontal axis

Flexion, extension, and hyperextension

what motion occurs in the transverse plane around the vertical axis.

Medial and lateral rotation Horizontal abduction and horizontal adduction

teres major muscle insertion

Medial lip of bicipital/intertubercular groove of humerus

most shoulder muscles originate and insert where?

Most shoulder muscles have their origin somewhere on the scapula, clavicle, or rib cage and will insert on the humerus

innervation of biceps

Musculocutaneous nerve (C5, C6)

innervation of coracobrachialis

Musculocutaneous nerve (C5, C6, C7)

innervation of triceps

Radial nerve (C7, C8)

what makes up the shoulder joint?

The humeral head articulating with the glenoid fossa of the scapula makes up the shoulder joint. It is one of the most movable joints in the body, and consequently, one of the least stable.

Arthrokinematic motions during shoulder flexion and extension.

When the shoulder joint flexes, the humeral head glides posteriorly. During extension, the humeral head glides anteriorly.

refers to the inflammation and fibrosis of the shoulder joint capsule, which leads to pain and loss of shoulder range of motion. also known as frozen shoulder

adhesive capsulitus

one of the most common joint dislocations of the shoulder. a forced shoulder abduction and lateral rotation tends to be the dislocating motion causing the humeral head to slide anteriorly out of the glenoid fossa

anterior shoulder dislocations

glenohumeral movement arthrokinematics p.157

as abduction occurs, the humeral head rolls superiorly across the glenoid fossa.

innervation of the deltoid

axillary nerve, c5, c6

_____usually involves the long head of the biceps proximally as it crosses the humeral head, changes direction, and descends into the bicipital groove. a rupture of the biceps long head tendon commonly occurs during repetitive or forceful overhead positions. irritation as it slides in the groove can lead to ____

bicipital tendonitis subluxing of the biceps tendon

chronic inflammation of the supraspinatus tendon can lead to an accumulation of mineral deposits and can result in

calcific tendonitis

The normal end feel for all shoulder joint motions is

firm

commonly seen in individuals who have hemiplegia, usually from a cerebrovascular accident (stroke) paralysis of the shoulder muscles leaves them no longer able to hold the head of the humerus in the glenoid fossa

glenohumeral subluxation

fibrous ring that surrounds the rim of the glenoid fossa

glenoid labrum

injury caused by a fall on the outstretched hand. common in the elderly and usually results in an impacted fracture

humeral neck fracture

overuse condition that involves compression between the acromial arch, the humeral head, and soft tissue structures

impingement syndrome

lateral rotation prime movers

infraspinatous, teres minor, posterior deltoid

tear that involves damage to the glenoid labrum. results in limited shoulder motion

labral tear

medial rotation prime movers

latissimus dorsi, teres major, subscapularis, pectoralis major, anterior deltoid

innervation of the teres major

lower subscapular nerve posterior cord c5, c6, c7

innervation of pectoralis major

medial and lateral pectoral nerves lateral cord c5,c6,c7

_____ are often caused by a direct blow or twisting force. spiral fractures in this region increase the risk of ___

midhumeral fractures radial nerve injury, as nerve passes next to the bone

horizontal, adduction prime overs

pectoralis major, anterior deltoid

horizontal, abduction prime movers

posterior deltoid, infraspinatus, teres minor

the tendinous band formed by the blending together of the tendinous insertions of the subscapularis, supraspinatus, infraspinatus, and teres minor muscles

rotator cuff muscles These muscles help to keep the head of the humerus against the glenoid fossa during joint motion. This rotating motion is what inspired the term rotator cuff, not the muscular action of medial or lateral rotation.

motion is similar to flexion or abduction but occurs in the scapular plane as opposed to the sagittal or frontal plane

scaption

ball-and-socket joint with movement in all three planes and around all three axes

shoulder joint

Rotator cuff showing the proximal tendinous portion of the SITS muscles blending together to form a "cuff."

subscapularis, supraspinatus, infraspinatus, and teres minor muscles

innervation of infraspinatus

suprascapular nerve superior trunk c5, c6

innervation of the supraspinatus

suprascapular nerve superior trunk c5, c6

The greatest amount of arthrokinematic motion is possible at the glenohumeral joint when?

the glenohumeral joint is in the open packed position of 55 degrees abduction and 30 degrees horizontal adduction

innervation of the latissimus dorsi

thoracodorsal nerve posterior cord c6, c7, c8

superficial fibrous sheet that attaches to the spinous processes of the lower thoracic and lumbar vertebrae, the supraspinal ligament, and the posterior part of the iliac crest, covering the sacrospinalis muscle. It provides a very broad attachment for the latissimus dorsi muscle.

thoracolumbar fascia

involves the distal tendinous insertion of the supraspinatus, infraspinatus, teres minor, and subscapularis on the greater/lesser tubercle area of the humerus

torn rotator cuff

innervation of the subscapularis

upper and lower subscapular nerve posterior cord c5, c6

force couple of the deltoid and rotator cuff muscles (SITS)

while the deltoid pulls upward on the humerus, the rotator cuff muscles pull the humeral head down and into the glenoid fossa, allowing it to rotate in place during shoulder abduction

There are four groups of motions possible at the shoulder joint

(1) flexion, extension, and hyperextension; (2) abduction and adduction; (3) medial and lateral rotation; and (4) horizontal abduction and adduction.