2.7.1. ANAT LAB - Sole of Foot Flashcards
What is considered the mortise of the lower extremity?
Ankle-Joint
What is considered the tenon of the lower extremity?
Leg
What fractures are we concerned about?
The tibia and/or the ankle joint, NOT the fibula We also worry about disruption of the interosseous membrane
What is a stress fracture?
Constant stress, not enough to break a bone instantly, but causing failure eventually
What are the compartments of the leg?
Anterior, lateral and posterior
What causes compartment syndrome?
Anything that affects the volume of the compartment (fracture, exercise, missed injection, scar tissue, tight cast, weight) Pain is the initial and most important sign of compartment syndrome
What is a shin splint?
Very mild compartment syndrome (usually anterior) that resolves with R.I.C.E.
Action of the Talocrural joint
aka Ankle: flexion/extension
Action of the Talocalcaneal joint
aka Subtalar: inversion/eversion
Action of the Talonavicular joint + Calcaneocuboidal joint
Forefoot motion
What does the Sustentaculum Tali do (what lies beneath it)?
Sustains the talus; FHL tendon runs beneath it
Which components of the foot support most of the weight?
The calcaneus and the metatarsals
What is the spring ligament?
Plantar Calcaneo-Navicular Ligament (medial side of the foot)
What is an ankle strain?
Overloading of any of the ankle ligaments
What is Pes Planus
Flat-foot: failure of bony construct and ligamentous structures Patients cannot sustain long distance walking
What do all the extensor tendons run under to enter the foot?
The superior and inferior extensor retinaculum
What is/are the function(s) of the Plantar Aponeurosis?
Provides stability/strength of the arch
What muscles are in the first layer of the foot?
Flexor Digitorum Brevis Abductors of Great and Small Toes (AH & ADM)
What two tendons and 2 muscles are in the second layer of the foot?
Flexor Digitorum Longus Tendon and the Flexor Hallucis Longus Tendon
Lumbricals
Quadratus Plantae
~Look for lateral & medial plantar Aa & Nn~
What is a hallux valgus?
Bunion (deformity of the MP joint) Usually of great toe
What muscles are in the third layer of the foot?
Flexor Hallucis Brevis (sesamoids)
Flexor Digiti Minimi Brevis
Adductor Hallucis: Transverse & Oblique Heads
What muscles are in the fourth layer of the foot?
Plantar (3) and Dorsal (4) Interossei
Gastrocnemius strain complications?
Can result in a hematoma which leads to compartment syndrome
Nerves to the sole of the foot?
Saphenous N.
Medial/Lateral Plantar N.
Sural N.
Calcaneal Branches of Tibial & Sural Nn.
Where does the Medial Plantar Nerve innervate?
Motor to:
1st Layer: flexor digitorum brevis (FDB) and ABductor Hallucis
2d layer: Lumbrical of 2nd toe
3d layer: Flexor Hallucis Brevis (FHB)
Lateral Plantar Nerve
Everything else that the MPN does not innervate
1st Layer: ABductor digiti minimi
2d layer: quadratus plantae, lumbricals of toes 3, 4, & 5
3d layer: Flexor Digiti Minimi Brevis and ADductor Hallucis (transverse and long heads)
4th layer: plantar and dorsal interossei
Plantar aponeurosis
- Flexor Digitorum Brevis
- Abductor digiti minimi
- Abductor hallucis
- Plantar Aponeurosis (Cut and Reflected)
- Quadratus plantae (looks somewhat squared = quadratus)
- Lumbricals
- Flexor Hallucis longus (First layer - flexor digitorum brevis, reflected anteriorly)
- Flexor digitorum longus
- Adductor hallucis - Oblique head
- Adductor hallucis - transverse head
- Flexor hallucis brevis
- Flexor digiti minimi brevis
- (Abductor hallucis tendon - cut)
- (Abductor Digiti minimi tendon - cut)
Dorsal interossei (4)
- medial plantar n.
- medial plantar a. (GA p 452, 454; N 522)
- lateral plantar a.
- lateral plantar n.
***NOTE: the nerves and vessels run between the second and third layers
Describe: fibrous septae (singular = septa) and skin ligaments (M p 610)
Fibrous septae are highly developed skin ligaments that divide the plantar region into fat-filled regions, forming a shock absorbing pad (particularly over the heel of the foot) The skin ligaments also anchor the skin to the underlying deep fascia, improving the “grip” of the sole
Describe: plantar aponeurosis (M p 610; Fig. 5.67B, p 611)
arises posteriorly from the calcaneous and functions like a superficial ligament distally, the longitudinal bundles of the collagen fibers of the aponeurosis divide into five bands that become continuous with the fibrous digital sheaths that enclose the flexor tendons that pass to the toes at the anterior end of the sole, the aponeurosis is stabilized by the superficial transverse metatarsal ligament
Describe: medial longitudinal arch (M Fig. 5.103, p 656) What bone is the “keystone” of this arch? (M p 654) - the talar head is the keystone of the medial longitudinal arch
medial side of foot is higher and more important than the lateral longitudinal arch composed of: calcaneous, talus, navicular, three cuneiforms, and three metatarsals the tendons of the tibialis anterior and posterior stabilize the arch - the talar head is the keystone of the medial longitudinal arch
Describe: lateral longitudinal arch lateral side of foot much flatter than the medial part of the arch rests on the ground during standing made up of the calcaneous, cuboid, and lateral two metatarsals
-lateral side of foot -much flatter than the medial part of the arch -rests on the ground during standing -made up of the calcaneous, cuboid, and lateral two metatarsals
Describe: transverse arch (M Fig. 5.103C, p 656) – Review how the tendons of the fibularis longus (FL) & tibialis posterior (TP) support this arch like a stirrup (M p 654; Note: Fig 5.68F, p 613 & Fig. 5.101A, p 655 show this very well).
- runs from side to side (hence, transverse) - formed by the cuboid, cuneiforms, and bases of the metatarsals - the medial and lateral parts of the lateral arch serve as pillars for the transverse arch -the tendons of the fibularis longus and tibialis posterior cross under the sole of the foot, like a stirrup, and help to maintain the curvature of the transverse arch
Describe: the plantar calcaneonavicular (“spring”) ligament (M p 654 & Fig. 5.101, p 655)
-extends across and fills a wedge shaped gap between the sustentaculum tali and the inferior margin of the posterior articular surface of the navicular -supports the head of the talus and plays an important role in the transfer of weight from the talus and in the maintenance of the longitudinal arch of the foot (remember that the talus is its keystone)
Where do most diabetic foot ulcers often begin?
The weight bearing areas of the foot picture
Why is the ankle tighter (more stable) in dorsiflexion than in plantar flexion?
the ankle is relatively unstable during plantarflexion because the trochlea is narrower posteriorly and, therefore, lies relatively loosely in the mortise
Define the midline (axis) of the foot. This is different from how the midline of the hand is organized. Through which toe does it pass?
The mid-line of the foot is considered to be bisecting the second toe
What does the Babinski sign (an abnormal one) indicate (M p 625)? Remember: This “sign” can be normal in infants and children up to 4 yrs of age (excepting infants with brain injury or cerebellar disease).
-flexion is normal -fanning is abnormal (Babinski sign) and indicates brain injury or disease (except in infants) [usually not accurate until 4 years of age]
What is: talipes equinovarus (clubfoot)
-refers to a foot that is twisted out of position -all types are congenital -the most common type involves the subtalar joint -the foot is inverted and plantarflexed, and the forefoot is adducted
What is hallux valgus?
-foot deformity caused by pressure from footwear and degenerative joint disease -characterized by lateral deviation of the great toe -more common in females and with age -causes a decrease in the medial longitudinal arch
What is: hammer toe
-foot deformity in which the proximal phalanx is permanently and marked dorsiflexed -deformity usually results from weakness of the lumbrical or interosseous muscles -a callus will often develop on the top of the toe
What is pes planus?
-flatfeet -may be flexible or rigid -result from loose or degenerated intrinsic ligaments (if congenital) -if acquired, usually due to dysfunction of the tibialis posterior -head of the talus becomes displaced inferomedially and becomes prominent
Where would you make an incision on the foot (e.g., for an infection) to avoid a painful scar?
When possible, the incision is made on the medial side of the foot, passing superior to the abductor hallucis to allow visualization of critical neurovascular structures
