Torsional Anatomy Faye Chiou Tan MD Professor PMR

Torsional Anatomy Faye Chiou Tan, MD Professor PMR, Baylor COM Chief PMR, Director EMG, HCHD

Disclosures ©Royalties – EMG Secrets Textbook – Elsevier

Thanks to the Team ©Dr. John Cianca ©Dr. Joslyn John ©Dr. Erin Furr-Stimming – Neurology ©Dr. Sindhu Pandit ©Dr. Katherine Taber

Background ©Frequently we are asked to perform procedures on patients who cannot be positioned in “anatomic neutral” ©Yet, anatomic references display the human body in anatomic neutral. ©No anatomic references to examine where to inject in altered position

Anatomic neutral

Anatomy in motion ©where do structures move to © In sports? © In movement disorders – dystonia? ©In spasticity? ©In contractures/ casting?

Anatomy in motion ©The study of anatomy in the position of altered posture (ie other than anatomic neutral).

Torsional MSK Anatomy ©Study of MSK anatomy in torsion - NEW ©Definition of torsion (Merriam Webster): © 1. the twisting or wrenching of a body by the exertion of forces tending to turn one end or part about a longitudinal axis while the other is held fast or turned in the opposite direction; also : the state of being twisted © 2. the twisting of a bodily organ or part on its own axis

Other Torsion Examples ©Testicular torsion ©Intestinal torsion ©Limb budding of the leg - embryology

Limb budding of the leg ©“Anatomic neutral” is not free of torsion ©Embryonic limb budding of the leg © Leg bud begins with great toe cephalad © Leg twists internally so great toe is medial © Similar to stripes on a candy cane

Limb budding of the leg © Eg: Plexus ©Upper anterior – obturator – medial ©Upper posterior – femoral – anterior ©Lower anterior – tibial – posterior ©Lower posterior – peroneal - anterior

Week 10 Gestation

Week 15 Gestation

Week 30 Gestation

Differentiate Torsional MSK Anatomy from Rotational ©Torsional anatomy : origin and insertion turn at different rates (in the same direction) ©Rotational anatomy : origin and insertion turn at the same rate (in the same direction) © Ref: Chiou-Tan FY, Cianca J, Pandit S, John J, Furr-Stimming E, Taber KH: Procedure oriented torsional anatomy of the proximal arm for spasticity injection, J Comput Assist Tomogr, 39(3): 449 -452, 2015.

Topical Anatomy Challenges ©Edema ©Soft tissue ©Altered anatomy (trauma, surgery) ©Contractures ©Spasticity

Overview ©I. Neck ©II. Arm ©III. Forearm

Part 1: Muscles in Torticollis

Anatomy of Neck Injection : SCM *

Fig 1 a: Sternocleidomastoid – anatomic neutral position Fig 1 b: Sternocleidomastoid – left torticollis position

Anatomy of Neck Injection: Upper trapezius *

Fig 1 d: Trapezius – left torticollis position

Take Home#1 in Torsional Anatomy © The anchored or tethered end of torsion does not move as much as the free end. © (Eg. The door hinge does not have as wide an excursion as the door knob. ) © Injection sites near the tethered end will not move as much as the free end.

Anatomy of Neck Injection: Scalenes **

Fig 1 e: Scalenes – anatomic neutral position Fig 1 f: Scalenes – left torticollis position

Take Home#2 © Structures which were viewed easily in cross section can be difficult to view or “disappear” after torsion (i. e. are oblique) due to anisotropy. Adjusting the probe may (or may not) assist in achieving the desired view. © Eg. Cannot find the honeycomb appearance of the brachial plexus © Eg. Muscles bunch up and are not in either longitudinal or cross-sectional view.

Summary Torticollis NEUTRAL POSITION TORTICOLLIS POSITION Sternocleidomastoid Trapezius, Levator scapula Upper Trapezius Scalenes (Brachial plexus visible) (Brachial plexus difficult to view)

Part 2: Upper Arm Torsional Changes with Internal Rotation

Anatomy of Upper Arm Injection: Proximal – Pectoralis Major *

Neutral Internal Rotation Fig 2 a: Proximal 1/3 Upper Arm

Anatomy of Upper Arm Injection: Middle - Biceps and Brachialis *

Fig 2 b: Middle Upper Arm

Anatomy of Upper Arm Injection: Distal 1/3 and 1/6 – Biceps and Brachialis * *

Neutral Internal Rotation Fig 2 c: Distal 1/3 Upper Arm

Anatomy of Upper Arm Injection: Distal 1/6 – Radial Nerve *

Neutral Internal Rotation Fig 2 d: Distal 1/6 Upper Arm

“Rising Sun Sign” ©Supination – Radial nerve is lateral ©Pronation – Radial nerve is anterior © Ref: Chiou-Tan FY, Cianca J, Pandit S, John J, Furr-Stimming E, Taber KH: Procedure oriented torsional anatomy of the proximal arm for spasticity injection, J Comput Assist Tomogr, 39(3): 449 -452, 2015.

Summary Upper Arm

Part 3: Forearm Changes with Internal Torsion

Supination/Pronation ©Study of supination/pronation dates to 1800’s ©Broken forearm bones that healed had limited supination/pronation ©“Functional alignment” of bones ©Both radius and ulna move, but not to same degree.

Supination/Pronation Refs © Duchenne GB. Physiology of Motion, Demonstrated by Means of Electrical Stimulation and Clinical Observation and Applied Study of Paralysis and Deformities. Philadelphia: Lippincott, 1949 © Heibern J. Movements of the ulna in rotation of the fore-arm. J Anat Physiol. 1855; 19: 237 -240. © Dwight T. The movement of the ulna in rotation of the fore-arm. J Anat Physiol. 1855; 19: 186 -189. © Weinberg AM, Pietsch IT, Helm MB, et al. A new kinematic model of pro- and supinaton of the forearm. J Biomech. 2000; 33: 487 -491. © Nakamura T, Yabe Y, Horiuchi Y et al. Three dimensional MRI of interosseous membrane of forearm: a new method using fuzzy reasoning. Magn Reson Imaging. 1999; 17: 463 -470.

Pronator Teres *

Pronator Teres Neutral Medial Rotation

Flexor Carpi Radialis *

FCR Neutral Medial Rotation

FCU/FDP *

FCU and FDP Neutral Medial Rotation

Brachioradialis * *

Brachioradialis (BR) Neutral Medial Rotation

Flexor Digitorum Superficialis *

Flexor Digitorum Superficialis Neutral Internal Rotation

Take Home #3 in Torsional Anatomy © Missing the intended muscle could lead to: © 1. injecting too much total medication in another muscle (i. e. Brachialis twice rather than Biceps once, Brachialis once) © 2. injecting an extensor rather than flexor and worsening the imbalance of muscles. © 3. injecting an unintended target (eg. nerve, artery, vein, tendon)

Biceps tendon ©Hypovascular – at risk for injury ©Mechanical impingement in pronation ©Biceps tendon occupies 85% of radioulnar position in pronated position © Ref: Miyamoto RG, et al. Distal biceps tendon injuries. J Bone Joint Surg Am. 2010; 92: 2128 -2138.

Summary Distal Arm MSKUS Probe centered over muscle listed in supinated anatomic neutral position and held immobile while subject turned to hemispastic pronated position. NEUTRAL POSITION INTERNAL TORSION POSITION Pronator Teres Brachialis, Biceps tendon, and median nerve (more superficial) Flexor Carpi Radialis Pronator Teres, median nerve FCU, FDP FCR, PT, median nerve Brachioradialis Extensor Carpi Radialis Flexor Digitorum Superficialis Brachioradialis, ECR, radial nerve

Conclusions © Torsional MSK anatomy is NEW © Torsional anatomy is provided to help injectors localize targets precisely and avoid injecting other non intended structures. © Learn which structures move and which do not.

Torsional Anatomy References Neck - Movement disorder society – Stockholm Sweden: Furr-Stimming, Cianca J, Pandit S, John J, Chiou-Tan FY, 2014 Upper arm – Movement disorder society – Stockholm Sweden: Chiou-Tan FY, Cianca J, Pandit S, John J, Furr. Stimming, 2014 Upper arm - AAPMR-San Diego: Chiou-Tan FY, Cianca J, Pandit S, John J, Furr-Stimming, Taber K, 2014 Distal arm – Association of Academic Physiatrists – San Antonio: Chiou-Tan FY, Cianca J, John J, Pandit S, Furr. Stimming, Taber K, 2015

Torsional Anatomy References © Chiou-Tan FY, Cianca J, Pandit S, John J, Furr-Stimming E, Taber KH: Procedure-Oriented Torsional Anatomy of the Proximal Arm for Spasticity Injection. J Comput Assist Tomogr 39(3): 449 -452, 2015. © Chiou-Tan FY, Cianca J, John J, Furr-Stimming E, Pandit S, Taber KH: Procedure-Oriented Torsional Anatomy of the Forearm for Spasticity Injection. J Comput Assist Tomogr (in press), 2015.

Comments from Sweden ©“ I have this (localization) problem all the time when I teach my students” ©“I use ultrasound guidance. I bet my colleagues free lunch to whoever gets the right spot – I haven’t paid for lunch yet”

Thank You!