Analytical Anatomy
What are the orientations of the components of deltoid muscle force acting on the GH joint during abduction?
Compression toward the joint surface and shear force (superior shear force in the early phase; inferior shear force in the late phase of abduction). The contributions of the deltoid muscle force to the compression and shear to the GH joint change as the abduction angle changes. (See lecture slides for force vectors).
Joint forces are classified by their alignment to the joint surface Describe compresseive and shear
Compressive contributes to joint stability Shear "threaten the stabilizing tissue but creates rotation
Locate the coracoacromial arch. Which structure forms this arch? Name the structures that lie in the subacromial space? What is a common pathology associated with the coracoacromial arch?
The coracoacromial arch is formed by the undersurface of the acromion, the coracoid process and the coracoacromial ligament. Structures that lie in the subacromial space include the long head of biceps tendon, supraspinatus tendon, subacromial bursa and the superior joint capsule of the glenohumeral joint. A common pathology associated with this arch is impingement of the supraspinatus tendon. Impingement of other structures passing beneath the arch can occur as well. Causes of impingement include weakness of the rotator cuff muscles (these muscles restrict upward translation of the humeral head during flexion and abduction), variations in acromial morphology (flat vs. curved vs. hooked), arthritis or instability of the AC joint, subacromial bursitis etc.
Observe the T4-T10 costotransverse joints. Note the change in joint shape from cranial to caudal. What difference do you see between the T4 costo-transverse joint and the T10 costo-transverse joint?
The costotransverse joints (T4-T10) connect the articular tubercle of ribs to the costal facet on the transverse process of the corresponding thoracic vertebrae. Each costotransverse joint is stabilized by the costotransverse and superior costotransverse ligaments. The orientation of costotransverse joint facets changes from frontal plane to more transverse plane as they move caudally, making it a more weight-bearing type of joint. In addition, the costotransverse joints on the upper thoracic are concave facets whereas flattened facets on the lower thoraci. Compared to the upper thoracic, the costotransverse joints in the lower thoracic have more mobility.
Is there a way the interveterbral foramen open and irratate the facet?
flexion, SB towards side and then rotate to opposite side. So now you are compressing the facet while keeping the intervertebral foramen open.
What is the key to understanding coupling in the spine?
understand path of least resistance
Locate the Alar ligament. Slide a probe under the left Alar ligament. Name the attachments of this ligament.
The alar ligament runs from the lateral aspect of the odontoid process (dens) to the margins of the foramen magnum.
Between the variety of supraspinatus repairs some research suggests that there is no difference in the functional outcomes, but there are improved structural and biomechanical outcomes including:
Increased load to failure Decreased stress (increased contact area) Improved cuff integrity as assessed by a MRI
Post operative complications of
Retropharyngeal hematoma leading to airway obstruction Graft extrusion - more likely when posterior elements of vertebral column are unstable. Less common when arthrodesis is done for disc degeneration. Unless the graft extrudes more than 50% of its depth or unless it causes dysphagia, revision surgery usually is not indicated. The extruded portion will be resorbed, and the graft will ossify as the arthrodesis heals. If healing time is protracted, external immobilization time should be adjusted accordingly. Non-union/ pseudoarthrosis are uncommon.
Surgical procedures for rotator cuff repair
Surgical repair is recommended for acute, full thickness rotator cuff tears in otherwise healthy individuals. Surgical repair of the rotator cuff can be performed arthroscopically or open. Open procedures involve either a standard or a "mini-open" technique. The majority of current repairs are outpatient, arthroscopic. A partial tear may need only a trimming or smoothing procedure called a debridement. If the tear comprises less than 50 percent of the tendon's thickness, surgery, if performed, consists of light debridement with or without a subacromial decompression. Arthroscopic repair is said to provide: o Provide a better view of the glenohumeral joint o Does not compromise the integrity of the deltoid musculature Tears can come in different shapes, each of which requires different methods to repair - Arthroscopic repair can be divided in a single row and double row repair. In all cases, bone anchors with a varied number of sutures are inserted into the humerus.
Cervical arthrodesis fusion indications
Vertebral body fractures Dislocations with or without fracture of the posterior elements Radiculopathy Myelopathy Spondylosis: Including disc degeneration, disc herniation, facet arthrosis, and osteophytic spur formation
Neumann's words of wisdom of the shoulder complex? The joints in the shoulder
"The joints of the shoulder complex function as a series of links, all cooperating to maximize the range of motion available to the upper limb. A weakened, painful or unstable link anywhere along the chain significantly decreases the effectiveness of the entire complex." - Neumann
In the early phase of abduction, how do rotator cuff muscles contribute to the inferior glide of the humerus?
- Infraspinatus, teres minor, subscapularis provide inferior shear force component which contribute to the inferior glide. -Supraspinatus provide mostly compression to increase stability of GH joint. Even though supraspinatus does not provide inferior shear force in this phase, the tautness o fthe muscle and tendon during contraction provide a "spacer" that restricts the superior movement. -The passive force from the muscle bring stretched during abduction, such as latissimus dorsi, teres major, can also exert an inferior - directed force on the humeral head.
Describe the transverse ligament
- Mostly collagen fibers, few elastic fibers in the peripheral layers - In the central portion, the collagen fibers cross each other at an angle of ~ 30˚ -close to the dens, the TL has fibrocartilage -restricts flexion of AA, atlas gliding anterior on axis
Alar ligament functions?
- Restrics rotation - Mostly collagenous, few elastic fibers in peripheral layers
Describe the functional role of structures in the spine
- Spinal facet joints and costal joint guide the direction of motion - Intervertebral discs dictate the quantity of motion (higher the discs the more motion the spine will have at that spinal unit) - Vertebral ligaments prevent excessive motion - Muscle activation controls motion
Types of cervical surgery
1) Autograft - iliac crest, fibula, ribs 2) Allograft 3) Bone substitutes like bone morphogenetic protein
What joints are involved in the motion of ribs?
1. Sternocostal (Articulation with the sternum, ribs 1-7) 2. Costotransverse (CT) (rib articulates with the transverse processes of the corresponding vertebra) 3. Costovertebral (CV)= costocorporeal joint (e.g., the 6th rib articulates with the 6th and 5th vertebral bodies)
For every 3 degrees of shoulder abduction....
2˚ occur by GH joint abduction, 1 by scapulothoracic joint upward rotation
OA SB to right causes what osteokinematic? and what degrees in SB and Rot?
5˚ in SB and Rot.
What are the six kinematic principles associated with full shoulder abduction
5) not because of a muscle because of the coracoclavicular lig 6) clearing the greater tubercle under the acromion
scapulo-humeral rhythm: Upward rotators at the scapulothoracic (ST) joint:
AOR of ST: early phase root of scapular spine, late phase lateral of the scapular spine (near AC joint) - serratus anterior (most effective because of longest MA), upper, lower, middle trapezius.
Abduct your arm in the frontal plane without externally rotating the arm. Now abduct your arm in the scapular plane without external rotation. Which of the two was easier to perform? Why? Describe the orientation of the glenohumeral joint surface with respect to the three cardinal planes. Perform an AP mobilization of the GH joint in slight abduction on the cadaver paying attention that your force is applied tangent to the plane of the joint.
Abduction of the arm in the frontal plane beyond 90 degrees leads to abutment of the greater tubercle against the acromion if the arm is not externally rotated. The glenoid fossa lies approximately 30-45 degrees anterior to the frontal plane and often a minor amount of anterior tilt (5 degrees). When performing the AP mobilization, the force of the application should be applied tangent to the glenoid fossa (ie force directed posterolateral).
Clinical Application of Movement at the Occipito-Atlanto-Axial Complex Initiated with Occipital Sidebening Variances on performance of the clinical test?
Alar ligament test and the variances are related to where the alar space is
What is the static scapular posture?
Although highly variable, the resting posture for the scapula is approximately between the second and seventh rib, 6cm lateral to the spine, 10° of anterior tilt, 5°-10° of upward rotation and about 35° of internal rotation - Neumann 2010
Supraspinatus repair: Describe the single row
Anchor is placed on the greater tubercle of the humerus.
Anatomy of the cervical spine: Anterior longitudinal ligament, posterior longitudinal ligament, Intervertebral discs, Unconvertebral joints
Anterior Longitudinal Ligament: Attaches to the end plates and intervertebral discs Posterior Longitudinal Ligament: Within the spinal canal and tends to be thicker in the center portion and thins as move out towards the uncinate proceses. Bulging/ossification of this ligament can compress the spinal cord. Intervertebral Discs: Attach to the subchondral bone. However, at the outmost rim of the disc, it is not attached to the bone and thus this could be a site of arthritic spurs. Unconvertebral Joints: Critical landmarks for this surgery. Spurs can also commonly arise here and impinge the nerve roots.
Which muscles attach to the 1st rib? What structures are immediately adjacent to the first rib? Thoracic outlet syndrome and 1st rib mobilization. Perform a caudal mobilization on the 1st rib to improve mobility of the 1st rib.
Anterior and middle scalene muscles attach to the first rib. Structures immediately adjacent to the first rib include the brachial plexus, subclavian artery and subclavian vein (as you recall the brachial plexus and subclavian artery pass between the anterior and middle scalene on their way to the axilla). Thoracic outlet syndrome: An elevated first rib and/or scalene muscle tightness can be a potential cause of thoracic outlet syndrome. Other causes include cervical rib. Thoracic outlet syndrome refers to the neurovascular symptoms produced in the upper extremity due to compression of the brachial plexus and/or subclavian artery.
What are the primary movers for GH joint abduction? How do their moment arms (MA) change during GH joint abudction?
Anterior, middle, posterior deltoid and supraspinatus are the primary movers for GH joint abduction. Middle deltoid and supraspinatus have longest MA in the early phase of the abduction; this is observed by the perpendicular distance between their line of pull to AOR for abduction. MA of the deltoid (take three into consideration) increase from 0-150˚ while MA of supraspinatus stays consistent.
Terrible Triad Injury of the Elbow
As described previously in relation to Fig. 6.13, falling onto an outstretched and supinated arm can result in injury to the MCL. In some cases, however, this type of fall can traumatize additional structures, often referred to as the terrible triad of the elbow. The three primary components of this complex and severe injury are elbow joint dislocation (with extensive ligamentous injury), fracture of the radial head, and fracture of the coronoid process. The extreme compression, hyperextension, and valgus-producing force generated at ground contact can injure the MCL as well as fracture the bones. In addition, the valgus-producing force is often coupled with a large posterior-lateral torsional (rotary) stress at the elbow, often completely tearing the LUCL and other anatomically related soft tissues. The resulting posterior-lateral rotary instability of the elbow can be expressed clinically by manually placing an excessive external rotation (supination) stress to the proximal forearm (relative to a fixed humerus). Depending on the severity of the injury, the rotary instability can involve both the humeroradial and the humero-ulnar joints. Because of the extensive trauma, treatment of this injury can pose a significant challenge to the surgeon and rehabilitation specialist. In particularly severe cases, prognosis may be hindered by persistent instability, residuals of nerve damage, heterotopic ossification, and stiffness in the elbow. The goals of surgery typically include restoring bony and ligamentous integrity of the humero-ulnar and humeroradial joints. The restoration encourages earlier postsurgical movement, with aims of limiting long-term stiffness. Surgical treatment often involves the insertion of a prosthetic radial head, attempting to fortify the lateral column of the elbow.
Take the cranium and move it into left side bending. Which Alar ligament becomes taut? Explain the kinematics created by the Alar ligament during this movement. (What motion is created at C2? What is the relative motion created at C1?)
As the occiput LEFT side bends, the RIGHT superior Alar ligament becomes taut. Further LEFT side bend results in the alar ligament pulling C2 into LEFT rotation of the vertebral body, resulting in C1 positioned in a relative RIGHT rotation on C2
Locate the annular ligament of the elbow. Name its attachment sites. What is the function of the annular ligament?
Attachment sites include the ulna on either side of the radial notch. This annular ligament is important to maintain the radial head position and allows the radial head to spin during pronation/supination.
Scapulo-humeral rhythm: Determine the relative contribution of scapula and glenohumeral joint motions to shoulder elevation
Based on the scapulo-humeral rhythm, for 180˚ of motion during arm elevation, GHJ abduction contributes approximately 120˚ while scapular upward rotation contributes the remaining 60˚
What potentially occurs to the vertebral artery that is contralateral to the rotation and side bending? (Assume the left artery is the contralateral artery, i.e., rotation is performed to the Right).
Because of the rotational motion of the C1 to C2, the artery on the contralateral side is bent around the bony structures of C1-C2, thus kinking the artery and reducing the blood flow to the brain. (imagine bending a garden hose to shut off water flow). This is not a symptom producing position if the ipsilateral vertebral artery is not occluded (the vascular system is redundant). Conclusion: This test is performed to test the patency of the vertebral artery on the side of rotation by reducing the blood flow on the contralateral side. That is, you are purposefully occluding blood flow on the contralateral side. Possible scenarios contributing to a positive VBI test: 1) existing ipsilateral vascular occlusion along the path of the vertebral artery, 2) bone spurring on the ipsilateral side contributing to transient occlusion; and "stretching" of the ipsilateral artery due to excessive rotation of C1 to C2.
Why should non-coupled testing and treatment procedures be avoided at the upper cervical spine?
Because the coupling is not only dictated by the osseous structures but also by ligaments and we want to be respectful of them.
Describe thoracic movement with arm elevation Bilaterally, unilaterall
Bilaterally - extension Unilateral - thorax rotates and laterally flexes towards the same side of the elevating arm (not always)
How is a "traction" at the left C6-C7 facet joint performed?
By side bending right and rotating left and then traction what's left
Which of the following is false? a. Right side bend of the occiput creates tension in the superior left Alar ligament. b. The Transverse ligament attaches to the anterior arch of the atlas at both ends. c. Right side bend of the occiput results in right rotation of C1 on C2.
C - Right side bend of the occiput results in right rotation of C1 on C2. Because the motions are opposite at the AA joint.
Causes of combined (coupled) motions at the spine, in addition to the integrity of the vertebral ring at L1-L5 T4-T9 C2-C7 C1-C2 C0-C1
C2-C7; facet orientation, and intervertebral joint but not posture!
What nerves and muscles does Erb's palsy affect?
C5 and C6 Serratus anterior, Subclavius, Deltoids, Supraspinatus, Infraspinatus, Subscapularis, Teres, Pectoralis major, Biceps, Brachialis (BR, CB also), Supinator, ECR *Rhomboids and Levator scapulae typically not affected since dorsal scapular nerve splits before most common injury location*
What nerves and muscles does total plexus palsy affect?
C5, C6, C7, C8, T1 Serratus anterior, Subclavius, Deltoids, Supraspinatus, Infraspinatus, Subscapularis, Teres, Pectoralis major, Biceps, Brachialis (BR, CB also), Supinator, ECR *Rhomboids and Levator scapulae typically not affected since dorsal scapular nerve splits before most common injury location* Latissimus dorsi, Triceps, Pronator teres, FCR, ECU Pronator quadratus, FCU, Hand and digit muscles
What nerves and muscles does extended erb's palsy affect?
C5,C6,C7 Serratus anterior, Subclavius, Deltoids, Supraspinatus, Infraspinatus, Subscapularis, Teres, Pectoralis major, Biceps, Brachialis (BR, CB also), Supinator, ECR *Rhomboids and Levator scapulae typically not affected since dorsal scapular nerve splits before most common injury location* Latissimus dorsi, Triceps, Pronator teres, FCR, ECU
Bifid processes?
C2 to C5 or C6. Why?Supraspinous ligament occupies this space
Describe the structure of the Cervical spine
Cervical spine is in lordosis and the spinous processes are shorter from C3-C4 and then get longer as you go down the cervical spine.
Function of the rotator cuff muscles?
Control dynamic stability Uniarticular muscles approximate the humeral head into the glenoid fossa Directly impact dynamic joint stability Allow larger muscles to do the real work of moving the shoulder
How does increased kyphosis affect the cervical spine?
Excessive thoracic kyphosis translates the cervical spine and head anteriorly. To compensate and maintain head position, cervical spine may increase its lordosis curve.
Identify the osteokinematic motions of the cervical spine during the VBI Test.
Extension plus ipsilateral rotation and side-bending of the C-spine
Strongest shoulder muscle?
Extensors
Observe the orientation of the facet joints of thoracic spine. Describe the possible/theoretical motions of thoracic spine based on its facet orientation.
Facet joints become progressively more vertical. Motions occur in all three planes; however, we do not see much motion in thoracic spine during physical assessment because the rib cage restricts some motion. In general, Flex/Extension ROM increases from upper to lower thoracic and Axial Rotation decreases from upper to lower segments due to facet joint orientation. Lateral Bending does not systematically change very much from the upper to lower thoracic spine. (See graph next page)
Considering your knowledge of the anatomy surrounding the elbow/forearm complex, how might falling on an outstretched hand (FOOSH) cause injury to this region?
Falling on an outstretched hand (FOOSH) may cause proximal radial fracture at the elbow region. When a compression force is applied through the hand, it is transmitted primarily through the wrist at the radiocarpal joint and to the radius. This force stretches the interosseous membrane that transfers a part of the compression force to the ulna. Despite the transmission of force by IO membrane, because the radius is on the primary force transmission pathway. Also, contact area between radial head and distal humerus is small. So the stress (which is force over contact area) is large and a fracture in this region is very likely in a FOOSH injury.
What is scapulo-humeral rhythm?
For a healthy shoulder joint complex, a natural kinematic rhythm exists between glenohumeral (GH) abduction and scapular upward rotation. Generally speaking, there is a 2 to 1 ratio between GH abduction and scapular upward rotation through the range of motion of abduction. (i.e. for every 3˚ of shoulder abduction, 2˚ occurs by GH joint abduction and 1˚ by scapulothoracic joint upward rotation) Note. Various ratios have been reported in literature. For this lab, to make it simple, we are going with the 2:1 ratio throughout the range of motion.
Children with BPBP have greater... and reduced...?
Generally, children with BPBP have greater scapulothoracic contributions to shoulder motion and reduced glenohumeral motion.5 In a traditional arm elevation (abduction) task, contributions to global abduction are described as a ratio:𝑮𝒍𝒆𝒏𝒐𝒉𝒖𝒎𝒆𝒓𝒂𝒍 𝑨𝒃𝒅𝒖𝒄𝒕𝒊𝒐𝒏/𝑺𝒄𝒂𝒑𝒖𝒍𝒐𝒕𝒉𝒐𝒓𝒂𝒄𝒊𝒄 𝑼𝒑𝒘𝒂𝒓𝒅 𝑹𝒐𝒕𝒂𝒕𝒊𝒐𝒏.
Label the following image with the osteokinematic and identify the plane of each motion.
Glenohumeral Ab/Adduction Frontal
Label the following image with the osteokinematic and identify the plane of each motion.
Glenohumeral Flexion/Extension Sagittal
Label the following image with the osteokinematic and identify the plane of each motion.
Glenohumeral internal/external rotation Transverse
Osteokinematics of the elbow from the start of acceleration to the end of deceleration
Humero-Ulnar Joint: Extension Humeroradial Joint: Extension Proximal Radioulnar Joint: Pronation Distal Radioulnar Joint: Pronation
Arthrokinematics of the elbow from the start of acceleration to the end of deceleration
Humero-Ulnar Joint: Roll and Glide in the same direction Humeroradial Joint: Roll and Glide in the same direction Proximal Radioulnar Joint: Rotation of the radial head within a ring formed by the annular ligament and the radial notch of the ulna Distal Radioulnar Joint: Concavity of the ulnar notch of the radius rolls and slides in similar directions on the convex ulna head.
Label the following image with the osteokinematic and identify the plane of each motion.
Humerothoracic Ab/Adduction Frontal
Label the following image with the osteokinematic and identify the plane of each motion.
Humerothoracic Flexion/Extension Sagittal
Label the following image with the osteokinematic and identify the plane of each motion.
Humerothoracic Internal/External Rotation Transverse
Sternoclavicular Joint Osteokinematics & Arthrokinematics
Hyphens respectfully -Elevation (45°) and Depression (10°) -Protraction (15°-30°) and Retraction (15°-30°) -Posterior Clavicular Rotation (20°-30°) -SR/IG and IR/SG -AR/AG and PR/PG -PS
Scapulothoracic Joint Osteokinematics & Arthrokinematics
Hyphens respectfully -Elevation and Depression -Protraction and Retraction -Upward (60°) and Downward Rotation -Not Described (Not a true joint)
Glenohumeral Joint Osteokinematics & Arthrokinematics
Hyphens respectfully -Flexion (120°) and Extension (65°a and 80°p) -Abduction (120°) and Adduction -Internal (75°-85°) and External Rotation at neutral (60°-70°) and at 90° of abduction (90°) -Horizontal Adduction (Horizontal Flexion) and Horizontal Abduction (Horizontal Extension) -PS and AS -SR/IG and IR/SG -AR/PG and PR/AG at neutral, primarily spin at 90° of abduction -AR/PG and PR/AG
Acromioclavicular Joint Osteokinematics & Arthrokinematics
Hyphens respectfully -Upward and Downward Rotation (~30°) -Internal and External Rotation (5°-30°) -Anterior Tilting and Posterior Tilting (5°-30°) - Not Described (Gliding/Plane Joint)
Ignore text and explain picture
Illustration showing a high velocity abduction and external rotation motion of the glenohumeral joint during the cocking phase of pitching a baseball. This motion twists and elongates the middle GH ligament and anterior band of the inferior GH ligament (depicted as red thin arrows pointed toward the rim of the glenoid fossa). The humeral head has been removed to show the aforementioned stretched structures and glenoid fossa. This active motion tends to translate the humeral head anteriorly (thick black arrow), toward the anterior glenoid labrum and Subscapularis muscle. Tension in the stretched ligaments and Subscapularis muscles naturally resists this anterior translation.
Describe the study by Russo with the Erbs palsy
In a study by Russo et. al. (2013), twelve children (mean age 8.7 yrs) with Erb's palsy and eight children (mean age 6.4 yrs) with extended Erb's palsy as well as six unaffected contralateral limbs were tested. Children raised their unaffected limbs to 95° with a ratio of 1.30:1. Patients with Erb's palsy raised their limbs to 47° with a ratio of 0.53:1. Patients with extended Erb's palsy raised their limbs to 42° with a ratio of 0.06:1 (almost no glenohumeral motion. Mostly scapula. glenohumeral motion:scapulothoracic
Which portion of the spine demonstrates a kyphotic curve? How is a kyphotic curve assessed?
In the normal spine (at rest), the thoracic spine and sacrum display kyphosis. The kyphotic curve of T-spine can be assessed using X-ray The Cobb's angle of kyphosis is calculated from perpendicular lines drawn on a standard thoracic spine radiograph: a line extends through the superior endplate of the vertebral body, marking the beginning of the thoracic curve (usually at T4), and the inferior endplate of the vertebral body, marking the end of the thoracic curve (usually at T12). The normal kyphotic curve angle is about 40 degrees. The natural curvatures within the vertebral column are not fixed: they change shape during movements and different postures. The Cobb angle increases as kyphosis increases. (Katzman WB, et al "Age-Related Hyperkyphosis: Its Causes, Consequences, and Management" J Orthop Sports Phys Ther. 2010 June; 40(6): 352-360. doi: 10.2519/jospt.2010.3099)
How does increased kyphosis affect the loading on the thoracic and cervical spines?
Increased kyphosis increases the external moment arm (from the thoracic AOR to the line of body weight). See figure below. In a static position, internal=external torque. Torque= Force * moment arm. Since body weight force vector and the internal moment arm of the muscles are constant, increasing the external moment arm due to kyphosis means an increased muscle force necessary. This increases the shear and compression loads on T-spine and C-spine. Also, increased kyphosis may reduce the contact area between vertebra bodies. Pressure equals force/contact area. Both the potential increase in compression force (due to increased muscle force) and decrease in contact area will dramatically increase the pressure (Double whammy!).
Define kyphosis
Kyphosis is the curvature that is concave on the anterior side (or convex posteriorly) of the spine.
Can the symptoms in the neck created by irritation of the facet joint be differentiated from those caused by the irratation of the nerve root?
Location of sx, type of sx. but in some cases they aren't as distinct. Palpation of the nerve root!! Press nerve root into the gutter. Should be sensitive to palpation.
If you were to violently distract the radius, what do you imagine might occur at the annular ligament? How would this injury alter the mechanics at the elbow joint? Radioulnar joint? To what population does this injury occur?
Mechanisms of the Nurse maid's elbow: Violent distraction of the radius in an extended arm may result in a radial head dislocation or a "nurse maids' elbow." The radial head slips out of the annular ligament and the ligament is "stuck" between the radius and the humerus.Active muscle contraction force can prevent pull-elbow being caused.(if the kid is warned before the parent pulls his/her arm.) This injury would likely affect the radioulnar mechanics the most, followed by radiohumeral mechanics and have a small affect on humeroulnar mechanics. The dislocation can be reduced "easily" by through a supination technique restoring normal mechanics at the joint. However, there is a high probability of recurrence following the first incidence so parent education is critical. This injury commonly occurs in children below 5 years of age.
How does the muscle length of the biceps brachii change through the range of motion? How does this change in length affect muscle force production?
Muscle length is the longest at full elbow extension, and decreases as elbow flexion angle increases. The relationship between muscle length and force generation capacity is called "length-tension" relationship. Each muscle has its optimal length for generating the maximal muscle force. Generally, force production capacity of the muscle decreases as the muscle length decrease or increase from the optimal length.
Normal translation of C1 on C2
Not exceeding 2-3 mm
What functions of muscle are needed during each respiration phase? What muscles are involved during inspiration / expiration? During forced inspiration / expiration?
Quiet inspiration (need ↑volume, ↓pressure) - Increase intrathoracic volume: Diaphragm (primary) - Elevate the ribs: External intercostales (primary), Scalene (accessary) New Table 11-4 Forced Inspiration (need ↑volume, ↓pressure) - Elevate the ribs, sternum : pectoralis major & minor, sternocleidomastoid, serratus anterior, serratus posterior superior, lastissimus dorsi, levator costarum - Stabilize the lower ribs for contraction of the diaphragm: Serratus posterior inferior, quadrates lumborum - Extend the trunk: iliocostalis thoracis and cervicis, New Table 11-5 Quiet expiration (need ↓volume, ↑pressure): - passive, due to relaxation of diaphragm and elastic recoil of thorax & lungs Forced expiration (need ↓volume, ↑pressure) - Depress the ribs: four abdominal muscles, transverses thoracis, and internal intercostales
What are the only two flexors for atlanto-occipital joint?
Rectus capitis anterior & Longus capitis (New 10-23). The action of rectus capitis anterior is limited to flexion of atlanto-occiputal joint while longus capitis is to flex and stabilize the upper craniocervical region (based on the insertions). Both of the attachments on the occiput are anterior to occipital condyle and they are both antagonists of sub-occipital muscles in sagittal plane. These two muscles are targeted in a small range of motion craniocervical flexion (nodding) exercise.
Rib movement during breathing Visualize the axis of these movements.
Ribs 1-7 posteriorly rotate in full inhalation and anteriorly rotate in full exhalation It hurts with inhalation or exhalation this guides you where you need to go with the treatment
What are the coupled-motions of the lower cervical spine? Why?
Rotation and side-bending are to the same side, regardless of cervical flexion or extension. The couple motions of the lower cervical spine are primarily due to the orientation of the facet joint (more superior anterior relative to posterior) and also affected by uncovertebral joint and integrity of the vertebral ring.
Anatomy and demographics of rotator cuff pathology
Rotator cuff pathology is the most common condition of the shoulder for which patients seek treatment. The cause of rotator cuff tears is likely multifactorial. Degeneration, impingement, and overload (specifically overhead activity) may all contribute in varying degrees to the development of rotator cuff tears. Most often rotator cuff lesions appear to start as partial tears of the articular portion of the supraspinatus tendon. Over time they can progress to full thickness tears and can spread to include the supraspinatus, infraspinatus, subscapularis and biceps tendons. Rotator cuff tears most often involve damage to the supraspinatus tendon. When the rotator cuff tendons are injured or damaged, the bursa can also become inflamed and painful (subacromial bursitis).
Does the pattern vary with the sagittal plane posture of the spine?
Seems to matter more with the mid and lower thoracic spine
Label the following image with the osteokinematic and identify the plane of each motion.
Scapulothoracic Anterior/Posterior Tilt Sagittal
Label the following image with the osteokinematic and identify the plane of each motion.
Scapulothoracic Internal/External Rotation Transverse
Label the following image with the osteokinematic and identify the plane of each motion.
Scapulothoracic Upward/Downward Rotation Frontal
What joints are involved with scapulo-humeral rhythm?
Scapulothoracic, glenohumeral, acromioclavicular, sternoclavicular
How does flexion torque production of the biceps brachii change through the range of motion? How do you apply this to clinical exercise testing or training?
Several factors need to be considered when estimating torque production capacity of biceps brachii at different joint angles. During isometric contraction (contraction velocity =0), three factors must be considered: 1) moment arm; 2) muscle PCSA; and 3) length-tension relationship. For the same muscle of the same person (same muscle PCSA), flexion torque production capacity is the greatest around 85-95 degree where the muscle length is optimal to produce force and also the moment arm is the greatest. Torque production decreases as elbow flexion angle increases or decreases because both the lever arm and force generation ability (based on length-tension relationship) decrease from this position. (see figure below) Fig 6-38/ New Fig 6-37 Understanding the torque production ability of the muscle and the external load through range of motion is helpful for designing an exercise training program. The different tools (external load) provide different pattern of external torque. The changes of external moment arm of using a free weight and using a theraband are bell-shape curves with highest part around 90° of flexion. While the external load of a free weight is consistent throughout the range of motion, the external load of a thera-band increases linearly. Both free weight and theraband could provide external torque in bell shape. However, the curve may not fit the torque production ability of the muscle throughout the whole range of motion. An ideal tool that produces the external torque for muscle strengthening would have the curve close to the curve of the torque production ability from the muscle. (Note: the curves drew on the blackboard were theoretical curve. The curves can shift with different parameter settings)
Hypothesize why the groups in the Russo study utilized different contributions from the scapulothoracic and glenohumeral joints based on nerve roots and muscles affected by the palsy.
Since primarily glenohumeral muscles (rotator cuff, deltoids, etc.) muscles are affected by the palsy, abduction may be achieved through scapular elevation and upward rotation using scapulothoracic muscles like the trapezius.
Arthrokinematics of the shoulder from the start of early cocking to the end of late cocking2.
Sternoclavicular Joint: SR/IG, PS and possible PR/PG Acromioclavicular Joint: N/A Scapulothoracic Joint: N/A Glenohumeral Joint: SR/IG, PS and possible PR/AG
Osteokinematics of the shoulder from the start of early cocking to the end of late cocking.
Sternoclavicular Joint: elevation, posterior rotation and possible retraction Acromioclavicular Joint: upward rotation, external rotation, posterior tilt Scapulothoracic Joint: upward rotation, retraction (adduction and external rotation) and possibly elevation Glenohumeral Joint: abduction, external rotation and possible horizontal abduction
What is the strongest rotator cuff muscle and why?
Subscapularis. Biggest PCSA and lever arm
Describe the mobility of the Transitional vertebrae of the thoraco-lumbar junction
Sudden change of mobility: Upper facets engage in flexion extension and allow rotation, lower facets restrict rotation resulting in a harder end-feel on rotational testing.
What is the arthrokinematics of GH joint during abduction? Why is the glide important?
Superior roll and inferior glide. The diameter of the articular surface of the humeral head is almost twice the size of the glenoid fossa. If there is insufficient inferior glide during abduction, a jamming of the humeral head against the coracoacromial arch occurs.
scapulo-humeral rhythm: Sternoclavicular and acromioclavicular joint during full abduction
The 60˚ of scapular upward rotation of the 180˚ abduction is the combined kinematics at the SC and AC joints.
Identify the AC joint. Which plane does this joint lie in? What is a common mechanism of injury of this structure? Which muscles or ligaments support this joint?
The AC joint lies mostly in the sagittal plane. The most common MOI for this joint is falling onto the tip of the shoulder with the arm adducted. The acromion is forced inferiorly and medially with respect to the clavicle and the clavicle appears visually to protrude superiorly, often called a "piano key deformity." No muscles support this joint directly so rehab of this injury is focused on improving the scapulohumeral mechanics as best as possible through strengthening. The acromioclavicular ligament and the coracoclavicular (trapezoid especially and conoid) ligaments prevent this injury.
Determine the biceps brachii moment arm for flexion at 0, 90, and 135 degrees of elbow flexion. What is the influence of forearm position on the moment arm for biceps brachii?
The AOR for the biceps runs medial-laterally, passing through the vicinity of the lateral epicondyle. The perpendicular distance from that AOR to the biceps brachii (its moment arm) is the greatest at about 90-100 degrees. As the flexion angle increases or decreases from this angle, the moment arm decreases with the shortest moment arm at the end range of elbow extension. Moment arm of the biceps is also affected by the position of the radioulnar joint. Given the same elbow flexion angle, the biceps brachii moment arm for elbow flexion is largest in full supination and decreases going into pronation. (Remember how the biceps tendon rolls around the radius during pronation!) Therefore, moment arm of the biceps is the largest at approximately 90O of flexion with forearm in full supination.
Identify the articulating facets of C1 with the occiput. Pretend you are the C1 vertebrae and display the orientation of the facets to your classmates. Relate this to the three cardinal planes.
The articulating facets of C1 are concave and lie in the transverse plane tilted slightly posterior and medial. They tend to cradle the occiput and allow some flexion/extension (nodding) and minimal sidebending and rotation.
Locate the transverse ligament. Push the head into extension and slide a thin probe under the transverse ligament. Name the attachments of the ligament
The attachment site for both ends is the posterior aspect of the anterior arch of C1.
Identify the dens. To what vertebrae does this osseous structure belong? What is the purpose of the transverse ligament? What are the dangers associated with a rupture of this ligament?
The dens is part of the C2 vertebra. The transverse ligament holds the dens against the anterior arch of the atlas. Rupture of this ligament can lead to impingement on the spinal cord as C1 may glide anteriorly unchecked. The spinal cord would then be pinched between the dens and the posterior arch of the atlas. The vertebral artery may also be compromised. The function of the transverse ligament should be understood and translated to the clinical tests such as the Sharp-Purser test for example.
Describe the lower cervical facet joints
The facet joints are 45˚ in reference to the vertebral bodies - allows flex/ext, SB, Rot, and linear motion. The facet joints share weight with the interveterbral discs; changes with position of the head
Put the shoulder of the cadaver in the most common position to create potential for a glenohumeral dislocation. Describe this anatomical position. Why is this position unstable?
The most common direction of dislocation is anterior and inferior. The most common position for this to occur is in 90 degrees abduction and full external rotation. This position rotates the inferior glenohumeral ligaments superiorly creating instability inferiorly and anteriorly. In addition, the labrum is weakest anterior and inferior. The primary passive restraint to anterior/inferior dislocation is the anterior band of the inferior glenohumeral ligament and the labrum. The primary passive restraint to anterior displacement at 45 degrees abduction is the middle glenohumeral ligament.
Identify the line of pull of the biceps brachii at 25, 90, and 135 degrees of elbow flexion. What component of the force vector contributes to flexion? What does the other component of force contribute to? How do the magnitudes of the two components change through range of motion? Application in manual muscle testing:
The line of pull is the line connecting the origin and insertion of the biceps brachii. The orientation of this line is referenced relative to the forearm. The force vector (red arrow in figure below) for this muscle is directed along this line of pull. See figures bellow. When we decompose a muscle force vector (M), we do one direction that is perpendicular to the segment that the muscle is moving (Mx, rotary component); and the other direction that is parallel to the segment (My, compression or distraction component). Use rectangular method to decide the length of the component vectors. The force component perpendicular to the forearm contributes to elbow flexion and shear. Depending on the elbow flexion angle, the force component parallel to the forearm contributes to either compression or distraction of the forearm to the elbow: in small flexion angle (more extension), it is oriented toward the joint and is thus compressive, while in large flexion angle, it is distraction force. For patient with osteoarthritis, we prefer the position with larger flexion angle. The parallel force component is distractive, so that the method can avoid pain induced by compression force. For patient with hypermobility joint, we prefer the position with small flexion angle (more extended position). The compression force can help to increase the stability of the joint.
A person with forward head posture is putting stress where?
The load of the facets increase with the forward head posture; there are some people who get closer to the cervical thoracic junction where there is less motion so you get even less motion and then you get more loading on the facet joints, so the intervertebral joints contribute to radiculopathy - more common in the lower cervical than upper. That's why C5C6C7 are the most common radiculopathy.
Russo et. al. (2013) conducted a statistical analysis technique called discriminant functional analysis. This technique allowed the authors to determine which measurement variables could predict a patient's (or limb's) diagnosis (unaffected, Erb's or extended Erb's). Below, two models are shown. Global Shoulder Motion Model Inputs: humerothoracic motions Results: 76.9% accuracy Significant predictors: Ab/Adduction during ER Ab/Adduction during IR Int/Ext Rotation during hand-on-spine Glenohumeral/Scapulothoracic Model (Figure in key) Inputs: glenohumeral motions, scapulothoracic motions, acromion translations Results: 92.6% accuracy Significant predictors: ST Up/Down Rotation during hand-to-mouth GH Int/Ext Rotation during abduction GH Int/Ext Rotation during hand-on-spine Acromion Med/Lat Translation during hand to-mouth Which model better predicted diagnosis? What does this tell us about the importance of evaluating not only humerothoracic motion but also the scapulothoracic and glenohumeral contributions to that motion? (Glenohumeral/Scapulothoracic Model chart in key)
The model breaking down shoulder motion into glenohumeral and scapulothoracic contributions was a better predictor of diagnosis. This shows that we as clinicians and researchers may miss important movement impairments if we only look at global shoulder or humerothoracic motion.
Locate the most cranial vertebral body of the cervical spine. To which vertebrae does this belong?
The most superior vertebral body belongs to the axis. The atlas consists only of a body-less ring.
Describe the motion of a single rib and rib cage during inspiration and expiration.
The motion of a single lower rib can be described as "bucket handle action". Bucket handle action occurs because the ribs are "hinged" both anteriorly and posteriorly (articulate anteriorly with the sternum and posteriorly with the thoracic spine), whereas the curved portion is free to move. The axis of rotation of the movement of a given rib runs through the costotransverse and costovertebral joint. The axis displaced horizontally about 35 ° (25°-45°) from the frontal plan. Therefore, the movement of the shaft of the rib rotates upward and outward. Boyle's law (ideal gas law): PV=nRT, inverse relation between pressure and volume, explains movement of air during inspiration (high volume, low pressure= gas in) and expiration
Locate the right nerve trough of C3. Pretend you are the C3 vertebrae and display the orientation of these structures with your arms to your classmates. Point on a classmates' neck where these can be found topographically.
The nerve troughs are more anterior than most people think.
Do spinal nerves exit superior or inferior to the vertebral body with the same name?
The nerves exit superior to the vertebrae for which they are named in the cervical spine. This is true for C1-7. The C8 nerve root exits inferior to C7 and from that level on, the nerves exit inferior to the vertebrae for which they are named.
Is the total cross-sectional area for the anterior neck muscles the same as for the posterior neck muscles? Are the lever arms for the anterior neck muscles similar to that of the posterior neck muscles?
The posterior neck muscles (extensor) have a considerably larger cross-sectional area (greater force production). In general, posterior muscles also have a larger lever arm than the anterior muscles. The posterior neck muscles (extensor), therefore, can generate more muscle torque (torque = force x lever arm).
Observe the relationship between spinous processes and vertebral bodies throughout the thoracic spine, what do you see?
The rule of 3's is a clinical rule that attempts to generalize the orientation of the thoracic spinous processes. There are certainly deviations as can be appreciated by observing the wide variability of several cadavers. Our information is based on this very source (above). It makes sense to us that from T9 to T10 to T11 to T12 the spatial relationship between spinous and transverse processes has a gradual change according to Geelhoed et al (2006). But again the rule of three's is very general and basic.
Locate the spinous process of C2. What is the name of this variation in morphology of spinous processes?
The spinous processes are typically bifid with the C2 spinous process being the first palpable spinous process.
scapulo-humeral rhythm: The clavicle posteriorly rotates around its own long axis during shoulder abduction
The upward rotation at the AC joint is stretching the relatively stiff coracoclavicular ligament. The tension of the ligament is transferred to the conoid tubercle (inferior/posterior of the clavicle) and the application of the force rotates the clavicle posteriorly. The posterior rotation of the clavicle unloads the ligament slightly and permitting the AC joint to have further upward rotation.
What potentially occurs to the side of vertebral artery that is ipsilateral to rotation and side bending? (Assume the right artery is the ipsilateral artery, i.e., rotation is performed to the Right).
This position is similar to the position of the Spurling's Test. Therefore, any bony "spurring"/osteophyte formation in the cervical spine may encroach on the artery, thereby causing occlusion of the artery on the right (ipsilateral) side. Excessive rotation of C1 to C2 can also lead to ipsilateral "stretching" effect on that vertebral artery.
Determine the axis of rotation (AOR) of the glenohumeral (GH) joint?
Three axes of rotation all pass through the centroid of the humeral head and are perpendicular to each other.
What are the clinical guidelines for WCP technique?
To reduce overuse: reaching further back at initial contact rather than releasing more anteriorly was more advantageous
Upward rotators of the scapula?
Trapezius, serratus anterior (inferior)
Supraspinatus repair: Describe Dual Row (Suture-Bridging Repair):
Two anchors are placed at the lateral edge of the articular surface of the humeral head (medial row). One anchor is placed for each 1 cm of damage (i.e. 2 cm tear means 2 anchors are placed) A second row of anchors is placed at the greater tuberosity (lateral row). If 2 medial row anchors are placed, 2 lateral row anchors are placed. If 3 medial row anchors are placed, 2 lateral row anchors are placed.
What's the big deal about uncinate processes?
Uncinate processes create uncovertebral joint. No capsule but cartilage on the surface. Controls/minimizes lateral translation, guide side bending, and rotation. First to develop arthroses in the cervical spine. A "uni" articular morphological change in joint; like there are spurs the joint is larger the cartilage is not as smooth. May restrict movement but it's close to the nerve root. They are subject to anterior and posterior shear forces with flexion and extension(especially in the presence of disc lesions). Close to both vertebral nerve root artery - therefore source of nerve irritation and radicular symptoms.
What are the regions of the Thoracic spine and ribs?
Vertebro-manubrial T1-T2 Vertebro-sternal T3-T7 Vertebro-chondral T8-T10 Thoracolumbar junction T11-T12
What is the postoperatice care for rotator cuff repair/supraspinatus repair? Early versus delayed therapy for rotator cuff?
While early may improve ROM, it could impair bone-tendon healing and subsequently lead re-injury.
Knowing these two questions: (Is the total cross-sectional area for the anterior neck muscles the same as for the posterior neck muscles? Are the lever arms for the anterior neck muscles similar to that of the posterior neck muscles?) What implications does this have for whiplash injuries?
Whiplash injuries refer to injuries resulting from neck hyperflexion and hyperextension. Whiplash injuries are difficult to prevent from muscular perspective. The cervical spine and associated musculature is designed to counter gravity, i.e. by extending the head and neck to keep the mass of the head over the base of support. The anterior neck musculature is not well-designed to resist a rapid posterior acceleration of the head. Injuries, therefore, are more likely to occur during neck hyper-extension (also because of ROM). This could result to injury to both anterior (e.g., muscle strain) and posterior structures (e.g., fracture of facet joint).
Phases of throwing?
Wind Up: Begins with initial movement of the contralateral lower extremity, ends with elevation of lead leg to its highest point and with separation of the throwing hand from the glove. Early Cocking: Begins once the lead leg reaches its maximal height and the ball is removed from the glove, ends when the lead foot contacts the pitching mound. Late Cocking: Begins with lead foot contacting the mound, ends with maximal external rotation of the throwing shoulder. Acceleration: Begins at the point of maximal external rotation of the shoulder, ends with ball release. Deceleration: Begins with ball release, ends with maximal humeral internal rotation and elbow extension. Follow-through: Begins with maximal humeral internal rotation and elbow extension, ends with the pitcher in a fielding position.
Describe the effect of coupled motion on maintaining horizontal gaze
With right cervical spine rotation the lower cervical spine will be coupled with right sidebend while the upper cervical spine will be coupled with left sidebend. This allows us to maintain horizontal gaze during functional rotation patterns of the cervical spine in everyday life. Assessment of active range of motion of the cervical spine rotation can be utilized to hypothesize impairments limiting functional range of motion. Quality of movement can also provide insight into preferred movement patterns during assessment of the cervical spine. For example: A patient presenting with limitations in OA joint mobility may demonstrate rotation of the cervical spine with ipsilateral sidebend and inability to maintain horizontal gaze. This may prompt you to assess OA joint mobility as a potential impairment impacting the quality of their cervical spine rotation range of motion. Additionally, a patient may demonstrate right cervical rotation with right sidebend but ability to actively left sidebend upon cueing to maintain horizontal gaze. This patient may fall into the "motor control" category of impairments as opposed to "mobility" deficits.
Palpate the lateral collateral and medial collateral ligaments of the elbow. Perform a valgus stress test on the elbow provided. What sport can boast of the greatest number of medial-collateral ligament injuries?
You should be able to identify both the lateral collateral and medial collateral ligaments of the elbow. MCL is also called the UCL (ulnar collateral ligament). The MCL consists of three discrete bands: anterior, posterior and tranverse/oblique. The anterior band is the most important part of the MCL that provides the maximum valgus stability at the elbow throughout the flexion range of motion. Posterior band becomes taut during flexion and the transverse band provides little to no stability against a valgus stress. MCL tears are most commonly found in baseball pitchers. Repeated overhead activities may lead to chronic laxity of the MCL leading to pain/instability at the elbow. Other structures that contribute to stability at the elbow joint in addition to MCL and LCL are the joint capsule, bony congruity, radial head, annular ligament (prevents lateral subluxation of radius), and muscles crossing the elbow joint (dynamic stability).
For post-operative care: If anterior instrumentation is used what should you do?
immobilization with a cervical orthosis is usually adequate.
Describe the A-A joint
three seperate joints - lateral - circular facets on both atlas and axis, biconvex articular surface -median dens on axis pivots on atlas (allows rotation) no disc superior facets of the axis slope downward and lateral IAR - in the center of the dens
Who has the largest moment arm with upward rotation?
serratus anterior (inferior)
Describe the coupling pattern of the upper cervical
• Coupling paLern is side bend with opposite side rota7on independent on posture and how ini7ated (i.e. ini7ated with side bend or with rota7on) • Anatomical contribu7ons: - CO-‐C1: Convex (CO) and concave (C1). Think about a marble rolling in a bowl. Right side bend with leY rota7on allows for the marble to return to the center of the bowl. - C1-‐C2: If ini7ate with a side bend, during the few ini7al degrees of side bending, the alar ligament becomes taught, pulling C2 into rota7on to same side (i.e. with right side bend C2 pulls into right rota7on under C1). This achieves a rela7ve contralateral rota7on of C1-‐C2 • If ini7ated with side bend or rota7on, C1 facet is convex as is C2; therefore it is a biconvex joint. This contributes to the coupling paLern observed (see previous slides).