tendons and ligaments - biomechanics

connective tissue is _____ meaning it is related to or being the tissues that surround a joint

periarticular

define periarticular

related to or being the tissues that surround a joint

what do periarticular (connective) tissues do in response to functional demands and a changing loading environment

change structure

2 common elements in periarticular tissue

cells and extracellular matrix

3 connective tissues

bone, cartilage (hyaline and fibrocartilage), and dense (capsule, ligament, tendon)

2 elements of extracellular matrix

interfibrillar (ground substance) and fibrillar (fibrous)

cells in connective tissue synthesize what

extracellular matrix

what are the most basic cells in the connective tissue

fibroblasts

fibroblasts (most basic cells in connective tissue) may ____ into specialized cells

differentiate

interfibrillar part of the EC in connective tissue is ___ ___

ground substance

what is the interfibrillar part of the EC made of

water and proteins

2 parts of the extracellular matrix in connective tissue

intrafibrillar and fibrillar

what is in the fibrillar part of the extracellular matrix of connective tissue

collagen (type 1, 2, 3) and elastin

define type I collagen

most common, thick, tensile strength

define type II collagen

thinner, found in cartilage where compressive forces are common

define type III collagen

found in skin, capsule, muscle/tendon sheaths where tensile stresses are common

type 1, 2, 3 collagen help with what stresses, respectively

tensile, compressive, tensile

elastin (in ____ part of EC in connective tissue) resists ____

fibrillar, tension

4 types of cells found in connective tissue

fibroblasts, tenoblasts, chondroblasts, osteoblasts

fibroblasts found in ____

tenoblasts in ____

chondroblasts in _____

osteoblasts in _____

ligaments, tendons, cartilage, bone

dense connective tissue is ___ and ___

tendons and ligaments

fibrous tissue has few _____, moderate _____ and ____, and lots of tightly packed ____

fibroblasts, elastin, PG, collagen

dense connective tissue (tendons and ligaments) is _______

fibrous

ligaments connect ___ to ____

bone to bone

3 roles of liagments

allow normal joint motion (guide arthrokinematics), provide stability (prevent abnormal motion) and have a role in proprioception (nerve fibers)

tendons connect

bone to muscle

role of tendons

transmit muscle forces to move bones

ligaments resist _____ only

tension

ligaments do no resist _____

compression

ligaments are ___ not ___

ropes, bars

since _____ in ligaments runs in many directions, they can resist forces in more than one direction

collagen

ligaments guide motion:

ankle - ___

PCL - ___

ACL - ___

guides linear action of muscles into rotation

femoral rollback

screw home

ligaments 3 main features

resist tension only

guide motion

provide stability

during dynamic movement, ____ are the first line of defense

muscles

enthesis = ______

attachment

tendons and ligaments attachment is either

____ or ____

direct, indirect

direct attachment in tendons and ligaments is via

fibrocartilage

indirect attachment in tendons and ligaments is via

fibrous attachments

direct attachment via fibrocartilage in tendons and ligaments is __ or __ zones of increasing _____ with continuous ____ fibers

3, 4, calcification, collagen

the indirect attachment in tendons and ligaments is when ___ fibers blend into the ____ and the ____ is linked to cortical ____ via ____ fibers

collagen, periosteum, periosteum, bone, Sharpeys

bone to tendon junction has

4 zones of increasing calcification

tendon to bone and tendon to muscle connections are both ____

direct

tendons and ligaments contain mostly type ___ collagen, which has the most ____ strength of all types

I, tensile

tendons have a more ____ alignment of collagen than ligaments; this is a reflection of the ____ placed on them

parallel, stresses

ligaments vascular supply inside is ____

endoligamentous

ligaments vascular supply outside the tissue is ____

epiligamentous

vascular supply in ligaments is through diffusion of nutrients to cells from ____ _____

synovial fluid

normal turnover of collagen - half in ___-___ days

300, 500

ACL and PCL theories (4)

no initiation of inflammatory response

inhibition of inflammatory response

lack of nutrition

clot washed away by synovial fluid

special new surgery for ACL

BEAR (bridge enhanced ACL repair)

if injury is sustained in one component, ___ is ___ in other components

loading, increased