Faye Chiou Tan, MDProfessor PMR, Baylor COM

Chief PMR, Director EMG, HCHD

Torsional Anatomy

Disclosures

Royalties – EMG Secrets Textbook – Elsevier

Thanks to the Team

Dr. John CiancaDr. Joslyn JohnDr. Erin Furr-Stimming – NeurologyDr. Sindhu PanditDr. 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 - NEWDefinition 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 torsionIntestinal torsionLimb budding of the leg - embryology

Limb budding of the leg

“Anatomic neutral” is not free of torsionEmbryonic 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: PlexusUpper anterior – obturator – medialUpper posterior – femoral – anteriorLower anterior – tibial – posteriorLower 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

EdemaSoft tissueAltered anatomy (trauma, surgery)ContracturesSpasticity

Overview

I. NeckII. ArmIII. Forearm

Part 1:Muscles in Torticollis

Anatomy of Neck Injection : SCM

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Fig 1a: Sternocleidomastoid – anatomic neutral position

Fig 1b: Sternocleidomastoid – left torticollis position

Anatomy of Neck Injection: Upper trapezius

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Fig 1d: Trapezius – left torticollis position

Take Home#1 inTorsional 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

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Fig 1e: Scalenes – anatomic neutral position

Fig 1f: 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 Upper Trapezius

Scalenes 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

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InternalRotation

Neutral

Fig 2a: Proximal 1/3 Upper Arm

Anatomy of Upper Arm Injection:Middle - Biceps and Brachialis

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Fig 2b: Middle Upper Arm

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

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Fig 2c:Distal 1/3 Upper Arm

Neutral

InternalRotation

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

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Fig 2d: Distal 1/6 Upper Arm

Neutral

InternalRotation

“Rising Sun Sign”

Supination – Radial nerve is lateralPronation – 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 bonesBoth 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

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Pronator Teres

MedialRotation

Neutral

Flexor Carpi Radialis

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FCR

Neutral

MedialRotation

FCU/FDP

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FCU and FDP

Neutral

MedialRotation

Brachioradialis

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Brachioradialis (BR)

Neutral

MedialRotation

Flexor Digitorum Superficialis

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Flexor Digitorum Superficialis

Neutral

InternalRotation

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 injuryMechanical impingement in pronationBiceps 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!