Q7-4: Forefoot Flashcards
(61 cards)
how many bones in forefoot?
21 bones (5 MTs, 5 PPs, 4 IPs, 5 DPs, 2 sesamoids)
how many joints in the forefoot?
15 joints (5 MTPJs, 4 PIPJs, 4 DIPJs, 1 hallux interphalangeal joint, 1 distal intermetatarsal joint)
lesser metatarsophalangeal joints (MTPJs): bones and articular surfaces
MTs 2-5: convex heads (dorsal-plantar, medial-laterl); dorsal tubercles near surgical neck, plantar projections separated by a notch
Proximal phalanx bases: ovoid and concave (plantar tubercles)
lesser metatarsophalangeal joints (MTPJs): type of joint
synovial ellipsoidal joint
lesser metatarsophalangeal joints (MTPJs): mvmt of joint
biaxial movement (along 2 planes), motion is primarily in sagittal plane (dorsiflexion/plantar flexion), adduction/abduction) joint capsule attaches firmly medially and laterally, but is loose dorsally and plantarly
clinical significance of lesser MTP joint capsule
able to dorsiflex/plantarflex more than adduct and abduct
joints holding lesser MTPJ joint together?
5 capsular ligaments (plantar MTP ligaments, collateral ligaments x2, and suspensory ligaments x 2)
describe the plantar metatarsophalangeal ligament x 1 (plantar pads)
thick, fibrocartilaginous pad indicative of inc pressure/force to deal w/ the stress it encounters
has metatarsal and phalanx attachments
metatarsal attachment of plantar metatarsophalangeal ligament
loosely attached to the plantar MT neck; thin and flexible
phalanx attachment of plantar metatarsophalangeal ligament
firmly attached to plantar base; thick and strong
plantar metatarsophalangeal ligament is continuous with/reinforced by…
plantar aponeurosis, deep transverse metatarsal ligament, and distal plantar ligaments
what can result if the groove formed by plantar projections doesn’t keep the tendon in place?
if the groove doesn’t work, the toe alignment can be affected –> creating hammer toes
collateral ligaments x 2; course & involved in which joint
run obliquely from dorsal tubercles on the metatarsal heads to the plantar tubercle on the phalangeal bases;
involved in lesser MTPJ
suspensory ligaments x 2; course & involved in which joint
run from those same dorsal tubercles on the metatarsal heads to the edge of the plantar pad;
involved in lesser MTPJ
lesser MTPJs: clinical significance
*NO dorsal ligaments; metatarsal parabola (2>1=3>4>5)
dorsiflexion versus plantarflexion
plantar pads and plantar tubercles as sesamoids of the lesser MTPJs
what reinforces the ligaments and affect of the function of the MTPJ joint?
extensor expansion (sling and wing)
distal intermetatarsal joints: define and characteristics
distal connection b/w each of the metatarsals; *NOT a true joint, but there is a ligament
ligaments in the distal intermetatarsal joint?
deep transverse metatarsal ligament
deep transverse metatarsal ligament: define and characteristics
short, strong ligaments connecting plantar pad to plantar pad (does not attach to bone)
deep transverse metatarsal ligament: clinical significance
allows distal MTs to function as a unit –> prevents spreading or “splaying” of the MTs –> limits more proximal stress –> serves as surgical anatomic landmark
how many interphalangeal joints possible?
9 possible (2 Hallux IPJs, 4 digits x each with PIPJ and DIPJ)
where are synostoses most common in the foot?
particularly in the DIPJ of the 5th digit (remember: synostoses are connections b/w bones)
interphalangeal joints: bones involved
proximal head & distal base
proximal head of interphalangeal joints: characteristics
central sagittal groove rendering the structure pulley-like; roughly convex, dorsal tubercles
