Dorsum of the Foot

00:01 Now let's move on to the dorsum of the foot.

00:06 So we can see here, the dorsum of the foot.

00:08 So we're looking at the superior surface of the foot, the anterior aspects of the lower leg, and this is a right foot.

00:16 We can see here, we have the inferior extensor retinaculum and this is holding in place those extrinsic muscle tendons.

00:23 Here we can see we've got the tendons of extensor digitorum longus.

00:27 And here we can see, we've got the long tendon of extensor hallucis longus.

00:32 These are those extrinsic extensor muscles we spoke about.

00:36 And they live most superficial on this dorsal surface.

00:40 We can then start to see some intrinsic muscles here, we've got extensor digitorum brevis, we've got extensor hallucis brevis.

00:49 And these two muscles make up the intrinsic extensor muscles.

00:53 They reside solely within the dorsum of the foot.

00:59 So let's have a look at these in a little bit more detail starting off with extensor digitorum brevis.

01:04 So here we have extensive digital and brevis, which is originating from the supralateral surface of the calcaneus.

01:12 It then gives rise to a long tendon that runs towards the tendons of extensor digitorum longus of toes II to IV.

01:20 So this is important, it's passing it's long tendons to actually insert onto another tendon, that of the tendons of extensor digitorum longus of toes two to four.

01:31 Here we've got extension of the 2nd-4th digits.

01:35 Extension digitorium brevis allows extension of the 2nd-4th digits of the foot.

01:41 Extensor hallucis brevis, you may remember, we have extensor hallucis longus.

01:46 So here we have extensor hallucis brevis.

01:48 This muscle originates from the supralateral surface of the calcaneus.

01:53 And it goes and inserts on the proximal phalanx of the 1st digit, the great toe.

01:58 This muscle is associated with extension of that 1st digit.

02:04 The innervation of these muscles is via the deep fibular nerve.

02:07 Remember, the deep fibular nerve is the bifurcation of the common fibular nerve, which itself came from the sciatic.

02:16 If we then were to add in some arteries here as well, we'd see the anterior tibial artery is passing down the anterior aspect of the leg.

02:23 It passes deep to the extensor retinaculum, where it gives rise to this blood vessel which is known as the dorsalis pedis artery.

02:32 As the dorsalis pedis artery runs along the 1st metatarsal, we can see it gives rise to a blood vessel that moves laterally.

02:39 This is the lateral tarsal artery.

02:42 A second one is also given off more distally and this is the accurate artery.

02:47 We can see it's running along the base of those metatarsals.

02:51 This gives rise to a series of dorsal metatarsal arteries, which we see run along the metatarsals and then a series of dorsal digital arteries, which run alongside the phalanges of the foot.

03:03 So we can see these arteries are all originating from the anterior tibial artery.

03:09 The deep fibular nerve is running alongside the anterior tibial artery, it then continues running alongside the dorsalis pedis artery which we can see here.

03:18 And it will give off branches that go to supply these intrinsic muscles of the foot.