Anatomy
Lower Limb
Which of the following structures primarily supports the medial longitudinal arch rather than the lateral longitudinal arch of the foot:
Answer:
The medial longitudinal arch is supported by the spring ligament, the deltoid ligament, the plantar aponeurosis, the small muscles in the sole of the foot and the tendons of the tibialis anterior, tibialis posterior and flexor hallucis longus muscles which provide passive and dynamic support. The lateral longitudinal arch is supported by the the long and short plantar ligament and the fibularis longus tendon together with the extensor tendons and the short muscles of the little toe.Foot Arches
Anatomy / Lower Limb / Ankle and Foot Joints
Last Updated: 10th April 2019
The bones of the foot form longitudinal and transverse arches (relative to the ground) which absorb and distribute weight bearing forces during standing and moving.
The longitudinal arch is formed between the posterior end of the calcaneus and the heads of the metatarsals and has a medial and lateral part.
Table: Constituent Bones and Prime Supporting Factors of the Longitudinal Foot Arches
| Arch | Constituent Tarsal Bones | Prime Supporting Factors |
|---|---|---|
| Medial longitudinal arch | Calcaneus, talus, navicular, three cuneiforms and medial three metatarsal bones | Spring ligament, deltoid ligament, plantar aponeurosis and tendons of the tibialis anterior and tibialis posterior muscles |
| Lateral longitudinal arch | Calcaneus, cuboid and lateral two metatarsal bones | Plantar aponeurosis, fibularis longus tendon, long and short plantar ligament |
Medial Longitudinal Arch
The higher medial longitudinal arch is formed and maintained by the interlocking of the calcaneus, the talus, the navicular, the three cuneiforms and the medial three metatarsal bones. The medial longitudinal arch is supported by the spring ligament, the deltoid ligament, the plantar aponeurosis, the small muscles in the sole of the foot and the tendons of the tibialis anterior, tibialis posterior and flexor hallucis longus muscles which provide passive and dynamic support.
Lateral Longitudinal Arch
The lateral longitudinal arch is formed from the calcaneus, the cuboid and the lateral two metatarsal bones. The lateral longitudinal arch is flatter than the medial part and rests on the ground during standing. The lateral longitudinal arch is supported by the the long and short plantar ligament and the fibularis longus tendon together with the extensor tendons and the short muscles of the little toe.
Arches of the Foot: Medial and Lateral Views. (Image by OpenStax College [CC BY 3.0 , via Wikimedia Commons)
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
