Gross Anatomy- Muscles of the Foot

Question 1

Describe the functions of the Muscles of the Foot.

Answer 1

• From plantar aspect, muscles are arranged in 4 layers
o Still function primarily as a group
o Help maintain arches of foot
o Become most active during push off
o Help adjust to uneven ground

Question 2

Describe the Abductor Hallucis m

Answer 2

• Part of 1st layer
• Lies on medial side of foot

• O: Medial tubercle of tuberosity of calcaneus; flexor retinaculum; plantar aponeurosis

• *I:** Medial side of base of proximal phalanx of 1st digit
• *A:** ABD and flexion of great toe (hallux)
• *N:** Medial plantar n. (S2, S3)
• *B**: Medial plantar a.

Question 3

Describe the Flexor Digitorum Brevis m

Answer 3

• Part of 1st layer
• Lies immediately deep to plantar aponeurosis
• *• O:** Medial tubercle of tuberosity of calcaneus; plantar aponeurosis; intermuscular septa
• *I:** Both sides of middle phalanges of lateral 4 digits
• *A:** Flexion of lateral 4 digits
• *N:** Medial plantar n. (S2, S3)
• *B:** Medial plantar a.

Question 4

Describe the Abductor Digiti Minimi m

Answer 4

• Part of 1st layer

• O: Medial and lateral tubercles of tuberosity of calcaneus; plantar aponeurosis;
intermuscular septa
I: Lateral side of base of proximal phalanx of 5th digit
A: ABD and flexion of 5th digit (little toe)
N: Lateral plantar n. (S2, S3)
B: Lateral plantar a.

Question 5

Describe the Quadratus Plantae m

Answer 5

• Part of 2nd layer
• Realigns pull of FDL
• O: Medial surface and lateral margin of plantar surface of calcaneus
I: Posterolateral margin t. of FDL
A: Assists FDL in flexing lateral 4 digits
N: Lateral plantar n. (S2, S3)
B: Lateral plantar a.

Question 6

Describe the Lumbricals (1-4) mm

Answer 6

• Part of 2nd layer

• O: Individual tendons of FDL
I: Medial aspect of expansion over lateral 4 digits
A: Flexion of proximal phalanges; extend middle and distal phalanges lateral 4 digits
N: 1st lumbrical – Medial plantar n. (S2, S3)
2nd-4th lumbricals – Lateral plantar n. (S2, S3)

Question 7

Describe the Flexor Hallucis Brevis m

Answer 7

• Part of 3rd layer
• Lies on either side of FHL t.
• *• O:** Plantar surface of cuboid, intermediate and lateral cuneiforms
• *I:** Both sides base of proximal phalanx of 1st digit
• *A:** Flexion of proximal phalanx of 1st digit
• *N:** Medial plantar n. (S2, S3)

Question 8

Describe the Adductor Hallucis m

Answer 8

• Part of 3rd layer
• Has two heads

• Looks like the number 7

• *• O: Oblique head** – Bases of metatarsals 2-4
  * * Transverse head –** Plantar ll. of MTP joints
• *I:** Lateral side base of the proximal phalanx of 1st digit
• *A**: ADD of 1st digit; assists maintaining transverse arch by pulling lateral 4 digits medial
• *N:** Deep branch of lateral plantar n. (S2, S3)

Question 9

Describe the Flexor Digiti Minimi Brevis m

Answer 9

• Part of 3rd layer

• *• O**: Base of 5th metatarsal
• *I:** Base of proximal phalanx of 5th digit
• *A:** Flexion of proximal phalanx of 5th digit
• *N:** Superficial branch of lateral plantar n. (S2, S3)

Question 10

Desribe the Plantar Interossei m

Answer 10

• Part of 4th layer
• Numbered 1-3 medial to lateral
• Unipennate
• *• O**: Bases and medial sides of metatarsals 3-5
• *I:** Medial sides of bases of phalanges of 3rd-5th digits
• *A:** ADD digits2-4; flex MP joints
• *N:** Lateral plantar n. (S2, S3)

Question 11

Desribe the Dorsal Interossei m

Answer 11

• Part of 4th layer
• Numbered 1-4 medial to lateral
• Bipennate

• O: Adjacent sides of metatarsals 1-5
I: 1st – medial side of proximal phalanx of 2nd digit
2nd-4th – lateral side of 2nd-4th digits
A: ABD digits 2-4; flex MP joints
N: Lateral plantar n. (S2, S3)

Question 12

Differentiate between the PAD and DAB

Answer 12

• *• Plantar** interossei ADduct (PAD)
• *• Dorsal** interossei ABduct (DAB)