Anatomy
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Upper Limb
A 39 year old man is brought to ED having sustained a stab wound to the posterolateral trunk at the level of the T7 vertebra. Which of the following muscles is most likely affected:
Answer:
The latissimus dorsi originates from the spinous processes of the lower six thoracic vertebrae and related interspinous ligaments, via the thoracolumbar fascia to the spinous processes of the lumbar vertebrae, related interspinous ligaments and iliac crest and from the inferior 3 or 4 ribs. The latissimus dorsi muscle inserts onto the floor of the intertubercular sulcus of the humerus.Latissimus Dorsi Muscle
Anatomy / Upper Limb / Pectoral Region
Last Updated: 8th April 2019
The latissimus dorsi muscle forms much of the muscle mass underlying the posterior axillary skin fold extending obliquely upwards from the trunk to the arm.
Table: Function and Innervation of the Latissimus Dorsi Muscle
| Muscle | Latissimus Dorsi |
|---|---|
| Origin | Spinous processes of lower 6 thoracic vertebrae and related interspinous ligaments; via the thoracolumbar fascia to the spinous processes of the lumbar vertebrae, related interspinous ligaments and iliac crest; lower 3 – 4 ribs |
| Insertion | Floor of intertubercular sulcus |
| Function | Adduction, medial rotation and extension of arm at glenohumeral joint |
| Innervation | Thoracodorsal nerve |
Origin
The latissimus dorsi originates from the spinous processes of the lower six thoracic vertebrae and related interspinous ligaments, via the thoracolumbar fascia to the spinous processes of the lumbar vertebrae, related interspinous ligaments and iliac crest and from the inferior 3 or 4 ribs.
Insertion
The muscle inserts onto the floor of the intertubercular sulcus of the humerus.
Function
The latissimus dorsi produces adduction, medial rotation and extension of the humerus at the glenohumeral joint.
Innervation
The latissimus dorsi is innervated by the thoracodorsal nerve.
![By Mikael Häggström (Image:Gray409.png) [Public domain or Public domain], via Wikimedia Commons](https://mrcemsuccess.com/wp-content/uploads/2016/12/Latissimus-Dorsi-649x1024.png)
Latissimus Dorsi Muscle. (Image by Mikael Häggström (Image:Gray409.png) [Public domain or 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 |
