Download muscles of the foot dissection guide

MUSCLES OF THE FOOT DISSECTION GUIDE
Lower Extremity Lab 5
Mark W. Cornwall, PhD, PT, CPed
1. Carefully remove the skin on the plantar surface from the heel to the ball of the foot, without
disrupting the heel pad. Be sure to remove all the subcutaneous and fatty tissue from the medial
and lateral longitudinal arch regions so that only the heel pad remains. Use caution when
removing subcutaneous and fatty tissue in the medial and lateral longitudinal arch regions to
preserve the superficial branches of the medial and lateral plantar nerves that exit on each side of
the plantar fascia. Note the fibrous septa of the plantar heel pad that function to hold the heel fat
pad in place. Clinically, it is important to remember that the skin over the heel pad is directly
innervated by the tibial nerve, prior to it dividing into the medial and lateral plantar nerves,
through the medial calcaneal branches.
2. Remove the plantar heel pad and identify the three bands of the plantar aponeurosis or fascia.
Note that the central and lateral bands are usually well defined where as the medial band may or
may not be present. It is the central band that can be involved in the common clinical condition
affecting the foot termed plantar fasciitis.
3. Completely remove the medial band of the plantar aponeurosis so that you can observe the
abductor hallucis, and then remove the lateral band so that you can identify the abductor digiti
minimi.
4. Approximately 2 to 3 cm. distal (toward the toes) from the attachment of the central band of the
plantar fascia, carefully cut through the fascia and separate the fascia from the flexor digitorum
brevis, located just inferiorly, to the ball of the foot. Identify the five diverging aponeurotic
bands that pass to each toe.
5. Once the central band of the plantar fascia has been dissected, identify the three muscles in the
first layer of plantar muscles:
1. Flexor Digitorum Brevis
2. Abductor Hallucis
3. Abductor Digiti Minimi
Review the origin, actions, & innervations of these muscles. Note that the deep fibers of the
medial and lateral plantar nerves are located on either side of the flexor digitorum brevis.
7. On only one extremity of the cadaver, cut through the muscle belly of the flexor digitorum brevis
at the same location where you cut through the central band of the plantar fascia. Identify the
following two muscles that are located in the second layer of plantar muscles:
1. Lumbricals
2. Quadratus Plantae or Flexor Accessorius
Review the origins, innervations and actions of these muscles.
PT525-Clinical Anatomy I
Department of Physical Therapy and Athletic Training
1
8. On the same side that the flexor digitorum brevis was dissected, remove the quadratus plantae
from the flexor digitorum longus tendon and then cut the tendon of the flexor digitorum longus
as far back as possible toward the heel as possible and reflect the distal portion of the tendon
toward the toes.
9. Now identify the three muscles of the third layer of plantar foot muscles:
1. Adductor Hallucis (oblique head only can be observed)
2. Flexor Hallucis Brevis
3. Flexor Digiti Minimi
Review the innervations and actions of these muscles.
10. Observe that the origin of the oblique head of the adductor hallucis is the insertion of the long
plantar or plantar calcaneocuboid ligament. The long plantar ligament creates a tunnel for the
peroneus longus tendon in traveling from the lateral aspect of the foot, via the groove on the
cuboid, to the medial aspect of the plantar surface of the foot to insert on the base of the 1st
metatarsal and 1st cuneiform bones. The 1st metatarsal and 1st cuneiform bones form what is
termed the 1st Ray.
11. The muscles in the 4th layer of the plantar foot cannot be observed without extensive dissection
that would create too much cadaver destruction. The muscles located in the 4th layer are the
plantar and dorsal interossei.
You should be able to identify the following structures on a cadaver or a skeleton.
1.
2.
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Heel pad
Medial plantar nerve
Lateral plantar nerve
Medial calcaneal branches
Plantar aponeurosis or fascia
Abductor hallucis
Digiti minimi.
Flexor digitorum brevis
Abductor hallucis
Abductor digiti minimi
Lumbricals
Quadratus plantae or flexor accessorius
Adductor hallucis
Flexor hallucis brevis
Flexor digiti minimi
Long plantar or plantar calcaneocuboid ligament
PT525-Clinical Anatomy I
Department of Physical Therapy and Athletic Training
2