Anatomical variations and dimensions of the popliteus muscle in cadaveric specimens

Introduction

     The popliteus muscle is located at the flexor aspect of

the leg and is supplied by the tibial nerve. This is the only muscle in the

back of leg, which actions on the knee joint and never over the ankle joint.

This is considered as the knee’s unlocking muscle. It laterally swaps the femur

over tibia, while walking when one foot is on the ground. It also causes medial

rotation of the tibia on the femur bone, once the foot is over the ground. Along

with lateral collateral ligament and popliteo-fibular ligament, the tendon of

popliteus plays instrumental role in the stabilization of the posterolateral part

of knee (1). The lateral femoral condyle

and lateral meniscus at its posterior horn, offers the origin of popliteus. Its

origin is tendinous and it is interesting to know that there exists variability

in its origin like from the styloid process of the fibula (2).

Aims and Objective

  The

goal of this investigation is to describe the morphology of popliteus muscle with

its tendon in context to its variability in origin, mode of insertion, innervation

patterns and its dimensions. The objectives are to measure the length,

thickness and width of the popliteus at various locations.

Methodology

Study setting: Department

of Anatomy, Kasturba Medical College, Mangalore

Study design: Institutional

Based Descriptive Cross Sectional Study

Study participants: A meticulous dissection will be done in adult human cadaveric lower limb

specimens and the morphology of the popliteus muscle will be tabulated for the statistical

analysis.

Inclusion criteria: Lower limb

specimens with an intact posterior compartment will be included

Exclusion criteria: The

specimens showing fractures, any visible deformities and missing parts will be

excluded.

Study duration: 3 months

Sample size: 25adult cadavers (25 right and 25 left sided lower limbs)

Sampling method: The

sample size is similar to the earlier study performed by Olewnik et al. (1).

Data collection methodology:    The variability of the origin of popliteus

and the insertion of popliteus will be noted down. To study the morphometry,

the popliteus muscle is divided into certain sections extending from the origin

to its final insertion into the posterior surface of the tibia. The parameters

considered in the study are measuring the length, width and thickness of the

muscle belly and its tendon, which will be taken by digital Vernier caliper.

Data analysis: The

data collected as above will be analyzed by applying paired samples t test.

Implications

The anatomy and biomechanics of popliteus makes it an

important structure, which keeps the knee stable. But its involvement is

ignored in the complex injury of the knee joint (3). The isolated

involvement of popliteus is seen in sports injuries and it may be

misinterpreted as a tear of lateral meniscus. The sports like tennis,

basketball and downhill running may put additional stress on the tendon of

popliteus (3). In this context, the morphometric data of popliteus are clinically important for the effective treatment of the

popliteus muscle spasticity (4).