Cross-Section Atlas

and Mark T. Dahl2



(1)
Department of Orthopedic Surgery, University of California – Irvine, Orange, CA, USA

(2)
Limb Length and Deformity Correction Clinics, Gillette Children’s Specialty Healthcare and University of Minnesota, St. Paul / Minneapolis, MN, USA

 



Keywords
Cross sectionAtlasOsteotomyCorticotomyNerve injuryVessel injurySafe zones



Development of the Atlas



Background


In 1981, the senior author’s book Complications of External Skeletal Fixation: Causes, Prevention and Treatment [1] contained a cross-section atlas to help surgeons avoid injuring nerves, arteries, and veins while inserting transcutaneous pins during external skeletal fixation . Originally, the atlas was designed to aid in the application of Hoffmann-type full- and half-pin fixators, as well as those frames that used similar mounting strategies. Needless to say, the book subsequently proved useful for the application of the Ilizarov external fixation method, which typically employed even more transcutaneous implants (specifically, tensioned wires) than did a complex quadrilateral multi-pin Hoffmann frame in the Vidal configuration [2].

Indeed, the senior author was not surprised when, while attending the first English-language course on the Ilizarov method in Kurgan, Siberia, USSR (1988), cross-section diagrams were affixed to the walls of the workshop where frame application principles were taught. Moreover, the concept of utilizing cross-section anatomy for safe transcutaneous implant insertion is hardly new. During the Second World War, Kreuz and Shaar produced a manual of fracture treatment for use by medics in the US Navy [3] that contained cross-section diagrams derived from a classic 1911 atlas of cross-section anatomy by Eycleshymer and Schoemaker [4].

Although Complications of External Skeletal Fixation is out of print after three successful press runs (copies being sold on rare medical book websites) because the publisher stopped selling medical books, the pin and wire atlas lives on in recent editions of Browner’s Skeletal Trauma [5].


Derivation of the Atlas


In 1911, Eycleshymer and Schoemaker created a cross-section atlas of human anatomy by freezing 11 human cadavers solid and band-sawing the bodies into 1-inch thick slices. They then mapped out the position of every structure on a piece of tracing paper preprinted with grid marks. They next averaged the size and position of each structure and created a composite transverse section drawing of these averaged elements, the unique feature of the atlas. A talented medical illustrator, Michele Predesik, used the Eycleshymer and Schoemaker images to create 3D-appearing slices in the senior author’s external fixation monograph. These were recently updated by the senior author for inclusion in the present monograph.


The Need for a Cross-Section Atlas for Intramedullary Lengthening


One could reasonably assume that intramedullary limb lengthening has eliminated the need for a cross-section atlas because, after all, the main implant is an intramedullary nail, with well-defined entry portals developed to avoid injury to neurovascular structures. Such, however, is not the case: both the osteotomy and the insertion of transverse locking screws and pillar blocking screws are percutaneous procedures, with risks similar to, if not identical to, external fixation pins (Figs. 11.1, through 11.16).

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Fig. 11.1
The sciatic nerve is posteromedial to the femur throughout Zone A, more than a bone diameter away. The deep femoral artery comes to lie medial to the femur in the lower end of Zone A, separated from it by the origin of the vastus medialis muscle, but only one half bone width away


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Fig. 11.2
The sciatic nerve is posteromedial to the femur, separated by one bone diameter. The superficial femoral artery crosses the coronal plane of the femur between Zone B and Zone C. The deep femoral artery and vein are medial to the femur in proximal Zone B and posterior to the femur in distal Zone B. Caution is necessary in proximal Zone B, because the superficial and deep femoral vessels are in a straight line and can both be injured with a plunge


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Fig. 11.3
The sciatic nerve passes from medial to lateral behind the femur, approximately one bone width away. The superficial femoral artery passes the coronal plane of the femur in Zone C and is posterior to the bone at the lower end of this zone. The deep femoral artery and vein are adjacent to the posterior surface of the femur but terminate at the lower end of Zone C


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Fig. 11.4
The femoral artery becomes the popliteal artery and, with the popliteal vein, is immediately posterior to the femur in Zone D. The synovial cavity of the knee joint enlarges to encompass the anterior half of the femur immediately above the joint line

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Nov 5, 2018 | Posted by in RHEUMATOLOGY | Comments Off on Cross-Section Atlas
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