Wet Lab 7 - Instrinsic Muscles Of The Foot Flashcards
How is the plantar foot best studied?
In layers, from superficial to deep
What are the dorsal intrinsics muscles of the foot?
Extensor Digitorum Brevis and Extensor Hallucis Brevis
Where does EDB and EHB insert onto ?
The extensor expansion (extensor mechanism) of the toes
What is the superficial pre-msucle layer of the foot?
Plantar Aponeurosis (Plantar Fascia)
Where is the plantar aponeurosis msucle located?
On the underside of the foot
What does the attachment of the planatar aponeurosis muscle ensure ?
It ensures that it grows taut (tight/stretched/flexed) when we rise on our toes and extend the metatarsophalangeal joints
What muscles make up the 1st layer of the plantar muscles ?
The short flexor of toes and abducts of the outside toes
- Flexor digitorum brevis
- abductor hallucis (greater toe abductor)
- abductor digits minimi
Where is the axis for abduction-adduction of the toes at their metatarsophalangeal (MTP) joint along ?
The middle of the 2nd metatarsal
What nerves/vessels make up the foot?
The medial and lateral plantar nerves and vessels (Arteries and veins)
What are the medial and lateral plantar nerve and vessel branches of?
The tibial nerve and the posterior tibial artery and vein
What muscles make up the 2nd layer of plantar muscles ?
2 tendons and 2 muscles attaching to one of them
- tendons of flexor digitorum longus
- lumbricals
- flexor accessorius (quadratus plantae)
- tendon of flexor hallucis longus
Where does the quadratus plantae/flexor accessorius insert onto ?
The tendon of flexor digitorum longus
Where do the lumbrical muscles arise from ?
The tendons of flexor digitorum longus
Where are sesamoids located in the foot
- there are two tubercles at the base of the back of the calcaneus which press against the ground
- there are also 2 sesamoids at the great toe’s MTP joint
What is the function of the sesamoids at the great toe’s MTP joint?
They increase the moment arm which therefore increased the torque movement ability of the bone. They also decrease friction between the 2 joints and experience high levels of compressive stress
What tendon are the sesamoid bones within ?
Tendons of flexor hallucis brevis
What is the function of quadratus plantae?
Because the tendon of FDL crosses the foot diagonally, QP helps to redirect its LOP so that it is closer to the longitudinal axis of the toes
What muscles make up the 3rd layer of plantar muscles ?
Short flexors of outside toes and adductor of the greater toe
- flexor hallucis brevis (check for sesamoids bones)
- flexor digiti minimi
- adductor hallucis
- transverse head of adductor hallucis
- oblique head of adductor hallucis
- flexor digiti pedis
What is the function of the sesamoids bones at the MTP joint ?
The FHB passes through the middle of the sesamoids to ensure that is does not get squished
Which muscles are responsible from abduction adn adduction of the toes at the MTP joint ?
- plantar interossei muscles
- dorsal interosseous muscles
What is the rule for the axis of abduction-adduction at the MTP joint ?
PAD and DAB
What is the action of the plantar interossei muscle ?
Adduct the MTP joints
What is the action of the dorsal interossei muscle ?
Abduct the MTP joints
What other actions of plantar and dorsal interossei can be observed from a side-on view?
Flexion or extension of the joints they cross
What muscles make up layer 4 of plantar foot?
Interossei
- plantar Interossei
- dorsal Interossei
- tendon of Fibularis longus
- tendon of Tibialis posterioir
What is the origin of the plantar interossei ?
Bases and medial sides of bodies of 3rd, 4th and 5th metatarsal bones
Where does both the plantar and dorsal Interossei go into ?
They go into the extensor mechanism and attach on the metatarsals
What is the extensor mechanism ?
It is a complex structure that provides detailed function to the joints of the fingers and toes.
Mechanism = multiple parts to it
What is present in the extensor mechanism ?
There is a hood/expansion that the lumbricals and interossei insert onto as well as loosely the extensor tendons (EDL, EDB). There is also a continuation of this that inserts into the base of the middle phalanx
What is the function of the lateral bands ?
They run around the PIP joint, reunite and insert into the base of the top of the distal phalanx
What ligaments make up the plantar foot?
- long plantar ligament
- short plantar ligament
- “spring” ligament (plantar calcaneonavicular ligament)
What does dorsum of the foot mean ?
the upper surface of the foot
What muscles make up the dorsum of the foot?
Tendons of the intrinsic extensor muscles
- extensor digitorum brevis
- extensor hallucis brevis
