SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
Sonographic Anatomy of the Distal Sesamoidean Ligaments, Pastern and Foot
MDSL
The MDSL can be scanned from its origin at the base of the medial and lateral
sesamoid bones to its insertion on the palmar or plantar aspect of mid to distal P1. The
origin of the medial or lateral branch of the MDSL is best found by placing the
ultrasound transducer over the medial or lateral proximal sesamoid bone and scanning
distally over the bone to its base. Immediately distal to the base of the proximal
sesamoid bone is the origin of the middle distal sesamoidean ligament, best located
initially in its transverse section as a large oval to round structure. This ligament is the
most difficult to follow to its insertion because the ligament extends diagonally from the
lateral or medial aspect of the proximal pastern to the midline in the mid pastern region.
Following the medial or lateral branch from its origin to its juncture with the opposing
branch requires that the transducer be angled at approximately a 45 o angle across the
palmar or plantar aspect of the proximal pastern from the base of the proximal
sesamoid bone to the midline of the first phalanx.
SDSL
The SDSL can be imaged from its origin or near its origin on the base of the proximal
sesamoid bones to its insertion on the proximal palmar or plantar aspect of the second
phalanx. The origin of the SDSL is found by angling the transducer in a proximal and
dorsal direction from the proximal most aspect of the pastern just underneath the ergot
to image the ligament and the base of the proximal sesamoid bones.
Palmar/plantar ligaments of the PIP joint
The palmar/plantar ligaments are paired on the medial and lateral aspects of the
pastern and are located by placing the transducer dorsal to the branch of the SDFT
at the level of mid P1. The more abaxial branch originates proximal to the branch.
Each branch has a somewhat oval shape and must be followed individually from
origin to insertion.
The Ultrasonographic Examination
Patient Preparation
A thorough knowledge of the anatomy of the structures under investigation and their
interrelationships to one another is crucial for the accurate interpretation of the
sonogram. Patient preparation is also important in obtaining a quality
ultrasonographic image. The hair over the structures to be scanned should be
surgically clipped with a #40 blade and the skin thoroughly cleaned. The skin should
be free of all debris or “scurf”(dead sloughing skin cells) prior to beginning the
sonographic examination. If there is a large amount of “scurf” on the limb, soaking
the leg in warm water for 10 – 15 minutes will often soften the scurf adequately so
that its removal is possible. In situations where clipping or shaving the hair overlying
the superficial digital flexor tendon is not an option, hosing the palmar or plantar
aspect of the leg with water for 10 – 15 minutes or the application of a wet bandage
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