Corpus: Scalp
1. Definition
The scalp is a robust and highly resistant composite tissue made up of the skin, subcutaneous layer, and the epicranial aponeurosis, which is stretched over the calvaria.
2. Anatomy
The scalp in adults has a thickness of approximately 4 to 5 mm. The epicranial aponeurosis is connected to the periosteum of the skull bones (pericranium) by loose connective tissue, which allows some degree of mobility of the scalp. This mobility is influenced by the tension of the epicranial muscles.
2.1. Vascular supply
The scalp receives its arterial blood supply primarily from the temporal and occipital arteries. Venous drainage involves the superficial temporal, occipital, posterior auricular, and retromandibular veins. These veins communicate with the cerebral sinuses inside the skull through diploic veins, forming a connection between the external and internal venous systems.
2.2. Nerves
Sensory innervation of the scalp is provided by:
3. Clinic
Injuries to the scalp, such as lacerations caused by direct trauma, often result in significant bleeding due to the rich vascularization of the region, even for relatively small wounds. Treatment typically involves surgical suturing. Swelling or hematomas of the scalp can occur due to perinatal injuries during birth or as a result of traumatic brain injuries. These conditions are classified by location:
- Caput succedaneum: Subcutaneous above the epicranial aponeurosis
- Subgaleal hematoma: Between the epicranial aponeurosis and the pericranium
- Cephalohematoma: Subperiosteal between the pericranium and the cranial bone, and limited by cranial sutures
4. Memory aid
The English acronym SCALP serves as a mnemonic for the structure of the cephalic ridge:
- S - Skin
- C - Dense connective tissue
- A - Epicranial aponeurosis
- L - Loose areolar connective tissue
- P - Periosteum