Elbow Anatomy and Biomechanics PDF

1 / Anatomy Feel comfortable with the end feels and normal ranges for each movement; you probably don’t have to memorise them, but make sure they make sense so you can spot an abnormal end feel. Review the radial nerve, median nerve, and ulnar nerve; Know which nerves run in or close by which anat...

1 / Anatomy Feel comfortable with the end feels and normal ranges for each movement; you probably don’t have to memorise them, but make sure they make sense so you can spot an abnormal end feel. Review the radial nerve, median nerve, and ulnar nerve; Know which nerves run in or close by which anatomical structures and therefore where each is commonly compressed. The three true joints of the elbow above all share one joint capsule, so injury to any one joint will affect the whole elbow complex. If there is joint effusion/edema, it would be most evident in the triangular space between the radial head, tip of the olecranon and lateral epicondyle. Palpate this spot on yourself! It’s important to know which movements each ligament restricts so we can understand MOI. 2 / Biomechanics Carrying Angle 1.​ The elbow has a normal slight valgus -​ On full EXTENSION the MEDIAL part of the olecranon is not in contact with the trochlea (medial gap) -​ On full FLEXION the LATERAL part of the olecranon is not in contact with the trochlea (lateral gap) Mid Radioulnar ‘Joint’ Radius connection to ulna via the interosseous membrane -​ The interosseous membrane is taut midway bt/ supination and pronation (neutral position) -​ The interosseous membrane prevents proximal displacement of the radius on the ulna which most likely occurs with pushing movements -​ Helps to dissipate forces from the hand so they are less at the elbow  -​ The oblique cord (ulnar tuberosity to radial tuberosity) runs @ right angles to the interosseous membrane and assists in preventing distal displacement of the radius on the ulna, which occurs during pulling motions 3rd Order Lever Fulcrum-Effort-Load (Trochlea-Muscle attachments-weight in the hand) The lever structure means -​ Load in the hand is 10x more at the elbow joint -​ The joint therefore has poor mechanical advantage -​ However, it is a good speed multiplier (eg throwing) 3 / Pathologies Tendonitis (Tendinopathy) Tendonitis is inflammation of a tendon due to overuse. Tendinopathy is a degenerative condition of the tendon due to overuse. For our purposes, they are the same thing. Think of them as overuse of a tendon which causes some combination of degeneration and inflammation. In both cases, the approach to treatment is to offload the tendon so it can recover, and then strengthen the tendon so it can handle more load. Offloading a tendon is achieved by reducing the provocative movement for a short period of time and through massage to the muscle belly. Often, the muscle belly is hypertoned, full of trigger points, not recovered etc, so as the muscle is used, the tendon has to handle more of the load, leading to the tendon being overloaded. The best way to strengthen a tendon is with eccentric resistance exercises. Stretching the muscle is fine, but ultimately, the tendon needs to be stronger, so eccentric strength is more indicated than stretching. Assessing for tendonitis Affected tendons are painful with -​ AROM or PROM of the antagonist direction (aka lengthening) -​ RROM (or MMT) of the affected muscle (resisted contraction, especially if held and w/ an eccentric component) -​ Palpation Most Commonly Affected Tendons of the elbow Common Extensor Tendon -​ Most common -​ ‘Tennis elbow’ -​ Provoked by repetitive, forceful extension, supination, radial deviation (tennis backhand) -​ ECR Brevis most commonly affected individual tendon/part of the CET because of its position; it is irritated by the radial head in pronation-supination movements -​ Also provoked by any repetitive forceful movements such as gripping, manual work, using vibration equipment, or activities that involve a vibration component such as from a tennis racquet -​ Pain from this condition can radiate through the whole forearm extensor compartment down to the wrist, sometimes looking like a C7 dermatome pattern -​ Can be most tender at the supracondylar ridge, epicondyle, or just distal over the bulk of the tendon Common Flexor Tendon -​ ‘Golfer's elbow’ -​ Provoked by repetitive, forceful pronation and flexion -​ Pronator teres most common, followed by FC radialis -​ Also provoked by forceful gripping (climbing, gymnastics, strength training) or manual labour Triceps Brachii Tendon - ‘Posterior tennis elbow’ Review Grades of Tendonitis: Grade 1: Grade 2: Grade 3: Grade 4: Bursitis (Olecranon) MOI -​ Trauma to elbow (either sudden or accumulated micro-trauma) -​ Overuse of the structures surrounding the bursa > excessive friction upon bursa > inflammation of bursa. (goes with triceps tendonitis sometimes) Any activity (desk work, MMA, jiu jitsu, wrestling, labour) which involves a lot of time on the elbows How to differentiate from tendonitis? Pain with compression that does not get worse with load, especially eccentric load PROM empty end-feel Bursitis is aggravated by compression – meaning it is usually positional, or from friction of surrounding tissue. Tendons are aggravated by load/contraction. Fractures: Assessment: ROM – Active, Passive and Resisted ROM -​ (POP is Contra-Indicated before consolidation has occurred.) With PTs permission the therapist may contact the attending physician. (Consolodation = complete heal 6-12 weeks no P or weakness with weight bearing healthy tone/ union = 3-6 weeks still visible fx line, tender ,weak fragile, calcified callus) Further testing may involve: -​ Tests for normal perfusion distal to fracture (eg, capillary refill test) -​ Tests for swelling (girth measurements) -​ Tests for muscle tone (MMT) -​ Tests for tissue health (palpation) Precautions: During Immobilization -​ No Tractioning before union -​ No Hot Hydro Distal to or immediately proximal to the cast (do not increase congestion) -​ No AROM or RROM at Fx site of mm attachment or if laceration or severance of tendon crossing fx site -​ No Heat or Ice if hardware has been used (internal fixation)  -​ No direct work with Open Wound -​ No local massage for Stress Fx. When site has pt tenderness After Immobilization has been removed (before consolidation) -​ No POP Testing to joint if prior to consolidation -​ No Hydro Extremes on tissues that were under a cast -​ No Deep Longtitudinal Techniques on Hypotoned Tissues -​ Exercise Caution with passive stretching until tissue health is restored -​ Do Not Stretch Hypo toned or Flaccid Tissues Nursemaid’s Elbow -​ Radial head subluxation due to having too much fun -​ Caused by the shape (conical) of the radial head before 8 years old, which allows it to slip out of the annular ligament and become subluxated -​ Reduced by a doc or chiro Nerve Compressions: Review the radial nerve, median nerve, and ulnar nerve; Know which nerves run in or close by which anatomical structures and therefore where each is commonly compressed. 4 / Orthopedic Tests (finish this table) Under indication -​ What about the person’s presentation would make you choose this test? -​ What is the give-away sign or symptom that makes you want to confirm or rule out a condition? Test Relevant Condition Positive Indication Ligamentous valgus Valgus instability (MCL) instability test Ligamentous varus Varus instability (LCL) instability test Cozen’s test (method 1) Lateral epicondylitis Sudden severe pain at lat Complains of pain in the epicondyle, supracondylar area especially if MOI is ridge, or CET repetitive muscle-use of forearm Mill’s test (method 2) Lateral epicondylitis Maudsley’s test Lateral epicondylitis (method 3) Medial epicondylitis Medial epicondylitis test Pronator teres Median nerve entrapment syndrome Especially for post-immobilisation, palpation is a valuable assessment. Note down: -​ What might you find in palpation post-immobilisation? -​ Describe what structures you would palpate and how 5 / Home Care Principles Programs must -​ Not cause pain/inflammation -​ Be progressive and gradual -​ Start as early as possible (no inflammation) Exercise selection -​ Loaded exercises performed in mid-range -​ Exercises which try to increase range performed unweighted -​ In other words, we do not load at the end-range -​ Passive before active -​ Isometric before eccentric before concentric before plyometric -​ Open chain (such as theraband) before closed chain (such as push up) Signs that program is too challenging -​ Discomfort post exercise lasting more than 2 hours in acute/subacute stage -​ Discomfort post exercise lasting more than 4 hours in the chronic stage -​ Need pain medication to control discomfort after activity or exercise -​ Pain @ rest / Extreme fatigue / Rebound muscle spasm / Increased weakness Finish this table Exercise/Hydro Condition/Tissue FIDS Practice doing these Resisted pronation so that when you need Resisted supination to use them in a Strength CET Tendinopathy clinical or exam Strength CFT Tendinopathy situation, you look as Stretch CET Tendinopathy Stretch CFT Tendinopathy cool as a cucumber Self-traction Contrast Arm Baths How would you progress someone through a tendon rehab from acute - early subacute - late subacute - chronic? Plot out a progression of four home care, one per week, for either CFT, CET, or Triceps.