14 Leg and Foot Joints

Question 1

Superior (proximal) Tibiofibular joint

Answer 1

Articular Surfaces
lateral condyle of tibia and head of the fibula
Surfaces are flat, oval facets covered by cartilage and connected by capsule and ligaments.

Classification – Synovial (diarthrodial) planar (gliding)
This joint has a synovial membrane that lines the fibrous capsule.
The popliteus tendon runs close & sometimes communicates with the synovial cavity.

Ligaments
Anterior Tibiofibular Ligament of the head of the fibula
Posterior Tibiofibular Ligament of the head of the fibula
Interosseous Membrane – firm connection with syndesmosis superiorly & inferiorly

Motion
This joint is more active on dorsiflexion and plantar flexion. There is small superior gliding movement of this joint with dorsiflexion and small inferior gliding movement with plantar flexion.

Motion at the superior tibiofibular joint is impossible without motion first at the inferior tibiofibular joint

Question 2

Inferior (distal) tibiofibular joint

Answer 2

Classification; Syndesmosis (fibrous)

Articular Surfaces
Formed by a rough convex surface on the medial side of the distal fibula and the rough concave surface on the lateral side of the distal tibia (fibular notch).
A strong interosseous ligament continues with the interosseous membrane and forms the strong connection between distal ends of tibia & fibula.

Ligaments
Posterior tibiofibular ligament
Anterior tibiofibular ligament
Strengthen the joint posteriorly & anteriorly respectively.
They extend from the fibular notch of the tibia to the ant., post. surface of the lateral malleolus.
Interosseous Membrane

Motion
a few degrees of “gliding” motion inferiorly & superiorly in both plantar & dorsiflexion.
Maleoli are held firmly together by anterior & posterior ligaments
This joint forms a strong union between the distal ends of the tibia & fibula and contributes to much of the strength of the ankle joint itself.

Question 3

Talocrural joint (ankle joint, mortise joint)

Answer 3

Between the talus and the crus (lower leg-tibia & fibula)
Classification: synovial hinge joint
DOF: one or uniaxial

The Articular Surfaces of the Ankle Joint
The superior or trochlear surface of talus, convex antero-posteriorly, is depressed centrally by a longitudinal groove (1) bounded by the medial (2) and lateral (3) lips of the pulley. This groove runs anteriorly and laterally (D). This surface is broader anteriorly than posteriorly. The trochlear surface of the talus corresponds to a reciprocally shaped surface on the inferior aspect of the tibia which is concave antero-posteriorly (G) and has a sagittal ridge (4) to fit into the trochlear groove.
The medial surface (A) of the body of the talus articulates with the facet (8) on the lateral surface of medial malleolus (9), which is lined by cartilage.
The lateral surface (12) is in contact with the articular facet (13) of the medial surface (A) of the lateral malleous (14).
The articular surfaces are covered by cartilage and are within a fibrous capsule which is thin anteriorly & posteriorly, but is supported by strong collateral ligaments both laterally & medially.
The tibia and fibula are bound together by the anterior & posterior tibiofibular ligaments thus forming a strong mortise for the trochlea.

Question 4

The ligaments of the ankle joint

Answer 4

These ligaments may be divided into two main groups, i.e. the lateral and medial (Deltoid) collateral ligaments. The deltoid ligament is stronger than the lateral collateral ligament.
Lateral collateral ligament (LCL): In general it attaches the lateral malleolus to the talus & calcaneus and is made up of three separate bands (B) that can be considered as different ligaments including : Anterior Talofibular ligament (3) , Calcaneofibular ligament (2), and Posterior Talofibular ligament (1).
Medial collateral (deltoid) ligament (MCL), is made up of four different bands (A) ) that can be considered as different ligaments including : Anterior Tibiotalar ligament (4), Tibionavicular ligament (3), Tibiocalcaneal ligament (2), and posterior Tibiotalar ligament (1).

Question 5

Ankle joint axis of motion

Answer 5

Ankle Joint Axis of Motion
The line joining the distal tips of the malleoli is the axis of motion for dorsiflexion/plantarflexion at the ankle joint
Since the medial malleolus is anterior & superior to the lateral malleolus, therefore the axis is an oblique line.
Rotated 30 degrees in the transverse plane
With dorsiflexion you toe OUT
With plantar flexion you toe IN

Question 6

What is the difference between a sprain and a strain?

Answer 6

A sprain is the forcible wrenching or twisting of a joint that stretches or tears its ligaments but does not dislocate the bones.

A strain is a stretched or partially torn muscle or muscle and tendon

Question 7

Inversion sprain: 1st degree, 2nd degree, 3rd degree

Answer 7

1st Degree: Tear one ligament
Anterior Talofibular Ligament
2nd Degree: Tear of two ligaments
Talofibular Ligament (anterior or posterior)
Calcaneofibular Ligament
3rd Degree: Tear all 3 lateral ligaments

Question 8

What the most common sprained ankle?

Answer 8

The anterior talofibular ligaent

Question 9

Eversion sprains

Answer 9

Excessive eversion
Most commonly associated with fracture

Question 10

High ankle sprain or syndesmotic ankle sprain

Answer 10

Talus shoved between tibia and fibula
Tear of interosseous membrane
Very difficult recovery time

Question 11

3 functional areas of the foot

Answer 11

Hindfoot – Talus and Calcaneus
Midfoot – Navicular, Cuboid, 3 Cuneiforms
Forefoot – Metatarsals and Phalanges

Question 12

Subtalar (Talocalcaneal) Joint

Answer 12

A synovial joint between the inferior surface of the body of the talus & the superior surface of the calcaneus

Articular Surfaces:
Talus – inferior surface has 3 articular facets
Calcaneus – superior surface has 3 facets
Classification – planar synovial joint

Motions:
Inversion/Eversion (term often used in open chain motions)
Supination/Pronation (term often used in closed chain motions)
Interchangeable terms with inversion/eversion

Question 13

Subtalar joint ligaments

Answer 13

Interosseous Talocalcaneal ligament
A thick strong band that binds the talus & calcaneus runs through the sinus tarsi (a canal between these two bones)
Medial Talocalcaneal ligament
Lateral Talocalcaneal ligament
Posterior Talocalcaneal ligament
Anterior Talocalcaneal ligament

Question 14

Transverse Tarsal Joint (Midtarsal or Chopart’s Joint)

Answer 14

Made up of 2 joints that work together; they do not create motion independently. They are synovial planar joints.
Talonavicular joint
Calcaneocuboid joint

Motion:
Motion is generally inversion/eversion
Participate in movement of the forefoot on the hindfoot to lower the longitudinal arch in pronation and to elevate it in supination.

Major ligaments are:
Plantar calcaneonavicular ligament (Spring ligament )
Very important for maintaining the longitudinal arch of the foot.
Long Plantar ligament

Question 15

Tarsometatarsal (Lisfranc) Joints

Answer 15

Any separation or fracture at this site is called a Lisfranc fracture.

Articular Surfaces
Metatarsal bones with all three cuneiforms & cuboid bones

Classification: Synovial planar
Motions
Gliding of bones upon each other with plantar flexion and dorsiflexion

Question 16

Tarsometatarsal (Lisfranc) Joints Ligaments

Answer 16

Plantar metatarsal ligaments
Dorsal metatarsal ligaments
Dorsal Tarsometatarsal
Plantar Tarsometatarsal

Question 17

Metatarsophalangeal (MTP) Joints

Answer 17

Articular Surfaces
MTPs: Between the head of the metatarsals and the base of the proximal phalanges of toes # 1to 5
Classification: Synovial condylar joints
Motions
Flexion – Extension
Abduction – Adduction
Ligaments : Collateral and plantar ligaments as well as the deep transverse metatarsal ligaments

Question 18

Interphalangeal (IP)Joints

Answer 18

Articular Surfaces
PIP: Between the head of the proximal phalange and base of the middle phalange of toes #2 to 5
DIPs: Between the head of the middle phalange and base of the distal phalange of toes # 2 to 5
In Big toe there is only one IP joint.
Classification: Synovial hinge joints
Motions
Flexion – Extension
Ligaments : Collateral and plantar ligaments

Question 19

Arches of the foot

Answer 19

The ability of the foot to change from a flexible to a rigid structure within a single step is dependent upon the:
Bony structure of the three arches of the foot,
Static ligament-fascial support
Dynamic muscle contraction

The body weight is transferred to the ground mainly through three points via three arches.
The medial longitudinal arch is the longest and the highest. It is composed of the calcaneus, the talus, the navicular, the medial cuneiform, and the first metatarsal bones.
The lateral longitudinal arch is lower and composed of the calcaneus, the cuboid, and the fifth metatarsal.
The transverse arch is concave from medial to lateral in the midtarsal and tarsometatarsal areas.

Ligaments connect the tarsal and metatarsal bones on the dorsal and plantar surfaces to bind the bones of the arches into a structure with properties of the solid curved beam.
When loaded, the curved beam bends, and compression forces occur on the top (convex side) and tension forces occur on the plantar surface (concave side).
As the amount of load increases, the beam eventually collapses. Larger forces can be supported by the beam if a tie-rod is placed across the base of the beam to prevent the two ends from moving apart.
In the foot, the tie-rod is represented by the plantar aponeurosis as well as by con­traction of intrinsic and extrinsic muscles of the foot.

Question 20

Muscles acting on the foot arches

Answer 20

TP & FL
FHL & Abd. H. (medial arch)
Abd. d. m. (lateral arch)
FDB, QP & FDL (Both arches)
ADD. H (Transverse arch)
Thus, the muscles of the toes, which, compared to the fingers, have limited function and use in open chain motion, have great importance in closed-chain motions of walking and running.