Biomechanics & arthrokinematics

Question 1

PTFJ Biomechanics - Knee flexion/extension

Answer 1

During knee flexion and tibial external rotation, the fibula glides anteriorly

During knee extension and tibial internal rotation, the fibula glides posteriorly

Question 2

PTFJ Surfaces

Answer 2

Convex tibial surface and a concave fibular surface

Question 3

PTFJ Biomechanics - Ankle dorsi/plantar flexion

Answer 3

Fibula moves superiorly and laterally rotates during dorsiflexion of the ankle.

Fibula glides inferiorly and internally rotates

Question 4

DTFJ Biomechanics - Ankle dorsi/plantar flexion

Answer 4

Inferior fibular glide and internal fibular rotation during ankle plantarflexion

Superior fibular glide and external fibular rotation during ankle dorsiflexion

Question 5

DTFJ Surfaces

Answer 5

concave tibia and a convex fibula

Question 6

TCJ Motions

Answer 6

Most dorsiflexion and plantarflexion occurs at the TCJ. This joint also goes through inversion and eversion, but these motions are very limited

Question 7

Pronation Definition

Answer 7

Combination of eversion, abduction and dorsiflexion

Question 8

Supination Definition

Answer 8

Combination of inversion, adduction and plantarflexion

Question 9

Pro/Supination Planes

Answer 9

Dorsiflexion and plantarflexion occur in the sagittal plane, whereas eversion and inversion occur in the frontal plane. Last, abduction and adduction occur in the transverse plane.

Question 10

STJ Axis of rotation

Answer 10

Plantar, lateral, and posterior position thru the subtalar joint in a dorsal, medial, and anterior direction

Question 11

STJ Articulating surfaces

Answer 11

Posterior articulation: convex calcaneus and concave talus

Anterior and middle: concave calcaneus and convex talus

Question 12

Talonavicular joint articulating surfaces

Answer 12

The convex head of the talus articulates with the concave proximal surface of the navicular and spring ligament

Question 13

Calcaneocuboid joint articulating surfaces

Answer 13

Each of the articulating surfaces of the calcaneus and cuboid bones have both a convexity and concavity to them that interlock and create a relatively immobile joint compared to the talonavicular joint

Question 14

Transverse Tarsal Arthrokinematics Pronation/supination

Answer 14

Open chain supination results in a spin of the concave navicular and spring ligament on the convex head of the talus. Pronation occurs as a result of contraction of the fibularis longus, the primary pronator, and follows reverse kinematics. This causes the navicular and spring ligament to spin in the opposite direction moving the lateral column of the foot outward.

Question 15

Medial Longitudinal Arch

Answer 15

The calcaneus, talus, navicular, cuneiforms, and medial 3 metatarsals, plantar fascia, spring ligament, and first tarsometatarsal joint form the MLA

Question 16

Where does most wrist extension occur?

Answer 16

Approximately 66.5% of extension occurs at the radiocarpal joint

Question 17

Radiocarpal joint arthrokinematics

Answer 17

In both the frontal and sagittal planes, the concave radius and articular disc of the TFCC articulate with the convex surface of the proximal row of carpal bones to form the wrist joint

Question 18

Where does most wrist flexion occur?

Answer 18

Approximately 60% of wrist flexion occurs at the midcarpal joint

Question 19

Midcarpal joint arthrokinematics

Answer 19

Flexion/extension: radial side concave on convex, ulnar side convex on concave

Radial/ulnar deviation: convex on concave

Question 20

1st CMC joint surfaces

Answer 20

The surface of the trapezium that articulates with the first metacarpal is convex in the radial-to-ulnar direction and concave in the dorsal-to-volar direction. The base of the first MC is just the opposite. It is concave in the radial-to-ulnar direction and convex in the dorsal-to-volar direction.