Anatomy
Upper Limb
Question 22 of 180
Regarding the distal attachments of the posterior forearm muscle tendons, which of the following is paired CORRECTLY:
Answer:
The extensor carpi ulnaris is attached to the tubercle on the base of the 5th metacarpal.Digital Attachments of Long Extensor Tendons
Anatomy / Upper Limb / Digital Attachment of Long Tendons
Last Updated: 29th January 2019
Table: Digital Attachments of the Long Extensor Tendons
| Muscle Tendon | Distal Attachment |
|---|---|
| Extensor carpi radialis longus | Dorsal surface of base of 2nd metacarpal |
| Extensor carpi radialis brevis | Dorsal surface of base of 2nd and 3rd metacarpal |
| Extensor digitorum | Dorsal aspects of bases of middle and distal phalanges of index, middle, ring and little fingers via extensor hoods |
| Extensor carpi ulnaris | Tubercle on base of 5th metacarpal |
| Abductor pollicis longus | Lateral side of base of 1st metacarpal |
| Extensor pollicis longus | Dorsal surface of base of distal phalanx of thumb |
| Extensor pollicis brevis | Dorsal surface of base of proximal phalanx of thumb |
| Extensor indicis | Extensor hood of index finger |
| Extensor digiti minimi | Extensor hood of little finger |
A detailed knowledge of the distal attachments of the extensor tendons is important to allow understanding of the clinical effects of division/injury at any given level of the finger.
- The abductor pollicis longus is attached to the lateral side of the base of the 1st metacarpal.
- The extensor pollicis brevis is attached to the dorsal surface of the base of the proximal phalanx of the thumb.
- The extensor pollicis longus is attached to the dorsal surface of the base of the distal phalanx of the thumb.
- The extensor indicis inserts into the extensor hood of the index finger.
- The extensor carpi radialis longus is attached to the dorsal surface of the base of the 2nd metacarpal.
- The extensor carpi radialis brevis is attached to the dorsal surface of the bases of the 2nd and 3rd metacarpals.
- The four tendons of the extensor digitorum insert via extensor hoods into the dorsal aspects of the bases of the middle and distal phalanges of the index, middle, ring and little fingers.
- The extensor digiti minimi inserts, together with the tendon of the extensor digitorum, into the extensor hood of the little finger.
- The extensor carpi ulnaris is attached to the tubercle on the base of the 5th metacarpal.
Digital Attachments of Long Extensor Tendons. (Image 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 |
