Day 3 - Shoulder

Know the structures that are transmitted through the axilla, including the axillary artery and vein

Axillary artery (and branches) - the main artery supplying the upper limb. It is commonly referred as having three parts; one medial to the pectoralis minor, one posterior to pectoralis minor, and one lateral to pectoralis minor. The medial and posterior parts travel in the axilla. Axillary vein (and tributaries) - the main vein draining the upper limb, its two largest tributaries are the cephalic and basilic veins. Brachial plexus (and branches) - a collection of spinal nerves that form the peripheral nerves of the upper limb. Axillary lymph nodes - they filter lymphatic fluid that has drained from the upper limb and pectoral region. Axillary lymph node enlargement is a non-specific indicator of breast cancer. Biceps brachii (short head) and coracobrachialis - these muscle tendons move through the axilla, where they attach to the coracoid process of the scapula.

Be able to discuss the clinical injuries that are associated with lesions to various parts of the brachial plexus

Because of the way that the plexus has nerve splitting and fusions specific pre-plexus, post-plexus, or plexus (e.g. upper trunk or medial cord) lesions will each produce a unique constellation of symptoms and signs which should be diagnostic to the specific neural structure involved Pre-plexus lesions occur proximal to the plexus either at the spinal cord, spinal nerve root, spinal nerve, or ventral rams level and cause sensory, motor and reflex deficits on a segmental basis ---> by dermatome Postplexus lesions occur distal to the plexus and may invovlve one or more peripheral nerves... Plexus legions can involve the plexus itself ex- upper plexus may be insured in forcible separation of the head and shoulders during birth or in an adult two major injury types = upper brachial plexus injury (eras palsy) occurs where there is an excessive increase in the angle between the neck and shoulder which stretches the nerve roots of the c5 and c6 so it affects Nerves derived from solely C5 or C6 roots: musculocutaneous, axillary, suprascapular and nerve to subclavius. and Muscles paralysed: Supraspinatus, infraspinatus, subclavius, biceps brachii, brachialis, coracobrachialis, deltoid and teres minor. etc lower brachial plexus injury results from excessive abduction of the arm (e.g. person catching a branch as they fall from a tree). It has a much lower incidence than Erb's palsy. Nerves affected: Nerves derived from the T1 root - ulnar and median nerves. Muscles paralysed: All the intrinsic hand muscles

identify the spinal cord segments that contribute to the different parts of the brachial plexus as well as to the terminal and pre-terminal nerves

FYI in general nerves are not named for their origin but rather their peripheral distribution (where they go)

Be able to describe how the intrinsic muscles provide muscular support to the shoulder joint and on which aspect of the joint each support is lacking

Intrinsic - originate from the scapula and/or clavicle, and attach to the humerus. Deltoid, Teres Major, & Rotator Cuff = The rotator cuff muscles are a group of four muscles that originate from the scapula and attach to the humeral head. Collectively, the resting tone of these muscles acts to 'pull' the humeral head into the glenoid fossa.

What are the five terminal nerves of the plexus

Musculocutaneous, Axillary, median, radial, ulnar MAMRU

Does the axillary nerve course posteriorly or anteriorly around the surgical neck of the humorous? What is it with?

Posteriorly and in company with the circumflex humeral artery as they ride thro the quadrangular space hollaaaaa ;P

Know the common injuries of the shoulder joint complex and their clinical symptoms

Shoulder instability - Shoulder instability happens most often in young people and athletes. When muscles and ligaments that hold it together are stretched beyond their normal limits, the shoulder becomes unstable. A shoulder separation, or sprain, happens when the ligaments that hold the clavicle to the acromion tear. If the ligaments holding the shoulder bones tear and can't hold the joint together, the shoulder is dislocated. Rotator cuff tear - As people age and are less active, tendons start to degenerate and lose strength. This weakening can lead to a rotator cuff tear. Most rotator cuff injuries happen to middle-aged or older adults who already have shoulder problems. Symptoms of a torn rotator cuff include tenderness and soreness in the shoulder when using the shoulder. If the tendon has ruptured, you may not be able to raise the arm at all. Frozen shoulder - This extreme stiffness in the shoulder can happen at any age. This scar tissue reduces flexibility in the shoulder and makes it more prone to injury. The main symptom is not being able to move the shoulder in any direction without pain. Overuse/strain - Although painful and inconvenient, overuse problems can often be treated with rest, NSAIDs, and stretching exercises. Arthritis - Starting as early as age 50, some people get osteoarthritis, which causes painful movement. This happens as the smooth surfaces of the cartilage that line the bones of the shoulder joint are worn away, and joints start to wear out. The most common cause of osteoarthritis is overuse.

How do the features of the shoulder joint influence its stability? What other structures contribute to joint stability?

TBD

Know the pattern of lymphatic drainage in axillary lymph nodes

TBD

What bony prominence on the humorous must move out from under this arch to raise the arm overhead completely?

TBD

What determines the motion in the shoulder? (bones, ligaments, muscles)

TBD

posterior circumflex humeral vessels

TBD

rotator cuff - where is there no muscular or tendinous reinforcement of the joint capsule?

TBD

understand the anatomic basis for tests used to evaluate each of the major peripheral nerves and segments of the spinal cord (C5-T1)

TBD

what are the neurovasucal structures supplying the infraspinatus muscle? These are continuations of which neuromuscular structures

TBD

intrinsic shoulder muscles

TBDsupraspinatus, infraspinatus, teres minor and major, subscapularis, deltoid

What ligament provides the strongest union between the scapula and the clavicle?

The Coracoacromial Ligament is a strong triangular band, extending between the coracoid process and the acromion. It is attached, by its apex, to the summit of the acromion just in front of the articular surface for the clavicle;

Describe the muscles that border the axilla including the axillary artery and vein

The axilla is the name given to an area that lies underneath the glenohumeral joint, at the junction of the upper limb and the thorax. It is an asymmetrical pyramidal shaped region largely bound by shoulder structures. Borders Apex - also known as the axillary inlet, it is formed by lateral border of the first rib, superior border of scapula, and the posterior border of the clavicle. Lateral wall - formed by intertubercular groove of the humerus. Medial wall - consists of the serratus anterior and the thoracic wall (ribs and intercostal muscles). Anterior wall - contains the pectoralis major and the underlying pectoralis minor and the subclavius muscles. Posterior wall - formed by the subscapularis, teres major and latissimus dorsi.

What are the roles of the intrinsic muscles of the shoulder in the movements of the glenohumeral joint: abduction, adduction, flexion, extension, and lateral and medial rotation of the arm?

The shoulder joint (glenohumeral joint) is a ball and socket joint between the scapula and the humerus. Extension (upper limb backwards in sagittal plane) - posterior deltoid, latissimus dorsi and teres major. Flexion (upper limb forwards in sagittal plane) - pectoralis major, anterior deltoid and coracobrachialis. Biceps brachii weakly assists in forward flexion. Abduction (upper limb away from midline in coronal plane):The first 0-15 degrees of abduction is produced by the supraspinatus.The middle fibres of the deltoid are responsible for the next 15-90 degrees.Past 90 degrees, the scapula needs to be rotated to achieve abduction - that is carried out by the trapezius and serratus anterior. Adduction (upper limb towards midline in coronal plane) - pectoralis major, latissimus dorsi and teres major. Internal rotation (rotation towards the midline, so that the thumb is pointing medially) - subscapularis, pectoralis major, latissimus dorsi, teres major and anterior deltoid. External rotation (rotation away from the midline, so that the thumb is pointing laterally) - infraspinatus and teres minor.

Describe the location and muscular relationships of the subacromial/subdeltoid bursa

The subdeltoid bursa is a fluid-filled sac located under the deltoid muscle in the shoulder joint. It plays an important role in decreasing friction in the shoulder joint and protects the surrounding tissues of the joint.

supra scapular nerve

The suprascapular nerve is a nerve that arises from the brachial plexus. It is responsible for the innervation of some of the muscles that attach on the scapula, namely the supraspinatus and infraspinatus muscles.

Describe the intrinsic muscles that produce movement at the shoulder joint and know the body attachments, innervations, and actions of each muscle

There are six muscles in this group - the deltoid, teres major, and the four rotator cuff muscles (supraspinatus, infraspinatus, subscapularis and teres minor).

What movements are permissible at the shoulder joint?

Type of joint - ball and socket joint. TBD

determine the movements that result from the total or partial contraction of the deltoid muscle. what would be the appearance of an individual with paralysis of the deltoid muscle?

When the deltoid muscle in the shoulder is paralyzed due to an upper brachial plexus injury, the person with the injury may be unable to move the shoulder. However, the person's triceps may still function, providing the ability to extend the arm

Why does abduction and flexion of the arm overhead require both upward rotation of the lateral angle of the scapula (glenoid fossa) and external (lateral) rotation of the humeras?

When we perform flexion, the glenohumeral (GH) joint contributes 100°-120°. The scapula on the thorax contributes to elevation (flexion and abduction) of the humerus by upwardly rotating the glenoid fossa 50° to 60° from its resting position.[1

skeletal anatomy of the axilla

anterior wall (clavicle, pectorals major and minor muscles), posterior wall (scapula, Subscapularis, teres major and latissimus dorsi), medial wall (ribs and serrates anterior muscle), lateral wall (inter tubercular groove of the humerus), base of axilla, apex

omohyoid muscle

attachment is medial to the scapular notch

axillary fossa

between axillary folds

What are the pre-terminal nerves of the BP

dorsal scapular, suprascapular, medial and lateral pectoral, and thoracordorsal nerves

Posterior axillary fold

formed by the Teres major and latissimus dorsi

anterior axillary fold

formed by the pec major and minor

thoracoacromial artery

from the axillary artery

Subscapularis artery

from the thoracoacromial artery and gives rises to the thoracodorsal and circumflex scapular arteries

what structural and functional relationships might explain why subacromial bursitis is the most frequent type of bursitis in the body?

happens in areas where you repeat the same motion over and over again check

axillary nerve

innervates deltoid and teres minor

long thoracic nerve

located on the lateral thoracic wall supplies the serratus anterior muscle. This nerve characteristically arises from the anterior rami of three spinal nerve roots: the fifth, sixth, and seventh cervical nerves(C5-C7) although the root from C7 may be absent.

lateral, medial, posterior cords of brachial plexus

named according to their position relative to the axillary artery

upper and lower Subscapularis nerves

preterminal nerves that arise from the posterior cord of the brachial plexus and innervate the subscapularis muscle

what movement of the upper extremity may be painful if there were tendonitis of the Supraspinatus muscle?

rotating

non intrinsic shoulder muscles

scapula, humerus, clavicle

Understand the nerve supply needed for muscle function

see muscle cards

teres major and minor

see muscle deck

subscapularis OIF

see muscle deckkkk

wWhat parts of what bone and what ligament form the coracoacromial arch?

subacromial bursae, rotator cuff tendons, portion of long head of biceps brachia - also called the subacromial space. normally 10mm wide but can reduce to 5mm on elevation of arm. repetitive activity can cause painful impingement syndrome.

learn the specific points at which the pulse can be evaluated in the arteries that supply the upper limb

subclavian artery - press downward behind the clavicle to compress the artery against the first rib Brachial artery - at mid arm compress the artery against the humerus

Rotator Cuff Muscles (SITS)

supraspinatus, infraspinatus, teres minor, subscapularis

Learn which peripheral nerves innervate the major muscle groups and major areas of skin

tbd

learn a test for each of the major muscles or muscle group

tbd

understand the major relationships among nerves, muscles, bones, and blood vessels in each area of the upper limb so that you can visualize what structures would likely be damaged in an injury at a particular site

tbd

what is the only rotator cuff muscle to insert on the lesser tubercle of the humerous

the subscapularis

be able to identify a muscles general area, origin, and specific insertions for the purpose of understanding its functions

these muscles - deltoid, tbd see muscle deck

Be able to draw and label the brachial plexus from its origin through the terminal and preterminal nerves...

work on this :)))

glenoid fossa

The part of the scapula that joins with the humeral head to form the glenohumeral joint.

posterior circumflex humeral artery

supplies blood to the deltoid insertion at the deltoid tuberosity