Muscles of Sole of Foot: Layer 1 – Anatomy of the Foot

00:00 at layer 1, there are really three muscles that I want to make you aware of. We have abductor hallucis, flexor digitorum brevis, and abductor digiti minimi. So, if we look here, we can go abductor hallucis passing along the medial aspect of the foot, and then we have abductor digiti minimi passing along the lateral aspect of the foot. And then most centrally, we have flexor digitorum brevis. So these muscles within the most superficial layer 1 of the foot. All of these three muscles share a common origin. They all originate from the calcaneus, specifically, the tuberosity of the calcaneus, and from the plantar aponeurosis.

00:52 As you can see, they have different functions. Therefore, they insert onto different regions of the foot. Abductor hallucis inserts into the base of the proximal phalanx of the great toe.

01:05 Flexor digitorum brevis inserts into the middle phalanges of digits 2 to 5.

01:11 And abductor digiti minimi attaches to the base of the proximal phalanx of the fifth digit.

01:18 So we can see they have a common origin, but depending on their function, they have a different insertion. All of these muscles are going to be supplied by either the medial or the lateral plantar nerve. And the medial and the lateral plantar nerve have divided from the tibial nerve. The medial plantar nerve is going to supply abductor hallucis and flexor digitorum brevis, whereas, the lateral plantar nerve is going to supply abductor digiti minimi.

01:51 As the name suggests, it can lead on to the function. So abductor hallucis is going to abduct, and it also can flex the great toe, the first digit. Flexor digitorum brevis is going to flex digits 2 to 5. And abductor digiti minimi is going to abduct, and it can also flex the fifth digit. So if we now move on to layer 2, we can see that we’ve had