Anatomy
Central Nervous System
Question 27 of 82
A 23 year old man is involved in a road traffic collision and sustains a lumbar fracture. On examination you note he is unable to extend his big toe. Which of the following spinal nerve roots has most likely been affected:
Answer:
The L5 nerve root has most likely been affected.Myotomes and Reflexes
Anatomy / Central Nervous System / Lower Limb / Innervation of Lower Limb / Upper Limb / Innervation of Upper Limb
Last Updated: 13th April 2023
Upper Limb
Table: Myotomes of the Upper Limb
| Myotome | Most Strongly Associated Movement |
|---|---|
| C5 | Elbow flexion (also shoulder abduction and external rotation) |
| C6 | Wrist extension |
| C7 | Elbow extension (also wrist flexion) |
| C8 | Finger flexion (also thumb extension) |
| T1 | Finger abduction |
Lower Limb
Table: Myotomes of the Lower Limb
| Myotome | Most Strongly Associated Movement |
|---|---|
| L2 | Hip flexion |
| L3 | Knee extension |
| L4 | Ankle dorsiflexion |
| L5 | Great toe extension |
| S1 | Ankle plantarflexion |
| S2 | Knee flexion |
Reflexes
Table: Reflexes of the Upper and Lower Limb
| Reflex | Root | Muscle |
|---|---|---|
| Biceps | C5 – C6 | Biceps brachii |
| Supinator | C6 – C7 | Brachioradialis |
| Triceps | C7 – C8 | Triceps brachii |
| Knee | L3 – L4 | Quadriceps |
| Ankle | S1 | Gastrocnemius |
Report A Problem
Is there something wrong with this question? Let us know and we’ll fix it as soon as possible.
Loading Form...
- 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 |
