Anatomy
Upper Limb
A 48 year old man presents to ED having sustained a superficial laceration to his wrist on broken glass. Which of the following structures passing superficial to the flexor retinaculum may be damaged in this injury:
Answer:
The ulnar artery, ulnar nerve, and tendon of the palmaris longus pass into the hand anterior to the flexor retinaculum. The median nerve and the flexor tendons pass into the hand deep to the flexor retinaculum, within the carpal tunnel.Flexor Retinaculum
Anatomy / Upper Limb / Wrist and Hand
Last Updated: 10th April 2019
The flexor retinaculum (transverse carpal ligament) is a thickened band of fibrous connective tissue on the volar aspect of the hand which forms the roof of the carpal tunnel. The flexor retinaculum holds the flexor tendons in place at the wrist and prevents them from bowstringing.
It is attached laterally to the scaphoid and trapezium and medially to the pisiform and the hook of the hamate. The thenar and hypothenar muscles arise from the flexor retinaculum.
Relations
- The ulnar artery, ulnar nerve, and tendon of the palmaris longus pass into the hand anterior to the flexor retinaculum, and therefore do not pass through the carpal tunnel.
- The flexor carpi radialis tendon passes through the lateral aspect of the flexor retinaculum into the hand.
- The four tendons of the flexor digitorum profundus, the four tendons of the flexor digitorum superficialis, the tendon of the flexor pollicis longus and the median nerve pass into the hand posterior to the flexor retinaculum, within the carpal tunnel.
Flexor Retinaculum. (Image modified by FRCEM Success. Original by Henry Vandyke Carter [Public domain], 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 |
