Lecture 14 - SQ Flashcards
- What are the bones of the foot?
1) The bones of the foot (7):
- talus
- calcaneus
- cuboid
- navicular
- cuneiforms (lateral, intermediate & medial)
- metatarsals
- phalanges
- What are the attachments and functional significance of the plantar aponeurosis?
2) The plantar aponeurosis, lying deep to the subcutaneous tissue, is very thick and strong; it
consists of both longitudinal and transverse bands of fibres. It is attached posteriorly to the
calcaneus. Anteriorly it divides into five slips, which attach to the proximal phalanges.
- What are the muscles in each layer of the plantar aspect of the foot? What is the nerve supply
to these muscles?
3) Layer 1:
-abductor digiti minimi (lateral plantar nerve)
-flexor digitorum brevis (medial plantar nerve)
-abductor hallucis (medial plantar nerve)
Layer 2:
-quadratus plantae (lateral plantar nerve)
-lumbricals (1st medial plantar nerve)
(2-4 lateral plantar nerve)
Layer 3:
-flexor hallucis brevis (medial plantar nerve)
-adductor hallucis (lateral plantar nerve)
-flexor digit minimi brevis (lateral plantar nerve)
Layer 4:
-dorsal interossei (lateral plantar nerve)
-plantar interossei (lateral plantar nerve)
All intrinsic muscles of the plantar foot are innervated by either medial or lateral plantar nerve.
- What are the palpable bony features of the ankle (talocrural) joint?
4) The palpable bony features of the ankle joint are the distal ends of the tibia and fibula
including the medial and lateral malleoli. Much of the talus anteriorly can also be palpated.
- What muscles plantarflex and dorsiflex the foot?
5) PLANTARFLEXION: DORSIFLEXION:
- gastrocnemius -tibialis anterior
- plantaris -extensor hallucis longus
- soleus -extensor digitorum longus
- flexor hallucis longus -peroneus tertius
- flexor digitorum longus
- tibialis posterior
- peroneus longus
- peroneus brevis
5) PLANTARFLEXION: DORSIFLEXION:
- tibialis anterior
- extensor hallucis longus
- extensor digitorum longus
- peroneus tertius
- What are the ligaments of the ankle joint?
6) The ankle joint is held together by both lateral and medial ligaments. The medial ligament is
called the deltoid ligament. The lateral ligament is actually composed of three ligaments; the
anterior talofibular ligament, the calcaneofibular ligament, and the posterior talofibular
ligament.
- What is the anatomical basis for maximum stability of the talocrural joint when in the
dorsiflexed position?
7) The ankle is at its most stable position when it is dorsiflexed, and is least stable when plantar
flexed. The reason for this is that the superior articular surface of the talus, which articulates
with the tibia and fibula, is wider anteriorly than posteriorly. Therefore when the foot is
dorsiflexed, the ankle mortise is tightest, thereby affording the least mobility.
- What motions are possible at the subtalar and transverse tarsal joints? To assess the stability
of these joints, in what position should the foot be held?
8) The subtalar joint has one long axis about which most of eversion and inversion occur. The
transverse tarsal joint is actually two joints; the talonavicular joint and the calcaneocuboid
joint. The movement of the transverse tarsal joint adds to the movements of inversion and
eversion.
To assess the stability of these joints, the foot should be held in a loose naturally relaxed
position.
- What are the bony components and ligaments of the medial and lateral longitudinal arches of
the foot?
9) The medial longitudinal arch is held in place by the plantar calcaneonavicular (spring)
ligament with help from the tibialis posterior tendon and through the arrangement of the
following bones: calcaneus, talus, navicular, 3 cuneiforms and 3 medial metatarsals.
The lateral longitudinal arch is composed of the following bones; calcaneus, cuboid, and 4
th
and 5th metatarsal, held in place by both the short and long plantar ligaments.
- What type of joints connect the tibia and fibula? What is/are the articulation(s) between the
tibia and fibula distally with the talus and what movements do those joints permit?
10) The tibia and fibula have three articulations. The proximal joint is synovial, the middle joint
is an interosseous membrane (syndesmosis), and the distal joint is a syndesmosis with short,
very strong ligaments.
The ankle joint consists of the articulations between the body of the talus and the distal ends
of the tibia and fibula. The tibia and fibula form a mortise for the body (trochlea) of the talus.
As a result of this mortise, the ankle joint has only a single primary axis of function around
which flexion and extension of the foot occurs.
- What are the relationships and functions of the medial and lateral ligaments of the ankle?
11) The medial (deltoid) ligament is a very strong ligament that radiates from the distal border of
the medial malleolus to the medial side of the talus, the sustentaculum tali, the medial edge of
the plantar calcaneonavicular (spring) ligament, the navicular bone and the talus. The lateral
ligament consists of three bands, of which the anterior and posterior are thickenings of the
fibrous capsule. The anterior talofibular ligament passes anteromedially from the anterior
border of the lateral malleolus to the neck of the talus. The stronger posterior talofibular
ligament runs medially and backwards from the fossa of the lateral malleolus to the posterior
tubercle of the talus. The calcaneofibular ligament is a round cord that passes posteroinferiorly
from the distal end of the lateral malleolus to the lateral surface of the calcaneus. Collectively
these ligaments stabilize the talus in relationship to the bones above and below. In a sprained
ankle the most commonly injured ligaments are the anterior talofibular ligament and/or the
calcaneofibular ligament.
- What are the attachments and functions of the subtalar ligaments?
12) The subtalar joint is between the slightly concave lower surface of the talus and the convex
upper surface of the calcaneus. The joint permits much of the eversion and inversion in the
foot. The medial and calcaneofibular ligaments of the ankle joint assist in holding the bones
together. The ligament of the neck of the talus (the interosseous talocalcanean ligament)
passes from the talus to the calcaneus. All of the ligaments below the subtalar joint, i.e., the
spring ligament, the short and long plantar ligaments, etc., collectively help support the talus
and the arch of the foot.
- What is the nerve supply of the flexors and extensors of the ankle joint?
13) The extensors (dorsiflexors) of the ankle are supplied by the deep peroneal nerve. The
flexors (plantar flexors) of the ankle are supplied by the tibial nerve.
