Superficial Veins of the foot

The superficial veins of the leg are the long and short saphenous vein. The short saphenous vein derives from the popliteal vein and travels laterally along the foot. It then travels posterior to the lateral maleolus to enter the dorsum of the foot. Here it forms the dorsal venous arch, which is also contributed by the long saphenous vein. The long saphenous vein arises as a branch from the femoral vein, near the saphenous opening (what is this? What fills it, and what does it contain?  check thigh and gluteal notes for answer) in the antero-medial aspect of the thigh. From here, it travels medially along the foot and contributes to the formation of the dorsal venous arch, but before travels anterior to the medial maleolus.

Retinacula Present

There are three retinacula present at the ankle joint. These are the extensor retinacula which has superior and inferior parts. The flexor retinacula extends medially attaching to the calcaneus bone. These function to hold the tendons of the leg in place and also allow the nerves and vessels of the leg to enter the leg.

Plantar aponeurosis

The plantar aponeurosis is the thickening of the deep fascia covering the sole of the foot. Proximally, it attaches to the medial and lateral tubercles of the calcaneus bone, and distally its fibres diverges to attach to the plantar metatarsal plates. These attachments are vital for maintaining longitudinal arches of the foot.

Possible T/F Q: The plantar aponeurosis contributes for maintenance of the longitudinal arches of the foot. T/F (Correct answer  True)

First Layer of Foot Muscles

Abductor Hallucis muscle  supplied by the medial plantar nerve  abduct the great toe

Flexor Digitorum Brevis  supplied by the medial plantar nerve  flex the proximal parts of toes

Abductor digitimi minimi  supplied by the lateral plantar nerve  abduct the little toe

Possible Question in short essay/answer  Describe the first layer of the foot muscles.

This layer of muscles consist of three muscles. Abductor hallucis is the medial most muscle, proximally attaching the medial calcaneal tubercle and distally attaching to the proximal phalanx of the great toe. This muscle is supplied by the medial plantar nerve and aids in abduction of the great toe. Flexor digitorum brevis muscle is the central muscle and attaches proximally to the medial calcaneal tubercle and distally to the proximal phalanx of the lateral four toes (note that it splits to allow for the longus tendon and remerges). This muscle is supplied by the medial plantar nerve and its action is to flex the proximal parts of the toes. The lateral most muscle is the abductor digiti minimi muscle and this aids in abduction of the little toe. This muscle is supplied by the lateral plantar nerve and it attaches to the proximal phalanx of the little toe and to the medial and lateral calcaneal tubercles. (Note: according to Derek, attachments and insertions need not be this detail  stating the bones is good enough, that too if asked!).

Major Points: What muscles are there?  Medial most muscle  innervation  action, attachments  middle muscle  innervation  attachments and actions  lateral most muscle  innervation  attachments and action.

Second Layer of Muscles (note that attachments are not required here according to lecturer)

Quadratus Plantae (Flexor Accessorius)  supplied by the lateral plantar nerve  flex the toes

Lumbricals  supplies by the medial (L1) and lateral plantar nerves (L2-L4)  extend toes + flex metatarsophalangeal joints.

Possible Question: What are the muscles of the second layer of the foot, their innervations and actions.

The muscles of the second layer of the foot are the lumbricals and the quadratus plantae. The former is supplied by the medial plantar nerve (L1) and lateral plantar nerves (L2-L4). The latter is supplied by the lateral plantar nerve. The action of the former is to extend the lateral four toes and flex the metatarsophalangeal joints. The action of the latter is to flex the toes.

Major Points: Muscles identified  innervation  actions

Third Layer of Muscles

Flexor Hallucis Brevis  supplied by the medial plantar nerves  flexes the proximal phalanx of the great toe

Adductor hallucis brevis  supplied by the lateral plantar nerve  adducts the great toe, flex proximal phalanx and supports the transverse arch of the foot

Flexor digiti minimi brevis  lateral plantar nerve  flexes the proximal phalanx

Question: Describe the third layer of the foot, including innervation and action. What is the important function of the adductor hallucis brevis muscle in terms of the structural features of the foot?

Flexor hallucis brevis is the medial most muscle. It is innervated by the medial plantar nerve (which other muscles are innervated by this nerve), and its major actions are to flex the proximal phalanx of the great toe. Adductor hallucis brevis contains a oblique head and a transverse head, it is innervated by the lateral plantar nerve and its main actions are: flex the proximal phalanx of the great toe, adduct the great toe and also maintain the transverse arch of the foot. The lateral most muscle is the flexor digiti minimi brevis muscle, it is innervated by the lateral plantar nerve (which other muscles are innervated by this nerve) and flexes the proximal phalanx of the little toe.

Fourth Layer of Muscles

Plantar Interossei (3)  lateral plantar nerve  extension of the phalanges and flexion of the metatarsophalangeal joints

Dorsal Interossei (4)  lateral plantar nerve  extension of the phalanges and flexion of the metatarsophalangeal joints

Tendons of the peroneus longus and tibialis posterior muscles also form part of this layer.

Category: Anatomy Notes