AKAB L9, L10, L11
Normal ROM for elbow flexions is what?
0*-140* PROM>AROM Increased ROM with forearm supination. *supination is an issue of muscle mass / when pronated will see subtle flucuation.
What is normal range of motion for internal rotation of the shoulder?
0*-70*
What is normal range of motion for external rotation of the shoulder?
0*-90*
At what angle is normal cubitus valgus?
18 degrees
Describe the contributions of the SC, AC, and GH joint to the full ROM of 180 degrees possible for shoulder abduction.
180* of shoulder abduction = GH joint abduction: 120* GH joint external rotation: 45* AC joint upward rotation: 35* AC joint external rotation: 10 AC joint posterior tilt: 20* ST joint upward rotation: 60* SC joint posterior rotation: 25* SC joint elevation: 25* SC joint retraction: 15*
What are the phases of flexion at the GH joint?
1: 0*-50*/60* Anterior deltoid, coracobrachialis, clavicular head of pectoralis, and long head of the biceps 2: 60*-120* Scapula upwardly rotates 60*, axial rotation of SC (elevation) and AC joint (upward rotation) ~30* each. Clavicle posteriorly rotates ~25*. Scapular contribution may be initiated earlier with increased resistance. 3: 120*-180* Requires contralateral trunk flexion or exaggerated lumbar lordosis if unilateral or bilateral, respectively.
What are the phases of shoulder abduction?
1: 0*-90* Deltoids and supraspinatus. Scapular contribution may be initiated earlier with increased resistance but starts as early as 30* abduction. 2: 90*-150* Scapula upwardly rotates 60*, axial rotation of SC (elevation) and AC joint (upward rotation) ~30* each. Clavicle posteriorly rotates ~25*. Scapular contribution may be initiated earlier with increased resistance. 3: 150*-180* Requires contralateral trunk flexion or exaggerated lumbar lordosis if unilateral or bilateral, respectively.
What is considered excessive valgus?
30 degrees
What is the functional range of the forearm?
50 degrees of supination and 50 degrees of pronation. Supination ROM: 80*-90* Pronation ROM: 70*-80*
What is the optimal length of the internal moment art (effort arm) for elbow flexion?
80*-100* degrees because the muscle is somewhat taut, the moment arm is smaller than at full extension, but not actively insufficient with the elbow at about 45 degrees of flexion.
How many degrees of freedom does a ball and socket joint have?
A ball and socket joint, like the GH joint, has 3 degrees of freedom. Horizontal (internal/external rotation), sagittal (abduction/adduction), and frontal (flexion/extension).
Describe the arthokinematics of the elbow in elbow flexion.
A concave surface moving on a convex surface. The radius rolls and slides anterior on the capitulum of the humerus. Arthokinematics are in the same direction as osteokinematic motion.
Describe the arthokinematics during abduction of the humerus.
A convex on a concave open chain motion, so the roll is superior and the slide inferior
Describe the arthokinematics of the SC joint during elevation of the clavicle.
A convex surface is sliding inferiorly on a concave surface, so the roll is superior in the osteokinematic motion.
What type of synovial joint is the elbow?
A hinge joint. Moves in the sagittal plane and has one degree of freedom. Flexion is primarily a function of the HU joint (not that HR isn't important too).
How does the glenoid labrum increase stability?
A joint can develop negative pressure or what can be considered suction.
Motions of the GH joint include:
Abduction Flexion External rotation Internal rotation Resisted adduction
Which ligaments support the acromioclavicular joint (AC)?
Acromioclavicular ligament: Rigid, but has to elongate to allow for the motion that happens at the AC joint. Coracoaromial ligament: Unique. Attaches to two non-moving segments on the same bone (scapula). Forms a roof for the tunnel below. Joint motion doesn't change it's length, but if humerus was allowed to move too superiorly and abut into the CA ligament then impingement would occur. Coracoclavicular ligament: Includes two portions, the conoid ligament and the trapezoid ligament.
Scapulohumeral rhythm
After 30 degrees of shoulder abduction, a 2:1 ratio of humeral to scapular movement occurs during elevation of the humerus in flexion or abduction. At 0-30 degrees of shoulder abduction, a 10:1 ration of humeral to scapular movement occurs during elevation of the humerus in flexion or abduction.
What type of synovial joint is the SC joint?
An atypical joint with three components, 2 points being saddle shaped. Arthokinematics: (Elevation/Depression) slide is in the opposite direction as the roll and osteokinematics. (Protraction/Retraction) slide is in the same direction as the roll and the osteokinematics.
Which muscles produce flexion at the GH joint?
Anterior deltoid: flex shoulder and because the fibers run oblique can internally rotate the shoulder. Long head of biceps: flex shoulder, flex elbow, supinates the forearm Coracobrachialis: pure shoulder flexion
What kind of shoulder dislocation is most common?
Anterior dislocation > posterior dislocation
Name the parts of the medial collateral ligament of the elbow.
Anterior part: primary restraint for valgus Taut when elbow extended. Throughout ROM some portion is alway taut. Posterior part: additional restraint for valgus Taut when elbow flexed Transverse part: stabilizing / no change in length as solely attached to the ulna and doesn't cross any articulation (therefore cannot restrain a joint).
What are the three motions of the clavicle?
Anterior rotation (resting position) of the clavicle / posterior rotation of the clavicle (from here can only rotate anteriorly only so far as to return to that initial resting position) Elevation of the lateral end of the clavicle / depression of the lateral end of the clavicle Protraction of lateral end in an anterior direction / retraction of lateral end in a posterior direction
When you bring your arm back to your side in adduction and extension, then what motions of the clavicle occur?
Anterior rotation, depression, and protraction of the clavicle occurs all at once.
The radial collateral ligament is comprised of what three portions?
Anterior: taut in extension Middle: taut throughout ROM Posterior: taut in flexion
What articulation occurs at the distal radial ulnar joint?
Articulation is between the ulnar notch of the radius and the ulnar head.
As elbow goes into flexion, what happens to the trochlear notch of the ulna?
As elbow goes into flexion, the trochlear notch of the ulna articulates with the trochlear grove of the humerus. It moves along the surface of the longitudinal crest of the trochlear groove.
If we land on outstretched hand, elbow in extension, our body weight over the humerus and the force is transmitted along the forearm, what happens?
Because we have a carrying angle, the ligament that takes the brunt of the injury is the MCL and both anterior and posterior portions will be overstretched. Force of fall is in the medial direction with excessive valgus.
If you wanted to mobilize the radial ulnar joint, what would you do?
Because you would want the interosseous membrane to be slack, perhaps you would contrive a distracting force (patient holds weight) or manually try to distract or pull down the radius in order to unload the interosseous membrane.
Which muscles move the elbow joint?
Biceps brachii: flexes shoulder, flexes elbow, supinates forearm. Brachialis: only flexes the elbow. Brachioradialis: supinates forearm and can pronate to neutral (can't bring from neutral to pronate tho) Pronator teres: secondary elbow flexor and can pronate the forearm unless another muscles acts as a neutralizing synergist. FCU, PL, FCR, FDS, PT, & supinator: secondary movers (remember: if a muscles crosses a joint, then it has potential to move that joint).
What are the muscles involved in supination of the forearm?
Biceps brachii: the long head crosses the shoulder axis of rotation, the elbow axis of rotation, it's a multi-joint muscle. Helps with powerful supination. Supinator: just supination. The go-to muscle for easy unresisted supination). Brachioradialis: both a forearm supinator and pronator, but limited ROM; can only supinate to neutral from full pronation. *Any muscle that runs oblique to the longitudinal axis of rotation can produce a supination torque depending on forearm position: EPB, EPL, APL, ECRL, ECRB
What happens to the coracohumeral ligament and the superior aspect of the capsular/GH ligament as the humerus abducts?
Both ligaments become slack
Explain concentric contractions and eccentric contractions involved in a wheel chair push up.
Concentrically contracting when you're pushing up and eccentrically contracting when you're lowering down.
Which ligaments support the sternoclavicular joint (SC)?
Costoclavicular ligament (CCL): attaches rib and clavicle and includes an anterior and posterior bundle Sternoclavicular ligament (SCL): attaches clavicle to manubrium of the sternum Interclavicular ligament (ICL): in between both clavicles
Throughout ROM of the elbow, some ligament is going to be taut. Why is that important?
Critical for stability of the elbow throughout ROM. The elbow needs ligamentous restrain to varus and valgus and distracting forces on the elbow, like when you carry objects in your hand. Wouldn't want your radius and ulna to get pulled away from the humerus.
Describe the arthokinematics of the PRU joint.
During supination, the radius is spinning in the radial notch of the ulna. During pronation, the radius is spinning in the radial notch of the ulna (opposite direction of supination).
When lowering yourself to a push up, active and passive tension is/has developed for which muscle group?
Elbow extensors
When lowering yourself from a pull up, active and passive tension is/has developed for which muscle group?
Elbow flexors
Capsular pattern for PRU and DRU joints?
Equal loss of pronation and supination.
Scapular winging
Excessive movement of the medial border of the scapula away from the thorax in a posterior direction. Could be the result of serratus anterior weakness, long thoracic nerve injury, vertebral column anomalies like scoliosis. Impacts ability to bring the arm overhead because the scapula needs to upwardly rotate. Best way to observe is with resisted abduction of the scapula or resisted protraction of the scapula, such as when someone does a push up.
What's the connection between shoulder rotation and forearm rotation?
External rotation of the shoulder is physiologically linked to supination of the forearm. Internal rotation of the shoulder is physiologically linked to pronation of the forearm.
Close-packed position for PRU and DRU joints?
Forearm supinated 5 degrees
When does downward rotation of the scapula occur?
From an upward rotated position in the inferior-medial direction. This motion occurs as a natural component of lowering the arm down to the side. We do no a lot of resisted downward rotation in our daily lives.
What are the closed packed position of the elbow joint capsule?
Full extension of the HU joint: stability produced when the olecranon process of the ulna sits in the olecranon fossa of the humerus + owing to the tightness of the anterior portion of the MCL Flexion and 5 degrees of supination of the HR joint: the two joint surfaces (capitulum and the fovea of the radius come closer together in flexion)
Which ligaments support the GH joint?
Glenoid labrum: a cartilage cuff that deepens glenoid fossa by about 50% and keeps the humeral head from moving out of position (aids in stability) Coracohumeral ligament: an important stabilizer for preventing inferior movement or downward movement of the humeral head. Capsular ligament / GH ligament (superior, middle, inferior): Long head of the biceps brachii & long head of the triceps:
What are the close-packed positions for the HU and HR joints?
HU: extension HR: elbow flexed to 90* and forearm supinated 5*
What are the close-packed positions of the GH joint?
Horizontal abduction and external rotation are the positions in which the articular surfaces fit the best and have the greatest surface contact, contributing to stability.
What are the 3 joints that make up the joint capsule of the elbow?
Humeroradial joint Humeroulnar joint Proximal radioulnar joint But when we talk about elbow flexion and extension we're talking about the HR and HU joints.
Capsular pattern of the GH joint
If the GH joint capsule was pathological, then ROM for external rotation of the shoulder would suffer the greatest loss, then shoulder abduction, then internal rotation of the shoulder.
How can the biceps brachii contribute to abduction torque of the GH joint?
If the shoulder is externally rotated then the long head of the biceps brachii tendon contributes.
In full elbow extension, what happens to the olecranon process?
In full elbow extension, the olecranon process articulates or comes closer to or sits in the olecranon fossa, just above the trochlea of the humerus.
How does the shape of the acromion contribute to pathological impingement?
Inferiorly curved: associated with rotator cuff tears "Hooked": most closely associated with impingement In the absence of an occupation that causes repetitive movements such that somebody is constantly overusing the muscles of the rotator cuff, then you might wonder if someone has an acromion that is predisposing them to impingement.
Which muscles are involved in external rotation of the GH joint?
Infraspinatus: has the more physiological cross sections than teres minor, but both are important to ER. Teres minor: Posterior deltoid:
Describe the arthokinematics that occur during flexion at the GH joint.
Inside the sagittal plane: a spine occurs. Outside of the sagittal plane: roll in the superior direction and slide in the inferior direction
The transverse ligament of the elbow joint restrains what?
It keeps the biceps tendon in place.
How does the interosseous membrane impact supination?
It restrains supination and gets taut in full supination, which is a nice therapeutic technique for stretching out the interosseous membrane, possibly following adaptive shortening of the membrane after injury.
Which scapula depressor is important for closed-chain action?
Latissimus dorsi is an important muscle for walking with crutches or wheel chair push ups. Because it attaches to the pelvis, along the scapula, and into the humerus, it helps elevate the pelvis when we engage in closed-chain action.
Which muscles produce resisted adduction?
Latissimus dorsi, rhomboids, posteriod deltoid, infraspinatus, teres major, and sternal head of the pectoralis major (?)
Which muscle produces elevation of the scapula with downward rotation?
Levator scapulae
Which muscles contract during resisted adduction?
Levator scapulae and rhomboids major and minor. Upper and lower trapezius can also contribute to powerful adduction of the scapula together, but not alone.
What ligaments of the forearm are likely to be injured in distal radius fracture when a person falls on outstretched hand?
Likely, PCL and DCL will be injured and the DRU joint will be unstable.
What is the capsular pattern for the HU joint?
Limited elbow flexion and elbow extension, but flexion more so than extension.
Which muscles depress the scapula?
Lower trap, pectoralis minor, latissimus dorsi, and subclavius
Which muscle is a pure adductor of the scapula?
Middle trapezius is the only muscle to only produce adduction and will be the first muscle to contract when the medial border is pulled posterior-medially on the thorax towards the midline.
Is subluxation the same as dislocation?
No, bitch. There are grades of subluxation to dislocation. Common to post-stroke or brachial plexus injury. OTs try to prevent subluxation.
Is the GH joint highly stable?
No. It is inherently unstable, but it is a highly mobile joint.
Do people move in valgus?
No. They rest in valgus. The carrying angle is just a position, how the forearm rests relative to the humerus. Most pronounced when in the anatomical position, you can't really see this when the elbow is flexed, it is seen mostly when the elbow is extended.
If your arm is overhead and you're returning your arm to the side, do you need to activate scapula depressors?
Nope. Gravity is producing the motion in this scenario. Scapula depressors would only be activated if the scapula was being depressed against resistance, such as when getting out of the pool, doing a pull up, closing a window blind, or closing an overhead trunk.
Functional arc of motion is 30-130 degrees (well expected range) for elbow flexion, which means that if you have this range you will likely be functional in most activities that you do (ADL, IADLS, does not account for athletic abilities). Why is this important?
OTs document how ROM affects function and need to make a case for highly specific activity to establish why patient needs continued therapy.
The ligaments of the PRUJ include:
Oblique cord: attaches proximally on the ulna and distally on the radius, restricting supination. Annular ligament: retains the radial head, prevents anterior/posterior movement and general movement away from the ulna. Quadrate ligament: restricts supination and pronation
Explain mechanical advantage of the deltoid
Optimal position for the anterior and middle deltoid to flex or abduct the humerus occurs when the humerus is in the scapular plane at 60-90 degrees. As the shoulder moves through abduction, some fibers that were once below the axis of rotation and were adductors become abductors, contributing to overall abduction torque. Those that remain below the axis of rotation will contribute to stability by producing adduction torque.
What is the capsular pattern for the HR joint?
Pain at the end of range.
The ligaments of the DRUJ include:
Palmar capsular ligament (palmar volar radial ligament): restricts supination Dorsal capsular ligament (dorsal ulnar radial ligament): restricts pronation Articular disk: fibrocartilage that resists compressive loads, absorbing shock and articulating with the ulna.
What is the most common subluxation of the shoulder?
Partial misalignment of joint surfaces in an anterior and inferior direction.
A client presents with a flexed and supinated forearm. You have them flex the shoulder and suddenly the shoulder extends and the forearm pronates. What happened?
Passive insufficiency of the long head of the biceps was limiting elbow extension. Shoulder flexion shortens the muscle.
When people sustain elbow fractures and are placed in a cast with elbow at 90 degrees, those ligaments are held in slack position. What might occur as a result?
Pathological tightness of soft tissue (also known as adaptive shortening). Same as when you've driven hours on end and you go to stand up and you stretch your legs out, but the ligaments that have been slack for an extended period of time are tight. Stretching something out that has been held in a slack position. With arm in a cast for 8 weeks, tissues become pathologically tight because tendon has been allowed to shorten, and has reduced the muscle's excursion value
What type of synovial joint are the proximal radial ulnar joint and the distal radial ulnar joint?
Pivot joints with one degree of freedom.
Closed-chain rotation of the forearm is a potential therapeutic technique, what's happening?
Plant hand on table (fixed distal segment). Scaphoid and lunate are well seated in the radius, so the primary articulation for the wrist is the radiocarpal joint. The wrist is locked into the forearm at the radiocarpal joint. So, now the ulna will do the movement. When the elbow is extended, the humeroulnar joint is locked. So, the humerus and ulna are spinning around the radius.
When you bring your shoulder in abduction or flexion, then what motions of the clavicle occur?
Posterior rotation, elevation, and retraction of the clavicle occurs all at the same time.
What is capsular pattern?
Predictable loses of ROM when the joint capsule is pathological.
What is the primary articulation at the proximal radial ulnar joint?
Primary articulation occurs between the head of the radius and the radial notch of the ulna. Secondary articulation is between the fovea of the radial head and the capitulum of the humerus.
What are the muscles involved in pronation of the forearm?
Pronator quadratus: only pronation, some stabilization of the DRU joint Pronator teres: pronation and elbow flexion Brachioradialis: both a forearm supinator and pronator, but limited ROM; can only pronate to neutral from full supination. Flexor carpi radialis: lies oblique to axis of rotation, so has some toque potential for forearm pronation
Resisted adduction is uncommon, but could occur during which activities?
Pulling a blanket out from under a dog, holding seated handles on rollercoaster, handrail on BART during movement, closing side door, holding child on the hip, pulling heavy mall door, getting out of a pool.
What does nursemaid elbow refer to?
Radial head dislocation, which can occur in either the anterior or posterior direction.
What is one reason that the radius can't spin around the ulna?
Radial ulnar synotosis is when the radius and ulna are fused, limiting the radius's ability to spin around the ulna.
What is the purpose of scapulohumeral rhythm?
Reduce shear forces Increase range in elevation of humerus while providing dynamic stability. Maintain a good length-tension ratio throughout the range of motion and prevent active insufficiency
The RCL is critical for what?
Restraining the elbow when you are carrying loads in the hand, stabilizing against varus torque.
Order the downward rotator muscles from most downward torque to least.
Rhomboid major > rhomboid minor > levator scapulae
Which muscle will contribute if you're elevating the scapula against a lot of resistance?
Rhomboids major and minor
What are the arthokinematics during internal rotation of the shoulder when the arm is adducted?
Roll in the anterior direction and slide in the posterior direction.
When the shoulder is adducted, what are the arthokinematics involved in external rotation of the shoulder?
Roll in the posterior direction and an anterior slide of the humeral head.
What is occurring at the SC and AC joint during scapular upward rotation when the arm is elevated in abduction?
SC joint: clavicle posteriorly rotates, elevates, and retracts. AC joint: scapula upwardly rotates
What is occurring at the SC and AC joint during scapular elevation when the arm is in the dependent position (resting at the side)?
SC joint: elevation of the lateral end of the clavicle medial end of clavicle slides inferiorly AC joint: scapula downwardly rotates
What is occurring at the SC and AC joint during scapular protraction when the arm is in the dependent position (resting at the side)?
SC joint: protraction of shoulder, protraction of scapula, protraction of clavicle AC joint: the medial border of the scapula moves away from the thorax (horizontal plane adjustment)
Which muscle group needs to be strong in order to relieve pressure from full time wheelchair use and minimize risk of developing bedsores?
Scapula depressors: Lower trap, pectoralis minor, latissimus dorsi, and subclavius
Motions of the AC joint include:
Scapular rotation (upward and downward rotation) Horizontal plane adjustments = internal and external rotation (winging) Sagittal plane adjustments = scapular tilting (tip)
Which muscle produces abduction (protraction) of the scapula?
Serratus anterior: found on the inferior surface of the scapula, attaches to the medial border of the scapula and the ribs. Pulls the scapula towards the thorax.
What are common injuries of the glenoid labrum?
Since the glenoid labrum stabilizes the humeral head, if there are lesions the humeral head will slide in the direction of the lesion. SLAP lesion: injury to the superior portion of the glenoid labrum; the humeral head will want to slide up Bankart lesion: injury to the inferior portion of the glenoid labrum; humeral head will want to slide down
Describe the arthokinematics during protraction of the clavicle at the SC joint as well as which ligaments would be taut or slack.
Slide would occur in anterior direction in the same direction as the roll. The posterior portion of the SC ligament would become taut and the anterior portion of the SC ligament and CC ligament would become slack.
When the shoulder is abducted, what are the arthokinematics involved in external rotation of the shoulder?
Spin of the humerus on the glenoid fossa
The muscles of the shoulder function to:
Stabilize the GH joint, move the GH joint, and move the pectoral girdle at the ST, SC, AC, and GH joints.
When the forearm is resting in extension, what is stretched and what is slack?
Stretched: dermis, flexors, anterior capsule Slack: extensors and posterior capsule
When the forearm is in full flexion, what is stretched and what is slack?
Stretched: posterior capsule and extensors Slack: flexors and anterior capsule
Which muscle initiates the "roll" in the arthokinematics during GH abduction?
Supraspinatus initiates the "roll" and can take the humerus through full ROM but with limited torque potential without the aid of the deltoid (which produces the sliding motion superiorly).
Which muscles are involved in internal rotation of the GH joint?
Supscapularis Latissmus dorsi (tendon comes from behind and attaches anteriorly) Teres major (tendon comes from behind and attaches anteriorly) Pectoralis major (sternal head)
The lateral (ulnar) collateral ligament is attached to both the ulna and radius, so it is taut when?
Taut in extreme flexion and with varus forces.
Pathological impingement - Rotator cuff damage
Tear and retraction of supraspinatus tendon. Supraspinatus poorly vascularized, doesn't heal very well, injuries compound, most often damaged of the RC muscles. Displacement of greater tuberosity. Displacement of lesser tuberosity.
During depression of the clavicle at the SC joint, which ligaments become slack and which become taut?
The CC ligament becomes slack because the clavicle is moving towards the first rib. The SC and IC ligament become taut as the clavicle rolls in an inferior direction.
During elevation of the clavicle at the SC joint, which ligaments become slack and which become taut?
The SC and IC ligaments become slack as the clavicle rolls in a superior direction. The CC ligament is pulled taut as the ribs stay stationary.
Which joints of the shoulder complex are not supported well by ligament of bony structures?
The ST and GH joint! They require significant muscular stabilization. Synergistic movements (force couples) occur in the shoulder for dynamic stabilization.
Describe the arthokinematics of the SC joint during depression of the clavicle.
The convex surface of the clavicle will slide in a superior direction while it rolls in an inferior direction while the clavicle depresses.
During AC separation, which ligaments are injured?
The coracoclavicular ligament (primary injury) and the acromioclavicular ligament. The acromion is pushed down, moving the scapula as a whole, which stretches the CCL between the clavicle and the coracoid process. There are grades of separation: stretched, partial rupture, complete rupture, clavicle displacement over acromion, clavicle displaced under skin, clavicle underneath coracoid process.
What sits in the coronoid fossa of the humerus during elbow flexion?
The coronoid process of the ulna articulates with the coronoid fossa of the humerus.
During active flexion, what happens to the fovea of the radius? Full extension?
The fovea of the radius gets pulled against the capitulum of the humerus in active flexion. There's minimal bony contact in full extension.
What does the capitulum of the humerus articulate with?
The head of the radius. This relationship is most profound as we move into elbow flexion and any disruption along either articular surface will typically result in some limitation to elbow motion.
How is the humeral head oriented in the pectoral girdle?
The humeral head is oriented in medial, posterior, and superior direction. Retroversion: 30 degrees relative to medial lateral axis of distal humerus. This aligns the humeral head within the scapular plane for articulation with the glenoid fossa. Angle of inclination: 135 degrees between longitudinal axis of shaft of humerus and head of humerus. This angle can be disrupted by fracture to the humerus.
What happens when there is posterior tilt at the AC joint?
The inferior angle is moving anteriorly, but the superior aspect of the scapula is moving posteriorly.
What happens when there is anterior tilt at the AC joint?
The inferior angle is moving posteriorly, but the superior aspect of the scapula is moving anteriorly.
What happens to the inferior portion of the capsular/GH ligament as the humerus elevates through flexion or abduction?
The inferior aspect of the capsular/GH ligament/axillary pouch elongates and becomes taut.
If the interosseous membrane becomes adaptively shortened or scarred then what occurs?
The interosseous membrane will have less excursion value than it used to and restrict supination even more than it did before.
What tendon contributes to dynamic support of the GH joint?
The long head of the BB tendon contributes to stability of the head of the humerus, preventing upward migration of the head of the humerus. Because the long head of the biceps travels up and superiorly over the head of the humerus, attaching into the joint capsule, blending into the glenoid labrum, when the biceps contracts, the tendon is getting pulled on by the muscle and as a result pushes down on the head of the humerus, keeping it from moving superiorly
How is the clavicle oriented in the pectoral girdle?
The longitudinal axis of the clavicle is 20 degrees posterior to the frontal plane.
What does the capitular trochlear groove articulate with?
The medial aspect of the radial head. Needs to be very clean with no anatomical misalignment.
Describe the arthokinematics during retraction of the clavicle at the SC joint.
The medial end of the clavicle is concave, so it's moving on a convex portion of the sternum, which means the slide is going to be in the same direction as the roll in osteokinematic motion (posterior).
What is the scapular plane?
The normal resting position of the scapula = tilted about 30-40 degrees anterior to the frontal plane against the posteror-lateral surface of the thorax. This plane influence how the humerus moves.
What would happen if you lost function of infraspinatus and teres minor?
The person would be chronically postured with arm internally rotated and would be predisposed to anterior subluxation of the shoulder.
What influences the RCL?
The position of the forearm because the radial head spins.
During retraction of the clavicle at the SC joint, which ligaments become slack and which become taut?
The posterior portion of the SC ligament (intrinsic capsule) becomes slack. The anterior portion of the SC ligament and the CC ligament become taut
What is the orientation of the bones of the forearm when in full supination?
The radius is most lateral and the ulna most medial, side by side.
During pronation what bone rotates around a fixed bone?
The radius rotates around the ulna. The ulna is fixed to the humerus. When the hand is palm down, the thumb is on the same side as the medial epicondyle of the humerus.
Which muscles contribute to dynamic support of the GH joint?
The rotator cuff muscles, which attach to the head of the humerus, collectively prevent upward migration of the head of the humerus, contracting to stabilize a bone segment (isometric), keeping the humeral head in the glenoid fossa. Subscapularis: shoulder adductor, shoulder internal rotator Supraspinatus: shoulder abductor Infraspinatus: shoulder external rotator Teres minor: shoulder external rotator
Which joint of the shoulder complex is a physiological joint?
The scapulothoracic joint (ST)
What contributes to the carrying angle of the humerus?
The slight obliquity of the trochlear groove of the humerus.
What prevents inferior migration of the shoulder?
The supraspinatus along with the ligaments around the GH joint.
Describe what occurs if there chronic subluxation at the GH joint.
The supraspinatus gets stretched out and loses its ability to stay tight. If a muscle is overstretched at the start of a contraction, it will be actively insufficient and can't generate sufficient force.
Describe the arthokinematics of the DRU joint.
The surface of the radius is concave, whereas the surface of the ulnar head is convex. The radius does all the moving. During supination, the radius is going to roll and slide in the same direction as the osteokinematic motion. During pronation, the radius is going to roll and slide in the same direction as the osteokinematic motion (opposite direction of supination).
Which ligament arises from the humerus and attaches to the humerus?
The transverse ligament serves as a tunnel for the long head of the biceps tendon and keeps it put because it travels up and over the head of the humerus and attaches into the GH joint capsule, into the labrum. This ligament doesn't cross a joint and is not articular.
What does the trochlea of the humerus articulate with?
The trochlea of the humerus articulates with the trochlear notch of the ulna. The trochlea has a medial and a lateral lip, in the middle is an obliquity of the trochlea (important as we consider how the forearm hangs off of the humerus).
What is the orientation of the glenoid fossa?
There is a five degree angle so that the glenoid fossa is facing slightly superiorly. This helps keep the humeral head within the glenoid fossa.
Describe normal impingement
There's a tendency for the head of the humerus to want to slide in a superior direction during flexion and abduction because of the pull of the deltoid. We avoid this by moving in the scapular plane (35 degrees anterior), not the frontal plane, OR if moving in the frontal plane, externally rotate the head of the humerus so that greater tuberosity is cleared from the acromion. If we couldn't, then this movement becomes pathological, the head of the humerus can't naturally clear the greater tuberosity from the acromion due to muscle weakness
What happens to someone who's injured the medial collateral ligament of their elbow's joint capsule?
They may have a resultant valgus deformity since this is an important ligament for restraining valgus.
What happens to someone who's injured the lateral collateral ligament of their elbow's joint capsule?
They may have a resultant varus deformity since this is an important ligament for restraining varus.
What happens to the middle portion of the capsular/GH ligament as the humerus goes into horizontal abduction or external rotation?
This ligament becomes taut.
Someone with a radial nerve injury may experience wrist drop. Why would they be offered a splint?
To prevent overstretching of soft tissue and ligaments to prevent future pain and pathology.
What is posterior dislocation usually caused by?
Trauma/accidents
Which muscles are involved in elbow extension?
Triceps long head: The last muscle recruited to contract for extension of the elbow. Triceps medial and lateral heads: The medial head will be the first of the triceps to contract, then the lateral head. Anconeus: Provides stabilization and is the first to contract in easy unresisted extension.
Which muscle produces elevation of the scapula while upwardly rotating?
Upper trapezius
Which muscles are synergists for upward rotation but antagonists for elevation and depression of the scapula?
Upper trapezius and serratus anterior. Upper trapezius produces elevation and serratus anterior produces slight depression.
Which muscles do you need to get the arm overhead?
Upward pull: Deltoid - in the absence of functional supraspinatus, the deltoid CANNOT take the arm through full ROM Anterior - flexion Middle and some posterior - abduction Medial pull: Supraspinatus - creates negative pressure, often injured, and active in all elevating movements of the humerus Medial pull & Downward pull: Subscapularis Infraspinatus Teres minor
Scapulothoracic motion includes:
Upward rotation/downward (inferior angle moves away from spine/ inferior angle moves towards spine) Protraction/retraction (medial border moves away from spine/ medial border moves towards spine) Elevation/depression (uppies and downsies of the scapula) Remember: all these motions take place at the SC and AC joints, we're just describing what's happening to the scapula
You can protract your scapula and retract your scapula without upwardly or downwardly rotating your scapula, but it's nearly impossible to do what?
Upwardly rotate scapula without protracting scapula or downwardly rotate scapula without also retracting scapula. Upward and downward rotation of the scapula isn't likely to occur alone without any addition motions of the scapula.
How can you know when a muscle will be actively insufficient?
What the muscle does + opposite of what it does. Ex: triceps when shoulder extended and elbow extended (actively insufficient) and when full elbow flexion and shoulder flexed ( actively insufficient).
Which muscle depresses the scapula and tilts the inferior angle posteriorly?
When pectoralis minor contracts it causes the scapula to pull down but is also causes the scapula to tip in an anterior direction.
Why do close-pack positions matter?
When people are immobilized, they are often immobilized in the closed pack position. So, this is challenging for the elbow because we have one joint that is in closed pack position when you're in full extension and we have one joint that is in the closed pack position when you're in flexion. When people are immobilized at the elbow, they're typically immobilized at about 90 degrees of flexion or something close to that.
Cubitus varus
When the angle of the forearm relative to the humerus is not enough (always abnormal). A degree of 0 could be varus, as well as -5 degrees.
When is the triceps at its most slack position?
When the forearm is in full extension. The internal moment arm (effort arm) is greater, but the triceps are slack so they are actively insufficient. Same would be true if the elbow was in full flexion.
Describe a pathological impingement
When the head of the humerus has been allowed to move too far in a superior direction, not aligned with glenoid fossa, pushing against the acromion and all the soft tissues between (suprahumeral soft tissue), those tissues get squished!
Explain interosseous membrane loading
When the head of the radius shifts in a proximal direction, compressive force (weight bearing) is transmitted up the radius (80% of the force) and because the radius has a place to go the interosseous membrane is pulled up and stretched out (taut) because it is attached to the radius and moves with it.
Give an example of a force couple in the shoulder complex?
When the upper trap (elevation, slight upper rotation torque), lower trap (depression), and serratus anterior (slight depression) move in different directions, they produce the same movement of the scapula (upward/lateral rotation). The lower trapezius alone will not upwardly rotate the scapula, but when working with upper trap and serratus anterior, then it contributes. The serratus anterior lies between the scapula and the thorax and as it contracts it pulls the scapula towards the thorax and abducts/upwardly rotates the scapula.
Explain interosseous membrane unloading
When there is a distracting force, like when carrying a load, the ulna is pulled distally and the interosseous membrane becomes slack. The interosseous membrane also becomes slack when the forearm is in pronation.
Which muscle produces elevation of the shoulder with the least amount of rotation?
When trying to describe what muscle will elevate the scapula without producing any other motion, there really isn't one. There's going to be some other motion also occurring. It may be slight, but of all the ones described as being elevators, the upper trapezius and the levator scapulae produce the least amount of some other movement of the scapula.
What could contribute to varus?
fracture above the elbow, ligament injury on lateral side of elbow, supracondlyar fracture, fall on outstretched hand (alignment disrupted between humerus and ulna)
Which activities involve downward rotation of the scapula against resistance and which muscles are contracting?
same activities as those for depression against resistance: using crutches, wheelchair pushups, getting out of the pool, doing a pull up, closing a window blind, or closing an overhead trunk Ou downward rotators: rhomboid major & minor will only contract when downward rotation is produced against resistance.
