34 Structure and Function
MFTPCP(A) (B)Figure 4.3 (A) Frontal plane section of the medial compartment of a dog’s stifle prepared with the Spalteholz
technique, showing the perimeniscal capillary plexus forming the red-red zone of the meniscus. Note that the red-red or
vascular zone is only about 25% of the radial width, which corresponds to about 2 mm-wide peripheral tissue. PCP,
perimeniscal capillary plexus; F, femur; M, avascular zone of the meniscus; T, tibia. (B) View of the entire medial
meniscus. The avascular axial margin of the medial meniscus is indicated (arrows). Sources: (A) Arnoczky & Warren
- Reproduced with permission from SAGE Publications. (B) Courtesy of Dr Steven Arnoczky.
Nerve fibers in the menisci appear to predomi-
nately serve propioceptive and mechanorecep-
tive roles, with little if any nociceptive function
recognized. Meniscal-derived sensory signals
during loading may contribute to protective
neuromuscular reflex control of joint motion.
Biomechanical and material properties
The meniscus demonstrates a complex set
of material properties that vary nonlinearly
with location (inhomogeneous) and direction
(anisotropic). These properties are important
for the biomechanical functions of the meniscus,
such as load transmission at the tibiofemoral
articulation, shock absorption, and stability.
These functions are important for normal home-
ostasis of the cartilage and the function of the
stifle. The tensile properties of meniscal tissue
are closely related to the collagen fiber architec-
ture. Variations in tensile stiffness and strength
of meniscal tissue correspond to local differ-
ences in collagen ultrastructure and fiber bun-
dle orientation.
In compression, the meniscal tissue should
be considered as a biphasic composite material
because of its composition of 75% water and
25% collagen and proteoglycan. During load-
ing, most of the water is forced to flow through
the matrix to redistribute within the tissue or to
exude from the tissue. The high frictional drag
forces associated with water flow through the
porous-permeable solid matrix give rise to time-
dependent viscoelastic behaviors such as creep
and stress relaxation. The significance of the vis-
coelastic behavior of the meniscus is that when
the joint is loaded for long periods the con-
tact area increases, thereby reducing the stress
per unit area of the tissue. The concentration of