Chapter 10 Shoulder Joint Kinesiology

Abduction and adduction

180 degrees of motion possible

Degrees of shoulder hyper extension

45 degrees from AP

Pectoralis Major (both portions)

A - Shoulder adduction, medial rotation, horizontal adduction N - Lateral and Medial Pectoral Nerve (C5-T1)

Glenoid labrum

A fibrous ring that surrounds the rim of the glenoid fossa; its function is to deepen the articular cavity.

Coracohumeral ligament

Attaches from the lateral side of the coracoid process and spans the joint anteriorly to the medial side of the greater tubercle. Helps strengthen the upper part of the joint capsule.

Motion possible at shoulder joint

Flexion, extension/hyperextension, abduction, adduction, medial and lateral rotation, horizontal abduction and horizontal adduction.

Glenohumeral ligaments

Poorly defined ligaments that actually are pleated folds of the capsule and reinforces the anterior portion of the capsule.

Joint capsule

The thin-walled, spacious container that attaches around the rim of the glenoid fossa of the scapula and the anatomic neck of the humerus. -formed by outer fibrous membrane & inner syn0vial membrane -when arm is hanging, superior part of capsule is taut, inferior is slack -when shoulder is abducted, inferior is taut, superior is slack

Acromioclavicular separation

Used to describe various ligament injuries at AC joint -1st degree sprain - acromioclav lig is stretched -2nd- acromioclav lig ruptured, coracoclav lig is stretched -3rd-both acromio and coracoclav ligs are ruptured

2. Lie prone on a table with your arm over the edge and with your shoulder flexed 90 degrees, elbow flexed 90 degrees, and weight in your hand. Lift the weight away from the table in a sideward motion. a. Does flexing the elbow shorten the force arm? b. Does flexing the elbow shorten the resistance arm? c. Why is this exercise easier than when the elbow is extended (like in question 1)?

a. No b. Yes c. With a shortened RA, there is less resistance that the force needs to move

Humerus

longest and largest bone in upper extremity -Head - semirounded proximal end, articulates with scap -Surgical neck - slightly constricted area just below tubercles where head meets body -Anatomical Neck - circumferential groove separating head from tubercle

9. Which shoulder joint muscles do not attach on the scapula?

- Pectoralis major muscle - Anterior deltoid muscle - Latissimus dorsi muscle

5. Tucking and holding a book under your arm

- Shoulder joint motion: adduction - Shoulder girdle motion: scapular downward rotation

4. Placing a book on the upper bookshelf (POST TEST)

- Shoulder joint motion: flexion - Shoulder girdle motions: scapular upward rotation & scapular protraction

2. Reaching up to get hold of your seat belt (driver's side with left hand)

- Shoulder joint motions: abduction and lateral rotation - Shoulder girdle motion: scapular retraction (lateral rotation) & upward rotation (abduction)

3. Fastening your seat belt with your left hand.

- Shoulder joint motions: medial rotation & adduction - Shoulder girdle motions: scapular protraction (medial rotation) & scapular downward rotation (adduction)

b. Which motions occur in the transverse plane around the vertical axis?

- Shoulder medial & lateral rotation - Shoulder horizontal abduction & adduction

Parts of Scapula Con't

- Subscapular Fossa - inc. most of the area on the anterior (costal) surface, providing attachment for subscapularis muscles -Infraspinous Fossa - below the spine, providing attachment for infraspinatous muscle

8. Name the shoulder joint muscles attaching on the anterior side of the scapula?

- Subscapularis muscle - Coracobrachialis muscle

6. What are the SITS muscles, and why are they called the "rotator cuff muscles"?

- Suprapinatus, infraspinatus, teres minor, & subscapularis muscles - They are called this because they hold the head of the humerus in toward the glenoid fossa as it moves within the socket

7. Name the shoulder joint muscles attaching on the posterior side of the scapula.

- Supraspinatus muscle - Infraspinatus muscle - Teres minor muscle - Teres major muscle - Posterior deltoid muscle

Identify the shoulder joint motions and the accompanying shoulder girdle motions in this action: 1. Putting your billfold in your left back pocket with your left hand.

- a. Shoulder joint motions: hyperextension & medial (internal) rotation - b. Shoulder girdle motion: scapular tilt (hyperextension) & protraction (medial rotation)

Parts of Scapula Con't

-Acromion Process - broad, flat area on the superior lateral aspect, provides attachment for middle deltoid muscle

Parts of Scapula Shoulder Joint Related

-Glenoid Fossa - shallow, somewhat egg shaped socket on the superior end, lateral side, articulates w/humerus -Glenoid Labrum - fibrocartilaginous ring attached to rim of the glenoid fossa, deepens articular cavity

Parts of Scapula Con't

-Supraspinous Fossa - above the spine, provides attachment to supraspinatus muscle -Axillary Border (lateral border)- provides attachment for teres major and minor muscles

Horizontal Abduction/Adduction (Pg 132, Fig 10-2) Abduction Supine, Arm Straight up at shoulder Adduction Supine, arm flat out perp. to body, bring back to adduction position

-occur in transverse plane around the vertical axis -start at 90 degrees of shoulder abduction and approximate 30 degrees of horizontal abduction (backward motion) and approximately 120 degrees of horizontal adduction (forward motion)

Degrees of shoulder flexion

0 - 180 degrees

Pathological fractures

A result of benign tumors or metastatic carcinoma from primary sites such as the lung, breast, kidney, and prostate

Subluxing of the biceps tendon

An irritation of the biceps long head as it slides in the groove. Caused by overloading the muscle in an abduction and laterally rotated position that tends to be the force subluxing the tendon out of the bicipital groove

Adhesive capsulitis

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

5. What landmarks can be used to determine if a model of an unattached bone is a right or left humerus?

Bicipital groove and the humeral head (with the humerus facing anteriorly, the bicipital groove facing anteriorly, and the head facing medially, the right humeral head faces toward the left)

Midhumeral fractures

Caused by a direct blow or a twisting force to the humerus, spiral fractures in this region increase risk of radial nerve injury as it passes close to the bone

Calcific tendonitis

Chronic inflammation of the supraspinatus tendon can lead to an accumulation of mineral deposits, may be asymptomatic or quite painful

Anterior shoulder dislocations

Common injury caused by 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

Torn rotator cuff

Involves the distal tendinous insertion of the supraspinatus, infraspinatus, teres minor, and subscapularis on the greater/lesser tubercle area of the humerus. Tears can be the result of active trauma or gradual degeneration

2. Describe circumduction and the shoulder joint motions involved.

It is the circular arc of the upper extremity formed by a combination of the should joint motions flexion, abduction, extension, & adduction

Middle Deltoid

O - Acromion Process I - Deltoid Tuberosity (same as anterior) A - Shoulder Abduction N - Axillary Nerve (C5, C6)

Pectoralis Major Muscle (clavicular Portion)

O - Medial 1/3 of clavicle I - Lateral Lip of bicipital groove A - Shoulder Flexion, 1st 60 degrees

Posterior Deltoid

O - Spine of Scapula I - Deltoid Tuberosity (same as anterior) A - Shoulder Abduction, extension, hyperextension, lateral rotation, horizontal abduction N - Axillary Nerve (C5, C6)

Latissimus Dorsi

O - Spinous process of T7-L5 (via dorsolumbar fascia), posterior surface of sacrum, iliac crest, lower 3 ribs I - Medial floor of bicipital groove of humerus A - shoulder extension, adduction, medial rotation, hyerextension N - Thoracodorsal nerve (C6-C8)

Pectoralis Major Muscle (Sternal Portion)

O - Sternum, costal cartilage of first 6 ribs I - Lateral lip of bicipital groove of humerus, same as clavicular portion A - shoulder extension - 1st 60 degrees (from 180 - 120 degrees)

Anterior Deltoid

O - lateral 1/3 of clavicle I - Deltoid Tuberosity A - Shoulder abduction, flexion, medial rotation, horizontal adduction N - Axillary Nerve (C5, C6)

Impingment syndrome

Overuse condition that involves compression between the acromial arch, humeral head, and soft tissue structures such as coracoacromial ligament, rotator cuff muscles, long head of biceps, and subacromial bursa

Teres Major Muscle "little helper" of lats

Prime mover in extension, adduction, medial rotation O - Axillary Border of scapula near the inferior angle I - crest below lesser tubercle inferior to latissimus dorsi muscle attachment A - shoulder extension, adduction, medial rotation N - Lower supscapular nerve (C5-C7)

Clavicular Fractures

Results from a fall on the lateral aspect of the shoulder of on the outstretched hand. Occurs more in children than adults.

7. Ability of this gymnast to perform this iron cross maneuver may be limited by the strength of which group of shoulder joint muscles?

Shoulder Adductors

1. There are four sets of motions that occur at the shoulder joint. a. Which motions occur in the frontal plane around the sagittal axis?

Shoulder abduction & adduction

c. Which motions occur in the sagittal plane around the front axis?

Shoulder flexion & extension

3. Which fossa is located on the anterior surface of the scapula?

Subscapular fossa

4. The spine of the scapula divides the posterior surface into which two fossas?

The supraspinous fossa & the infraspinous fossa

5. Stand and hold a cane or weight bar in both hands. With your elbows approximately 12 inches apart and elbows extended, raise the bar. a. What shoulder motion is occurring? b. With your arms as far apart as possible and elbows extended, raise the bar. What predominant shoulder motion is occurring? c. In what plane is the motion of shoulder horizontal abduction occurring?

a. Shoulder flexion b. Shoulder abduction c. Scapular plane (scaption)

1. Lie prone on a table with your arm over the edge and with your shoulder flexed 90 degrees, elbow extended, and weight in your hand. Lift the weight away from the table in a sideward motion. a. What is this shoulder joint motion? b. What type of contraction (isometric, concentric, or eccentric) is occurring? c. What muscles are prime movers in this shoulder joint movement ?

a. Shoulder horizontal abduction b. Concentric contraction of the shoulder horizontal abductors c. - Posterior deltoid muscle - Infraspinatus muscle - Teres minor muscle

3. Stand with your arm abducted at the side of your body, elbow flexed to 90 degrees, and hold a loop of elastic tubing whose other end is anchored in front of you at the same level as your hand. In a sawing motion (back and forth motion like you are sawing wood), pull back on the tubing. a. What is the shoulder joint motion? b. What type of contraction is occurring? (iso, con, ecc) c. What muscles are prime movers in this shoulder joint movement (shoulder hyperextension)?

a. Shoulder hyperextension b. Concentric contraction of the shoulder hyperextensors c. Lats and posterior deltoid

SECOND PART: Hold for a count of five. a. What is the shoulder joint motion? b. What type of contraction is occurring? c. What muscles are the prime movers?

a. Shoulder lateral rotation b. isometric c. shoulder lateral rotators: infraspinatus, teres minor, posterior deltoid

6. Lie on your right side with your left elbow flexed to 90 degrees and holding a weight in your hand. Keep your left elbow resting on the left side of your body. FIRST PART: Roll the weight up toward the ceiling. a. What is the shoulder joint motion? b. What type of contraction is occurring? c. What muscles are prime movers in this shoulder joint movement?

a. Shoulder lateral rotation b.Concentric contraction c.Shoulder lateral rotators - Infraspinatus muscle - Teres minor muscle - Posterior deltoid muscle

THIRD PART: Slowly return to starting position. a. What is the shoulder joint motion? b. What type of contraction is occuring? c. What muscles are the prime movers?

a. Shoulder medial rotation b. Eccentric c. shoulder lateral rotators: infraspinatus, teres minor, posterior deltoid

Shoulder joint

ball-and-socket joint with movement in all three axes. Three degrees of freedom.

Teres Minor Muscle

closely related to Infrasp in location and function, mostly superficial, some areas covered by traps and delts O - Axillary border of scapula I - Greater tubercle of humerus A - shoulder lateral rotation, horizontal abduction N - Axillary Nerve (C5, C6)

Glenohumeral subluxation

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

Coracobrachialis Muscle

derives its name due to attachments on coracoid process and the humerus, vertical line of pull so it is mainly a stabilizing muscle O - coracoid process of scapula I - Medial surface of humerus near midpoint A - Stabilizes shoulder joint N - Musculocutaneous Nerve (C6, C7)

Arthrokinematics of humeral head when shoulder joint flexes

inferior slide, superior roll, and posterior spin

Shoulder Extension

is Return to Anatomical Position

Medial and Lateral rotation

occur in transverse plane around vertical axis, 90 degrees in each direction (rotate shoulder in and out of socket)

Scaption

similar to flexion or abduction, occurs in the scapular plane (30 degrees forward of frontal plane) allows for 180 degrees of up and down motion.

Arthrokinematics of humeral head when shoulder joint adducts

superior slide, inferior roll, and anterior spin

Rotator Cuff

tendinous band formed by blending together the tendinous insertions of the subscapularis, supraspinatus, infraspinatous, and teres minor muscles which help keep the head of the humerus "rotating" against the glenoid fossa during joint motion

Circumduction

term used to describe the arc or circle of motion possible at the shoulder

Humerus Con't

-Deltoid Tuberosity - lateral side near midpoint, not well defined - Bicipital Groove aka intertubercular groove, the longitudinal groove btw tubercles, containing tendon of the long head of the biceps - Bicipital Ridges - aka lateral and medial lips of bicipital groove, or the "crests" of the greater and lesser tubercles. Lateral lip attaches pectoralis major, medial attaches latissimus dorsi and teres major

Prime Movers of Shoulder Joint

-Flexion - Anterior Deltoid, Pec Major (clavicular (C)) -Extension - Post.Delt, Lats, Teres Major, Pec Major (C) -Hyperextension - Lats, Post Delts -Abduction - Delts, Supraspinatus -Adduction - Pec Major, Teres Major, Lats -Horizontal ABD - Post Delt, Infraspinatus, Teres Minor -Horizontal ADD - Pec Major, Anter Delt -Lateral Rotation - Infraspinatus, Teres Minor, Post Delt -Medial Rotation - Lats, Teres Major, Subscaps, Pec Major, Anter Delt

Humerus Con't

-Shaft - body, btw surgical neck and eicondyles -Greater Tubercle - large lateral projection to head and lesser tubercle, provides attachment for supraspinatus, infraspinatus, teres minor -Lesser Tubercle - smaller projection on anterior surface, medial to greater tubercle, attachment for subscapularis muscle

Humeral neck fracture

Caused by a fall on the outstretched hand. Common in the elderly and usually an impacted fracture.

Supraspinatus Muscle

Deep to the traps above and delts laterally (ant view pic) O - supraspinous fossa of scapula I - greater tubercle of humerus A - Shoulder abduction N - Suprascapular nerve (C5, C6)

Muscles of Shoulder Joint

Deltoid pectorals major latissimus dorsi teres major supraspinatus infraspinatus trees minor subscapularis coracobrachialis biceps brachii triceps brachia (long head)

Infraspinatus Muscle

Mostly superficial, but traps and delts do cover some O - infraspinous fossa of scapula I - greater tubercle of humerus A - shoulder lateral rotation, horizontal abduction N - Suprascapular Nerve (C5, C6)

Normal end feel for shoulder joint

Soft tissue stretch

Deltoid

Superficial that covers shoulder joint on 3 sides, triangular shaped, 3 parts: Anterior, Middle, Posterior

Biciptial tendonitis

Usually involves the long of the biceps proximally as it crosses the humeral head, changes direction, and descends into the bicipital groove. Bicep long head tendon commonly ruptures during repetitive or forceful overhead positions

10. Regarding the pectoralis major: a. which portion of it is effective in shoulder flexion? b. what part of the range is it more effective? c. why?

a. The clavicular portion b. The first 60 degrees of shoulder flexion (first part of the range c. vertical line of pull makes it more effective in the early part of the range and less so as it approaches a more horizontal line of pull

4. Return to previous question starting point: Stand with your arm abducted at the side of your body, elbow flexed to 90 degrees, and hold a loop of elastic tubing whose other end is anchored in front of you at the same level as your hand. a. What is this shoulder joint motion? b. What type of contraction is occurring? (iso, con, ecc) c. What muscles are prime movers in this shoulder joint movement?

a. shoulder flexion b. eccentric contraction of shoulder hyperextensors c. lats and post deltoid

Subscapularis Muscle

gets name from location, meaning "under", bc it is deep to the scapula, on the anterior costal surface of the scapula, the concave area, subscapular fossa, lying next to ribcage O - subscapular fossa of scapula I - Lesser tubercle of humerus (anterior side) A - Shoulder medial rotation N - Upper and Lower subscapular nerve (C5, C6)